PSIX-4 Rumen Microbial Meta-Proteome and Milk Whey Proteome in Holstein Cows fed with High Starch and low Fiber Diet

Abstract Identifying milk biomarkers impacted by dietary starch and fiber profiles can support optimization of feeding concurrent promotion animal health. The objective this study was to characterize the rumen meta-proteome whey proteome in Holstein cows fed different levels physically effective undigestible NDF (peuNDF240) fermentable (RFS). Eight ruminally cannulated were included a 4 x Latin square design with four 28-day periods. From study, samples collected from each period receiving one two treatments: 1) low peuNDF240, high RFS (LNHR) or 2) (HNLR). Rumen fluid at end three timepoints, snap-frozen, stored -800C. microbial proteins isolated, quantified, isobarically labeled, analyzed LC-MS/MS. acquired product ion spectra searched against 71 composite databases cattle database, respectively. Data using PROC MIXED procedure SAS 9.4. Of 130 rumen-associated identified across 22 species, abundances 13 diet eight species. Six these associated core metabolism. Among 159 quantified proteins, 17 diet. Many host defense, nutrient synthesis, transportation. abundance CD14 lactadherin less LNHR (P < 0.05), whereas Prostaglandin-H2 D-isomerase lipoprotein lipase greater 0.05). Our results indicate higher concentration has influence on than profile highlight potential use as indicative nutrition.