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Table of Content

05 February 2022, Volume 49 Issue 2
Biotechnology
Cloning, Promoter Analysis and Transcriptional Regulation of p21 Gene in Goose
CHEN Zhe, YANG Pengxia, LEI Mingming, CHEN Jiabin, YAN Leyan
2022, 49(2):  405-415.  doi:10.16431/j.cnki.1671-7236.2022.02.001
Abstract ( 258 )   PDF (2279KB) ( 91 )  
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【Objective】 The aim of this study was to analyze the structure and promoter activity of p21 gene in goose, and investigate the transcriptional regulation mechanism.【Method】 The Taizhou goose was taken as the research object, the sequence characteristics of the full-length and 5′-flanking region of p21 gene were obtained using homologous amplification, RACE and biological analysis.The dual luciferase reporter vectors with 6 different deletion fragments of the promoter were constructed, its luciferase activities were analyzed, and the core promoter region of p21 gene was identified.Site-directed mutagenesis of the transcription factor binding sites MyoD (+25 to +36 bp) in the core promoter region was carried out, and the key transcription factors of p21 gene was preliminary identified in C2C12 cell line.【Result】 The full cDNA sequence of p21 gene in goose was 1 943 bp, containing 453 bp coding regions (CDS) which encoded 151 amino acids.p21 protein sequence had highly conserved CDI family binding sites.Phylogenetic tree analysis showed that p21 gene in goose was closely related to Anas platyrhynchos, and had a particularly strong evolutionary relationship with Gallus gallus and Meleagris gallopavo.The 5′-flanking region of p21 gene contained promoter elements, the core promoter was found to be located at —35 to +37 bp, which played a positive regulatory effect.Combined with site-directed mutation demonstrated that MyoD was the key transcription factor of p21 gene in goose.【Conclusion】 The complete cDNA sequence and promoter region of p21 gene in goose were obtained, and MyoD was the key transcription factor.The results provided a theoretical basis for exploring molecular regulation mechanism of p21 gene in embryonic muscle development of goose.
Effects of the Two-component System LisRK on Acid Resistance and Invasiveness of Listeria monocytogenes
CHEN Lingbo, ZHANG Yu, FANG Xiaowei, JI Junzhi, FANG Chun, YANG Yuying
2022, 49(2):  416-423.  doi:10.16431/j.cnki.1671-7236.2022.02.002
Abstract ( 226 )   PDF (2169KB) ( 45 )  
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【Objective】 This study was conducted to clarify the roles of two-component system LisRK of Listeria monocytogenes in stress resistance and infection.【Method】 The deletion strain ΔlisRK was constructed by homologous recombination with shuttle vector pKSV7 at the background of wild type strain 10403S and the complemental strain CΔlisRK was constructed with plasmid pIMK2.The growth and survival ability of the strains 10403S, ΔlisRK and CΔlisRK under various stresses including acidic (pH 4.5), osmotic (5% NaCl) and oxidative (10 mmol/L H2O2) conditions were analyzed.Then the invasion rate to MGC803 cells and Caco-2 cells, and bacteria load in the liver and spleen of infected mice of strains 10403S, ΔlisRK and CΔlisRK were compared.【Result】 The results of stress test showed that the deletion strain ΔlisRK significantly reduced the growth ability of Listeria monocytogenes under acid stress (pH 4.5), but did not affect the growth ability of Listeria monocytogenes in 5% NaCl and 10 mmol/L H2O2.The survival rate (0.57%) of the deletion strain ΔlisRK under severe acid stress (pH 2.5) was extremely significantly lower than that of strains 10403S (2.07%) and CΔlisRK (1.97%) (P < 0.01).Cell invasion test showed that the invasion rates of the deletion strain ΔlisRK on intestinal epithelial cell Caco-2 and gastric adenocarcinoma cell MGC803 were 2.04% and 0.13%, respectively, which were extremely significantly or significantly lower than that of strains 10403S and CΔlisRK (P < 0.01;P < 0.05).The mouse infection test showed that bacteria load in the liver and spleen of ΔlisRK infected mice were 7.42×107and 1.87×107CFU, which were lower than those of 10403S and CΔlisRK, respectively, but there were no significant difference (P > 0.05).【Conclusion】 These data demonstrated that knocking out the LisRK impaired the acid resistance and invasiveness of Listeria monocytogenes.
Surveillance and Genetic Variation Analysis of S1 Gene of Porcine Epidemic Diarrhea Virus in Part Provinces and Municipalities of China from 2018 to 2020
YAN Zhong, YANG Hanchun
2022, 49(2):  424-434.  doi:10.16431/j.cnki.1671-7236.2022.02.003
Abstract ( 244 )   PDF (3188KB) ( 63 )  
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【Objective】 This study was aimed to survey the prevalence of Porcine epidemic diarrhea virus (PEDV) in large-scale pig farms in China.【Method】 2 391 samples collected from 318 large-scale pig farms in 11 provinces and municipalities of China from 2018 to 2020 were tested for PEDV nucleic acid using RT-PCR.The S1 gene of 30 positive samples were amplified and sequenced, and analyzed by MegAlign, Mega 7.0 and other softwares.【Result】 From 2018 to 2020, the PEDV nucleic acid positive rates in pig farms were 48.57%, 10.96%, and 4.72%, respectively, and the PEDV nucleic acid positive rates in samples were 28.97%, 8.27%, and 7.50%, respectively.The positive rate of PEDV nucleic acid in pig farms and samples showed a downward trend year by year.The similarity analysis of S1 gene showed that all the 30 strains obtained in this experiment were GⅡ genotype, of which 17 strains were GⅡa subtype, 5 strains were GⅡb subtype, and 8 strains were GⅡc subtype, GⅡa subtype strains were the main types of strains circulating from 2018 to 2020.The nucleotide similarity among the 30 strains sequence was 93.0%-99.5%, and the amino acid similarity was 91.7%-100%, compared with the GⅡ genotype strains prevalent from 2017 to 2018, the S1 amino acid sequences of 22 strains showed characteristic insertion and deletion.【Conclusion】 The results provided clinical data support for surveying and analyzing the variation and evolution of PEDV in China, and provided reference for porcine epidemic diarrhea prevention and control and vaccine development.
Isolation, Identification, 16S rRNA Gene Sequencing and Genetic Evolution Analysis of Aeromonas aeruginosa from Duck
QIAO Hongxing, DING Yong, ZHANG Liheng, SONG Yuzhen, DONG Qing, BIAN Chuanzhou, ZHAO Junqiang
2022, 49(2):  435-442.  doi:10.16431/j.cnki.1671-7236.2022.02.004
Abstract ( 232 )   PDF (1706KB) ( 42 )  
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【Objective】 The experiment was aimed to study the pathogenic bacteria of acute death of ducklings in a duck farm in Henan province and its phylogenetic status.【Method】 The liver and spleen of dead ducks in the diseased duck farm were collected.The bacterial morphology, Gram-staining, biochemical characteristics, sequence analysis of 16S rRNA gene, drug sensitivity test and pathogenicity test were carried out.【Results】 The isolated bacteria grew on blood agar medium with smooth, convex, milky white and α-hemolytic Gram-positive cocci.Biochemical test results showed that the isolated bacteria were positive for maltose, sucrose, raffinose, nitrate reduction reaction, MP-VP test, urea, lysine decarboxylase, ornithine decarboxylase and aescin, and negative for xylose, lactose, glucose, sorbitol, hydrogen sulfide, citrate, peptone, mannitol, phenylalanine and methyl red.The results of 16S rRNA gene sequencing and BLAST comparison results showed that the 16S rRNA gene sequence of the isolated strain was 94.8%-99.9% similar to that of Aerococcus viridans published on NCBI, and the similarity with strains Mnlv1, Mnlv2 and W66 was the highest, up to 99.9%.The similarity with strain GXBl-1 was the lowest, which was 94.8%.Phylogenetic tree analysis showed that the isolated bacteria belonged to the same genus and group on the same branch as strains of Aerococcus viridans FL09, 15MS and Mnlv2 etc., and had the closest genetic relationship with FL09.The results of drug sensitivity showed that the isolated strain was sensitive to fosfomycin, ampicillin and amoxicillin, moderately sensitive to penicillin, neomycin and amikacin, it was resistant to rifampicin, neomycin, bacitracin, erythromycin and enrofloxacin.The results of pathogenicity test showed that the strain was lethal and increased with the increase of inoculation concentration.【Conclusion】 This study determined that the pathogen causing the acute death of ducklings in a duck farm in Henan province was Aerococcus viridans, which provided a reference basis for clinical diagnosis and treatment of the diseases caused by this bacteria.
Physiological and Biochemical
Effects of Antibacterial Peptide on the Immune Function and Intestinal Tissue Morphology of Growing Female Minks
YU Xiaojun, LI Dandan, LI Xuewu, WANG Qun, WANG Guang, WANG Lihua
2022, 49(2):  443-453.  doi:10.16431/j.cnki.1671-7236.2022.02.005
Abstract ( 204 )   PDF (9566KB) ( 44 )  
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【Objective】 Cecropin antimicrobial peptide is a commercial cationic antimicrobial peptide that has been seldom studied in minks.The experiment was conducted to determine the effects of antimicrobial peptide on organ coefficient, serum and jejunum immune indexes and intestinal tissue morphology of growing female minks.【Method】 A total of 60 healthy 65-day-old short-haired black female minks with similar body weight were selected and randomly divided into 6 groups with 10 replicates in each group and one mink in each replicate.Minks were separately fed diets supplemented with 0 (control group), 100, 200, 300, 400 and 500 mg/kg antimicrobial peptide, respectively.The pre-experimental period lasted for 1 week, and the experimental period lasted for 8 weeks.After the feeding experiment, 6 minks from each group were selected to collect samples of blood, internal organs, duodenum and jejunum, the immune indicators and intestinal tissue morphology were analyzed.【Result】 Compared with control group, the spleen indexes of 100, 300 and 400 mg/kg antimicrobial peptide groups significantly increased (P < 0.05).The contents of C3, C4 and IgM in experimental groups, and the contents of IgA and IgG in experimental groups (except for 200 mg/kg antimicrobial peptide group) were significantly increased (P < 0.05).The content of TNF-α in experimental groups significantly decreased, and the contents of sIgA, IFN-γ and IL-10 in 100, 200 and 300 mg/kg groups were significantly increased (P < 0.05).The villus heights of duodenum and jejunum in experimental groups were significantly increased (P < 0.05), the crypt depth of duodenum in 200 mg/kg antimicrobial peptide group was significantly lower than that in 400 and 500 mg/kg antimicrobial peptide groups, and V/C in 200 mg/kg antimicrobial peptide group was significantly higher than that in control, 400 and 500 mg/kg antimicrobial peptide groups (P < 0.05).V/C of jejunal in 200, 300 and 400 mg/kg antimicrobial peptide groups were significantly increased (P < 0.05).【Conclusion】 In conclusion, antimicrobial peptide could promote the development of immune organs, enhance body immunity and improve intestinal tissue morphology of growing female minks.The recommended level of antimicrobial peptide ranged from 100 to 200 mg/kg for growing female minks.
Changes of Sex Hormone Levels in the Process of PCOS Induced by DHEA in Mice
WENG Yu, WANG Qin, ZHAO Yufen, YU Kai, HAO HAO Shaoyu, YU Boyang, DU Chenguang, SUBUDENG Gerile, LI Haijun
2022, 49(2):  454-461.  doi:10.16431/j.cnki.1671-7236.2022.02.006
Abstract ( 303 )   PDF (6770KB) ( 87 )  
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【Objective】 In view of the controversy over the pathogenesis and treatment of polycystic ovary syndrome (PCOS), and the limited use of human PCOS materials for research, in the present study, PCOS mice model was constructed for further exploring the changes in sex hormone levels in this process.【Method】 Subcutaneous injection of dehydroepiandrosterone (DHEA) was chosen to produce KM female mice with PCOS-like clinical symptoms, mouse estrous cycle was identified by crystal violet staining.The ovarian development status was determined with HE staining.The changes of serum testosterone and estradiol concentrations during the modeling process were evaluated using ELISA method.【Result】 The vaginal epithelial cells of mice were stained with crystal violet, which could accurately distinguish the different stages of estrous cycle in mice.After 20 days of continuous induction with 6 mg/100 g DHEA, the estrous cycle of KM mice was arrested, and the change of body weight was significantly related to the addition of sesame oil solvent (P < 0.05), but there was no relation to DHEA treatment.After continuous treatment with DHEA, the serum testosterone level increased significantly (P < 0.05), and the serum testosterone level increased significantly from the 5th day of PCOS model establishment and maintained until the end (P < 0.05).The serum estradiol level was significantly higher than that of control group on the 10th and 15th day (P < 0.05), and lower than that of control group on the 20th day.【Conclusion】 The PCOS KM mouse model was successfully established by improving the DHEA dissolution method.During the modeling process, the concentration of androgen continued to be at a high level, while the concentration of estradiol increased at the early stage and decreased at the end of modeling, however, the possible pathological role on estradiol elevated instantly during the modeling process needed to be further verified.
