China Animal Husbandry and Veterinary Medicine ›› 2022, Vol. 49 ›› Issue (12): 4582-4592.doi: 10.16431/j.cnki.1671-7236.2022.12.008

• Nutrition and Feed • Previous Articles     Next Articles

Developmental Changes of Muscle Fiber Histology and Myogenic Regulatory Genes with Different Slaughter Weights in Yuxi Black Pigs

SHI Zhuoyan1, LIU Xiaoping1, JI Xiang1, CHU Xiaoran1, HOU Junjie1, SONG Zhen1,2, LI Xiaoxia1, YANG Youbing1, ZHANG Guluan3, WANG Jianping1, WEN Fengyun1,2   

  1. 1. Animal Biotechnology Laboratory, College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471003, China;
    2. Luoyang Key Laboratory of High Quality Livestock and Poultry Germplasm Resources and Genetic Breeding, Luoyang 471003, China;
    3. Luoyang Yiluan Agriculture and Animal Husbandry Development Co., Ltd., Luoyang 471500, China
  • Received:2022-04-21 Online:2022-12-05 Published:2022-12-01

Abstract: 【Objective】 The aim of this study was to reveal the developmental changes of muscle fiber histology, muscle fiber type and myoblast-related regulatory genes of longissimus dorsi muscle in Yuxi Black pigs and their relationship.【Method】 The average weight with 60, 75, 90, 105 and 120 kg Yuxi Black pigs were selected, each weight slaughtered 3 pigs, a total of 15 pigs, and the male and female randomly selected.HE staining and immunofluorescence staining were used to determine the composition of fast and slow muscle types and fibrous histological characteristics, and the mRNA expressions of myogenic differentiation (MyoD), paired-box 7 (Pax7), myostatin (MSTN), myogenin (MyoG), myocyte enhancer factor 2C (MEF2C) and myosin heavy chain (MyHC) subtypes were measured by Real-time quantitative PCR.【Result】 With the increase of weight in Yuxi Black pigs, the overall muscle fiber density showed a downward trend, which was extremely significantly higher than that of other groups at 75 kg (P<0.01), and the area and diameter of muscle fibers showed an overall upward trend.At 60 and 105 kg, the percentage of slow muscles area were significantly or extremely significantly lower than other weight stages (P<0.05 or P<0.01), and the total percentage of the area occupied by the fast and slow muscles were extremely significantly lower than that of other weight stages at 90 kg (P<0.01).Real-time quantitative PCR results found that the mRNA expression of MyHCⅠ gene at 75 and 105 kg was extremely significantly higher than other body weight (P<0.01), the mRNA expression of MyHCA gene as a whole showed a downward trend, the mRNA expression of MyHCX gene at 60 kg reached the highest, and the mRNA expression of MyHCⅡB gene at 75 kg was extremely significantly lower than other body weight (P<0.01).The mRNA expression of MyoD, Pax7, MSTN, MyoG and MEF2C genes reached their maximum values at 60, 75, 90, 120 and 120 kg, respectively.The correlation analysis results showed that in addition to MSTN gene, MyoG, MyoD, Pax7 and MEF2C genes had significant or extremely significant correlations with muscle fiber morphology and MyHC gene subtypes (P<0.05 or P<0.01).Through the comparison of 120 kg of Yuxi Black pigs and Duroc pigs, it was found that the diameter, area, density of muscle fiber, and the mRNA expression of MyHC gene and related muscle-forming regulatory genes between the two were extremely significant differences (P<0.01).【Conclusion】 During the growth stage of 60 to 120 kg in Yuxi Black pigs, the area and diameter of muscle fiber increased and the density of muscle fiber decreased, and the change of muscle fiber type composition was mainly the transformation of types Ⅰ, ⅡA and ⅡX muscle fiber to type ⅡB muscle fiber.Compared with Duroc pigs, the area and diameter of muscle fiber in Yuxi Black pigs were larger, the density of muscle fiber was lower, and the mRNA expression of MyHCⅠ and MyHCA genes were higher.

Key words: Yuxi Black pigs; longissimus dorsi muscle; muscle fibers; developmental changes; myogenic regulation

CLC Number: