-arginine reduces injury from heat stress to bovine intestinal epithelial cells by improving antioxidant and inflammatory response.

Heat stress (HS) has a negative impact on the health and performance of dairy cows, resulting in economic losses. Damage to the intestinal epithelium is the main cause of the adverse effects of heat stress on bovine health. This study investigated the repair capability of -arginine (-Arg) in reducing the adverse effects of HS on bovine intestinal epithelial cells (BIECs). BIECs were treated as follows: (1) control cells were cultured at 37 °C continuously and received no -Arg; (2) cells in HS group were grown at 42 °C for 6 h followed by 12 h at 37 °C; and (3) the -Arg group was cultured at 42 °C for 6 h, then treated with -Arg at 37 °C for 12 h. HS disrupted redox homeostasis and reduced viability in BIECs, while treatment with -Arg (6 mmol/L) for 12 h markedly reduced the negative effects of HS. -Arg protected cells by preventing HS-induced changes in mitochondrial membrane-potential, inflammation, apoptosis-related gene expression and regulation of antioxidant enzymes. The above results indicated that -Arg reduced the level of damage from HS in BIECs by lowering oxidant stress and inflammation, suggesting that -Arg could be an effective dietary addition to protect cows from adverse intestinal effects caused by HS.