Impact of deoxynivalenol on rumen function, production, and health of dairy cows: Insights from metabolomics and microbiota analysis.

Deoxynivalenol contamination in feed and food, pervasive from growth, storage, and processing, poses a significant risk to dairy cows, particularly when exposed to a high-starch diet; however, whether a high-starch diet exacerbates these negative effects remains unclear. Therefore, we investigated the combined impact of deoxynivalenol and dietary starch on the production performance, rumen function, and health of dairy cows using metabolomics and 16 S rRNA sequencing. Our findings suggested that both high- and low-starch diets contaminated with deoxynivalenol significantly reduced the concentration of propionate, isobutyrate, valerate, total volatile fatty acids (TVFA), and microbial crude protein (MCP) concentrations, accompanied by a noteworthy increase in NH3-N concentration in vitro and in vivo (P < 0.05). Deoxynivalenol altered the abundance of microbial communities in vivo, notably affecting Oscillospiraceae, Lachnospiraceae, Desulfovibrionaceae, and Selenomonadaceae. Additionally, it significantly downregulated lecithin, arachidonic acid, valine, leucine, isoleucine, arginine, and proline metabolism (P < 0.05). Furthermore, deoxynivalenol triggered oxidative stress, inflammation, and dysregulation in immune system linkage, ultimately compromising the overall health of dairy cows. Collectively, both high- and low-starch diets contaminated with deoxynivalenol could have detrimental effects on rumen function, posing a potential threat to production performance and the overall health of cows. Notably, the negative effects of deoxynivalenol are more pronounced with a high-starch diet than a low-starch diet.

The physiological dissimilarities of Holstein dairy cows with different milk yields.

BACKGROUND: Even if breed, parity, dietary and environmental management are same, dairy cows still have notable differences in milk yield that may be underpinned by physiologic differences. OBJECTIVES: This study aimed to investigate the physiological dissimilarities of dairy cows with different milk yields. METHODS: Thirty cows were sorted into high milk-yielding cows (group H: 58.93±2.31 kg/day), moderate milk-yielding cows (group M: 44.99±0.54 kg/day), and low milk-yielding cows (group L: 24.99±6.83 kg/day) according to milk yield. Blood was collected and serum parameters were assessed. Rumen fluid was collected for the evaluation of rumen fermentation parameters (RFPs) and bacterial community composition (BCC). RESULTS: Serum prolactin, growth hormone, glutathione peroxidase, immunoglobulin A and non-esterified fatty acid had a significantly positive correlation with milk yield (p < 0.05), whereas serum glucagon and total antioxidant capacity had a significantly negative correlation with milk yield (p < 0.05). The concentration of valeric acid and the ratio of acetic acid to propionic acid in the rumen fluid in group H was significantly lower than that in group L (p < 0.05). The concentration of acetic acid and butyric acid in group H was significantly lower than that in groups M and L (p < 0.05). The relative abundances of Ruminococcaceae_NK4A214_group, Prevotella_1, Rikenellaceae_RC9_gut_group, Christensenellaceae_R-7_group, Muribaculaceae, and Ruminococcus_2 were negatively correlated with milk yield, whereas the relative abundance of Succinivibrionaceae_UCG-001, Lachnospiraceae_NK3A20_group, Shuttleworthia and Dialister were positively correlated with milk yield (p < 0.05). CONCLUSIONS: This study indicates that dairy cows with different milk yields have clear divergence in serum indicators, RFPs, BCC and rumen microbial metabolism.

Correlation of oxidative stress-related indicators with milk composition and metabolites in early lactating dairy cows.

BACKGROUND: In highly intensive dairy farms, cows often suffer from metabolic disorders that cause severe oxidative stress. OBJECTIVES: This study aimed to observe correlations and associations of oxidative stress-related indicators with milk compositions and metabolites. METHODS: Twenty-two multiparous Holstein dairy cows in early lactation were randomly selected from a commercial dairy farm. The morning milk was collected for composition and metabolites analysis. Blood was sampled via the tail vein to analyze oxidative stress-related indicators (reactive oxygen species, ROS; catalase, CAT; superoxide dismutase, SOD; glutathione peroxidase, GPX; malondialdehyde, MDA) and metabolites. RESULTS: Results showed that ROS were positively correlated with CAT, GPX, SOD, and MDA. However, the levels of CAT, GPX, and SOD were negatively related to milk fat (P  <  0.05). Nineteen serum and 7 milk metabolites were selected from detectable metabolites according to their correlations with ROS, CAT, GPX, and SOD (P  <  0.05). Metabolic pathway analysis and the Kyoto Encyclopedia of Genes and Genomes (KEGG) database revealed that these metabolites are primarily involved in the metabolic pathways of carbohydrates and amino acids. CONCLUSIONS: This study gave us a better understanding on oxidative stress that ROS not only increased oxidative damage (MDA) in dairy cows, but also altered some metabolites involved in amino acid and carbohydrate metabolism.