Applied Research Note: Exogenous protease supplementation to reduced-energy, reduced-protein, and reduced-amino acid diets for broiler chickens from days 1 to 42

Supplementing exogenous proteases in poultry diets was shown to facilitate the digestion of dietary proteins. However, there is limited information on the effects of proteases inclusion on performance of broiler chickens fed reduced energy, protein, and essential amino acid (EAA) diets. This study aimed to address this gap in knowledge. A total of 720 one-day-old Cobb 500 male broilers were randomly allocated to 6 treatments and 6 replicates of 20 birds. The treatments included: positive control (PC; formulated as per the breeder guideline), negative control (NC; reduction in nutrition levels by 100 kcal/kg ME; 1% CP, and 5% EAAs), and NC diets supplemented with 50 g/t, 100 g/t, 200 g/t, 400 g/t of Vitazyme Pro protease (NC 50, NC 100, NC 200, and NC 400). From d1-14 and 14-28, all nutrient reduction groups, except for NC 100, had higher FCR (P < 0.05) than PC. From d28-42, the NC group had higher (P < 0.01) FI and FCR than PC. However, protease supplementation from 100 - 400 g/t maintained the higher FI (P < 0.01) while increased BWG (P < 0.01) compared to PC. For the entire 42-day period, PC and NC 100 had lower (P < 0.01) FCR than NC and NC 50. In conclusion, the results suggested that protease supplementation could mitigate the negative impacts of reductions in dietary nutrition levels on growth performance. The inclusion of Vitazyme PRO protease at 100 g/t seemed to be optimal for improving growth performance in diets with reduced energy, protein, and EAAs.