Comparative effects of dietary lactic acid and formic acid supplementation on growth performance, carcass characteristics, serum biochemical profile, antioxidant status, and cecal microbial population in broilers.

This investigation aimed to assess the influence of lactic acid (OLA) and formic acid (OFA) as dietary acidifiers with antioxidant potential in broiler feed on growth performance, carcass traits, blood parameters (ALT, AST, total protein, albumin, globulin, and lipids), and cecal microbial populations. A total of 300 one-day-old unsexed Ross 308 broiler chicks (42.5 ± 1.2 g) were randomly assigned to five treatments in a completely randomized design, with 5 replicate pens per treatment and 12 chicks per replicate pen. The treatments were as outlined: control - basal diet without addition; OLA1 and OLA2 - basal diet with 2 and 4 g/kg of lactic acid; OFA1 and OFA2 - basal diet with 2 and 4 g/kg of formic acid, respectively. Organic acid inclusion did not significantly alter growth performance parameters or carcass yields (P > 0.05). However, serum biochemical profiles improved significantly (P < 0.05); AST, ALT, urea, and creatinine decreased, whereas total protein, albumin, and the A/G ratio increased, exhibiting prominent linear responses (P < 0.05). Antioxidant status was significantly enhanced (P < 0.05), evidenced by elevated GPx and GST activities, higher GSH concentration (peaking in OLA2 at 81.8 nmol/L), and reduced MDA levels across all acid-supplemented groups (P < 0.001). Furthermore, beneficial shifts in cecal microbial populations were observed, characterized by a significant reduction in total bacterial counts, total coliforms, E. coli, Salmonella spp., and Clostridium spp., alongside an increase in Lactobacilli (P < 0.05). In conclusion, while dietary lactic and formic acid supplementation did not improve broiler growth performance or carcass yields, they significantly strengthened systemic metabolism, enzymatic antioxidant defense, and cecal microbial equilibrium.