Poultry By-Product Meal as a Potential Protein Source in Broiler Diets with Exogenous Protease Supplementation

The objective of this study was to investigate the effect of exogenous protease supplementation in diets formulated with poultry by-product meal on growth performance, small intestine magnitudes, and meat physiochemical characters in broiler chickens from 21 to 35 days post-hatch. A total of 120, one-day-old "Arbor Acres Plus" broiler chickens (male: female - 50:50) were allocated one of two dietary treatments to give six replicates and ten birds per cage. Two dietary treatments included a control diet (CON) and a diet supplemented with protease (CON+Pro). At day 35, body weight and feed intakes were measured to calculate the feed conversion ratio for the entire experiment period. Two birds from each pen were euthanized to measure the relative lengths and relative weights of three small intestine sections and meat samples were collected for physiochemical characteristic analyses at 35 days post-hatch. Exogenous protease supplementation did not influence ( P >0.05) growth performance but showed a tendency to improve FCR ( P =0.082). Protease supplementation showed a tendency to reduce proximal small intestine length ( P =0.091). Broilers offered dietary treatments influenced minced meat color where protease supplementation resulted in lower CIE b * ( P <0.001) colorimetric value for yellowness and showed a significant trend ( P =0.059) on reducing meat redness CIE a * . In conclusion, the addition of exogenous protease to a broiler diet formulated with poultry by-product meal did not affect the growth performance, small intestine magnitudes, and meat physiochemical parameters (except CIE b * ) in broiler chickens.