不同蛋白水平代乳粉对羔羊生长性能、血清生化指标及屠宰性能的影响OA

The experiment aimed to investigate the effects of different protein levels in milk replacer on lamb growth performance,serum biochemical indices,slaughter performance,and meat quality.A total of 48 healthy,disease-free,and genetically similar young lambs(initial body weight:4.34±0.15 kg)of three-day-old East Friesian × Hu sheep crossbred males were randomly divided into four groups in a ran-domized complete block design,with three replicates per group and four lambs per replicate.The groups were designated as follows:low-protein level group(L group,22％protein),moderate-low protein level group(ML group,24％protein),moderate-high protein level group(MH group,26％protein),and high-protein level group(H group,28％protein).The trial consisted of a 5-day pre-feeding period fol-lowed by a 49-day formal feeding period.The results demonstrated that on day 52 post-birth,lambs in the ML group exhibited significantly higher body weights compared to those in the L and H groups(P＜0.05).The average daily gain(ADG)in the ML group was also significantly higher than in the L and H groups(P＜0.05).Serum analysis revealed that total protein content and glutamic-oxaloacetic transaminase activi-ty in the ML and MH groups were significantly higher than in the L group(P＜0.05).Additionally,ser-um total cholesterol levels in the MH group were significantly higher than in the L and ML groups(P＜0.05),and serum glucose levels in the ML and MH groups were significantly higher than in the L group(P＜0.05).Serum urea nitrogen concentrations in the MH and H groups were significantly higher than in the L group(P＜0.05).Regarding slaughter performance,the pre-slaughter live weight,carcass weight,and dressing percentage were significantly higher in the ML group compared to the L and H groups(P＜0.05).The eye muscle area in the ML and MH groups was significantly larger than in the L group(P＜0.05).Meat quality assessment showed that the cooked meat ratio was significantly higher in the L group compared to the MH and H groups(P＜0.05).Moreover,meat color measurements indicated that redness was significantly greater in the H group than in the L and ML groups(P＜0.05),while yellowness was significantly higher in the L group compared to the MH and H groups(P＜0.05).In conclusion,feeding milk replacer with a 24％protein level can improve lamb growth performance,carcass weight,and slaugh-ter yield without adversely affecting the health of the lambs.Additionally,it does not negatively impact meat quality.Therefore,the protein content in lamb milk replacer should be maintained around 24％.