Heat stress mitigating effects of acidifier on growth performance, biochemical parameters, and immune status of broiler chickens

Heat stress (HS) is a major challenge in poultry production, impacting growth rate, metabolic function, and immune status, leading to economic losses and compromised animal welfare. Acidifiers are known as a potential growth promoter, particularly for their role in enhancing gut health and overall performance. This study aimed to evaluate the effects of dietary acidifier on growth performance, biochemical profile, and immune responses in broiler chickens under HS conditions. A total of 160, ten-day-old, broiler chicks were randomly divided into four equal groups (n = 40): Group A (Control), Group B (Acidifier-supplemented), Group C (Control in HS), and Group D (Acidifier-supplemented in HS). HS conditions were maintained at 31 to 36°C for six hours daily over 22 days. Feed intake and body weight were recorded weekly, while blood samples were collected for biochemical and immunological studies on the final day. Results demonstrated that acidifier supplementation significantly improved body weight and lymphoid organ weights, even in HS conditions. HS control birds exhibited elevated serum creatinine and uric acid levels, indicating renal stress, while acidifier helped mitigate the effect. Liver enzymes, ALT and AST, showed no significant changes. However, cholesterol and LDL concentrations were significantly lower in acidifier-supplemented birds in normal conditions, while triglyceride levels declined in both normal and HS conditions; HDL levels remained unchanged. Immunologically, acidifier enhanced humoral immunity, evidenced by higher antibody titers (log ₂ ) against sheep red blood cells (sRBC) in both conditions. Acidifier exhibited a stronger cell-mediated immune response, with increased skin thickness following phytohemagglutinin-P (PHA-P) injection in a time-dependent manner. In conclusion, dietary acidifier effectively mitigates the detrimental effects of HS in broilers, enhancing growth performance, metabolic health, and immunity. These findings suggest that acidifier offers a practical and effective nutritional strategy to promote physiological resilience, immune competence, and overall productivity in poultry exposed to HS.