Effect of Gynostemma pentaphyllum Polysaccharide on Antioxidative Ability of Liver in Aging Mice Induced by D-galactose
ZHANG Runxiang, BAI Yuting, ZHANG Yinglei, LIU Keke, WANG Xinyu, DONG Yinyu, WANG Xiaoli
2022, 49(2):  462-470.  doi:10.16431/j.cnki.1671-7236.2022.02.007
Abstract ( 192 )   PDF (3448KB) ( 35 )  
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【Objective】 The purpose of this study was to investigate the effect of Gynostemma pentaphyllum polysaccharides (GPP) on the antioxidant capacity of liver in aging mice induced by D-galactose (D-gal).【Method】 Sixty 4-week-old SPF Kunming mice were randomly divided into 6 groups (half male and half female): Blank control group (Control), model group (D-gal), positive control group (Vc), low (50 mg/kg), medium (100 mg/kg) and high (200 mg/kg) dose groups of GPP (GPP-L, GPP-M and GPP-H), with 10 mice in each group.Biochemical, enzyme-linked immunosorbent assay and histological techniques were used to determine the weight change, liver index, T-AOC levels in serum, SOD, GSH-Px and CAT activities, ROS and MDA contents in liver, as well as the liver tissue morphology and liver cord area ratio.【Result】 The weight of mice in each group was an increasing trend, and the weight gain was a decreasing trend, the weight of mice in GPP-M group was lower than that of the other groups, and the weight gain was the least.The liver index and serum T-AOC activity in each dose group of GPP were higher than that in D-gal group.The SOD activity in each dose group of GPP was no significant difference with D-gal group (P > 0.05).The activities of GSH-Px and CAT were increased compared with D-gal group, the GSH-Px activity in GPP-M group and the CAT activity in GPP-L group were significantly higher than that in D-gal group (P < 0.05), and the contents of ROS and MDA in GPP-L group were significantly decreased than that in D-gal group (P < 0.05).HE staining revealed that the cytoplasmic eosinophilia of D-gal group was enhanced, the connection between hepatocytes was loose, and the hepatic sinusoids were dilated significantly, while the liver tissue structure in GPP group was improved, especially GPP-M and GPP-H groups.The proportion of hepatic cord area in GPP-H group was equivalent to that in blank and positive control groups, and the proportion of hepatic cord area in GPP-M and GPP-H groups were significantly higher than that in GPP-L group (P < 0.05).【Conclusion】 GPP could effectively improve the antioxidant capacity of aging mice induced by D-gal and delay the aging, and 100 mg/kg GPP had a significant antioxidant effect on liver of aging mice induced by D-gal.
Effects of PRRSV-LPS Treatment on Neutrophil Adhesion to Porcine Pulmonary Microvascular Endothelial Cells
WANG Zhaoli, YANG Siyu, WU Yanmei, SONG Xiaoxiao, MU Xiang, ZHANG Tao
2022, 49(2):  471-479.  doi:10.16431/j.cnki.1671-7236.2022.02.008
Abstract ( 185 )   PDF (8057KB) ( 35 )  
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【Objective】 This study was aimed to study the effects of Porcine reproductive and respiratory syndrome virus (PRRSV) alone and in combination with lipopolysaccharide (LPS) stimulation on lung recruitment neutrophil (Neu), and the role of porcine lung microvascular endothelial cells (MVECs).【Method】 The primary MVECs were isolated and cultured by type Ⅱ collagenase digestion and differential adhesion method.Neu was isolated from porcine peripheral blood by density gradient centrifugation.After stimulating Neu and MVECs with PRRSV HN strain or PRRSV-LPS, Neu was added to the culture plate with MVECs, incubated for 1 h, fixed with 4% paraformaldehyde, stained with Wright's staining, and the number of Neu adhered in each group was observed, counted and analyzed.The expression of P-selectin and E-selectin in MVECs was detected by immunocytochemical staining.The quantitative changes of Neu adhesion to MVECs stimulated by PRRSV HN strain or PRRSV-LPS were measured and analyzed by rose bengal solution staining when MVECs were blocked by P-selectin and E-selectin antibodies.【Result】 The isolated and cultured MVECs were CD34 immunofluorescence positive, and the positive rate was about 92%.When PRRSV HN strain was stimulated for 18 h, the number of Neu adhered to MVECs increased significantly (P < 0.05).When stimulated with PRRSV-LPS, the number of adherent Neu was significantly higher than that stimulated with LPS alone (P < 0.05).When PRRSV or PRRSV-LPS stimulated Neu and MVECs, the increase in the number of adherent Neu was more obvious than that only stimulated MVECs or Neu.Immunocytochemical staining showed that MVECs strongly expressed P-selectin and E-selectin.When P-selectin and E-selectin antibodies blocked MVECs, the increase of Neu adhesion induced by PRRSV or PRRSV-LPS decreased in varying degrees, and there was a significant difference when E-selectin blocked MVECs (P < 0.05).【Conclusion】 PRRSV infection could not only promote the adhesion between Neu and MVECs, but also increase the number of Neu adhered during subsequent LPS stimulation.E-selectin expressed by MVECs was one of the important molecules mediating the increase of Neu adhesion caused by PRRSV.
Effects of Licochalcone A on Oxidative Stress Induced by Haemophilus parasuis Infection in Porcine Alveolar Macrophages
YANG Yu, GUAN Wenchao, CUI Xiaozhen, JIA Yongxin, YANG Shiyu
2022, 49(2):  480-487.  doi:10.16431/j.cnki.1671-7236.2022.02.009
Abstract ( 168 )   PDF (1325KB) ( 28 )  
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【Objective】 This study was to explore the effects of licochalcone A (Lico A) on the oxidative stress of porcine alveolar macrophages (PAMs) infected with Haemophilus parasuis, so as to provide reference for the development of new drugs for the treatment of Haemophilus parasuis infection.【Method】 PAMs were obtained from the lungs by bronchoalveolar lavage and divided into 6 groups. Negative control group, PAMs were not infected with Haemophilus parasuis; Positive control group, PAMs were infected with Haemophilus parasuis only; DMSO group, PAMs were treated with 0.1% DMSO after infection with Haemophilus parasuis; 5, 10 and 20 μg/mL Lico A group, PAMs were treated with 5, 10 and 20 μg/mL Lico A after infection with Haemophilus parasuis.PAMs were treated according to the above groups and cultured for 24 h.Cell viability were measured by CCK-8 method, the activities of lactate dehydrogenase (LDH), glutathione peroxidase(GSH-Px)and superoxide dismutase (SOD), and the levels of malondialdehyde (MDA), nitric oxide (NO) and total antioxidant capacity (T-AOC) in the supernatant were measured by enzyme labeling or visible light photometer, respectively.The intracellular reactive oxygen species (ROS) level was observed using a fluorescence probe, 2', 7'-dichlorofluorescin diacetate (DCFH-DA).【Result】 Compared with negative control group, after infection with Haemophilus parasuis, the activity of PAMs was decreased significantly (P < 0.05), the activity of LDH in supernatant was significantly increased (P < 0.05), the levels of MDA, NO and ROS and the activity of SOD were significantly increased (P < 0.05).Compared with positive group, the cell viability in 5, 10 and 20 μg/mL Lico A groups was significantly increased (P < 0.05), the activity of LDH in supernatant was significantly decreased (P < 0.05), the levels of MDA, NO and ROS in 10 and 20 μg/mL Lico A groups were significantly decreased (P < 0.05).The activities of GSH-Px, SOD and T-AOC in 5, 10 and 20 μg/mL Lico A groups were significantly increased in a dose dependent manner (P < 0.05).【Conclusion】 Haemophilus parasuis infection results in an imbalance between oxidant and antioxidant in PAMs, and 5-20 μg/mL Lico A could decrease the cellular response to oxidative stress.
Nutrition and Feed
Effects of Compound Probiotics on the Intestinal Microflora of Broilers
ZHANG Lihuan, JIA Hao, ZHANG Ruonan, WANG Yanfei, LIU Xuan
2022, 49(2):  488-500.  doi:10.16431/j.cnki.1671-7236.2022.02.010
Abstract ( 227 )   PDF (3615KB) ( 170 )  
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【Objective】 The aim of this study was to explore the effects of the compound probiotics composed of Lactobacillus casei, Lactobacillus acidophilus and Bifidobacterium lactis on the production performance and intestinal microflora of jute broilers, and provide theoretical basis for the application of compound probiotics in broiler production.【Method】 A total of 200 one-day-old male Jute broilers were randomly divided into 2 groups with 5 replicates per group and 20 broilers per replicate.Compound probiotics (Lactobacillus caseiLactobacillus acidophilusBifidobacterium lactis=1∶1∶2) were added to the drinking water of broilers in probiotics group at a ratio of 1%.The broilers received normal drinking water acted as control group.At 42 days, the growth performance indexes were measured, and the intestinal microflora was analyzed by high-throughput sequencing.【Result】 Compared with control group, the average daily gain of broilers in probiotic group increased significantly (P < 0.05), the average daily feed intake, carcass yield and eviscerated carcass proportion increased, and F/G was reduced, but the differences were not significant (P > 0.05);The total OTU of the intestinal microflora, and Sob, Chao, Pd, Shannon, Shannoneven indexes of ileum in probiotic group were decreased, and the Simpson index increased, with no significant differences (P > 0.05).Firmicutes had the highest abundance in intestinal tract of broilers and were dominant.Compared with control group, no Lachnoclostridium was found in ileum of probiotic group.The abundance of Firmicutes and Lactococcus in ileum increased significantly or extremely significantly in probiotic group (P < 0.05 or P < 0.01), the abundance of Actinomycetes and Staphylococcus decreased significantly or extremely significantly (P < 0.05 or P < 0.01), and the abundance of Lacetospiraceae in cecum increased significantly (P < 0.05).【Conclusion】 Compound probiotics could improve the composition, function and diversity of intestinal microflora by increasing the abundance of Lactobacillus and reducing the abundance of pathogenic bacteria in ileum.At the same time, it could increase the abundance of Lachnospiraceae to improve the ability of intestinal to ferment and degrade non-starch polysaccharides, thereby improving feed utilization efficiency and promoting the growth of broilers.
Study on Dietary Crude Protein Requirement of Silky Fowl During 1 to 25 Days of Age
FAN Qiuli, JIANG Shouqun, WANG Hanhua, RUAN Dong, CHENG Zhonggang
2022, 49(2):  501-509.  doi:10.16431/j.cnki.1671-7236.2022.02.011
Abstract ( 169 )   PDF (1102KB) ( 35 )  
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【Obiective】 The aim of this experiment was to investigate the effects of dietary crude protein level on growth performance, carcass traits and serum biochemical indices of male Silky fowl during 1 to 25 days of age, to investigate the crude protein requirment of Silky fowl at this stage.【Method】 1 625 1-day-old male Silky fowl were randomly assigned to 5 groups with 5 replicates per group and 65 chickens per replicate, crude protein levels in five groups were 18.5%, 19.5%, 20.5%, 21.5% and 22.5% respectively, and the experiment lasted for 25 days.At the end of this experiment, two chickens with body weight close to the average were selected from each replicate for slaughter, blood was collected for serum preparation and carcasses were separated, carcass traits and serum biochemical indexes were determined.【Result】 ①Dietary crude protein level significantly affected F/G (P < 0.05), with the increasing of crude protein level, F/G was decreased linearly and quadratically (P < 0.05).Crude protein level had no significant effects on final body weight, average daily gain (ADG), average daily feed intake (ADFI) and survival rate (P > 0.05).②Crude protein level had no significant effects on carcass weight, half-eviscerated weight, eviscerated weight, breast muscle rate, leg muscle rate and abdominal fat rate (P > 0.05).③Crude protein level significantly affected the serum contents of BUN and IGF-1 (P < 0.05), and with the increasing of crude protein level, both contents of BUN and IGF-1 were increased linearly and quadratically (P < 0.05).【Conclusion】 In conclusion, dietary 21.5% to 22.5% crude protein could improve growth performance and 18.5% to 21.5% crude protein could regulate nitrogen metabolism.Using the F/G, BUN and IGF-1 contents as evaluation criteria, according to the quadratic curve model, the optimal dietary crude protein levels of Silky fowl aged from 1 to 25 days were 23.18%, 19.20% and 22.62% respectively.
