Effect of β-mannanase supplementation in low-energy diets containing palm kernel meal on productive performance, egg quality, intestinal morphology, and liver characteristics in laying hens raised under heat stress conditions

Feeding low-energy diets containing 5.0% PKM decreased feed efficiency in laying hens under HS conditions. However, MN supplementation in PKM-containing low-energy diets had no beneficial effects on laying performance. Low-energy diets, irrespective of PKM inclusion, exacerbate stress responses and impair jejunal morphology. However, 0.10% MN supplementation in PKM-containing low-energy diets ameliorated stress responses and improved jejunal morphology in laying hens under HS conditions.