低蛋白质日粮对育肥绵羊生长性能、胴体性状及肌肉脂肪酸组成的影响

Effects of low protein diet on growth performance,carcass traits and muscle fatty acid composition of fattening sheep

本研究旨在研究降低全混合日粮蛋白质水平对育肥期绵羊生长性能、胴体性状及肌肉脂肪酸组成的影响。试验将32只平均体重为(38.14±0.45)kg的育肥期绵羊随机分为2组,每组8个重复,每个重复2头。两组绵羊在为期10周的试验期中分别饲喂蛋白质水平为13.5%和8.5%的全混合日粮。结果:将全混合日粮蛋白质水平从13.5%降低至8.5%显著影响绵羊的生长性能(P<0.05),其中对照组绵羊的末重、增重、日增重和日采食量较低蛋白组分别显著提高8.07%、19.82%、19.82%和10.07%(P<0.05),但对照组与低蛋白组对料重比的影响无显著差异(P>0.05)。对照组绵羊的屠宰率和脂肪相对重量较低蛋白组分别显著提高9.80%和19.93%(P<0.05),但对其他组织器官相对重量的影响无显著差异(P>0.05)。对照组绵羊肌肉滴水损失较低蛋白组显著提高117.59%(P<0.05),但肉色L和b值及肌肉n-6与n-3脂肪酸比值显著降低8.64%、7.27%和20.74%(P<0.05)。结论:尽管将育肥期绵羊全混合日粮蛋白质水平由13.5%降低至8.5%会对绵羊体重、采食量、日增重和屠宰率产生负面影响,但不影响其饲料效率及肌肉脂肪酸组成,同时显著改善了滴水损失及n-6与n-3脂肪酸的比值。

The purpose of this study was to study the effects of reducing the protein level of total mixed diet on the growth performance,carcass traits and muscle fatty acid composition of sheep in fattening period.Thirty-two sheep with an average body weight of 38.14±0.45 kg were randomly divided into 2 groups with 8 replicates per group and 2 sheep per replicate.Two groups of sheep were fed a total mixed diet containing 13.5%and 8.5%protein,respectively,during a 10-week trial.Results:The final weight,weight gain,daily gain and daily feed intake of sheep in control group were significantly increased by 8.07%,19.82%,19.82%and 10.07%(P<0.05)when the protein level of total mixed diet was reduced from 13.5%to 8.5%(P<0.05).However,there was no significant difference between control group and low protein group on feed/gain(P>0.05).The slaughter percentage and relative fat weight of sheep in control group were significantly increased by 9.80%and 19.93%in low protein group(P<0.05),respectively,but there was no significant difference in the relative weight of other tissues and organs(P>0.05).However,the L and B values of meat color and the ratio of muscle N-6 to N-3 fatty acids were significantly decreased by 8.64%,7.27%and 20.74%(P<0.05).Conclusions:Although reducing protein levels in total mixed diets from 13.5%to 8.5%in fattening sheep has negative effects on body weight,feed intake,daily gain and slaughter rate,feed efficiency and muscle fatty acid composition are not affected,and drop loss and the ratio of N-6 to N-3 fatty acids are significantly improved.