Hot-Melt Extruded Selenium: a Highly Absorbable Nano-Selenium in Lactating Sows Exposed to High Ambient Temperature

To study the role of hot-melt extruded (HME) selenium (Se) and in the lactating sows' reproductive performance and litter growth, a total of 60 crossbred sows (Yorkshire × Landrace; average body weight, 245.3 kg) were allotted to one of four treatments according to a 2 × 2 factorial arrangement. The performance of lactating sows was investigated in the different average room temperatures (high temperature (HT), 28.1 °C vs. low temperature (LT), 24.6 °C), and different selenium sources (INO, 0.15 mg common sodium selenite/kg diet; HME, 0.15 mg nano-sodium selenite/kg diet) during the summer season. At days 10 and 21, the serum glutathione peroxidase (GPx) activity and Se concentration were greater in lactating sows fed HME compared with sows fed INO diet. The concentration of Se in the serum was greater in piglets from the HME treatment compared with piglets from the INO treatment. The HT treatment had a significantly higher body weight loss, backfat thickness loss, and weaning-to-estrus interval. The piglets' survivability, total weight gain, daily feed intake, and average daily gain during the lactation were greater in the LT sows compared with the HT sows. A higher blood cortisol concentration was observed in the HT sows compared with the LT. Selenium contents of milk at days 10 and 21 postpartum were increased by dietary supplementation of HME. In conclusion, the results of the present study demonstrated that there are no performance differences between sows fed different Se sources; however, HME supplementation increased serum and milk Se content, resulting in increased serum GPx concentration in sows and a greater serum Se in the litters.