Impact of curcumin nanoparticles supplementation on antioxidant status, growth performance, immune function, gut microbiota, and hematobiochemical parameters in heat-stressed broiler chickens

This study evaluated the effects of dietary supplementation with curcumin nanoparticles (CurNPs) on growth performance, hematological and biochemical parameters, antioxidant status, immune response, and caecal microbiota in broilers subjected to HS. Five hundred one-day-old male Ross 308 broilers were randomly assigned to five groups: thermoneutral control (TN), heat stress control (HS), and three HS groups supplemented with CurNPs at 75, 150, and 300 mg/kg diet (CN1, CN2, CN3). From day 25 to 42, HS groups were exposed to 34 ± 2 °C for eight hours daily. Exposure to HS significantly decreased feed intake, body weight gain, antioxidant enzyme activities (GPx, SOD), haematocrit, haemoglobin concentration, and lymphocyte counts, while increasing feed conversion ratio, mortality, serum malondialdehyde, heterophils, total cholesterol, triglycerides, and liver enzyme activities (AST, ALT). Additionally, HS reduced serum immunoglobulins (IgG and IgM) and beneficial caecal lactic acid bacteria, while promoting coliform bacterial proliferation. Dietary CurNPs supplementation improved growth performance by increasing body weight gain and lowering feed conversion ratio and mortality in a dose-dependent manner. CurNPs also enhanced antioxidant defences, normalised hematological indices, boosted immune response through elevated IgG and IgM, and mitigated liver damage and dyslipidemia induced by heat stress. Furthermore, CurNPs positively modulated caecal microbiota by reducing harmful coliforms and restoring lactic acid bacteria populations. In conclusion, curcumin nanoparticles effectively alleviate heat stress-induced physiological, immunological, and microbial disturbances in broilers, highlighting their potential as a natural dietary additive to improve poultry resilience under thermal stress conditions.