Performance and nutrient utilization of broilers fed diets supplemented with a novel mono-component protease

Abstract

SUMMARY Two experiments were conducted to determine the effect of adding an exogenous protease to corn-, soybean meal-, and meat and bone meal-based broiler diets. In the first experiment, 1,764 male Ross 308 broiler chicks were placed in 63 floor pens, with 28 birds per pen. There were 7 treatments, with 9 replicates each, fed in the starter (d 1 to 21) and grower (d 22 to 40) phases. The dietary treatments were a positive control, formulated with 3,050 and 3,150 kcal of ME/ kg and 22.5 and 20% CP in the starter and grower phases, respectively, and a negative control, formulated with a 4.4% reduction in ME and CP as compared with the positive control diets. A mono-component protease (75,000 protease/g) was added to the negative control diets at 0, 100, 200, 400, 800, and 1,600 ppm of feed. Broilers fed the positive control diet grew better and had a better feed-to-gain ratio (FE) than did those fed the negative control diets, regardless of enzyme supplementation. Protease supplementation had no effect on BW; however, FE was improved in a quadratic manner as protease was increased. In experiment 2, a factorial arrangement of 2 protein (7% difference in CP), 2 energy (3% difference in ME), and 2 protease (0 and 200 ppm) concentrations was used, resulting in 8 treatments replicated 11 times (22 male Cobb 500 broilers per replicate). No 3-way interactions were observed for live performance measures. Broilers fed the high-protein and high-energy diets performed better (P ≤ 0.01) than those fed the low-protein and low-energy diets. Protease supplementation improved FE as well as digestibilities of fat and CP (P ≤ 0.01), regardless of dietary protein or energy concentration. The protease used in these studies improved FE and dietary determined AME values as well as dietary CP and fat digestibility values.