Effects Of Compound Probiotics And Glutamine On Growth Performance And Immune Function Of Holstein Calves

Diarrhea is one of the most common clinical problems in calves,which can slow down the growth of calves and even cause death,seriously affecting the healthy development of dairy farming industry.Probiotics have a variety of biological functions,and play a positive role in maintaining normal intestinal microecology,improving feed conversion rate,promoting animal growth,enhancing intestinal mucosal barrier and regulating body immunity.Glutamine(Gln)is a nonessential amino acid that can improve animal growth performance,improve immune status,improve antioxidant capacity and maintain intestinal barrier function.In this experiment,40 healthy newborn Holstein calves were randomly divided into 4 groups.Control group(NC,basal diet);compound probiotics group(P,basal diet + 0.1% compound probiotics);glutamine group(G,basal diet + 1%Gln);combined supplementation group(P+ G,basal diet + 0.1% compound probiotic + 1% Gln).The experimental period was 63 days.To explore the effects of dietary supplementation of probiotics and glutamine on growth performance,diarrhea rate,hematology-related indexes,serum biochemical indicators,intestinal barrier and intestinal flora of Holstein calves.The results showed that:(1)Addition of glutamine and compound probiotics alone or in combination increased the body weight of calves aged 56 and 63 days;the average daily gain(ADG)of calves aged 1 to 63 days in the glutamine group and the combined supplement group was significantly rise.Combined supplementation of glutamine and complex probiotics improved calf growth performance.(2)Compared with the control group,the addition of glutamine and compound probiotics alone or in combination decreased the fecal scores of calves aged 1-20 days and 1-63 days.In addition,the feces scores of calves aged 57-63 days in the compound probiotic group and the combined supplement group were significantly lower than those in the control group(P < 0.05);in each time period,the diarrhea rate of the calves in the combined supplement group was lower than that in the glutamine group and the control group(P < 0.05).The diarrhea rate of calves in the compound probiotic group,glutamine group and compound probiotic group was lower than that in the control group.The combined addition of compound probiotics and glutamine decreased the concentrations of diamine oxidase(DAO)and D-lactic acid(D-lac)in serum of calves aged 1-56 days and 57-63 days,and improved the calf’s health.Intestinal barrier function.(3)The combined addition of glutamine and compound probiotics in the diet increased the serum total protein concentration of calves aged 1-56 and 57-63 days.The concentration of serum interleukin-6(IL-6)in calves aged 1-56 days in the combined addition group was significantly decreased;)was significantly reduced.Combined addition of glutamine and compound probiotics increased the activity of glutathione peroxidase(GSH-Px)and total antioxidant capacity(T-AOC)in serum of calves from 1 to 56 days old,and decreased the serum oxidative end.The concentration of product malondialdehyde(MDA);in addition,the combined addition of compound probiotics and glutamine increased the serum GSH-Px activity and T-AOC of 57-63-day-old calves,and decreased the serum MDA concentration.The combined addition of glutamine and compound probiotics in the diet increased the serum total protein level of calves aged 1-56 and 57-63 days,adjusted the immune level of calves,and improved the ability of calves to resist oxidative stress.(4)Combined addition of glutamine and compound probiotics increased the abundance of lactic acid bacteria in the intestinal tract of calves from 1 to 56 days old,and decreased the abundance of Escherichia coli;The abundance of Lactobacillus and Bacillus significantly increased in the aged gut,and the abundance of Escherichia coli decreased significantly.In conclusion,the combined supplementation of compound probiotics and glutamine in the diet can improve the average daily gain,antioxidant capacity and serum total protein level of calves,decreased the level of inflammation,diarrhea rate and fecal score,improve intestinal barrier function and regulate intestinal flora.