Dietary fermented orange peel and selenium nanoparticles improve antioxidant status, immunity, intestinal integrity, and growth performance in heat-stressed broilers.

Heat stress is a major obstacle to the sustainability of poultry production, especially since modern breeds are highly sensitive to stress due to their high metabolic rate and limited ability to dissipate excess heat. This study investigated the effect of dietary supplementation with fermented orange peel and selenium nanoparticles on growth performance, oxidative stability, immune response, gut microbiota, and gene expression in heat-stressed chickens. Three hundred and twenty broiler chicks (Ross 308) were randomly distributed to four treated (8 replication/ group): a group fed a basal diet (control group, CON), and three groups fed a basal diet added with fermented orange peel (50 g/kg, FOP), selenium nanoparticles (0.2 mg/kg, SeNPs), and their mixture (MFOSe), respectively. Dietary MFOSe enhances body weight gain, feed conversion ratio, and carcass weight, while reducing abdominal fat. Serum decreased triglycerides, cholesterol, and uric acid levels, and increased triiodothyronine (T3) levels in broilers fed MFOSe-mixture. Moreover, supplementing MFOSe increases IgA, IgG, interleukin-10 (IL-10), glutathione peroxidase (GPx), catalase (CAT), total antioxidant capacity (T-AOC), and superoxide dismutase enzymes (SOD), whereas interleukin-6 (IL-6) and malondialdehyde (MDA) levels decreased. However, the MFOSe-mixture reduced pathogenic microbial content and upregulated expression of insulin-like Growth Factor 1 (IGF-1), mucin 2 (MUC-2), sodium-glucose co-transporter-1 (SGLT-1), zonula occludens-1 (ZO-1), Claudin-1 (CLDN-1), and cationic amino acid transporter-1 (CAT-1) gene. The study concluded that adding MFOSe-mixture enhanced immunity, antioxidant capacity, intestinal integrity, and growth performance in heat-stressed broilers.