Effect Of Sterilized Rumen Fluid Supplementation Ways In Lactation Period On Rumen Microflora Of Calves After Weaning

The presence of the rumen makes ruminants special,and the rumen microflora has an important influence on ruminants.The rumen of ruminants is not fully developed at young age.This study aimed to explore effect of sterilized rumen fluid supplementation ways in lactation period on rumen microflora of calves after weaning.To find the way which is beneficial to the growth of ruminant and the establishment of rumen microflora.The experiment selected 16 newborn Holstein male calves with the same feeding environment,and the age of each male calf was similar.They were randomly divided into 4groups,4 in each group.The treatments were as follows: adding sterilized rumen liquid to milk（Group M）,adding sterilized rumen fluid to starter（Group S）,and feeding active probiotics（Group P）,normal fed control group（Group C）.The growth performance index and blood index were measured,and the rumen fluid samples were collected after weaning,and16 SrDNA sequencing and LC-MS metabolome detection were performed.Compared with the control group,the growth performance of the group S was significantly increased,and the difference between the group M and the group P was not significant.For the immune indicators in the blood,the group M showed a higher difference from the group C,and the group P had a smaller difference from the group C.Compared with the control group in the group M,the relative abundance of Firmicutes,Ruminococcaceae,uncultured_bacterium_oGastranaerophilales,Oxalobacteraceae,[Eubacterium]_coprostanoligenes_group,Oxalobacter,Dialister were significantly increased,and the relative abundance of p-2534-18B5_gut_group was significantly reduced（P<0.05）.In the group S,the relative of uncultured_bacterium_oGastranaerophilales,Oxalobacteraceae,uncultured_bacterium_fErysipelotrichaceae,Dialister,Mitsuokella,Prevotella₇ were significantly increased,and the relative abundance of Deltaproteobacteria,Ruminococcaceae_NK4A214_group,Desulfovibrio,[Ruminococcus]_gauvreauii_group weresignificantly reduced（P<0.05）.In the group P,the relative of Deltaproteobacteria,Desulfovibrionales,Bacteroidales_BS11_gut_group,Desulfovibrionaceae,Ruminococcaceae_NK4A214_group,[Ruminococcus]_gauvreauii_group,Desulfovibrio,Selenomonas were significantly reduced,and the relative of Bacteroidales_S24-7_group,Acetobacteraceae,Asaia,Kingella,Lachnoclostridium were significantly increased（P<0.05）.Compared with the control group,in group M,the metabolite of 5-methylcytosine,xanthine,L-citrulline,myo-inositol,2-isopropylmalic acid,3-methoxy-4-hydroxyphenylethylene glycol,indoleacetic acid,deoxyadenosine,erucic acid,UDP-D-galactose,uracil and homovanillic acid were increased significantly（P<0.05）.In group S,the metabolite of cytidine,D-ribulose-5-phosphate,ergothioneine,thymidine5’-monophosphate,cytidine 5’-monophosphate,UDP-D-galactose,uracil,urocanic acid,xanthine,N-acetyl-L-glutamate and salidroside were increased significantly（P<0.05）.In group P,the metabolite of 2-methylbenzoic acid and myo-inositol were increased significantly（P<0.05）.The results showed that compared with calves fed with normal feeding,the calves fed with sterilized rumen fluid high production dairy cows from would have certain changes in growth performance and blood index,and there were significant differences in rumen fluid bacteria and metabolites.Metabolites are mainly involved in metabolic pathways such as amino acid metabolism,nucleotide metabolism,and carbohydrate metabolism.But different feeding methods have different effects.By feeding active probiotics,the growth performance and blood indexes of calves were changed,but the differences were not significant.There were significant differences in rumen fluid and a small amount of metabolites,which were mainly involved in the pathway of glucose metabolism.