Mineral interactions in lactating sows: evaluating oxidative stress and productivity during heat stress

This study investigated the effects of dietary minerals at different levels on reproductive performance of lactating sows during high ambient temperature. The sows were divided into eight treatments according to a 2 × 4 factorial arrangement including two levels of Zn and Cu (ZC100, 100 mg/kg of Zn, and 20 mg/kg Cu; ZC150, 150 mg/kg of Zn and 25 mg/kg Cu) and four levels of Fe, Mn, and Se (FMS; 80 mg/kg Fe, 25 mg/kg Mn, 0.15 mg/kg Se; FMS150, 120 mg/kg Fe, 37.5 mg/kg Mn, 0.225 mg/kg Se; FMS200, 160 mg/kg Fe, 50 mg/kg Mn, 0.30 mg/kg Se; and FMS300, 240 mg/kg Fe, 75 mg/kg Mn, 0.45 mg/kg Se). The serum composition showed higher Se, Mn, and Fe levels in the FMS200 and FMS300 compared with the FMS. A decrease in serum Zn levels was observed in the FMS200 and FMS300 compared with the FMS. A lower loss of both BW and backfat during lactation was observed in the FMS300 and FMS200 compared with NRC and FMS150. An increase in piglet survivability was observed in the FMS200 group compared to the FMS150 and NRC groups. Total superoxide dismutase (SOD) and Mn-SOD were increased in the FMS200 and FMS300 compared with the FMS. An increase in Se, Mn, and Fe levels in the milk was observed in the FMS200 and FMS300 compared with the FMS. The abundance of Proteobacteria phylum and Clostridium_sensu_stricto_1 genus were higher in the NRC group than in the FMS300 group. In conclusion, increased Fe, Mn, and Se in sow diets reduced weight loss and raised antioxidant levels, however, the observed reduction of Zn in serum and a tendency for lower Zn in milk raises concerns about potential repercussions for litter growth.