中国畜牧兽医 ›› 2021, Vol. 48 ›› Issue (8): 2797-2808.doi: 10.16431/j.cnki.1671-7236.2021.08.013

• 动物营养与饲料科学 • 上一篇    下一篇

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

杨媛媛1,2, 韩云胜1,2, 李敬1,2, 贾雪婷1,2, 赵青余1,2, 汤超华1,2, 马青3, 马丽娜3, 张军民1,2   

  1. 1. 中国农业科学院北京畜牧兽医研究所, 动物营养学国家重点实验室, 北京 100193;
    2. 农业农村部华北动物遗传资源与营养科学观测实验站, 北京 100193;
    3. 宁夏农林科学院动物科学研究所, 银川 750002
  • 修回日期:2021-02-22 出版日期:2021-08-20 发布日期:2021-08-19
  • 通讯作者: 张军民 E-mail:zhjmxms@sina.com
  • 作者简介:杨媛媛(1994-),女,山西汾阳人,硕士生,研究方向:优质功能羊肉研究与开发,E-mail:yangyuan2018@163.com
  • 基金资助:
    宁夏高端滩羊肉生产关键技术研究与集成示范(2018BBF02016);中国农业科学院科技创新工程(ASTIP-AS-12)

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

YANG Yuanyuan1,2, HAN Yunsheng1,2, LI Jing1,2, JIA Xueting1,2, ZHAO Qingyu1,2, TANG Chaohua1,2, MA Qing3, MA Lina3, ZHANG Junmin1,2   

  1. 1. State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China;
    2. Scientific Observing and Experiment Station of Animal Genetic Resources and Nutrition in North China, Ministry of Agriculture and Rural Affairs, Beijing 100193, China;
    3. Institute of Animal Science, Ningxia Academy of Agricultural and Forestry Sciences, Yinchuan 750002, China
  • Revised:2021-02-22 Online:2021-08-20 Published:2021-08-19

摘要: 试验旨在研究舍饲(concentrate feeding,CF)、放牧(pasture feeding,PF)对滩羊股二头肌肉品质、肌纤维特性、宰后成熟过程中超微结构及蛋白降解变化的影响。选取体重接近的4~5月龄滩羊公羔28只,随机分为2组,每组14个重复,每个重复1只羊,分别以舍饲、放牧方式饲养,试验期60 d。试验结束后采集股二头肌作为试验样品,并对其肉质性状、肌纤维特性及宰后成熟过程中超微结构与蛋白降解各项指标进行测定分析。结果显示,放牧组羊肉剪切力、硬度和内聚性均显著高于舍饲组(P<0.05),弹性则显著低于舍饲组(P<0.05);放牧组羊肉肌纤维密度和Ⅱ型肌纤维的数量比例均显著低于舍饲组(P<0.05),Ⅰ型肌纤维的直径、横截面积和数量比例均显著高于舍饲组(P<0.05)。在宰后成熟过程中,舍饲组羊肉肌浆蛋白溶解度显著高于放牧组(P<0.05);两组肌原纤维蛋白溶解度在宰后24 h至最低后逐渐回升,但各时间点差异均不显著(P>0.05);肌原纤维小片化指数显著上升后趋于平稳,舍饲组增加率(50.97%)高于放牧组(41.94%);超微结构显示,宰后肌肉肌原纤维结构松弛、裂解,Z线发生降解,肌原纤维小片化出现,舍饲组肌原纤维结构破坏程度比放牧组更严重。舍饲组肌浆蛋白变性程度小,宰后降解速率较慢,而肌原纤维蛋白降解较明显,降解产生的小分子蛋白量高于放牧组。综上所述,饲养方式改变了滩羊股二头肌纤维特性,并对宰后成熟过程中肌肉超微结构及蛋白降解产生影响,舍饲饲养使得股二头肌纤维密度增加,肌纤维直径与横截面积减小,并降低了肌肉剪切力;此外,由于Ⅱ型肌纤维比例的增加,舍饲饲养提高了肌肉宰后肌原纤维小片化指数增长率、肌浆蛋白溶解度和蛋白降解速率,使宰后成熟过程加快,改善了股二头肌肉嫩度。

关键词: 滩羊; 舍饲; 放牧; 股二头肌; 肌纤维特性; 宰后成熟

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

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