Study on the Growth Performance and Intestinal Flora of Beagle Puppies Regulated by Probiotics
WANG Zhihua, JIA Junpeng, RADEBE Stoffel Matjeke, YU Qinghua
2022, 49(2):  510-520.  doi:10.16431/j.cnki.1671-7236.2022.02.012
Abstract ( 196 )   PDF (1840KB) ( 50 )  
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【Objective】 This experiment was to explore the effects of compound probiotics on the growth performance and intestinal flora structure of Beagle puppies during lactation.【Method】 Twelve 15-day-old Beagle puppies were selected and randomly divided into control group and probiotics group, with 6 in each group.The puppies in the probiotics group were fed with 20 mL probiotic preparation daily, and the puppies in control group were fed with 20 mL normal saline.The body weight was measured and the weight gain was calculated on days 0, 3, 9, 12, 15, 18, 21, 25 and 28.Whole blood, serum and fecal samples were collected at the 28th day.Red blood cell count (RBC) and hemoglobin (HGB) concentrations were measured in whole blood samples, alkaline phosphatase (AKP), inorganic phosphorus (IP), total cholesterol (TCHO) content, triglyceride (TG), immunoglobulin A (IgA), immunoglobulin G (IgG), interleukin-1β (IL-1β), lipopolysaccharide (LPS) contents were measured in serum samples.The fecal samples were sequenced for flora, the Goods coverage index, Observed species index, and Shannon index were counted.The samples were analyzed by PCoA, and the species distribution at the phylum, genus and species levels of each sample were counted.【Result】 Compared with control group, probiotics could significantly increase the weight of puppies (P < 0.05), and significantly increase the number of RBC and the content of HGB, AKP and IP in serum (P < 0.05), and promote the growth and development of Beagle puppies.Probiotics could significantly reduce serum TG content (P < 0.05), but had no significant effect on TCHO, IgA, IgG, IL-1β and LPS (P < 0.05).Observed species index and PCoA analysis results showed that the probiotics could significantly change the structure of puppies intestinal flora (P < 0.05).At the phylum level, the relative abundance of Bacteroides and Actinobacteriota in the puppies of the microecological preparation group was significantly lower (P < 0.05), the relative abundance of Fusobacteriota, Acidobacteria and Verrucomicrobia were significantly increased (P < 0.05).At the genus level, the relative abundance of Escherichia-Shigella, Holdemanella, Bifidobacterium and Blautia was significantly reduced (P < 0.05), the relative abundance of Clostridium sensu stricto 1, Streptococcus, Fusobacteria, Lactococcus and Pediococcus was significantly increased (P < 0.05).At the species level, the relative abundance of Escherichia coli and Bifidobacterium breve was significantly decreased (P < 0.05), the relative abundance of Clostridium colicanis, Lactococcus garvieae, Vagococcus teuberi, Bacillus velezensis, Enterococcus faecium and Fusobacterium mortiferum was significantly increased (P < 0.05).【Conclusion】 The probiotics for puppies could significantly promote the growth of puppies, increase their blood oxygen content, change the structure of the intestinal flora, and optimize the composition of the intestinal flora.
Effects of Heat Stress on Blood Biochemical Indexes of Murrah and Nili-Ravi Buffaloes
LIU Xinyong, TAN Zhengzhun, LI Hui, HUANG Jian, LUO Hua, ZENG Linghu, CHENG Juanru, ZHONG Huapei, YANG Chunyan, WANG Xiaoli, QIN Guangsheng
2022, 49(2):  521-528.  doi:10.16431/j.cnki.1671-7236.2022.02.013
Abstract ( 191 )   PDF (935KB) ( 40 )  
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【Objective】 The purpose of this study was to explore the changes of blood biochemical indexes of Murrah and Nili-Ravi buffaloes under heat stress.【Method】 11 Murrah and 11 Nili-Ravi buffaloes with similar physical conditions and healthy physique were selected.The experimental period was divided into heat stress period and non stress period, and four blood samples were taken in each experimental period, with an interval of one week.The blood samples were measured for biochemical indexes such as serum hormone concentration, antioxidant index and ion concentration.【Result】 For Murrah buffalos, the activity/content of superoxide dismutase (SOD), total cholesterol (CHOL), malondialdehyde (MDA), heat shock protein 70 (HSP70), potassium ion (K+), sodium ion (Na+) and chloride ion (Cl-) during heat stress were significantly higher than those in non stress period (P < 0.05), while the activity/content of alanine aminotransferase (ALT), aspartate aminotransferase (AST), insulin-like growth factor 1 (IGF-1), cortisol (CORT), leptin (LEP), glutathione peroxidase (GSH-Px), total antioxidant capacity (T-AOC) and calcium ion (Ca2+) were significantly lower than those in non stress period (P < 0.05).For Nili-Ravi buffaloes, the content/activity of albumin (ALB), CHOL and glutamyltransferase (GGT) in the heat stress period were significantly higher than those in the non stress period (P < 0.05), and the content of globulin (GLOB) in the heat stress period was significantly lower than that in the non stress period (P < 0.05).In heat stress period, the activity/content of ALT, total protein (TP), GLOB, CHOL, urea nitrogen (BUN) and triglyceride (TG) in Murrah buffaloes were significantly higher than those in Nili-Ravi buffaloes (P < 0.05), and the contents of ALB, tetraiodothyronine (T4) and K+ in Nili-Ravi buffaloes were significantly higher than those in Murrah buffaloes (P < 0.05).In non stress period, the contents of ALT, BUN, TG, glucose(GLU) and T-AOC of Murrah buffaloes were significantly higher than those of Nili-Ravi buffaloes (P < 0.05).【Conclusion】 Heat stress reduced the endocrine hormone level and antioxidant capacity of Murrah and Nili-Ravi Buffaloes, and affected the electrolyte balance of the body.The immune function of Nili-Ravi buffaloes also decreased to a certain extent.At the same time, Murrah buffaloes showed stronger ability to scavenge free radicals, and Nili-Ravi buffaloes showed better metabolism, thermoregulation and electrolyte compensation ability to deal with heat stress.
Effect of Exogenous Biological Agents on Silage Quality and Ruminal Degradability of Corn Stalk and Potato Pulp Mixed Silage
FENG Peng, WU Hongda, ZHENG Haiyan, YANG Zhao, WANG Di, SHI Chen, MENG Fankun
2022, 49(2):  529-538.  doi:10.16431/j.cnki.1671-7236.2022.02.014
Abstract ( 192 )   PDF (1122KB) ( 28 )  
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【Objective】 The purpose of the experiment was to study the effects of exogenous biological agents on the fermentation quality, nutritional value and 72 h rumen degradation rate of corn stalk and potato pulp mixed silage, screen efficient feed biological agents, and explore practical corn straw feed conversion technology.【Method】 The straw of grain and feed maize variety Zhongyuandan 32 was used as the experimental material.The corn variety Zhongyuan Dan 32 straw and Kexin 1 potato were used as experimental materials to mix silage in the ratio of 3∶1. A complete randomized experimental design was adopted. There were 15 treatments: enzyme preparation (CE1, CE2, CE3 and CE4), bacteria preparation (LAB) and enzyme bacteria compound treatment group (MCL1, MCL2, MCL3, MCL4, MCL5, MCL6, MCL7, MCL8 and MCL9), at the same time, the control group (CK) without any enzyme bacteria preparation was set.After 60 days of silage fermentation, the silage quality index and rumen degradation rate of mixed silage were measured.【Result】 The sensory evaluation of each treatment and control of mixed silage reached excellent grade.The contents of lactic acid and acetic acid in enzyme treated groups and enzyme bacteria treated groups were significantly higher than those in bacteria treated group and control (P < 0.05).The contents of lactic acid in MCL2 and MCL4 groups were the highest, 2.82% and 2.77% respectively.Compared with the control, the contents of cellulose, neutral detergent fiber (NDF) and acid detergent fiber (ADF) in the mixed silage of each treatment group decreased significantly (P < 0.05), and the MCL2 group was the lowest, 22.86%, 53.43% and 33.99%, respectively.The 72 h rumen degradation rate of cellulose in 1 g/3 kg cellulase addition groups (CE1, MCL2, MCL6, MCL7) were significantly higher than that in other groups (P < 0.05).【Conclusion】 The synergistic effects of enzymes, bacteria and bacterial enzymes promoted the fermentation of corn straw and potato residue mixed silage to varying degrees, improved the nutritional value of mixed silage, improved the degradation efficiency of nutrients in rumen of ruminants.Synthesizing the fermentation quality, nutritional composition and rumen degradation rate of corn straw, enzyme bacteria complex treatments > enzyme treatments > bacteria treatments, in which MCL2 group (xylanase 1 g/3 kg, pectinase 1 g/3 kg, β-glucanase 1 g/3 kg, Lactobacillus 3 g/3 kg and cellulase 1 g/3 kg) were the best.Cellulase could reduce the contents of cellulose, ADF and NDF in corn straw mixed silage, and the optimum amount of cellulase was 1 g/3 kg.
Effects of Dietary Metabolizable Energy Levels on Growth Performance, Carcass Traits and Serum Biochemical Indices of Ningdu Yellow Chickens
SONG Qiongli, SONG Wenjing, CHEN Xiaolian, WEI Qipeng, XIE Jinfang, ZOU Zhiheng, LIU Linxiu, XIONG Pingwen
2022, 49(2):  539-547.  doi:10.16431/j.cnki.1671-7236.2022.02.015
Abstract ( 229 )   PDF (971KB) ( 99 )  
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【Objective】 This experiment was conducted to study the dietary metabolizable energy(ME) requirements for Ningdu Yellow chickens at different growth stages.【Method】 A single factor complete randomized trial design was adopted.600, 480 and 360 Ningdu Yellow chickens with similar body weight at the age of 1, 29 and 57 days were selected and randomly divided into four treatments with 6 replicates and 25, 20 and 15 chickens per replicateat at three stages, respectively.Dietary ME was set at four levels (Low, lower, medium and high).From 1 to 28 d, the ME levels were 11.50, 11.95, 12.40 and 12.85 MJ/kg, respectively, from 29 to 56 d, the ME levels were 11.68, 12.14, 12.60 and 13.06 MJ/kg, respectively, from 57 to 105 d, the ME levels were 11.60, 12.20, 12.80 and 13.40 MJ/kg, respectively.The effects of dietary metabolizable energy level on growth performance, serum biochemical indices and carcass traits were investigated.【Result】 ① At 1 to 28 days of age, feed to gain ratio (F/G) in high ME group was significantly lower than other groups (P < 0.05).②At 29 to 56 days of age, average daily feed intake (ADFI)and F/G in medium and high ME groups were significantly lower than low and lower ME groups (P < 0.05), F/G in lower ME group was significantly lower than low ME group (P < 0.05).Serum total protein (TP) in high and medium ME groups were significantly higher than those in low group (P < 0.05), albumin (ALB) in medium ME group was significantly higher than those in lower and low groups (P < 0.05).③At 57 to 105 days of age, with the ME levels increasing, final weight and average daily gain (ADG) showed an increasing trend (0.05 < P < 0.1).ADFI in medium and high ME groups were significantly lower than low and lower ME groups (P < 0.05), F/G in high ME group was significantly lower than other groups (P < 0.05), F/G in low and medium ME groups were significantly lower than that in low ME group (P < 0.05).Serum triglyceride (TG) level was increased with dietary ME levels increasing (0.05 < P < 0.1).Abdominal fat percentage at 105 days of age was increased with dietary ME levels increasing (0.05 < P < 0.1).【Conclusion】 Based on the results of this experiment, high ME level was recommended for Ningdu Yellow chickens at 1 to 28 and 29 to 56 days of age, medium ME level was recommended for Ningdu Yellow chickens at 57 to 105 days of age.
