Versazyme supplementation of broiler diets improves market growth performance.

Day-old male broiler chicks were randomly assigned to 32 floor pens in a completely randomized block design and grown to 6 wk of age. Birds in experiment 1 were fed 1 of 2 basal diets supplemented with or without a protease containing feed additive, Versazyme (VZ). The 4 treatments were 1) control (C), a corn-soybean meal diet that contained 95% of amino acids recommended by NRC except for threonine and isoleucine; 2) C + 0.1% VZ (wt/wt) (C+) in the starter diet only; 3) high (HP) amino acid diet, a corn-soybean meal diet with 100 to 105% of amino acid recommended by NRC except for threonine and isoleucine; and 4) HP + 0.1% VZ (wt/wt) (HP+) in starter diet only. Supplementing both diets with VZ improved BW and feed conversion ratio (FCR) at 21 d of age and BW at 42 d of age. Cumulative 42-d FCR was only improved in birds fed the HP+ diet. Birds in experiment 2 received the following treatments: 1) HP, 2) HP + 0.1% VZ batch A (wt/wt) (A) in starter diet only, and 3) HP + 0.1% VZ batch B (wt/wt) (B) in starter diet only. Enzyme supplementation improved 22-d BW and FCR. There was no significant difference in BW at 43 d of age. Both A and B improved overall FCR (1.758 and 1.751 vs. 1.79 for A and B vs. HP, respectively). In conclusion, supplementation of starter broiler diets with VZ resulted in improved market growth performance.