Dietary effect of nano-encapsulated probiotics and alpha-lipoic acid in improving blood parameters, immunity, gut health, gene expression, and growth performance in heat-stressed broilers

Heat stress in broilers disrupts vital functions, leading to decreased performance and overall health, as well as significant economic losses. To alleviate the negative influences of heat stress on broilers, several strategies have been employed, most notably dietary supplementation. The present study investigates the impact of supplementing nano-encapsulated probiotics and alpha-lipoic acid on growth performance, gut microbiota, immune response, and gene expression in heat-stressed broilers. A total of 360 one-day-old male Ross 308 broiler chicks were randomly assigned to four groups (6 replicate per group): a control group fed a basal corn-soybean diet (CON) and three treatment groups receiving the basal diet supplemented with nano-encapsulated probiotics (NC-P, 1 × 10⁶ CFU/g of diet), alpha-lipoic acid (ALA, 300 mg/kg), or their combination (CNPA). Supplementing the CNPA mixture significantly improved growth performance, as evidenced by enhanced feed conversion ratio, body weight gain, carcass traits, and up-regulated IGF-1 gene expression (P < 0.05). Moreover, the mixture decreases cholesterol, triglycerides, LDL-cholesterol, and uric acid levels (P < 0.05). CNPA mixture improves the ability to adjust heat stress by enhancing antioxidant status, via increased superoxide dismutase (SOD), and decreased malondialdehyde (MDA, P < 0.05). Furthermore, CNPA mixture reduces pathogenic bacteria and up-regulates the expression of cationic amino acid transporter-1 (CAT-1, P < 0.05) and mucin 2 (MUC-2) genes, enhancing intestinal health. Overall, the combination of nano-encapsulated probiotics with α-lipoic acid effectively mitigates heat stress impacts in broilers.