Effects Of Feeding Milk Replacer On Growth Performance,Serum Index And Intestinal Flora Of Lambs

In this study,the effects of feeding milk replacer on serum index,intestinal flora and growth and development of lambs were investigated,and the effects of milk replacer on the growth and development of lambs were discussed.Fourteen healthy and disease-free 3-day-old lambs with similar parity size and birth date were randomly divided into control and treatment group.The pre-feeding period was 7days and the experimental period lasted for 50 days.During the experimental period,body size of the lambs was measured and samples were collected.The study consists of 3 experiments:Experiment 1:The changes of weight and body size of lambs in the treatment and the control group were recorded and analyzed.The results indicated that:compared with the control group,the weight of lambs in the treatment group was significantly reduced before 30 days(P ＜0.05),and there was no significant difference observed thereafter;In terms of body size,compared with the control group,the body height and body length of lambs in the treatment group were significantly increased(P ＜0.05),with no significant effect on chest circumference observed(P＞0.05).Experiment 2:Blood samples were collected from the jugular vein of animals in both groups,and serum biochemical and hormone parameters were measured.The results indicated that:1)compared to those in the control group,serum total protein(TP)and the content of albumin(propagated)were significantly higher from lambs in the treatment group(P ＜0.05).there were no significant differences observed in the serum glucose(GLU),triglyceride(TG),urea nitrogen(BUN),total cholesterol(TC),globulin(GLOB),alkaline phosphatase(AKP)and propagated/GLOB contents(P＞0.05);2)in terms of serum hormone indicators,compared to those in the control group,the content of growth hormone(GH)in the serum of lambs in the treatment group was significantly higher(P ＜0.05),and there were no significant differences in the contents of serum insulin(INS)and insulin-like growth factor-1(IGF-1)observed(P＞0.05).Experiment 3:In order to study the changes of intestinal microbial flora of lambs fed with milk replacer,rectal fecal samples from animals in both groups were collected,and intestinal microbial communities were detected and identified by 16S sequencing technology,respectively.The results showed that:1)at the level of phylum,compared to that in the control group,the contents of Tenericutes and Patescibacteria in the treatment group were significantly reduced(P＜0.05),and there were no significant effects on the contents of Firmicutes,Bacteroidetes,Actinobacteria,Spirochaetes and bacteriophaes(P＞0.05);2)at the class level,compared to that in the control group,the contents of Mollicutes and Negativicutes in the treatment group were significantly reduced(P＜0.05),but the contents of Deltaproteobacteria were significantly increased(P＜0.05).There were no significant changes in the contents of Clostridia,Bacteroidia,Erysipelotrichia and bacillus I observed;3)at the order level,compared to that in the control group,the contents of Mollicutes-RF39 and Selenomonadales in the treatment group were significantly reduced(P＜0.05),but the content of Desulfovibrionales was significantly increased(P＜0.05);4)feeding the milk replacer had no significant effects on the species abundance of intestinal flora at the family level and genus level(P＞0.05).Conclusion:Under the condition of this experiment,feeding the milk replacer can obviously increase the body height and body length of the lamb,promote the growth and development of the lamb,and improve the immunity of the nursing lamb.There was no adverse effect on serum biochemical index and intestinal microflora structure of the lambs.