Effects of dietary mineral level and creep feed provision on lactating sows during heat stress.

This study evaluated the interactive effect of mineral levels and creep feed provision (CF) on reproductive performance, stress level, and immune status of lactating sows during heat stress (HS). 2 × 2 factorial arrangement was assessed, involving two mineral levels (STD, the diet contains 20, 100, 80, 25, and 0.15 ppm of Cu, Zn, Fe, Mn, and Se, respectively; ADV, the diet contains 25, 150, 160, 50, and 0.30 ppm of Cu, Zn, Fe, Mn, and Se, respectively) with or without CF during HS. The CF group showed lower (P < 0.05) respiratory rate on days 8, 10, 11, and 14. ADV and CF groups showed lower (P < 0.05) body weight loss during lactation. A tendency for decreased (P = 0.063) loss of back fat thickness in the CF group. ADV group shows higher (P < 0.05) weaned piglet weight and survivability. CF group showed lower hair cortisol concentration (P < 0.05) with higher (P < 0.05) piglet survivability. ADV and CF groups showed lower (P < 0.05) serum TNF-α level, also increased (P < 0.05) superoxide dismutase and malondialdehyde levels. In milk, the level of Fe, Mn, and Se increased (P < 0.05) in the ADV group. Also, feces excreted higher (P < 0.05) Zn, Fe, Mn, and Se. In conclusion, while both ADV and CF had beneficial effects, ADV posed a risk of increased mineral excretion. Given stricter regulations on dietary trace minerals, CF could be an effective strategy to enhance the performance of sows and piglets under HS.