舍饲、放牧对滩羊股二头肌纤维特性及宰后成熟过程中蛋白降解的影响

doi:10.16431/j.cnki.1671-7236.2021.08.013

Abstract

Abstract: This study was aimed to investigate the effects of concentrates (CF) and pasture feeding (PF) on meat quality, muscle fiber characteristics, microstructure and protein degradation during postmortem aging of biceps femoris in Tan sheep.28 male Tan lambs aged 4 to 5 months were randomly divided into two groups with 14 replicates each.A replication consisted of 1 sheep.Each group was raised for 60 days under CF and PF, respectively.The results showed that the shearing force, hardness and cohesiveness of muttons in PF group were significantly higher than that in CF group (P<0.05), while the springiness of muttons in PF group was significantly lower than that in CF group (P<0.05).The muscle fiber density and quantity proportion of type Ⅱ muscle fiber of muttons in PF group were significantly lower than that in CF group (P<0.05).Meanwhile, the diameter, cross-sectional area and quantity proportion of type Ⅰ muscle fibers in PF group were significantly higher than that in CF group (P<0.05).During postmortem aging, the sarcoplasmic protein solubility in CF group was significantly higher than that in PF group (P<0.05).The myofibrillar protein solubility in two groups gradually increased after reaching the lowest at 24 h postmortem, but there was no significant difference in each time pointing (P>0.05).Myofibrillar fragmentation index significantly increased at 50.97% and 41.94% in CF and PF groups, respectively.The microstructure showed that the myofibril structure of postmortem muscle was loose and cracked, Z-line was degraded and myofibril fragmentation appeared.The damage of myofibril structure in CF group was more serious than that in PF group.The sarcoplasmic protein had less degeneration and slow degradation rate in CF group, while the degradation of myofibrillar protein was more obvious, and the amount of small molecular protein in CF group was higher than that in PF group.In conclusion, the feeding system affected the characteristics of the biceps femoris muscle fibers in Tan sheep, and had an impact on the microstructure and protein degradation during postmortem aging.CF increased the density and reduced the diameter and the cross-sectional area of muscle fibers of biceps femoris, and thus reduced the muscle shearing force.In addition, as the proportion of type Ⅱ muscle fibers increased, CF improved the growth rate of myofibril fragmentation index, sarcoplasmic protein solubility and protein degradation rate postmortem, it accelerated the process of postmortem aging and improved the tenderness of biceps femoris.

Key words: Tan sheep; concentrates feeding; pasture feeding; biceps femoris; muscle fiber characteristics; postmortem aging

CLC Number:

S826.5

YANG Yuanyuan, HAN Yunsheng, LI Jing, JIA Xueting, ZHAO Qingyu, TANG Chaohua, MA Qing, MA Lina, ZHANG Junmin. Effects of Concentrates and Pasture Feeding on Muscle Fiber Characteristics of Biceps Femoris in Tan Sheep and Its Protein Degradation During Postmortem Aging[J]. China Animal Husbandry & Veterinary Medicine, 2021, 48(8): 2797-2808.

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Effects of Concentrates and Pasture Feeding on Muscle Fiber Characteristics of Biceps Femoris in Tan Sheep and Its Protein Degradation During Postmortem Aging

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