饲粮蛋白质水平对藏羊生长性能、血清生化指标及肉品质的影响

Effects of Dietary Protein Levels on Growth Performance,Serum Biochemical Indicators,and Meat Quality of Tibetan Sheep

试验旨在探究不同蛋白质水平饲粮对藏羊生长性能、血清生化指标和肉品质的影响。试验选用初始体重相近[(15.40±0.81)kg]且体况良好的2月龄高原型藏羊公羔90只,随机分为3个组,每组5个重复。各组分别饲喂蛋白质水平为12%(A组)、14%(B组)和16%(C组)的饲粮。整个试验分预试期7 d和正试期90 d。结果显示:①各组间的平均日增重、平均日采食量及料重比均差异不显著(P>0.05)。②A组的血清谷丙转氨酶活性高于B组(P>0.05)和C组(P<0.05),B组的血清葡萄糖含量显著低于其他两组(P<0.05),A组的血清总蛋白含量低于B组(P<0.05)和C组(P>0.05)。③C组的肌肉中糖原含量显著高于A组(P<0.05),C组的肌肉中苹果酸脱氢酶活性显著高于其他两组(P<0.05)。④C组的肌纤维直径显著高于B组(P<0.05),B组和C组的肌纤维密度显著高于A组(P<0.05),B组的肌纤维横截面积显著高于C组(P<0.05)。综上,饲粮蛋白水平为16%时,有利于增强藏羊的生长性能。在饲粮蛋白水平为14%时,有利于增强育肥期藏羊肌肉品质。

The aim of the experiment was to investigate the effects of different protein levels on the growth performance,serum biochemical indexes and meat quality of Tibetan sheep.Ninety 2-month-old male lambs of plateau type Tibetan sheep with similar initial body weight(15.40±0.81)kg and good body condition were randomly divided into three groups with five replicates in each group and six lambs in each replicate.Each group was fed diets with protein levels of 12%(group a),14%(group B)and 16%(group C).The whole experiment was divided into a pre-test period of 7 d and a formal period of 90 d.The results showed that:①the differences in average daily weight gain,average daily feed intake and feed-to-weight ratio among the groups were not significant(P>0.05).②The serum ghrelin activity of group A was higher than that of group B(P>0.05)and group C(P<0.05),the serum glucose content of group B was significantly lower than that of the other 2 groups(P<0.05),and the serum total protein content of group A was lower than that of group B(P<0.05)and group C(P>0.05).③Glycogen content of muscles in group C was significantly higher than group A(P<0.05).Malate dehydrogenase activity of muscles in group C was significantly higher than the other 2 groups(P<0.05).④Muscle fibre diameter was significantly higher in group C than in group B(P<0.05).Muscle fibre density was significantly higher in groups B and C than in group A(P<0.05).Cross sectional area was significantly higher in group B than in group C(P<0.05).In conclusion,a dietary protein level of 16% is favourable to enhance the growth performance of Tibetan sheep.At 14% protein level,it is beneficial to enhance the muscle quality of Tibetan sheep during the fattening period.