Effect of selenium nanoparticles and mannan oligosaccharide supplementation on muscle and lymphoid histomorphometry and morphometry of tibia bone in broilers reared under high stocking density

The current study investigated the potential of selenium-nanoparticles (SeNPs) and mannan-oligosaccharide (MOS) supplementation in ameliorating the high stocking density (HSD) stress on breast muscle, immune organs, and tibia bone in broilers. Three hundred and ninety two (392) day-old Ross chicks were divided in seven groups with eight replicates each (n = 7): as NSD [basal diet (BD) + normal stocking density: 10 chicks/m2], HSD (BD + high stocking density: 16 chicks/m2), Se-HSD [BD + Selenium (Se) 0.15 mg/kg of BD], MOS-HSD (BD + MOS 05 g/kg of BD), Se-MOS-HSD (BD + Se 0.15 mg/kg of BD + MOS 05 g/kg of BD), SeNP-HSD (BD + SeNP 0.15 mg/kg of BD), and SeNP-MOS-HSD (BD + SeNP 0.15 mg/kg of BD + MOS 05 g/kg of BD). HSD decreased (p < 0.05) breast muscle fibre diameter, density and area, pH at 0 h, pH at 24 h postslaughter, and water holding capacity (WHC), area of lymphoid tissue in caecal tonsil and bursa of Fabricius, tibia bone morphometric parameters, and Se and Copper (Cu) concentrations in bone, muscle, and serum in the HSD group compared to the NSD group. Breast muscle fibre diameter and density increased (p < 0.05) in the Se-MOS-HSD and SeNP-MOS-HSD groups and WHC only increased (p < 0.05) in the SeNP-MOS-HSD group. The area of lymphoid tissue in caecal tonsil and bursa of Fabricius increased (p < 0.05) in the SeNP-MOS-HSD group. The tibia bone weight, medullar canal diameter, tibio-tarsal index, weight/length index, and ash% improved (p < 0.05) in the SeNP-HSD and SeNP-MOS-HSD groups. Se and Cu concentration improved (p < 0.05) in bone, muscle, and serum of the Se-MOS-HSD, SeNP-HSD, and SeNP-MOS-HSD groups. We concluded that supplementation of SeNPs-MOS proved to be a more superior combination in mitigating HSD stress on breast muscle, lymphoid organs, and tibia bone.