Micelle silymarin supplementation to sows’ diet from day 109 of gestation to entire lactation period enhances reproductive performance, and affects serum hormones and metabolites

The aim of the present study was to explore the influences of varying doses of micelle silymarin (0%, 0.05%, 0.1%, and 0.2%) supplementation on sows' feed intake, milk yields, serum hormones, and litter growth using 40 multiparous sows (Landrace × Yorkshire, parity from 3 to 5) from the 109th prenatal day to the 21st postnatal day. Each treatment included 10 sows and each sow was used as an experimental unit. On weaning day, litter weight and litter weight gain were linearly improved (P < 0.01, both), corresponding to the increasing dose of silymarin micelle in the diet. Also, litter weight, litter weight gain, and average daily gain (ADG) of piglets born to treated sows exceeded (P < 0.05) those of offspring from the control sows (0% micelle silymarin). Feed intake in week 1, week 2, and the entire lactation period was increased (linear, P < 0.01) as micelle silymarin dose increased. Body weight (BW) loss of sows during lactation was linearly reduced (P = 0.003) with the increasing amounts of micelle silymarin. Average daily milk yields during lactation were also linearly increased (P = 0.002) in treated sows, exceeding (P = 0.046) that of control sows. Also, uniform increases were observed (P = 0.037) in fat content in milk produced by treated sows on day 14 of lactation. Epinephrine concentrations and aspartate aminotransferase (AST) activity in sow serum on day 21 postpartum were linearly declined (P = 0.010) as micelle silymarin dose increased, and were both declined (P < 0.05) in treated sows compared with the control. In addition, treated sows' serum had higher activity of superoxide dismutase (SOD) at parturition and glutathione peroxidase (GSH-Px), lower oxidized glutathione (GSSG) concentrations, and GSSG/GSH (glutathione) ratio (all, P < 0.01) on day 21 of lactation. Moreover, offspring from micelle silymarin-treated sows tended to (0.05 < P <0.1) have higher serum catalase (CAT) activity and total antioxidant capacity (T-AOC) concentrations. Taken together, the results showed that sows fed increasing levels of micelle silymarin from the 109th prenatal day to the 21st postnatal day had an incremental dose-dependent effect on higher feed intake, diminished BW loss, greater milk yields, and greater litter weight at weaning, and 0.2% of micelle silymarin could be optimal to achieve the better effect.