Effect of Sterilized Rumen Fluid Supplementation Ways in Lactation Period on Rumen Microflora of Calves after Weaning

Abstract Background: The presence of the rumen makes the ruminant special, and the ruminal microbes has an important influence on the ruminant. The rumen have an important developed in young ruminants. This study want to investigate the ecological function of rumen fluid environmen from high-yielding dairy cows and effect of feeding of rumen fluid to suckling calves. For the experiment, 12 newborn Holstein male calves with the same feeding environment and similar ages were selected. They were randomly divided into 3 groups, with 4 in each group. The three treatments were: addition of sterilized rumen fluid to milk (Group M), addition of sterilized rumen fluid to starter feed (Group S), and control group fed milk and starter feed(Group C). The growth performance indices and blood indices were measured, and rumen fluid samples were collected after weaning,which used for 16S rDNA sequencing and LC-MS metabolome detection were performed. Results: Compared with the control group, the growth performance of group S was significantly increased. For the rumen fluid microbiome and metabolome detection, both groups M and S showed significant differences from group C.Conclusions: The microbes and metabolites were different due to different supplementary feeding methods. Metabolites with differential levels were mainly involved in metabolic pathways such as amino acid metabolism, nucleotide metabolism, and carbohydrate metabolism. These numerical differences indicate that there are specific ruminal microbes structures in the rumen fluid of high-yielding cows, which promoting better development of animals.