Impact of Exogenous Protease on Performance, Nutrient Digestibility, and Excreta Odor Emission in Broiler Chickens Fed Corn-Soybean-Based Diet

This experiment was conducted to evaluate dietary protease supplementation in broilers fed corn-soybean meal-based diets on performance, apparent ileal digestibility of nutrients and amino acids, ileal digesta viscosity, blood profile, and excreta odor content. A total of 2,000 1-day-old male broilers (Ross 308, 43.34±1.12 g) were allotted randomly to five dietary treatments on the basis of initial body weight (BW). Each treatment had 10 replicate pens with 40 birds per pen. The 4 dietary treatments were corn-soybean meal diets supplemented with 0, 3,750, 5,000, and 6,250 PCU/kg feed protease. Experimental diets were fed for 42 days in four phases (Pre Starter: d 0-11; Starter: d 12-21; Grower: d 22-32 and Finisher: d 33-42) in pellet form. During d 1 to 21, d 22-42, and the overall study period (d 0-42), with increasing dietary protease levels from 0 to 6, 250 PCU/kg feed, the BWG was improved (linear, P <0.05), whereas the FCR was decreased (linear, P <0.05). There was a linear (P <0.05), improvement in ATTD of CP and GE and most amino acids (with exception of arginine, phenylalanine, and tyrosine) as dietary protease level increased. Blood profiles including blood urea nitrogen and creatinine concentrations were not affected by dietary treatments, similarly, odor emission in excreta of broilers including ammonia, hydrogen sulfide, and total mercaptan was not affected with dietary protease. In conclusion, dietary protease supplementation in broilers corn-soybean meal-based diets had beneficial effects on growth performance, and apparent total tract digestibility of nutrients and amino acids.

• Protease supplementation linearly increased growth performance and feed conversion ratio.

• Dietary protease at 2.5 g kg−1 dose improved crude protein, gross energy, lysine, methionine, cysteine, threonine, tryptophan, isoleucine, leucine, and histidine.