Feeding a Saccharomyces cerevisiae fermentation product before and during a feed restriction challenge on milk production, plasma biomarkers, and immune function in Holstein cows.

Periods of decreased feed intake may disrupt function of the intestinal barrier. Feeding NutriTek® (NTK; Diamond V, Cedar Rapids, IA), a postbiotic from S. cerevisiae fermentation (SCFP), improved health and supported anti-inflammatory functions. We investigated the effects of feeding NTK to cows before and during a period of feed restriction (FR) designed to model periods of intestinal barrier dysfunction. In total, 16 multiparous cows (97.1 ± 7.6 DIM; n = 8/group) were fed a control diet (CON) or CON plus 19 g/d NTK for 9 wk (Phase 1; P1) and then were subjected to an FR challenge for 5 d, during which they were fed 40% of their ad libitum intake from the 7 d prior to FR. Milk yield (MY) and DMI were collected daily. During FR, milk was collected daily for composition, blood daily to measure plasma biomarkers and to measure monocyte and neutrophil phagocytosis and oxidative burst on d 1, 3, and 5. Data were analyzed using a mixed model in SAS 9.4. All data were subjected to repeated measures ANOVA. Dietary treatment (TRT), Day, and their interaction (TRT × Day) were considered as fixed effects and cow as the random effect. For analysis of P1, data collected during a 7-d adaptation phase were used as a covariate. During P1, NTK cows tended to have greater DMI and had greater fat, ECM and FCM yields, and feed efficiency (ECM/DMI and FCM/DMI). Protein yield tended to be greater in NTK compared with CON cows. A tendency for greater monocyte phagocytosis was detected with NTK. However, during FR, feeding NTK led to lower MY and lactose yield and tended to lower solids percentage. While NTK cows tended to have reduced neutrophil oxidative burst than CON cows during FR (NTK: 26.20%, CON: 36.93%), there was no difference in phagocytosis (NTK: 7.92%, CON: 6.31%). Plasma biomarkers of energy metabolism, liver function, inflammation, and oxidative stress during the FR period did not differ. Overall, results suggested that feeding NTK increased the yield of FCM, ECM, feed efficiency and milk components prior to FR.