Abstract
This study evaluates the effects of lactic, propionic and butyric acids, along with their salts, as natural antibiotic alternatives and growth promoters in broiler diets. Three hundred one-day-old Cobb broiler chicks (n = 60 per group), with six replicates of 10 birds each, were randomly allocated to five dietary treatments for 35 days: T1 (control, basal diet); T2 (basal diet + lactic acid and lactate, 0.5 g/kg each); T3 (basal diet + propionic acid and propionate, 0.5 g/kg each); T4 (basal diet + butyric acid and butyrate, 0.5 g/kg each); and T5 (basal diet + a mixture of lactic, propionic, and butyric acids and their salts, 0.17 g/kg each; total ≈ 1 g/kg). Growth performance, blood biochemistry, antioxidant indicators, thyroid hormones, carcass characteristics, intestinal microbiota, and humoral immune responses were assessed. The findings indicate that the blend of organic acids and their salts significantly improved (p ≤ 0.05) productive performance during the grower, finisher, and overall periods. Serum antioxidant indices (TAC, CAT) and RBC enzymatic activities (SOD, CAT) exhibited significant increases (p ≤ 0.05), whereas MDA levels were significantly decreased (p ≤ 0.05). T4 hormone levels increased (p ≤ 0.05) in the treated groups without affecting liver and kidney functions. The intestinal microbiota exhibited elevated (p ≤ 0.05) Lactobacillus levels and inhibited E. coli proliferation. Humoral immunity exhibited significantly higher (p ≤ 0.05) HI titers against avian influenza viruses (H9 and H5) than the control group. Overall, supplementation with organic acids and their salts offers a suitable natural growth promoter that enhances broiler productive performance, immunity, and antioxidant status without adversely affecting physiological functions.