Effects of Barley Worm Meal on Growth Performance, Intestinal Structure and Microflora Composition of Yellow-feathered Broilers
YU Qinping, HUANG Jingyu, ZHANG Cuiping, LIU Jing, HUANG Yuanbin, YU Ting, ZHANG Xiaoai, WANG Lei, CHEN Jinsheng, CHEN Wenqing, WANG Zhilin, CHEN Zhuang, RONG Ting
2022, 49(2):  548-558.  doi:10.16431/j.cnki.1671-7236.2022.02.016
Abstract ( 457 )   PDF (1026KB) ( 45 )  
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【Objective】 This study was conducted to investigate the effects of barley worm meal on growth performance, intestinal structure and microflora composition of Yellow-feathered broilers.【Method】 A total of 216 one-day-old healthy Yellow-feathered broilers with an average body weight (BW) of (30.03±0.23) g were randomly divided into 3 groups with 6 replicates and 12 broilers per replicate.The animals were fed with the following diets: basal diet (control group), basal diet +1% barley worm meal and basal diet +3% barley worm meal groups.The nutrient level of each group was the same, and the experimental period was 63 days.The average daily gain (ADG), average daily feed intake (ADFI), body weight (BW), feed weight ratio (F/G) and death rate of 21, 42 and 63 days old treatments were counted respectively.At 63 days old, duodenum, jejunum and ileum were slaughtered to measure the length and structure of intestinal segment, and the contents of ileum and cecum were taken for flora composition analysis.【Result】 Compared with control group, there was no significant difference in ADG of 1 to 21 days old, as well as BW, ADFI, F/G and death rate of 21 days old (P > 0.05).ADG of 22 to 42 days old and BW of 42 days old were increased significantly in 1% and 3% barley worm meal groups (P < 0.05), while F/G was decreased significantly (P < 0.05).At 43-63 days old, BW was increased significantly at 63 days in 1% barley worm meal group (P < 0.05), and ADFI was decreased significantly in 3% barley worm meal group (P < 0.05).Compared with control group, the length of cecum in 1% and 3% barley worm meal groups was increased significantly at 21 days od (P < 0.05), the length of duodenum in 3% barley worm meal group increased significantly at 42 days old (P < 0.05), there was no significant difference in the length of duodenum, jejunum, ileum and cecum among the treatment groups at 63 days old (P > 0.05), the villus height, recess depth and villus ratio of duodenum, jejunum and ileum in 1% barley worm group were not significantly different (P > 0.05).In terms of the composition of intestinal microbiota, the dominant bacteria in ileum of control group and 1% barley worm meal group were Lactobacillus, Rochebacillus and Bacteroides, and the dominant bacteria in the cecum were Bacteroides, Alistipes and Lactobacillus. Compared with control group, the proportion of Lactobacillus, Bacteroides and Alistipes in the ileum of 1% barley worm meal group increased, and the proportion of Roche decreased.The proportion of Bacteroides and Alistipes in cecum increased, while Lactobacillus and Roche decreased in the 1% barley worm meal group.【Conclusion】 Adding appropriate amount of barley worm meal could improve the production performance and digestive tract development of Yellow-feathered broilers, which could regulate the composition of intestinal microflora and bacteriostasis.
Effects of Fermented Mixed Meal Replacing Soybean Meal in Diets on Growth Performance, Nutrient Apparent Digestibility and Serum Biochemical Indices of Beef Cattle
ZENG Yu, LIU Yao, LI Youying, PENG Zhongli, WU Huazhuo
2022, 49(2):  559-568.  doi:10.16431/j.cnki.1671-7236.2022.02.017
Abstract ( 297 )   PDF (1036KB) ( 52 )  
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【Objective】 This experiment was conducted to investigate the effects of different proportion of fermented mixed meal replacing soybean meal in diets on growth performance, nutrient apparent digestibility, serum biochemical indexes of beef cattle, in order to provide a reference data for applying fermented mixed meal in beef cattle production.【Method】 35 healthy Simmental crossbred cattle with an initial body weight of (480.71±45.65) kg were randomly divided into 5 groups, and were fed total mixed rations (TMR) which used fermented mixed meal replacing 0 (group Ⅰ), 25% (group Ⅱ), 50% (group Ⅲ), 75% (group Ⅳ), and 100% (group Ⅴ) soybean meal, respectively.The experiment lasted for 74 days, the first 14 days were the adaptation period, and the last 60 days were the trial period.Growth performance was detected at the end of experiment.Diet and fecal samples were collected for nutrient apparent digestibility determination at last 3 days of the experiment.20 mL blood samples were collected from the vein of five beef cattle in each group at the end of experiment, and the serum biochemical indices were tested by veterinary automatic biochemical analyzer.【Result】 ①With the increase of the ratio of fermented mixed meal replacing soybean meal, the ADG first increased and then decreased (P=0.096), the F/G of group Ⅲ and Ⅳ was significantly higher than that of group Ⅱ (P < 0.05), and group Ⅳ had the highest ADG and the lowest F/G.②As the replacement ratio of fermented mixed meal increasing, crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) digestibility showed quadratic variation (P < 0.05).Compared with group Ⅰ-Ⅳ, the organic matter (OM) digestibility in group Ⅴ was significantly decreased (P < 0.05), and there was no significant difference in phosphorus (P) and calcium (Ca) digestibility among the five groups (P > 0.05).③The contents of urea nitrogen (UN) and the activity of alkaline phosphatase (ALP) in serum decreased linearly with the increase of the ratio of fermented mixed meal replacing soybean meal (P < 0.05), and the content of total cholesterol (TC) showed a tendency decreased linearly (P=0.098).④The unit price of feed in group Ⅰ-Ⅴ were 1.85, 1.84, 1.82, 1.81 and 1.80 yuan, respectively.The weight gain cost per kilogram of beef cattle was 7.09, 17.88, 15.32, 14.86 and 16.13 yuan, respectively.the gross profit per beef cattle in the whole experiment period was 702.07, 623.42, 954.21, 1 011.48 and 778.89 yuan, respectively.【Conclusion】 Under the conditions of this experiment, fermented mixed meal could completely replace soybean meal in diets and had no significant negative impact on growth performance and nutrient apparent digestibility of beef cattle, and 75% substitution in diets had the best effect on growth performance and economic benefits of beef cattle.
Isolation, Identification and Genomic Sequence Analysis of a Strain of Clostridium butyricum from Pigs Utilizing Lactic Acid
HU Xiaobing, LIN Biaosheng, WANG Zhenwei, ZHENG Lijing
2022, 49(2):  569-578.  doi:10.16431/j.cnki.1671-7236.2022.02.018
Abstract ( 191 )   PDF (2947KB) ( 44 )  
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【Objective】 The study was aimed to research the genomic information of a pig-isolate Clostridium butyricum utilizing lactic acid.【Method】 Using anaerobic culture method, strains with fast lactic acid utilization and high butyric acid conversion rate were isolated from the intestinal contents of healthy piglets fed lactic acid bacteria fermented feed through primary screening of lactic acid decomposition medium (LADM) and re-screening of Clostridium proliferating medium (RCM).The screened strains were identified by morphology, 16S rDNA sequence analysis, lactic acid transformation characteristic test, genome re-sequencing and frame map sequencing, and the functional annotation of their coding proteins was carried out.【Result】 A LY33 strain was isolated.The strain LY33 was identified as Clostridium butyricum based on its morphological and 16S rDNA sequence analysis.The strain LY33 had good ability to utilize lactic acid.On the 6th day of growth, 66 mmol lactic acid could be basically transformed into about 17 mmol butyric acid.The re-sequencing of LY33 strain showed that the overall variation of its coding gene was small.Compared with the reference genome, the whole genome heterozygosity ratio of LY33 strain was 0.022‰, the total number of single nucleotide polymorphism (SNP) site variants was 21 590 (0.4666% of the whole genome), the total number of insertion/deletion (Indel) mutations was 594 (0.0128%), the variation of copy number variation (CNV) was 0 (0), and the total number of structure variation (SV) annotated variants was 103 (0.0003%).The mutant genes in the genome of LY33 strain were mainly genes related to strain growth, energy metabolism regulation and vitamin synthesis (especially biotin), which were distributed on multiple sequences of two chromosomes.The frame diagram sequencing of LY33 strain and the functional annotation of its encoded gene protein showed that its genome sequence length was 4 627 127 bp, GC content was 28.60%, contained 4 171 genes, and the total length of coding region accounted for 84.12%, which was involved in the metabolic pathway transformation of various substances such as carbohydrate metabolism, membrane transport and amino acid metabolism.There were many genes resistant to macrolides, bacitracin and VanI glycopeptide in the genome of LY33 strain.【Conclusion】 In this study, a LY33 strain with fast lactic acid utilization and high butyric acid conversion rate was isolated from the intestinal contents of healthy piglets fed with 4% lactic acid bacteria fermented feed, which was identified as Clostridium butyricum.It had a good application prospect and could be used as a new microbial resource for probiotics products.
Effects of Exosomes on Animal Intestinal Health and Its Research Methods
WEI Wenzhuo, LIANG Zhenhua, WU Yan, LIU Jingbo, PI Jinsong, ZHANG Hao
2022, 49(2):  579-586.  doi:10.16431/j.cnki.1671-7236.2022.02.019
Abstract ( 268 )   PDF (958KB) ( 52 )  
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In the context of non-resistant breeding, the intestinal health of animals has attracted more and more attention.The intestinal tract is the main organ for digestion and absorption of nutrients, as well as the innate barrier to prevent intestinal microbial invasion.The integrity of the intestinal barrier function plays a crucial role in the normal growth and development of the body.Exosome is an endogenous regulatory substance that can be used as a starting point to solve intestinal health problems.Exosomes are nanoscale extracellular vesicles secreted by various types of cells, which are widely distributed in various body fluids and can carry bioactive substances such as proteins, nucleic acids and lipids.They participate in cell-to-cell transmission, cell migration and proliferation and play a role in physiological and pathological processes of the body.Recent studies have shown that exosomes can repair the intestinal barrier function of animals by regulating the composition of intestinal flora and inducing the proliferation of intestinal stem cells.In this paper, the effects of exosomes on intestinal health of livestock and poultry in recent years and the research methods of exosomes are reviewed and summarized to provide reference for subsequent studies.
Genetics and Breeding
Correlation Analysis of BMPRⅡ Gene Polymorphism and Its Haplotype with Lambing Traits in Tibetan Sheep
LI Mingming, WU Qingwei, DENG Yuting, JIN Shengwei, HE Na, ZHANG Junxia
2022, 49(2):  587-597.  doi:10.16431/j.cnki.1671-7236.2022.02.020
Abstract ( 183 )   PDF (973KB) ( 69 )  
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【Objective】 The aim of this study was to investigate the relationship between the polymorphism of bone morphogenetic protein receptor Ⅱ (BMPRⅡ) gene and its haplotype lambing traits of Tibetan sheep.【Method】 433 Tibetan ewes were used to detect the polymorphisms of 9 single nucleotide polymorphisms (SNPs) of BMPRⅡ gene in Tibetan sheep population by improved multiple ligase detection reaction (iMLDR).Haploview 4.2 software was used to analyze the linkage disequilibrium and construct haplotypes.Gene association analysis was used to explore the association between BMPRⅡ gene polymorphism and haplotype and lambing traits of Tibetan sheep.【Result】 The results showed that there were g.90192 T>C, g.142532 C>T, g.142614 A>G, g.142751 T>C, g.143138 A>G and g.143189 G>A in exon 12 of BMPRⅡ gene in Tibetan sheep, and there were one mutation site each in exons 3, 9 and 13, g.143570 C>G, g.124843 A>C and g.145233 A>G, respectively.All the 9 SNPs were synonymous mutations.Among the 9 SNPs, there were 3 genotypes except g.90192 T>C.Polymorphism information content analysis showed that the population was low polymorphic at g.90192 T>C, g.142614 A>G and g.145233 A>G (PIC < 0.25).g.124843 A>C, g.142532 C>T, g.142751 T>C, g.143138 A>G, g.143189 G>A and g.143570 C>G were all moderately polymorphic (0.25 < PIC < 0.5).The results of Chi-square fitness test showed that all mutation sites did not deviate from Hardy-Weinberg equilibrium state.Correlation analysis showed that there was no significant correlation between different genotypes at different SNPs and lambing traits of Tibetan sheep (P > 0.05), but the average lambing number of CT genotype at g.142532 C>T was higher than CC and TT genotypes, the average lambing number of CC genotype at g.142751 T>C was higher than TT and TC genotypes, and the average lambing number of GA genotype at g.143189 G>A was higher than GG and AA genotypes, the average lambing number of CG genotype at 143570 C>G was higher than that of CC and GG genotypes, and the average lambing number of GG genotype at g.145233 A>G was higher than that of AA and AG genotypes, and these differences were not significant (P>0.05).8 SNPs in BMPRⅡ gene except for g.90192 T>C formed 14 haplotypes (H1-H14) in Tibetan sheep, and there was no significant correlation between haplotypes and lamb number (P > 0.05).【Conclusion】 BMPRⅡ gene g.142532 C>T, g.142751 T>C, g.143189 G>A, g.143570 C>G and g.145233 A>G might have some potential effects on the number of lambing in Tibetan sheep.
