| Objective: In the present study,effect of Saccharomyces Boulardii on growth performance,nutrient digestibility,diarrhea rate,blood physicochemical index and fecal microbiota were studied in calf.We hope it can provide scientific reference for the application of Saccharomyces Boulardii in calf production.Methods: This thesis was divided into three parts,and the specific experimental methods are as follows:Forty-eight Chinese Holstein calves were selected and randomly divided into four groups with 12 calves per group(6 males,6 females).Group SB0(control)fed a basal diet,group SB1,SB3,and SB5 were supplemented with Saccharomyces boulardii at SB1,SB3,and SB5 g/d per head,respectively.The experiment was lasted for 42 days.The feed intake of the experimental calves was recorded daily,and the body weight were get before morning feeding on the 1th,21 th and 42 th day.These data were used to calculate the average daily feed intake(ADFI),average daily gain(ADG)and feedto-gain ratio(F/G;feed:gain).In addition,the body length,body height,chest depth and chest circumference were measured.Fecals were scored daily during the trial to calculate the rate of diarrhoea.Fecal samples from six cows in each group were collected for the last three days of the experiment to determine the apparent digestibility.On the 1th,21 th and 42 th day,blood samples were collected before morning feeding for blood biochemical indicators.Fecal were collected at the day of 21 and 42.Results:(1)The weight of the calves in the SB3 and SB5 groups were significantly higher than that in the SB0 group(P <0.05).Comprised with 0 group,the average daily weight gain in groups SB1,SB3,and SB5 of 1 to 21 days was higher(P<0.05).The average daily feed intake of calves from 1 to 21 days was significantly higher in groups SB1,SB3,and SB5 than in the control group(P <0.05).1 to 21 days of feed conversion rates were significantly lower in the SB1,SB3,and SB5 groups than in the control group(P <0.05).Compared with SB0 group,calves fed with SB3 group diet had higher levels of apparent digestibility of dry matter,crude protein,ether extract,neutral detergent fiber and acid detergent fiber(P<0.05).At 21 days,the serum TP and GLB concentrations in group SB3 were higher than control group(P<0.05).At 42 days,the serum TG concentrations in group SB3 and SB5 were significantly lower(P<0.05).(2)At 1-21 days,the fecal scores of the calves in the SB3 and SB5 groups were significantly lower than in the control group(P<0.05).and the diarrhea rates of the calves in the SB1,SB3 and SB5 groups were 35%,52% and 42% lower than those in the control group(P<0.05).At the age of 21 days,SB3 and SB5 had lower serum concentration of Ig A,Ig M,Ig G,IL-2,and IL-4(P <0.05)compared to other two groups.The serum concentration of IL-1?and TNF-? were increased in SB0 than other three groups(P<0.05).In addition,calves fed with SB3 and SB5 had lower serum MDA than CON at the ages of 21 and 42 d.(3)At 21 days,the observed_species and shannon index of fecal microorganisms in calves in the SB1 group were significantly higher than SB3 group(P<0.05).At day of 42,the chao1 indexes of the SB5 group were significantly higher than those in other groups(P < 0.05).The number of unique OTU in the test group was higher than that in the control group both at 21 and 42 days.At the level of phylum,Saccharomyces Boulardii t increased the relative abundance of Firmicutes at the day of 21,and decreased the Bacteroidetes(P<0.05).At the day of 42,Saccharomyces Boulardii decreased the relative abundance of Firmicutes,and increased the Bacteroidetes and Fusobacterium(P<0.05).On the genus level,the predominant microbial flora in fecal consisted the Bacteroidetes and Lactobacillus at the 21 and 42 days.Saccharomyces Boulardii reduced the relative abundance of Bacteroidetes and Fusobacterium,and increased the Lactobacillus(P<0.05).On the 42 nd day,Saccharomyces Boulardii increased the relative abundance of Fusobacterium,Bacteroidetes and Lactobacillus(P<0.05).Lef Se analysis results showed that at the day of 21,there were 6 significant differences microbial communities in the SB3 group compared with the other three groups(P<0.05),inculding Subdoligranulum,Lactobacillus_gasseri,Lactobacillales,Bacilli,Lactobacillus,Lactobacillaceae.Conclusion: In the early stage of calf,Saccharomyces Boulardii can increase the relative abundance of beneficial bacteria in the fecal,such as Lactobacillus and Ruminococcus and inhibit the colonization of intestinal pathogenic bacteria.Saccharomyces Boulardii can promote the digestion,absorption and growth of calves by improving the immunity and antioxidant capacity. |
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