Latest ArticlesHeat stress poses a significant challenge to the ruminant livestock industry under the context of global warming, severely impacting animal production performance, immune function, and reproductive efficiency. Chromium, as an essential trace element for animals, plays a key role in regulating glucose and lipid metabolism, enhancing antioxidant capacity, and maintaining immune function. This review summarized the detrimental effects of heat stress on ruminants and its underlying mechanisms, and introduced the sources, types, and application effects of chromium under heat stress conditions. It focused on the ameliorative effects of chromium supplementation on the lactation performance, growth performance, and reproductive performance of ruminants. Furthermore, the review explored the mechanisms of action, including enhancing insulin sensitivity, regulating glucose metabolism, improving antioxidant capacity, boosting immune function, and modulating the rumen microbiota. This review also analyzed existing research limitations, such as insufficient comparability among different chromium sources and the lack of standardized dosage, and proposed future research directions, aiming to provide a theoretical basis and practical reference for alleviating heat stress in ruminants.
The immune function of dairy ruminants is a core factor in safeguarding their health status, production performance, and product quality. Nutrients, as the material basis for life activities, also serve as key signaling molecules regulating immune function. Through multiple pathways, such as directly acting on immune cells or indirectly modulating the gastrointestinal microbiota, nutrients profoundly influence the immune function of dairy ruminants. This paper systematically reviewed the direct regulatory mechanisms of key nutrients, such as amino acids and fatty acids, on immune cells, the indirect immune regulatory pathways of nutrients via the gastrointestinal microbiota and their metabolites, the role of nutrients in maintaining the intestinal physical and immune barrier, and the functions of nutrients in alleviating oxidative stress and regulating the balance of inflammatory cytokines. Furthermore, it summarized application strategies for immune enhancement, including the use of functional feed additives, precision nutrition, and phase-feeding. The aim is to provide a theoretical reference for formulating precision nutrition plans, enhancing immunity, and promoting healthy farming practices for dairy ruminants.