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Evaluation of keratinase stability in pelleted broiler diets¹

^* Department of Poultry Science, North Carolina State University, Raleigh 27695; and BioResource International Inc., Raleigh, NC 27560

² Corresponding author: charles_stark{at}ncsu.edu

Versazyme (VZ) is an approved keratinase-based feed additive produced naturally as a fermentation product of Bacillus licheniformis PWD-1. The experiment was designed to test the recovery and efficacy of VZ using typical feed industry pelleting parameters. The pelleted diets were conditioned to 85°C for 30 s and pelleted using a 4 x 32 mm die, cooled, and crumbled. A total of 192 male broiler chicks were fed a corn-soybean meal starter diet formulated at 18.5% CP to 21 d of age. The 4 treatments used in the feeding study were as follows: VZ 0.0%-mash, VZ 0.0%-pellet, VZ 0.1%-mash, and VZ 0.1%-pellet. Body weight and feed consumption were determined at 21 d of age. The recovery of VZ in feed was 93% in the mash diet and 66% in the pelleted diet. There was a 55-g increase in BW gain and 0.17 improvement of FCR when birds were supplemented with 0.1% VZ. Pelleting improved BW gain (P < 0.05) but did not significantly improve the FCR. Growth performance results indicate that pelleting did not affect the efficacy of VZ.

Key Words: pelleting • dietary protein • protease • keratinase

¹ Use of trade names in this publication does not imply endorsement by the North Carolina Agriculture Research Service or the North Carolina Cooperative Extension Service of the products mentioned.