Diet-ruminal microbiome-host crosstalk contributes to differential effects of calf starter and alfalfa hay on rumen epithelial development and pancreatic ?-amylase activity in yak calves

Dietary supplementation of alfalfa hay or calf starter during the preweaning period was beneficial to gastrointestinal development in dairy calves and lambs. In present study, we designed 2 experiments using weaning with investigate diet-ruminal microbiome-host crosstalk yak by analyzing ruminal microbiota rumen epithelial transcriptome. During period, either significantly promoted animal growth organ calves, including increases body weight, height, length, chest girth, liver, spleen, thymus. These improvements could be attributed increased dry matter intake, fermentation, development. Butyrate concentration fed starter, which further promote epithelium Using 16S rRNA gene amplicon sequencing, determined that butyrate-producing genera were starter. Transcriptomic analysis epithelia revealed PI3K-Akt signaling pathway, is critical mediating many aspects cellular function such as cell growth, upregulated response supplementation. The also jejunal ?-amylase activity, whereas reduced ileal activity. Furthermore, co-supplementation both intestinal propionate concentration, exhibited opposite trend. observed effects on corresponded up- downregulation, respectively, cholecystokinin involved pancreatic secretion thereby decreased conclusion, calves. differentially affected activities due their different chemical components especially production.