Effect of yeast culture supplementation on rumen microbiota, regulation pathways, and milk production in dairy cows of different parities

Abstract

The present study elucidated the alterations and distinctions in the regulatory pathways of the rumen microbiota, metabolome, and oxidative stress–immune homeostasis in primiparous and multiparous cows after administering yeast cultures (YCs) during the late periparturient period. This study aimed to evaluate the effect of these changes on productive performance and health status during lactation. A total of 60 Holstein cows with similar body condition score (3.5 ± 0.25) were selected and divided into four groups based on parity— including 30 primiparous cows (parity 1.0 ± 0.00) and 30 multiparous cows (parity 2.6 ± 0.14)—and postpartum serum reactive oxygen species levels (100–200 ng/mL) using the following pairing principle: primiparous control (C1), multiparous control (C2), primiparous experimental (T1), and multiparous experimental (T2). The control groups received a basal diet, whereas the experimental groups received the same basal diet supplemented with YC (150 g/head/d) at the same feeding time. Cows in the experimental groups exhibited significantly higher dry matter intake during early lactation (22.26 ± 0.12 kg/d) than those in the control groups (21.66 ± 0.22 kg/d) (P < 0.05). YC supplementation significantly increased milk production in postpartum cows (P < 0.01). Furthermore, the experimental group showed notably improved antioxidant capacity and immunity compared to those in the control group, with primiparous cows (T1) outperforming multiparous cows (T2). YC supplementation notably increased the rumen abundance of beneficial microbes, including Ruminococcus and Acetobacter, in the T1 group. Although the T2 group also showed an increase in Bifidobacterium, Ruminococcus, and Acetobacter, it exhibited a lower abundance of Butyrivibrio than the C2 group. YC supplementation significantly reduced the rumen abundance of Moraxella. Lastly, metabolomic analysis revealed that YC supplementation significantly upregulated specific metabolites such as spermine, spiraeoside, and betaine in the rumen of primiparous dairy cows, enhancing their antioxidant capacity and immunity. Additionally, metabolites such as DL-threonine, 1-methylhistamine, and phenylephrine were upregulated in multiparous cows, influencing branched-chain amino acid biosynthesis and metabolism and promoting energy balance and metabolism. In conclusion, YC enhances production in dairy cows by promoting specific microbial pathways and optimizing nutritional metabolism, with distinct effects observed between primiparous and multiparous cows.