China Animal Husbandry and Veterinary Medicine ›› 2021, Vol. 48 ›› Issue (11): 4014-4024.doi: 10.16431/j.cnki.1671-7236.2021.11.011

• Animal Nutrition and Feed Science • Previous Articles     Next Articles

Effects of Plant Essential Oil-Citric Acid Complex on Intestinal Barrier Function and Inflammatory Response of Broilers

WEI Qing1, WEI Zhaoyang2, WANG Kewei2, WU Zhiwei1, QIAO Jiayun2, LI Haihua1   

  1. 1. Tianjin Key Laboratory of Agricultural Animal Breeding and Healthy Husbandry, College of Animal Science and Veterinary Medicine, Tianjin Agricultural University, Tianjin 300384, China;
    2. Tianjin Key Laboratory of Conservation and Utilization of Animal Diversity, College of Life Sciences, Tianjin Normal University, Tianjin 300387, China
  • Received:2021-04-16 Online:2021-11-20 Published:2021-11-01

Abstract: The effects of adding different levels of plant essential oil-citric acid complex in the diet on the intestinal barrier function, serum cytokine content and key immune protein gene expression in broilers were studied in this experiment, in order to explore the appropriate additive dosage of the complex for broilers. A total of 1 344 one-day-old healthy broilers (Cobb) were divided into 4 groups with 12 replicates per group and 28 birds per replicate. Broilers in the control group were fed with basal diet, and those in the experimental groups (T1, T2, T3) were fed the basal diets supplemented with 0.8, 1.0 and 1.5 kg/t plant essential oil-citric acid complex, respectively. The experiment lasted for 42 days. On the ending of the test period, 6 broilers close to the average weight were selected for each repetition to collect blood and slaughtered. The jejunum, spleen, mesenteric lymph nodes (MLNs) were taken and the contents of D-lactic acid (D-LA), cytokine and activity of diamine oxidase (DAO) in serum were measured. Meanwhile, the mRNA expression of tight junction protein in the jejunum mucosa and Toll-like receptors (TLRs) in spleen and MLNs were measured. The results showed that:Compared with the control group, the contents of serum D-lactic and diamine oxidase(DAO) activity of broilers were extremely significantly decreased in T2 group (P<0.01) and significantly decreased in T3 group (P<0.05). The relative expression of Claudin-1 mRNA in broilers in both T2 and T3 groups were significantly increased (P<0.05), and the relative expression of ZO-1 mRNA in T2 group was increased significantly (P<0.05). The content of serum IL-1β was decreased significantly (P<0.05), and the relative expression level of TLR4 mRNA in MLNs was decreased significantly (P<0.05) of broilers in T1 group. The content of serum IL-1β was decreased extremely significantly (P<0.01), the content of serum IL-2 was increased significantly (P<0.05), and the relative expression level of TLR4 mRNA in spleen (P<0.01) and MLNs (P<0.05) were decreased of broilers in T2 group. The contents of serum IL-1β (P<0.01) and TNF-α (P<0.05) were decreased, and the relative expressions of TLR4 mRNA in spleen and MLNs was decreased extremely significantly (P<0.01) of broilers in T3 group. Compared with T1 group, the contents of serum D-lactic, DAO and TNF-α in T2 group were decreased significantly (P<0.05), and the content of serum IL-1β of broilers in T3 group was decreased significantly (P<0.05). In conclusion, adding plant essential oils-citric acid complex to broiler diets could increase the expression of intestinal tight junction proteins, reduce intestinal permeability, and down-regulate the expression of pro-inflammatory cytokines, thereby enhancing the intestinal barrier function and alleviating inflammation. Under the experimental conditions, the appropriate addition level of plant essential oil-citric acid complex was 1.0 kg/t.

Key words: plant essential oil-citric acid complex; broiler; intestinal barrier; inflammatory reaction; cytokine

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