| Calf stage is the golden period of its growth and development,which directly affects its production performance.However,diarrhea often occurs in young calves,which not only affects their growth and development,but also leads to death in severe cases.In this experiment,compound probiotics(composite lactic acid bacteria+yeast,composite yeast and compound lactic acid bacteria)were fed to newborn calves based on microecological theory and early gastrointestinal flora characteristics of calves by early intervention of gastrointestinal flora colonization of calves in order to prevent and control diarrhea of calves,improve growth performance and immune function of calves,and provide a practical basis for microbiotics in calf breeding.The twenty-eight Chinese holstein calves(within 3 days of age and body condition similar)divided into 4 groups,respectively lactic acid bacteria+yeas group(LS group),yeast group(S group),lactic acid bacteria group(L group)and blank group(D group).Except the control group,the other groups were fed with compound probiotics for 14 days,and the experiment lasted for 45 days.The sampling period was 1 d,15 d and 45 d.Including the following three tests:Experiment 1 : Effects of compound probiotics on body weight,body size and diarrhea of calves.The results showed that there were no significant differences in body size between the 4 groups on the 15 days and 45 days(P>0.05).On the first and 15 th day of the experiment,there was no significant difference in the body weight of calves among the four groups(P>0.05).On the 45 th day,the body weight of calves in the LS group was significantly higher than that in the D group(P<0.05),and the body weight of calves in the L and S groups tended to be higher than that in the D group.There were no significant differences in the body weight gain and average daily gain of calves in groups D,LS,L and S from day 1 to 15(P>0.05),but the body weight gain and average daily gain of calves in groups LS and L from day 16 to 45 were significantly higher than those in group D(P<0.01),and the body weight gain and average daily gain of calves in group S were significantly higher than those in group D(P<0.05).During the whole experiment period(1-45 d),the weight gain and average daily gain of calves in LS groups and L groups were significantly higher than those in D group(P<0.01),and the weight gain and average daily gain of calves in S group were significantly higher than those in D group(P<0.05).There was no significant difference between LS,S and L groups(P>0.05),which showed a trend of LS group >L group > S group.The fecal score and diarrhea rate in LS,S and L groups were significantly decreased during 1-30 d of the experiment(P<0.05),but the fecal score was lower than that in D group after 30-45 d of the experiment(P >0.05).Experiment 2: Effects of compound probiotics on serum indexes of calves.The results showed as follows: there were no significant differences in the contents of serum biochemical indexes among D group,LS group,S group and L group(P>0.05).The concentrations of Ig A,Ig M and Ig G in LS group,S group and L group were significantly higher than those in D group(P<0.01).On day 45 of the experiment,the concentrations of Ig A and Ig G in LS group were significantly higher than those in L group and S group(P<0.05).The T-AOC activity and SOD concentration in LS group,S group and L group were significantly higher than those in D group on the 15 th and 45d(P<0.01).On the 45 th dayof the experiment,the T-AOC activity and SOD concentration in LS group were significantly higher than those in S group and L group(P<0.05).There were no significant differences in the T-AOC activity,SOD concentration and between S group and L group(P>0.05).On day 45 of the experiment,the serum MDA content of LS group was significantly lower than that of D group,S group and L group(P<0.01),but there was no significant difference between S group,L group and D group(P>0.05).Experiment 3: Effects of compound probiotics on rectum flora and short chain fatty acids in calves.The results showed as follows: On the 15 th day,the number of Escherichia coli in rectum contents of calves in LS group,S group and L group was significantly lower than that in D group(P<0.05),but there was no significant difference among all groups on the 45 th day(P>0.05).There was no significant difference in the number of lactic acid bacteria in the rectum contents of calves among all groups on day 15 and 45 of the experiment(P>0.05).The total acid,acetic acid,propionic acid and butyric acid in rectal contents of LS group,S group and L group were not significantly different from those of D group on the 15 th and 45d(P>0.05),but there was a tendency to increase. |
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