Genome-wide Association Study of Body Size Traits in Danzhou Chickens
JIANG Hongzheng, YANG Dezhi, MA Zhonghua, XUN Wenjuan, SHI Liguang, HOU Guanyu
2022, 49(2):  598-607.  doi:10.16431/j.cnki.1671-7236.2022.02.021
Abstract ( 181 )   PDF (5852KB) ( 33 )  
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【Objective】 This experiment was aimed to explore the effective SNP and functional genes related to body size traits in chickens, and provide effective theoretical support for Danzhou chickens.【Method】 Blood samples of 200 Danzhou chickens were collected and used to extract genomic DNA.Genome-wide SNP markers were obtained by using a depth of 10× whole genome resequencing, and analyzed the genotypes of individuals.Genome-wide association study (GWAS) was performed using a mixed-effects model and linear regression approach for body size traits (shank length, shank circumference, body slope length, breast width, pelvis width, breast depth, and fossil bone length) of 70-day-old Danzhou chickens by EMMAX.【Result】 The results showed that 12 and 8 SNPs were significantly related to the shank length and the shank circumference.SNPs associated with shank length traits were located on chromosomes 1, 2, 4 and 8.SNPs associated with shank circumference traits were located on chromosomes 2, 4, 8 and 13.The experiment predicted that the candidate genes associated with shank length were KCNA1, TPK1, EZH2, FSTL5 and AMY2A, and the candidate genes associated with shank circumference were TPK1, FSTL5, AMY2A, TGFBI, LECT2 and IL-9.Through KEGG pathway analysis and GO annotation, it was found that 8 genes were involved in biological processes such as potassium ion transmembrane transport, thiamine metabolism, cell proliferation, calcium binding, skeletal muscle satellite cell maintenance and skeletal muscle regeneration, cell receptor interaction, growth factor activity and so on.【Conclusion】 In this experiment, 20 SNPs associated with body size traits were found, and 8 candidate genes for the target traits were screened, which provided candidate molecular markers for Danzhou chickens breeding and new ideas for marker assisted selection of local.
Effect of bFGF on in vitro Development of Mouse Zygotes Treated with 3-nitropropionic Acid
TIAN Wei, FANG Yanya, LIU Haixing, LI Zhongshu
2022, 49(2):  608-614.  doi:10.16431/j.cnki.1671-7236.2022.02.022
Abstract ( 154 )   PDF (2420KB) ( 33 )  
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【Objective】 This experiment was to study the effect of adding basic fibroblast growth factor (bFGF) to the in vitro development medium of mouse fertilized eggs treated with 3-nitropropionic acid (3-NPA), in order to provide reference for improving the in vitro development quality of early embryos under oxidative stress.【Method】 0, 20, 50, 100 and 150 ng/mL bFGF were added to the in vitro culture medium of mouse zygotes, cultured for 24, 48 and 96 h, and the 2-cell rate, 4-cell rate and blastocyst rate were counted to screen the best bFGF treatment concentration.In vivo zygotes were produced by intraperitoneal injection of 12.5 mg/kg 3-NPA, and the same volume of normal saline was injected intraperitoneally as the control, the fertilized eggs were divided into 3-NPA and 3-NPA+bFGF groups, control group (C) and bFGF group.After blastocysts were obtained, the level of reactive oxygen species (ROS) in embryos was detected by DCFH-DA, the level of glutathione (GSH) was detected by CMF2HC, and the mitochondrial membrane potential intensity of early embryos was detected by JC-1.【Results】 There was no significant difference in 2-cell rate among 0, 20, 50, 100 and 150 ng/mL bFGF groups (P > 0.05), and the blastocyst rate in 100 ng/mL bFGF group was significantly higher than that of the other groups (P < 0.05), the 4-cell rate and blastocyst rate in 150 ng/mL bFGF group were significantly lower than those in the other groups (P < 0.05), so 100 ng/mL bFGF was used in subsequent experiments.The 4-cell rate in 3-NPA+bFGF group was significantly higher than that in 3-NPA group (P < 0.05), the blastocyst rate in bFGF group was significantly higher than that of the other groups (P < 0.05).The blastocyst rate in bFGF+3-NPA group was significantly higher than that in 3-NPA group (P < 0.05). Compared with control group, the level of ROS in 3-NPA group was increased significantly (P < 0.05), and the level of ROS in bFGF group was decreased significantly (P < 0.05). GSH and mitochondrial membrane potential were decreased significantly in 3-NPA group (P < 0.05), and were increased significantly in bFGF group (P < 0.05). The level of ROS in bFGF+3-NPA group was significantly lower than that in 3-NPA group (P < 0.05), and the levels of GSH and mitochondrial membrane potential were significantly higher than those in 3-NPA group (P < 0.05).【Conclusion】 The addition of 100 ng/mL bFGF to the in vitro culture medium could reduce the embryonic oxidative stress induced by 3-NPA and improve the function of embryonic mitochondria, so as to improve the in vitro development ability of mouse zygotes.
Effect of Adding Seminal Plasma to the Thawing Diluent on the Quality of Frozen-thawed Boar Sperm
WANG Yinan, KONG Lingmin, XU Haifeng, ZHANG Zhengwen, LI Chunyu, YIN Yi, JIN Yi, LYU Yanqiu
2022, 49(2):  615-623.  doi:10.16431/j.cnki.1671-7236.2022.02.023
Abstract ( 166 )   PDF (3269KB) ( 97 )  
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【Objective】 The purpose of this experiment was to explore the effects of adding heat shock protein A8 (HSPA8) before freezing and adding different concentrations of seminal plasma (SP) after thawing on frozen-thawed boar sperm.【Method】 The semen of Landrace boars was collected by hand holding method, 0.5 μg/mL HSPA8 was added to the boar semen cryopreserved agent for French straws, and then stored in liquid nitrogen for 3 weeks before thawing.After thawing, different concentrations of seminal plasma (0, 10%, 30% and 50%) were added again.The athletic ability, plasma membrane integrity, acrosome integrity, apoptosis, mitochondrial membrane potential, protamine deficiency and in vitro capacitation level of Landrace boar sperm after freezing and thawing were evaluated.【Result】 Compared with control group (no HSPA8 and sperm plasma), in 0.5 μg/mL HSPA8 treatment group (no sperm plasma), the sperm kinetic parameters VSL, VCL, VAP and STR were significantly increased (P < 0.05), and LIN and WOB were not significantly different (P > 0.05), the sperm quality parameters such as sperm motility, plasma membrane integrity and acrosome integrity were significantly increased (P < 0.05), the sperm apoptosis level and mitochondrial membrane potential were significantly reduced (P < 0.05), the sperm protamine deletion rate was significantly decreased (P < 0.05), the tyrosine phosphorylation level of sperm protein was significantly increased (P < 0.05).After that, adding different concentrations of seminal plasma treatment group to the thawing solution, compared with 0.5 μg/mL HSPA8 treatment group (no seminal plasma), when the amount of seminal plasma reached 50%, VSL, VCL, VAP, LIN, STR and WOB were significantly increased (P < 0.05), the sperm motility, plasma membrane integrity, acrosome integrity and mitochondrial membrane potential were significantly increased (P < 0.05), the sperm apoptosis level was significantly reduced (P < 0.05), the sperm protamine deletion rate was significantly decreased (P < 0.05), the tyrosine phosphorylation level of sperm protein was significantly increased (P < 0.05).【Conclusion】 In conclusion, the combination of adding 0.5 μg/mL HSPA8 to the freezing base solution and adding 50% seminal plasma to the thawing diluent could effectively improve the quality of frozen-thawed sperm, which would provide certain reference value for the cryopreservation and commercial production of boar semen.
Advance on the Role of microRNA in Mammalian Gametogenesis
HUANG Xiaogang, HAN Beibei, LI Ju, ZHANG Shouquan
2022, 49(2):  624-630.  doi:10.16431/j.cnki.1671-7236.2022.02.024
Abstract ( 180 )   PDF (788KB) ( 82 )  
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The gene expression regulation of gametogenesis in mammals includes stage-specific expression regulation of coding genes together with transcription and post-transcriptional regulation of non-coding genes.As a type of small non-coding RNA, miRNA can lead to mRNA degradation or protein translation inhibition by recognizing the binding site of the untranslated region of the target gene, thereby playing a regulatory role at the post-transcriptional level.In recent years, the role of miRNA in mammalian reproduction has been gradually revealed.More and more studies have shown that miRNA plays an important regulatory role in mammalian spermatogenesis, sperm maturation, oocyte maturation, follicular development, and early embryonic development.miRNA can indirectly or directly play a regulatory role in different stages of spermatogenesis by regulating the proliferation and apoptosis of Sertoli cells or the cell cycle progression of spermatogonia, spermatocytes and sperm cells.miRNA can also regulate the development and maturation of oocytes by regulating the proliferation, apoptosis, hormone synthesis and intercellular interaction of oocytes, cumulus cells and granulosa cells.This article mainly introduces the tissue- and stage-specific expression of miRNA during mammalian gametogenesis and their regulatory effects on target genes, in order to provide reference for further research on the regulatory mechanism of mammalian gametogenesis.
Analysis of Differentially Expressed Genes in Glucose-induced Senescence of Sheep Follicular Granulosa Cells Based on RNA-Seq Data
ZHANG Peiying, SONG Pengyan, ZHOU Ying, CHEN Xiaoyong, ZHOU Rongyan
2022, 49(2):  631-640.  doi:10.16431/j.cnki.1671-7236.2022.02.025
Abstract ( 158 )   PDF (2084KB) ( 106 )  
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【Objective】 This study was to investigate the effect of glucose on the senescence and gene expression of sheep follicular granulosa cells.【Method】 Primary isolated sheep follicular granulosa cells were cultured in vitro with 17.5 (H group) and 2 mmol/L (L group) glucose.Each group was treated for 72 h, and cellular senescence was detected by β-galactoside staining.Transcriptome sequencing was performed on the preadipocytes by RNA-Seq technology, and the differentially expressed genes (DEGs) were analyzed by GO function enrichment analysis and KEGG signal pathway enrichment analysis.The expression levels of ankyrin repeat domain-containing protein 1(ANKRD1), interleukin-8(IL-8), oxytocin(OXT) and NADPH oxidase 4(NOX4) genes were detected by Real-time quantitative PCR.【Result】 The percentage of β-galactoside-positive cells in group H was extremely significantly higher than that in group L (P < 0.01).RNA-Seq results showed that there were 401 DEGs between the two groups, including 153 up-regulated genes and 248 down-regulated genes, including 9 genes related to cell abnormalities induced by high glucose and 6 genes related to cell cycle.The GO function enrichment analysis showed that the DEGs were involved in biological processes such as cellular process, biological regulation, metabolic process, multicellular organismal process and locomotion.The concentration of cellular component mainly included extracellular region, membrane, synapse, organelle and supramolecular complex.The enrichment of molecular function was mainly in catalytic activity, binding, transporter activity, molecular function regulator and structural molecule activity.KEGG signal pathway enrichment analysis showed that the DEGs were mainly concentrated in AGE-RAGE signaling pathway in diabetic complications, TNF signaling pathway, PPAR signaling pathway.The Real-time quantitative results showed that compared with L group, the expression level of IL-8 gene was extremely significantly up-regulated (P < 0.01), the expression level of ANKRD1 gene was significantly up-regulated (P < 0.05), and the expression level of OXT gene was extremely significantly down-regulated (P < 0.01), NOX4 gene expression showed an upward trend, but the difference was not significant (P > 0.05).The result of Real-time quantitative PCR was basically consistent with that of transcriptome sequencing.【Conclusion】 17.5 mmol/L glucose induced senescenc and genes expression changes in sheep follicular granulosa cells.The results provided a basis for the functional and molecular mechanism of glucose induced senescence of granulosa cells.
Differential Expression Analysis of Plasma Exosomes microRNA Between Donor and Recipient Cattle Before Embryo Transfer
ZHAI Yaying, SHI Qiaoting, CHU Qiuxia, ZHU Xiaoting, HUA Liushuai, ZHANG Zijing, CHEN Fuying, QI Xinglei, WANG Eryao, LYU Shijie
2022, 49(2):  641-649.  doi:10.16431/j.cnki.1671-7236.2022.02.026
Abstract ( 173 )   PDF (1939KB) ( 38 )  
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【Objective】 This study was to explore the difference in the expression of plasma exosome miRNA between donor and recipient cattle before embryo transfer, and to detemine the role of plasma exosome miRNA in bovine pregnancy.【Method】 Xianan cattle aged 3-6 years and weighing 480-600 kg were used as the research object, 10 donor cattle were selected for simultaneous estrus, superovulation and artificial insemination, and 23 recipient cattle were treated for simultaneous estrus. On the 7th day after artificial insemination, the donor bovine uterus was washed to obtain blastocysts, 3 donor cattle with similar number of blastocysts and three recipient cattle with similar body weight and age to the donor cattle were selected to collect blood from jugular vein, and plasma exosomes were collected.After extracting miRNA from plasma exosomes, the expression level was analyzed.Target genes of differentially expressed miRNA were predicted.While the P value was calculated with DESeq algorithm in R package, the miRNA with P < 0.05 were screened, and the differentially expressed miRNA were analyzed by target gene prediction, GO function enrichment analysis and KEGG signaling pathway analysis.【Result】 The vesicles particle size of the 6 samples was about 135 nm, which was consistent with the diameter characteristics of exosomes.Nine miRNAs were significantly up regulated in recipient cattle compared with donor cattle (P < 0.05), and 13 miRNAs were significantly down regulated (P < 0.05).Among the 22 differentially expressed miRNAs, 15 miRNAs predicted 2 990 target genes without duplication.The results of GO function enrichment analysis and KEGG signal pathway analysis indicated that these target genes were mainly concentrated in the functional pathways related to biological adhesion, localization and cell junction, and significant accumulation of signal pathway was related to focal adhesion and adherens junction, suggested that plasma exosomal miRNA might be involved in the regulation of embryo implantation.【Conclusion】 These results could provide reference for screening and exploring the plasma exosomal miRNA affecting embryo implantation, and provide a basis for further elucidation of the role of plasma exosomal miRNA in the regulation of early pregnancy in cattle.
