We aimed to study the effects of ammonia on carcass traits, organ indices and fatty acid composition of broilers. Four hundred 21-d-old male Arbor Acres broilers with initial weight 563.52 ± 2.82 g were randomly allotted to 1 of 4 groups treated with ammonia at <3 mg/kg (control), 25 ± 3, 50 ± 3, and 75 ± 3 mg/kg concentrations. Each group consisted of 4 replicates of 25 birds. Broilers from 21 to 42 d were reared on the net floor in the respiration-metabolism chambers where similar environmental conditions were maintained. At 32 and 42 d of age, carcass traits and organ indices were determined for 4 birds per pen. At 42 d of age, fatty acid composition in the breast and thigh muscle of broilers was measured. Results showed as follows: 1) At 32 d, the dressing percentage of broilers exposed to 25 and 75 mg/kg ammonia were lower than those in the control group (P < 0.05); eviscerated yield percentage of broilers in the 25 mg/kg ammonia group was also lower (P < 0.05). At 42 d, the dressing percentage of broilers in the ammonia treatments and the thigh muscle percentage of broilers in the 50 and 75 mg/kg ammonia groups were lower (P < 0.05) than those in the control. Breast muscle percentage of broilers exposed to 25 and 50 mg/kg ammonia and eviscerated yield percentage exposed to 50 mg/kg ammonia were lower than those in the control (P < 0.05). 2) The kidney index of broilers (d 32) exposed to ammonia was greater (P < 0.05) than that of the control. At 42 d, hepatic index of broilers exposed to ammonia was increased (P < 0.05), and spleen index was decreased (P < 0.05). 3) At 42 d, stearic (C18:0) and saturated fatty acids (SFA) in the thigh muscle of broilers were higher, while the unsaturated fatty acid:saturated fatty acid (U:F) ratio and unsaturated fatty acid (UFA) were lower in the 50 mg/kg ammonia treatment than in the control group (P < 0.05). In conclusion, ammonia over 25 mg/kg could decline carcass traits and immune organ indices and increase the kidney and hepatic indices. Further, exposure to 50 mg/kg ammonia could also decrease breast and thigh muscle yield percentage while increasing SFA content and decreasing UFA content in the thigh muscle of broilers.
Keywords: Ammonia; Broiler; Carcass traits; Fatty acid; Organ indices.