Effects Of Rumen Microbiota Transplantation On Growth Performance,Blood Metabolism And Fecal Microbiota Structure Of Calves

The objective of this study was to investigate the effects of rumen fluid on growth performance,blood metabolism and fecal microflora structure of calves.Forty five healthy newborn Holstein calves with similar birth weight were randomly divided into three groups,with 15 calves in each group.Calves in treatment 1 group were fed fresh raw milk(Control),calves in treatment 2 group were fed milk+fresh ruminal fluid(FRF),calves in treatment 3 group were fed milk+autoclaved ruminal fluid(ARF).Rumen fluid was collected from three healthy adult Holstein steers with permanent rumen fistula.The calves were fed 50 mL fresh rumen fluid(FRF)or inactivated rumen fluid(ARF)at 7-11 days old,80 mL fresh rumen fluid(FRF)or inactivated rumen fluid(ARF)at 21-25 days old,and 100 mL fresh rumen fluid(FRF)or inactivated rumen fluid(ARF)at 42-46 days old.The experiment lasted for 56 days.The results showed that:1.There were no significant differences in weaning weight,average daily gain and average daily dry matter intake of calves in each group(P>0.05),the feed conversion efficiency of calves in FRF group was significantly higher than that in ARF group(P<0.05);There was no significant difference in body height,body oblique length,chest circumference and abdominal circumference among different treatments(P>0.05),but the tube circumference of FRF group was significantly higher than that of the other two groups(P<0.05).2.There was no significant difference in DM digestibility among different sampling days(P>0.05),the digestibility of NDF and ADF were significantly affected(P<0.05),and There was significant interaction between treatment and age on NDF and ADF digestibility(P<0.05).At 15 days of age,the NDF digestibility of calves in FRF group was significantly higher than that in the other two groups(P<0.05).At 35 days of age,the NDF and ADF digestibility of FRF group were significantly higher than those of the control group and ARF group(P<0.05).At 56 days of age,different treatments had significant effects on NDF and ADF digestibility of calves(P<0.05).According to the results of the whole lactation period,the NDF and ADF digestibility of the FRF group were significantly higher than those of the control group and ARF group(P<0.05).3.The treatment had significant effects on T-AOC and MDA of calves in the whole period(P<0.05),the T-AOC of FRF group was significantly different from that of control group and ARF group(P<0.05).T-AOC of FRF group was significantly higher than that of ARF group at 35 and 56 days of age(P<0.05).MDA of FRF group was significantly different at 15 days,35 days and the whole period.At 35 days of age,ALT in FRF group was significantly higher than that in control group and ARF group,which was increased by 74.33%and 62.33%respectively(P<0.05).AST in FRF group was significantly higher than that in control group at 35 days(P<0.05).The T-CHO of FRF group was significantly lower than that of the other two groups(P<0.05).GLU in FRF group was significantly lower than that in ARF group at 15 and 35 days of age(P<0.05).4.The results showed that different treatments had no significant effects on pH,NH3-N,TVFA,acetic acid,propionic acid,butyric acid and the ratio of B/C(P>0.05).The concentration of NH3-N in FRF group was the lowest,8.09%and 15.93%lower than that in control group and ARF group,respectively.5.According to the Shannon index,there was no significant difference among different treatments(P=0.57),but the age had a significant effect on the Shannon index(P<0.05).The t-SNE diagram showed that there was no significant difference between treatments on calves(P>0.05),and there was no significant clustering.The age composition had a significant difference in the composition of microorganism in digestive tract(P<0.05).According to the species BC distance picture,the microbial composition of digestive tract of calves fed with fresh rumen fluid tended to be the same,and the microbial diversity increased to a certain extent compared with the control group(P<0.05).However,the microbial composition and microbial diversity of the digestive tract in ARF group were lower than those in the control group(P<0.05).In conclusion,although feeding fresh rumen fluid did not affected the average daily gain and dry matter intake,the digestibility of netural and acid detergent fiber and total antioxidant capacity was improved in calves fed fresh rumen fluid,the digestive tract microbes of calves tend to mature and stable about one month after birth,and feeding rumen fluid can improve their digestive and antioxidant potential by affecting the development of digestive tract microbes.