不同蛋白质水平饲粮对舍饲公牦牛肉品质影响

Impact of varying protein levels in meals on the meat quality of housed male yaks

为研究不同蛋白水平饲粮对牦牛肉品质以及饲养效益影响,选取24头健康状况良好,年龄接近,初始体重(200±20)kg的健康公牦牛,随机分为Ⅰ、Ⅱ组,每组各12头。Ⅰ组(低蛋白组)饲粮蛋白质水平为12%,Ⅱ组(高蛋白组)饲粮蛋白质水平为16%,两组饲粮代谢能水平均为11.7 MJ/kg。试验预试期10 d,正试期180 d,记录试验期间牦牛增重和饲喂耗料量,以计算养殖收益。试验结束后每组随机选取5头公牦牛,进行屠宰。屠宰后进行肉品质测定。结果表明:(1)不同蛋白水平饲粮对牦牛背最长肌pH45 min影响显著(P<0.05),均在正常范围。不同蛋白水平饲粮对于公牦牛背最长肌pH24 h、肱三头肌pH45 min和pH24 h影响均不显著(P>0.05),不同蛋白水平饲粮对于公牦牛肉色亮度、黄度、红度、剪切力和蒸煮损失均影响不显著(P>0.05)。(2)不同蛋白水平饲粮对于公牦牛肉硬度影响显著(P<0.05),对黏性、弹力、内聚性、可恢复形变、可恢复功、弹性、胶着性均影响不显著(P>0.05)。(3)相较于高蛋白组,低蛋白组养殖毛利润更高,毛利润提升约81.5%。不同蛋白质水平饲粮对公牦牛肉品质影响有限,综合考虑养殖效益,代谢能水平为11.7 MJ/kg时,舍饲公牦牛全混合饲粮的粗蛋白质水平为12%时最为合适。

The purpose of this research was to surveys the influence of different protein level of rations on the quality and feeding efficiency of yak meat.Twenty-four healthy male yaks of similar age,and primary weight(200±20)kg were selected and randomly divided into two groups of 12 yaks each.The protein level of the diet was 12%for the low-protein groupⅠand 16%for the high-protein groupⅡ,and the energy level was 11.7 MJ/kg for both groups,with the two groups serving as controls for each other.The test pre-test period was 10 d,and the normal test period was 180 d,at the end of the feeding,five male yaks were random selection from each group.The longest dorsal muscle and triceps muscle of yaks were cut for meat quality evaluation.The results showed that:(1)Compared with groupⅠand groupⅡ,the effect of different protein level rations on pH45 min in the longest back muscle of yaks was significant(P<0.05),both were in the normal range.Diets with different protein levels had no significant effects on pH24 h of longest back musele and pH45 min and pH24 h of triceps brachii muscle(P>0.05).Diets with different protein levels had no significant effect on meat color brightness,yellowness and redness of triceps muscle of yaks(P>0.05).(2)There were no significant effects of different protein levels on adhesion,elasticity,cohesion,recoverable deformation,recoverable work,elasticity and adhesion of the longest back muscle of yaks(P>0.05).(3)Compared to the high-protein group,the low-protein group had higher gross profit,with an increase of about 81.5%in gross profit.Limited effect of different protein diets on the quality of male yak meat,taking into account the feeding efficiency,when the metabolic energy level was 11.7 MJ/kg,the crude protein level of the whole mixed ration for housed male fattened yaks at 12%was the most suitable.