Dietary Fiber for Gestating Sows During Heat Stress: Effects on Reproductive Performance and Stress Level

Abstract Background: Heat stress is an important issue in swine farms, which causes economic loss and compromises sows health. The addition of fiber to the diet is an option in modifying intestinal health. This study was designed to evaluate the effect of fiber level on reproductive performance, intestinal microbiota and integrity, and metabolism of gestating sows, and its carry-over effect on the lactation period during heat stress. Methods: A total of 36 gestating sows (90 day-pregnant) were allotted to three treatments with 12 replicates. The diets included 3% (LF), 4.5% (MF), and 6% (HF) crude fiber. All gestating sows fed 2.5 kg of diet daily and diets contained 3150 kcal/kg of ME, 14% crude protein (CP), and 0.58% standardized ileal digestibility of lysine. Results: Sows fed the HF diet showed a lower respiratory rate and hair cortisol concentration compared with the LF treatment. The HF diet increased the feed intake of sows compared with the LF diet, while it decreased the farrowing duration. The HF diet increased the constipation index compared with the MF and LF diets. Sows in the HF treatment showed a greater piglet weight and litter weight compared with the LF treatment at weaning. Sows in the LF treatment showed the highest digestibility of CP and the greatest digestibility of acid detergent fiber was observed in sows fed HF diet. The HF diet increased lying and decreased standing, and sham chewing behavior compared with the LF diet. The concentration of acetate and total short-chain fatty acid were increased in sows fed the HF diet. The gene expression of glucose transporter 3 and 4 was increased in the HF treatment. The gene expression of heat shock protein70 was decreased in the HF treatment.Conclusion: Increasing dietary fiber level decreased stress level and improved farrowing duration and reproductive performance.