Preventive Veterinary Medicine
Construction of Recombinant Heat-resistant Newcastle Disease Virus Expressing Fiber2 Protein of Fowl Adenovirus Serotype 4 and Evaluation of Its Immune Effect
SHANG Yu, LI Lintao, LI Li, XU Yingying, FENG Helong, WANG Hongcai, ZHANG Rongrong, ZENG Zhe, WANG Honglin, LUO Qingping, SHAO Huabin, WEN Guoyuan
2022, 49(2):  650-659.  doi:10.16431/j.cnki.1671-7236.2022.02.027
Abstract ( 205 )   PDF (5129KB) ( 30 )  
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【Objective】 This study was aimed to develop a heat-resistant genetically engineered vaccine against Newcastle disease virus (NDV) and Fowl adenovirus (FAdV).【Method】 Using reverse genetic manipulation techniques, the HN gene of NDV heat-resistant strain was substituted into the LaSota vaccine strain and then the Fiber2 gene of FAdV serotype 4 (FAdV-4) was inserted into its genome to generate a recombinant heat-resistant NDV plasmid pTS-HN-Fiber2, expressing Fiber2 protein.Recombinant NDV rTS-HN-Fiber2 was rescued by virus rescue technology, and its biological characteristics, immunogenicity and challenge protection as a vaccine candidate was determined.【Result】 The mean death time of rTS-HN-Fiber2 was > 168 h and the intracerebral pathogenicity index was 0, which belonged to the category of lentogenic strain.The results of growth curve on BHK-21 cells showed that rTS-HN-Fiber2 had similar growth curve with LaSota strain, but the final growth titer was slightly lower than LaSota strain.The titer of rTS-HN-Fiber2 decreased by about 103 TCID50/mL after treatment at 56 ℃ for 15 min, while NDV LaSota strain showed almost no infection after treatment at 56 ℃ for 5 min.Indirect immunofluorescence assay result showed that rTS-HN-Fiber2 could express Fiber2 protein efficiently.The results of immunization and challenge test showed that rTS-HN-Fiber2 could produce NDV antibody, significantly improve the survival rate of chicks exposed to FAdV-4, reduce the tissue lesions caused by FAdV-4 virulence and reduce the virus load in the tissues.【Conclusion】 The recombinant heat-resistant NDV expressing FAdV-4 Fiber2 protein was successfully constructed.The recombinant virus maintained the lentogenic strain characteristics of the LaSota strain, but the thermal stability was significantly improved.Chickens immunized with recombinant NDV could produce protection against NDV and FAdV-4.The recombinant NDV could be used as a candidate virus strain for the development of dual genetic engineering vaccine against FAdV-4 and NDV.
Isolation, Identification and Pathogenicity Analysis of Porcine Rotavirus Group A Strain SCJY-13
CHEN Xiaofei, ZHANG Bin, ZHANG Chunhong, ZHANG Jianfeng, LIAO Ming
2022, 49(2):  660-668.  doi:10.16431/j.cnki.1671-7236.2022.02.028
Abstract ( 164 )   PDF (12561KB) ( 49 )  
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【Objective】 This study was aimed to isolate and identify porcine Rotavirus group A (RVA) from feces of piglets suffered from diarrhea, and understand the pathogenicity of the isolate strain.【Method】 RVA was isolated and identified from piglet diarrhea feces by MA-104 cells, and orally infected healthy newborn piglets.The clinical symptoms were observed, the detoxification was detected by Real-time quantitative PCR, the pathological changes were observed by HE staining, and the distribution of virus was tested by immunohistochemistry (IHC).【Result】 A strain of G9P[23] RVA, named RVA/Pig-tc/CHN/SCJY-13/2017/G9P[23] (SCJY-13 strain for short), which could cause obvious cytopathy of MA-104 cells, was isolated, and the virus titer was 105.5 TCID50/100 μL.Diarrhea occurred at 11 h post infection and lasted until 165 h post infection.The incidence rate was 100% (7/7), and the mortality rate was 28.57% (2/7).Viral nucleic acid could be detected from piglet anal swabs at 8 h post infection until 192 h post infection, and the peak appeared at 24 h post infection.At the same time, the viral load in each segment of small intestine reached the highest 54 h post infection, and the viral load in ileum was the highest, which was significantly higher than that in duodenum, jejunum and feces (P < 0.05).HE staining and IHC detection showed that SCJY-13 accumulated in villi and crypts of small intestine of infected piglets, especially in ileum.SCJY-13 strain infection caused a large number of lymphocyte infiltration in duodenum, jejunum and ileum villus lamina propria, mucosal epithelial cells and vacuolar degeneration at the tip of intestinal villus, increase of columnar cells, villus breaking and falling off, especially in ileum.【Conclusion】 The SCJY-13 strain could cause 100% morbidity of neonatal piglets and shed virus for a long time, and the virus was mainly distributed in the ileum of small intestine.These results provided a valuable reference for the pathogenicity study of procine RVA.
Expression and Immunogenicity Analysis of Classical Swine Fever Virus E2-GM-CSF Fusion Protein in HEK293T Cells
ZHANG Yanmin, ZHOU Yanan, CAO Lei, TIAN Yuan, LIU Xuping, TAN Wensong, ZHAO Liang
2022, 49(2):  669-676.  doi:10.16431/j.cnki.1671-7236.2022.02.029
Abstract ( 186 )   PDF (1338KB) ( 35 )  
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【Objective】 A HEK293T cell pool expressing E2-GM-CSF fusion protein was established to evaluate the immunogenicity of E2-GM-CSF fusion protein, in order to provide a new option for the development of Classical swine fever virus (CSFV) subunit vaccine.【Method】 Firstly, E2-GM-CSF fusion gene was amplified by PCR and cloned into the pCDH lentivector.Then, the recombinant plasmid pCDH-E2-GM-CSF was constructed and packaged into lentiviral particles.Secondly, recombinant HEK293T cell pools expressing E2-GM-CSF fusion protein were obtained by the transduction of the lentiviral particles and the selection of puromycin.The immunogenicity of the purified E2-GM-CSF fusion protein was evaluated in mice.【Result】 The pCDH-E2-GM-CSF plasmid was identified by double-enzyme digestion, and the vector fragments and E2-GM-CSF gene fragments with sizes of 8 172 and 1 521 bp were obtained respectively, indicating that E2-GM-CSF gene was successfully cloned into pCDH vector.A 1 686 bp band was obtained by PCR amplification of cells genomic DNA, which showed that E2-GM-CSF gene was integrated into the genomic DNA of HEK293T cells.Western blotting analysis obtained a band of about 70 ku, proving the successful expression of E2-GM-CSF fusion protein.The SDS-PAGE verification showed that the purified E2-GM-CSF fusion protein was a single band about 70 ku with high purity.The immunization trail showed the good immunogenicity of E2-GM-CSF fusion protein produced by HEK293T cells.The E2 specific antibody of 1∶300 was detected in mouse serum after 14 days of immunization, and the titer of antibody reached 1∶900 after 21 days of immunization.At the 28th day post immunization, the E2 specific antibody titer reached a maximum of 1∶8 100, which was much higher than 1∶1 800 of E2 protein.【Conclusion】 In this study, a HEK293T cell pool expressing E2-GM-CSF fusion protein was established, and the immunogenicity of E2-GM-CSF fusion protein was preliminarily confirmed, providing a novel candidate subunit vaccine against CSFV.Therefore, the development of this vaccine could also provide a reference for the rapid expression of other subunit vaccines in mammalian cells.
Preparation of Cathepsin L1 Monoclonal Antibody Against Fasclala gigantica and Establishment of Double Antibody Sandwich ELISA
WANG Leming, WANG Yurui, ZENG Zixuan, RAO Guoshun, WU Zhengjiao, JIN Weikun, WANG Dongying
2022, 49(2):  677-686.  doi:10.16431/j.cnki.1671-7236.2022.02.030
Abstract ( 229 )   PDF (1422KB) ( 66 )  
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【Objective】 This study was intend to obtain cathepsin L1(rFgCat L1) specific monoclonal antibody and construct the double antibody sandwich ELISA.【Method】 Five BALB/c mice were immunized with 1 mg/mL rFgCat L1 protein for four times.Mouse splenocytes were isolated and fused with SP2/0 cells to construct hybridoma cells.Strong positive hybridoma cell lines were screened, 1×106 cells were injected intraperitoneally per mouse to prepare monoclonal antibodies.Antibody titer and antigenic epitope were detected using ELISA method, antibody subtype and specificity were identified using Western blotting method.The double antibody sandwich ELISA was constructed by combining the anti-rFgCat L1 polyclonal antibody, and its sensitivity and specificity were tested.The positive and negative critical value was screened by 20 negative sera with positive control, and the constructed double antibody sandwich ELISA was verified by 47 goat positive sera and 47 dairy cow positive sera.【Result】 After immunization, the antibody titers in serum of 4 mice were all more than 104.After isolated mouse with the highest immune response spleen cells were fused with SP2/0 cells total of 8 of them were positive cell lines were obtained after selective culture.5D5 and 7G6 were identified as strong positive strains with stable antibody secretion.After multiple subcloning screens and subcultures, the antibodies secreted in the cell supernatant were stable, with titers of 29 and 210 respectively, with ascites titers of 107 and 108.Western blotting and antibody subtype identification kits identified that the two antibodies were IgG1 type and the light chain was kappa type, both of which could specifically bind FgESP.According to the same antigen site was recognized by the two kinds of antibodies, the antigen titer of the two monoclonal antibodies were comparied, 7G6 was used as the coating antibody, and anti-rFgCat L1 was used as the enzyme-labeled secondary antibody.The optimized condition of method was that 7G6 was coated at a concentration of 2 μg/mL, the dilution concentration of anti-rFgCat L1 polyclonal antibody was 25 μg/mL, the dilution of Don-HRP-conjugated was 1∶4 000, 5% skimmed milk powder was selected as the blocking solution and the color development time was 25 min.The method was proved that could recognize the lowest antigen concentration of 0.625 μg/mL, also could specifically recognize antigen of Fasciola fasciatus.The constructed sandwich ELISA method was used for antigen detection of 47 dairy cow positive serum and 47 goat positive serum infective samples kept in the laboratory and the positive antigen rate were 72.3% and 78.7%, respectively.【Conclusion】 Anti-rFgCat L1 monoclonal antibody was successfully prepared and the double-sheet sandwich ELISA method for fascioliasis was constructed, which provided a good theoretical basis and material basis for the development of low-cost and rapid diagnostic kits.
Basic Veterinary Medicine
Study on Joint Toxicity of Enrofloxacin, Quinocetone, Oxytetracycline and Polymyxin B Sulfate to Cells
FU Yuhan, HOU Lirui, ZHAO Chong, HU Hongbo, YIN Shutao
2022, 49(2):  687-699.  doi:10.16431/j.cnki.1671-7236.2022.02.031
Abstract ( 253 )   PDF (4424KB) ( 37 )  
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【Objective】 The study was aimed to investigate the single and combined toxic effects of enrofloxacin (ENR), quinolone (QCT), oxytetracycline (OTC) and polymyxins B sulfate (PMB) on cells.【Method】 L02, AML12, Marc145, HEK293T, TM3 and SK-N-SH cells were used as models.The inhibition rates of four drugs on six kinds of cells at different concentrations were obtained by crystal violet staining and the concentration-effect equations were fitted.ECF(the drug concentration at F% inhibition rate (F=10, 20, 25, 33, 50)) was calculated.Binary, ternary and quaternary medicines were mixed respectively at the toxicity ratio of EC50∶EC50, EC33∶EC33∶EC33, EC25∶EC25∶EC25∶EC25 and then diluted with a dilution ratio of 1/2.The inhibition rates were calculated and the actual action curves were fitted.Concentration addition model (CA) and independent action model (IA) were used to evaluate the combined effects of different drugs.【Result】 There was a dose-effect relationship between the four drugs on the growth inhibition of six kinds of cells.QCT showed the strongest toxicity while PMB showed the weakest toxicity.Binary combination showed high probability of synergism, especially the combination with OTC, and OTC+QCT showed significant synergistic inhibition in the six kinds of cells.The joint effects were prone to addition on TM3 while had a greater possibility of synergy on liver and kidney cells, and the same combination might have different effects on different cells.In ternary and quaternary combinations, the probability of additive effect increased, and the change of the combined effect was more complex, which was easy to appear multi-segment effect with the change of concentration.【Conclusion】 Common veterinary drugs had certain toxicity to liver, kidney, nerve and germ cells, and the combined toxic effects of these drugs were not simply additive, which were affected by components, concentration and so on, so incompatibility should be paid attention in the application.
