Effects of chestnut tannins on performance and antioxidative status of transition dairy cows.

This study was conducted to evaluate the effects of chestnut tannins (CT) on performance and antioxidative status of transition dairy cows. Twenty multiparous Chinese Holstein cows in late gestation were paired according to expected calving date and randomly assigned either to a diet supplemented with CT (CNT, 10 g of CT/kg of diet, dry matter basis) or to an unsupplemented control (CON) diet from 3 wk prepartum to 3 wk postpartum. Blood samples were taken on d -21, 1, 7, and 21 relative to calving for analysis of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), total antioxidant capacity (T-AOC), and malondialdehyde (MDA). Liver samples were taken by puncture biopsy on d 1 and 21 relative to calving for analysis of SOD, GSH-Px, and MDA. Data were analyzed for a completely randomized block design with repeated measures. The addition of CT had no significant effects on dry matter intake, body weight, body condition score, milk yield, 3.5% fat-corrected milk yield, and milk composition but did decrease milk MDA and somatic cell score in transition dairy cows. Dry matter intake decreased from d -21 to 0 and increased from d 1 to 21 relative to calving across treatments. During the experimental period, body weight and body condition score decreased, whereas milk MDA and somatic cell score increased across treatments. A time effect was also observed for plasma MDA, which peaked on d 1 relative to calving and remained higher than that on d -21 relative to calving across treatments. Addition of CT decreased MDA concentrations in plasma and liver. Neither time nor CT × time effects were observed for SOD and T-AOC in plasma and SOD and GSH-Px in liver; a time effect was observed for plasma GSH-Px, which peaked on d 1 relative to calving and remained higher than those on d -21 relative to calving across treatments. Addition of CT increased SOD, GSH-Px, and T-AOC activities in plasma and SOD and GSH-Px activities in liver. In conclusion, addition of CT might inhibit lipid peroxidation and increase antioxidant enzymes activities in plasma and liver of transition dairy cows. Supplementation of CT may be a feasible means to improve the antioxidative status of transition dairy cows.