Abstract
OBJECTIVE: This study investigated the impact of supplementation of protease and organic acid on growth performance and other biological parameters in broilers fed poultry byproduct meal (PBM) based diet. METHODS: Five hundred 1-day-old broiler chicks (Ross 308) were distributed into five treatments with 5 replicates, each pen having 20 birds, and fed each group one of five isocaloric and isonitrogenous diets in two phases: stater phase (1 to 21 days) metabolizable energy (ME) 3000 kcal/kg; crude protein (CP) 22%, and a finisher phase (22 to 35 days) ME 3,200 kcal/kg; CP 19.5%. The dietary treatments were: i) standard broiler ration (Cont); ii) The control diet with 25% of the soybean meal replaced by PBM on an equivalent protein basis (PBM); iii) PBM diet supplemented with 0.5 g/kg of protease (PBMP); iv) PBM diet supplemented with 1 g/kg organic acid (PBMO); and v) PBM diet addition with 0.5 g/kg protease and 1 g/kg organic acid (PBMPO). RESULTS: The overall data showed that feed conversion ratio was improved (p<0.05) in the PBMP group. Apparent CP digestibility was higher (p<0.05) in both Cont and PBMP groups. Jejunal villus height increased (p<0.05) in PBMP and PBMPO groups, while only the PBMO group exhibited a higher (p<0.05) crypt depth. Lipase activity was increased (p<0.05) in the PBMP, PBMO, and PBMPO dietary treatments. However, trypsin activity showed a significant increase (p<0.05) in the PBMP and PBMO groups. Serum biochemistry increased (p<0.05) globulin and total protein levels in the PBMP group. CONCLUSION: PBM could partially replace the soybean meal with supplementation of either protease or organic acid in broiler diets without impairing overall growth performance. Furthermore, careful optimization must be considered when combining protease and organic acids.