Isolation, Identification and Drug Resistance Analysis of Klebsiella pneumoniae from Minks
CHEN Qiang, CHENG Yuening, FENG Qiuju, GUO Li, ZHANG Shuqin, TAN Bin, YI Li, ZHAO Quan, CHENG Shipeng, SUN Na
2022, 49(2):  700-708.  doi:10.16431/j.cnki.1671-7236.2022.02.032
Abstract ( 224 )   PDF (1663KB) ( 45 )  
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【Objective】 Klebsiella pneumoniae is a zoonotic opportunistic pathogen, and also one of the common pathogenic bacteria causing mink pneumonia.In order to guide rational drug use and provide the basis for treatment to 6 dead minks suffering from pneumonia provided by mink farms in Jilin province, the bacterial isolation and identification, drug resistance spectrum and drug resistance gene analysis were carried out.【Method】 Strains were isolated from samples by isolation and purification method, and identified by PCR method, and ST typing was performed by multilocus sequence typing technique(MLST) method.The pathogenicity of the strain was learned by infecting mice.Serotype and the virulence gene was detected by PCR.The susceptibility of the strains to 18 drugs was detected by agar dilution method, and the carrying status of drug-resistant genes was detected by PCR.【Result】 The results showed that 6 isolates were identified as Klebsiella pneumoniae by PCR.MLST analysis results showed that 6 strains had 6 ST types, namely ST2594, ST1782, ST2844, ST2330, ST86 and ST661, respectively.Pathogenicity analysis results showed that all 6 strains could cause the death of mice, and a total of 6 virulence genes were detected in the isolates.No more virulent serotypes were detected.The results of drug sensitivity test showed that 6 strains of Klebsiella pneumoniae were more sensitive to ceftazidime, ceftriaxone, imipenem, meropenemand amikacin, and more resistant to streptomycin, gentamicin, kanamycin, penicillin, ampicillin, ciprofloxacin, enrofloxacin, levofloxacin, doxycycline and florfenicol.There were 18 resistance genes detected in 6 strains, including blaSHV, blaTEM-1, blaCTX-M-1G, aadA1, aac(3')-Ⅳ, aac(3')-Ⅱc, aph(4')-Ⅰa, aph(3')-Ⅶ, aph(3')-Ⅳ, aph(2')-Ⅰb, rmtB, qnrB, qnrD, qnrS, qepA, oqxAB, floR and mcr-1.【Conclusion】 6 isolates of Klebsiella pneumoniae had different phylogenetic evolutionand strong pathogenicity and drug resistance, they brought difficulties to clinical drug treatment.
Effects of Honeysuckle, Forsythia and Their Drug Pair on Resistance Genes and Virulence Genes of Streptococcus equi subsp. equi
MAI Zhanhai, LU Yabin, LI Jianlong, ZHAO Lu, SUN Danlan, TONG Panpan, KUANG Ling
2022, 49(2):  709-717.  doi:10.16431/j.cnki.1671-7236.2022.02.033
Abstract ( 168 )   PDF (2523KB) ( 28 )  
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【Objective】 This study was to investigate the effects of honeysuckle, forsythia and their drug pair (honeysuckle-forsythia 1∶1) on drug resistance genes and virulence genes of Streptococcus equi subsp. equi (SEE) carrying fneB virulence gene in Northern Xinjiang.【Method】 The water extract of 1 g/mL honeysuckle, forsythia and honeysuckle, forsythia drug pair 1∶1 (honeysuckle-forsythia 1∶1) were tested by traditional Chinese medicine ratio concentration gradient test.The concentration gradient test of traditional Chinese medicine was carried out, and the three strains were co-cultured with L1 strain carrying fneB virulence gene, D1 strain carrying lytA+fneB+ply virulence genes and Y1 strain carrying qnrA+blaTEM+fneB genes.The effects of traditional Chinese medicine on drug resistance genes blaTEM, qnrA and virulence genes ply, fneB of SEE strains were detected.192 SPF Kunming mice were divided into 16 groups: Control group (normal saline), honeysuckle group, forsythia group, honeysuckle-forsythia 1∶1 group, negative control group (Y1, L1 and D1 strain groups) and three strains were co-cultured with honeysuckle, forsythia and honeysuckle-forsythia 1∶1 respectively.The drugs or bactering fluid in each group were injected intraperitoneally with 0.5 mL per mouse for antibacterial test in vivo, and the effects of drugs on pathogenicity and fneB virulence gene in mice were detected.【Result】 The optimal concentration of Chinese herbal medicine was as follows∶Water extract of Chinese herbal medicine∶THB medium∶bacteria solution (D600 nm value was 0.6) was 1 000 μL∶500 μL∶20 μL.The drug resistance gene and virulence gene were not detected in the three SEE strains co-cultured with the aqueous extract of traditional Chinese medicine, and their morphological structure did not change.The results of mouse pathogenicity test showed that the survival rates of negative control group were 16.7%, 8.3% and 0, respectively.The survival rate of mice in the co-culture of L1 strain+forsythia group and L1 strain+honeysuckle group were 83.3% and 75.0%, respectively.The survival rate of mice in the co-culture group of honeysuckle-forsythia 1∶1 and 3 SEE strains were 41.7%, 16.7% and 50.0%, respectively.The results of pathological anatomy of mice showed that the livers of other groups were normal except that the livers of mice inoculated with the original SEE strain was swollen and congestion, and the edge was blunt and round.The results of fneB virulence gene detection showed that Y1+honeysuckle, Y1+forsythia, Y1+honeysuckle-forsythia 1∶1, L1+honeysuckle, L1+honeysuckle-forsythia 1∶1, D1+honeysuckle, D1+forsythia and D1+honeysuckle-forsythia groups carried fneB virulence gene, but not in L1+forsythia group, which indicated that the SEE strains in mice had the ability to regain fneB virulence gene again, and the strain had anti-virus rejuvenation, and its mechanism needed to be further studied.【Conclusion】 honeysuckle, forsythia and their drug pair could weak the virulence gene and eliminate the drug resistance gene of SEE strain, which had guiding significance for the prevention and treatment of horse adenosis disease, and provided theoretical support for reducing and replacing resistance.
Preparation of Oregano Oil Macleaya cordata Oral Solution and Its Antibacterial Activity in vitro
LI Weihao, SUN Yuanyuan, LIU Juxiang
2022, 49(2):  718-730.  doi:10.16431/j.cnki.1671-7236.2022.02.034
Abstract ( 293 )   PDF (2529KB) ( 34 )  
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【Objective】 This study was aimed to prepare oregano oil Macleaya cordata oral solution, determine its antibacterial activity in vitro and provide theoretical reference for clinical use of new veterinary drugs.【Method】 The formulae were optimized by pre-test and Box-Behnken response surface method.The main components of oral solutiom were determined by high performance liquid chromatography (HPLC).The inhibition zone diameters of oral solutiona against Escherichia coli, Salmonella, Staphylococcus aureus and Streptococcus faecalis were determined by disk diffusion method.The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of oral solution, 5% oregano oil solution and 1% Macleaya cordata solution against 4 kinds of bacteria were determined by tube double dilution method.The combined susceptibility test in vitro of 5% oregano oil solution and 1% Macleaya cordata solution was carried out with checkerboard microdilution test.【Result】 The optimal formula of oregano oil Macleaya cordata oral solution was 5% oregano oil, 1% Macleaya cordata, 25% solubilizer RH40, 0.02% antioxidant BHT and water.The concentration of carvacrol and sanguinarine was 42.59 and 6.51 mg/mL in oral solution, respectively.The inhibition zone diameters of oral solution to 4 bacteria were 16.9, 16.4, 23.7 and 17.0 mm, MIC were 3.125, 3.125, 1.5625 and 1.5625 μL/mL, and MBC were 12.5, 6.25, 3.125 and 3.125 μL/mL, respectively; The MIC of 5% oregano oil solution to 4 bacteria were 25, 12.5, 6.25 and 100 μL/mL, and MBC were 100, 50, 25 and > 200 μL/mL, respectively.The MIC of 1% Macleaya cordata solution to 4 bacteria were 6.25, 12.5, 3.125 and 6.25 μL/mL, and MBC were 50, 25, 6.25 and 25 μL/mL, respectively.The combined susceptibility test showed that the two combined components had additive effect on Escherichia coli and Salmonella, irrelevant effect on Staphylococcus aureus, and synergistic effect on Streptococcus faecalis.【Conclusion】 Oregano oil Macleaya cordata oral solution was prepared in this study, it had good inhibitory effects on Escherichia coli, Salmonella, Staphylococcus aureus and Streptococcus faecalis.
Effect of Polysaccharide from Rhodomyrtus tomentosa Fruit on Immunological Function in Immunosuppressed Mice
YIN Huihui, TONG Yanmei, ZENG Xueyan, LU Guangqiang, ZHAO Wu, JIANG Yuanming, LIU Wei
2022, 49(2):  731-737.  doi:10.16431/j.cnki.1671-7236.2022.02.035
Abstract ( 262 )   PDF (802KB) ( 27 )  
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【Objective】 This study was aimed to investigate the effect of Rhodomyrtus tomentosa fruit polysaccharide on immunological function in immunosuppressed mice.【Method】 Cyclophosphamide was injected intraperitoneally with 80 μg/g BW, once a day, for 3 consecutive days, and mice immunosuppressive model was established.The successfully modeled mice were divided into 5 groups randomly (16 in each group): model group, astragalus polysaccharide group and Rhodomyrtus tomentosa fruit polysaccharide low, medium and high dose group.Another 16 healthy mice were set as normal group.Each mouse in astragalus polysaccharide group was intraperitoneally injected with astragalus polysaccharide suspension at a dose of 200 μg/g BW, and in Rhodomyrtus tomentosa fruit polysaccharide low, medium, and high-dose groups was treated with 50, 100 and 200 μg/g BW Rhodomyrtus tomentosa fruit polysaccharide suspension, respectively.The mice in normal group and model group were treated with normal saline of equal volume.This injection was administered once a day for 7 days.After the test, thymus index, spleen index, the content of IL-1β, IL-2, IL-6, IFN-γ, LZM and POD activity in serum were determined.【Result】 The thymus index and spleen index were increased by different doses of Rhodomyrtus tomentosa fruit polysaccharide, and the differences between the medium dose group and model group were extremely significant (P < 0.01).The contents of IL-6 and IL-1β in different doses of Rhodomyrtus tomentosa fruit polysaccharide group were extremely significantly higher than those in model group (P < 0.01).Compared with model group, the IFN-γ and IL-2 levels in low and medium dose groups increased, but the difference was not significant (P > 0.05).The contents of IFN-γ and IL-2 in high-dose group were extremely significantly higher than those in the model group (P < 0.01).The POD activity and LZM content of mice in different doses of Rhodomyrtus tomentosa fruit polysaccharide groups were extremely significantly or significantly higher than those in the model group (P < 0.01;P < 0.05).【Conclusion】The medium dose of Rhodomyrtus tomentosa fruit polysaccharide (100 μg/g BW) had the best effect on the recovery of immune function in immunosuppressive mice.
Application Prospect of Adiponectin and Its Receptor Agonists in Avian Fatty Liver Disease
CUI Chengyu, MA Ben, ZHAO Jiahui, ZHAO Zijuan, CHEN Yu, CAO Zhongzan, LUAN Xinhong
2022, 49(2):  738-745.  doi:10.16431/j.cnki.1671-7236.2022.02.036
Abstract ( 178 )   PDF (773KB) ( 81 )  
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Adiponectin is a hormone that can participate in the regulation of glucose and lipid metabolism, energy regulation, immune response, resistance to inflammation, oxidative stress and apoptosis.Avian fatty liver disease is lipid metabolism disorder, hepatocyte steatosis and inflammatory reaction caused by abnormal lipid metabolic pathways such as fatty acid synthesis and esterification, fatty acid transport, fatty acid oxidation, lipolysis and utilization in avian liver.This paper introduces adiponectin and its molecular structure, adiponectin receptor and its involved signal pathways, and focuses on the regulatory role and mechanism of adiponectin on liver lipid metabolism, inflammation, oxidative stress, hepatocyte apoptosis and autophagy, as well as the physiological role of adiponectin receptor agonists.At the same time, combined with the occurrence and development mechanism of avian fatty liver disease, the application prospect of adiponectin and its receptor agonists was prospected.This article provides a new idea for the prevention and treatment of fatty liver disease in poultry and even other animals.
