Effects of Sodium Butyrate Forms on Carcass Performance, Pulmonary Hypertension, Metabolic Health and Oxidative‐Inflammatory Responses in Broiler Chickens Under Cold Stress at High Altitude

OBJECTIVES: This study aimed to evaluate and compare the effects of non-encapsulated sodium butyrate (SB) and encapsulated sodium butyrate (ESB) on carcass performance, pulmonary hypertension, metabolic health and oxidative-inflammatory responses in broiler chickens exposed to cold stress at high altitude (2100 m). METHODS: A total of 675 one-day-old male broiler chicks were randomly allocated to nine dietary treatments: a control basal diet, diets supplemented with SB (0.05% or 0.1%), ESB (0.05% or 0.1%), or their combinations. Birds were reared under a cold stress temperature regime for 42 days. Carcass traits, organ weights, the right ventricle-to-total ventricle weight ratio (RV:TV) and ascites mortality were assessed. Blood samples were analysed for lipid profiles, liver enzymes and oxidative stress, including malondialdehyde (MDA), nitric oxide (NO) and the heterophil-to-lymphocyte (H:L) ratio. RESULTS: ESB and SB-ESB combinations significantly improved carcass performance, increasing breast and thigh yields while reducing abdominal fat. The RV:TV ratio, an indicator of pulmonary hypertension and ascites mortality were reduced in the SB0.1% and specific combination groups. Supplementation improved metabolic health, evidenced by enhanced lipid profiles (reduced cholesterol, increased HDL) and decreased liver enzyme activities (ALT, AST, ALP). Oxidative stress was mitigated, with reduced MDA and increased NO levels across treated groups. Immunomodulatory benefits were observed, including a decreased H:L ratio. CONCLUSIONS: Dietary supplementation, particularly with ESB at 0.1%, effectively mitigated the adverse effects of high-altitude cold stress by improving carcass yield, reducing pulmonary hypertension, enhancing metabolic and liver health and strengthening antioxidant and anti-inflammatory responses. ESB is identified as an optimal nutritional strategy for supporting broiler production in challenging environments.