Study on the Antibacterial and Anti-PRRSV Activities of Four Heat Clearing and Detoxifying Compound Chinese Herbal Medicine in vitro
SUN Lu, ZHANG Jing, YIN Miao, CHENG Yaodie, DAI Kun, WU Qian, ZHAO Hong, CHEN Xiwen
2022, 49(2):  746-754.  doi:10.16431/j.cnki.1671-7236.2022.02.037
Abstract ( 318 )   PDF (1012KB) ( 52 )  
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【Objective】 The purpose of this study was to explore the effects of 4 heat clearing and detoxifying compound Chinese herbal medicines, Xiexin decoction, Sanhuang Huzhang decoction, Huanglian Jiedu decoction and Qingwen Baidu powder on inhibiting Escherichia coli and Staphylococcus aureus combined with anti Porcine reproductive and respiratory syndrome virus (PRRSV) in vitro, in order to provide reference to clinicuse.【Method】 Active ingredients of 4 kinds of compoud Chinese herbal medicines were extracted by the conventional decoction method.Double dilution method was used to determine the in vitro antibacterial activities of 4 kinds of Chinese herbal medicines and their compound against Escherichia coli standard strain ATCC 259222 and Staphylococcus aureus standard strain ATCC 25923.Based on the study of the maximum safe concentration of Chinese herbal medicine on Marc-145 cells, the inhibitory effect of compound traditional Chinese medicine on PRRSV was determined by Real-time quantitative PCR.【Result】 Xiexin decoction had the best antibacterial activity against Escherichia coli in vitro, its minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were both 7.81 mg/mL, followed by Sanhuang Huzhang decoction and Huanglian Jiedu decoction, which MIC and MBC were 31.25-125 mg/mL.Qingwen Baidu powder had poor inhibitory effect on Escherichia coli, the MIC and MBC were more than 250 mg/mL, while Staphylococcus aureus was very sensitive to Xiexin decoction, Huanglian Jiedu decoction and Sanhuang Huzhang decoction.The MIC and MBC were 0.24-0.98 mg/mL.In the experiment of anti PRRSV effect in vitro, the maximum safe concentrations of Xiexin decoction, Sanhuang Huzhang decoction, Huanglian Jiedu decoction and Qingwen Baidu powder on Marc-145 cells were 0.49, 0.49, 3.90 and 1.95 mg/mL, respectively.4 compound Chinese herbal medicines had good inhibitory and direct inactivation effects on PRRSV.Huanglian Jiedu decoction and Qingwen Baidu powder had blocking effects on PRRSV at 0.98 mg/mL, while Xiexin decoction and Sanhuang Huzhang decoction had blocking effects on PRRSV at 0.24 and 0.12 mg/mL, respectively.【Conclusion】 It was suggested that among 4 compound Chinese herbal medicines, Xiexin decoction had the best antibacterial and anti PRRSV effects in vitro, followed by Sanhuang Huzhang decoction, Huanglian Jiedu decoction and Qingwen Baidu powder.4 heat clearing and detoxifying compounds had certain antibacterial and antiviral activities, which could provide reference basis for clinical application.
Research Progress on the Interaction Between Small Molecules of Veterinary Drugs and Biometric Elements
WU Shuangmin, LI Long, HOU Ren, CHEN Yushuang, PENG Dapeng
2022, 49(2):  755-764.  doi:10.16431/j.cnki.1671-7236.2022.02.038
Abstract ( 130 )   PDF (1046KB) ( 19 )  
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At present, due to unreasonable or illegal use of veterinary drugs, their prototypes or metabolites remain in animal derived food and water, which will endanger human health and damage the ecological environment.Therefore, the establishment of rapid detection methods of veterinary drug residues is particularly important.Receptors, antibodies, aptamers and other biometric elements have molecular recognition ability.According to its characteristics, different detection methods have been developed such as immunoassay, receptor detection and biosensor method, which are widely used in biomedical research.Because molecular recognition elements are the main body of analysis and affect the selectivity of analysis, the mechanism of interaction between different recognition elements and veterinary drugs has been paid more and more attention.With the development of computer technology, homologous modeling and molecular docking are widely used in residue detection, mainly used in the study of the interactions between drugs and proteins, antigens and antibodies, receptors and ligands and other biomolecules.This paper focused on the interaction mechanism between three recognition elements of single chain variable fragment (ScFv), receptor and aptamer and veterinary drug small molecules.It mainly analyzed the hydrogen bonds, hydrophobicity and key amino acids or bases formed at the binding site of biometric elements and veterinary drugs.The mechanism and law of drug and recognition element were explored at molecular level, so as to find out the key factors affecting the combination of drug and recognition element, and three recognition elements were summarized, in order to provide theoretical support for the comprehensive understanding of recognition mechanism and in vitro evolution, and prepare ScFv, receptors and aptamers with wider affinity, and lay a foundation for subsequent drug residue detection technology and drug development.
Research Progress on Pathogenic Mechanism and Control of Aflatoxin B1
QIAO Chunyu, LIU Jiahe, ZHANG Boxi, HE Yuxi, ZHENG Yuwei, LYU Hongming
2022, 49(2):  765-775.  doi:10.16431/j.cnki.1671-7236.2022.02.039
Abstract ( 221 )   PDF (1462KB) ( 85 )  
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Aflatoxins (AFs) are a kind of poisonous substances from mold, among which aflatoxins B1(AFB1) is the most toxic and harmful.AFB1 is a bifuranocyclic toxin with strong carcinogenicity and intense toxicity, which is widely distributed in moldy corn, peanut, rice and soybean and other food and oil crops, human and animal poisoning caused by AFB1 has resulted in serious harm to food safety, livestock breeding and other industries.AFB1 has been shown to cause oxidative stress, apoptosis, cytotoxicity, gene mutation and immune system damage.The immunotoxic effects of AFB1 on inhibiting immune system and destroying immune tolerance were discussed.AFB1 promotes the production of reactive oxygen species and activates the Nrf2-ARE pathway to induce oxidative stress and inflammatory response, thus causing organ damage.AFB1 regulates exogenous apoptosis through cell death-related receptors and induces endogenous apoptosis through a series of apoptosis-related proteins.AFB1 can also trigger inflammatory response through the classical pyroapoptotic pathway of liver cells, which can lead to abnormal cell death.The mechanism and research progress of AFB1 genotoxicity and its detoxification measures were reviewed.This review is expected to provide a reference for in-depth research on the pathogenic mechanism of AFB1 and the development of related control drugs, and afford an effective basis for the selection of detoxification measures for moldy grain and oil crops.
Clinical Veterinary Medicine
Prevention and Treatment Effect of Escherichia coli Phage BP16 on Chicken Colibacillosis
LI Min, ZHAO Zunfu, YANG Tingting, ZHANG Huanrong
2022, 49(2):  776-782.  doi:10.16431/j.cnki.1671-7236.2022.02.040
Abstract ( 231 )   PDF (749KB) ( 31 )  
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【Objective】 The study was aimed to investigate the effect of Escherichia coli phage BP16 on the prevention and treatment of chicken colibacillosis caused by O2 serotype avian pathogenic Escherichia coli (APEC) and the optimal therapeutic dose of phage BP16.【Method】 The fresh culture of O2 serotype APEC was diluted 5×1010, 5×109, 5×108, 5×107 and 5×106 CFU/mL 5 concentration gradients to determine the 50% lethal dose (LD50) of APEC and determine its infection dose.13 kinds of commonly used drug disks with antibacterial or bactericidal effects on Gram-negative bacteria were selected for drug sensitivity test, and the positive control drugs were selected.The sterility and safety of phage lysate were determined by sterility test and safety test for subsequent tests.80 chicks were randomly divided into 5 experimental groups and 3 control groups.The experimental groups was intraperitoneally injected with Escherichia coli phage BP16 at different time before and after challenge, and the three control groups were intraperitoneally injected with florfenicol, Escherichia coli bacterial solution and normal saline respectively.The other conditions were the same.They were kept for 7 d, and the mortality of chicks was recorded, to evaluate the prevention and treatment effect of Escherichia coli phage BP16 on experimental chickens artificially infected with Escherichia coli.【Result】 The LD50 of O2 serotype Escherichia coli was 1.5×108 CFU/mL, florfenicol was selected as the positive control drug.The phage lysate was sterile and the phage suspension was safe for chicks and could be used in subsequent control tests.The use of phages in chickens 6 h before Escherichia coli infection could effectively prevent colibacillosis.The use of phage from the same time of infection to 6 h after infection could effectively treat colibacillosis, and the phage treatment effect was better than florfenicol.When the challenge dose of Escherichia coli was 1.5×108 CFU, the phage treatment dose was 1.5×109 PFU had the best therapeutic effect.【Conclusion】 Escherichia coli phage BP16 could prevent and treat colibacillosis.This study provided a scientific basis for the further application of phage to prevent and treat colibacillosis and the development of Escherichia coli phage preparation.
Isolation and Evaluation of Sterilization Effect of an Avian Escherichia coli Phage
LI Jinmin, GAO Xuna, SANG Ruixin, GONG Benzhi, XU Haiyan, GU Wei, HAO Muqiang, LAN Jianghua, WANG Hong
2022, 49(2):  783-190.  doi:10.16431/j.cnki.1671-7236.2022.02.041
Abstract ( 175 )   PDF (1905KB) ( 50 )  
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【Objective】 The study was aimed to explore a new way to control environmental pathogenic Escherichia coli (E.coli).【Method】 The isolation and corresponding index evaluation of Escherichia coli phages were carried out in this study.The lytic phages of avian pathogenic E.coli were isolated from breeding environment by double-layer plate method.The phage was comprehensively evaluated through electron microscopy and enzyme digestion identification, stability, optimal multiplicity of infection, one-step growth curve and its bactericidal effect in simulated environment.【Result】 The isolated phage had a regular polyhedron head and a slender tail structure, with a head diameter of about 98 nm and a tail length of about 123 nm.Combined with the results of enzyme digestion, it was preliminarily identified as a double-stranded DNA phage of Cauda muscularis.Its temperature tolerance range was 37-50 ℃, pH tolerance range was 3.0-11.0.When the multiplicity of infection was 0.00001, the titer of progeny phage was the highest.One-step growth curve showed that the incubation period of the phage was about 20-40 min, the lysis time was about 80-100 min, and the lysis amount was 4 133 PFU/cell.It could be seen from the bactericidal effect of the phage on the host E.coli in the simulated environment that the bactericidal rate of phage ФECP2-1 with the concentration of 1×104-1×106 PFU/mL against the target E.coli in the liquid for 1-6 h was above 99.9%.The phage ФECP2-1 with the concentration of 2×104-2×106 PFU/g could kill more than 99% of the target E.coli in chicken manure for 5-10 h.The phage ФECP2-1 had a slightly lower bactericidal effect on the target E.coli in chicken manure than on the target E.coli in liquid.【Conclusion】 ФECP2-1 conformed to the characteristics of phage disinfectants, and was a phage with good application prospect.It could be used as a biological disinfectant for the prevention and control of avian E.coli in aquaculture environment.
Research Progress on Therapeutic Mechanism and Application of Canine Hematopoietic Stem Cell Transplantation
TIAN Yangqing, WANG Yayuan, ANG Yanfen, YAN Han, LIU Xin, YAN Yulin
2022, 49(2):  791-799.  doi:10.16431/j.cnki.1671-7236.2022.02.042
Abstract ( 367 )   PDF (1018KB) ( 44 )  
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Hematopoietic stem cells (HSCs) are located at the top of the hematopoietic system, they are the only cells that have pluripotency and self-renewal ability in the hematopoietic system.They can differentiate into blood cells with various functions to maintain the establishment and dynamic balance of the blood system, which were the most thoroughly studied adult stem cells with the most mature clinical application.These important characteristics of hematopoietic stem cells have made great progress in the study of disease treatment mechanisms and clinical applications based on hematopoietic stem cells.Regenerative medicine treatment based on hematopoietic stem cells is currently the first choice for the treatment of hematological malignancies and genetic diseases, such as treatment of canine leukocyte adhesion defect syndrome, canine hereditary anemia, canine lymphoma, canine leukopenia, canine X-linked severe combined immunodeficiency using HSCs, etc., but due to the scarcity of leukocyte antigen-matched donors and the limited number of available hematopoietic stem cells, it cannot meet clinical needs.Therefore, how to obtain hematopoietic stem cells to meet clinical needs through in vitro culture has become a hot issue for scholars in recent years.With reference to existing research results, the authors systematically described the sources, in vitro isolation and culture, and treatment mechanism of hematopoietic stem cells, and summarized the clinical research of hematopoietic stem cell transplantation in the treatment of hereditary hemolytic anemia, leukocyte adhesion deficiency syndrome, lymphoma, leukopenia and X-linked severe combined immunodeficiency disease, in order to provide references for the wide application of hematopoietic stem cells in clinical treatment in the future.