Effects of Protease on Growth Performance and Carcass Characteristics of Finishing Pigs

The purpose of this study was to evaluate effects of protease on growth performance and carcass characteristics of finishing pigs. A total of 96 pigs (initial BW of 69.82 ± 2.30 kg; equal number of barrows and gilts) were randomly assigned to 2 dietary treatments (8 pigs/replicate; 6 replicates/treatment) in a randomized complete block design (BW as a block). Dietary treatments were 1) a diet based on corn, soybean meal, and wheat (CON) and 2) CON + 0.02% protease (PRO). The protease was a commercial product (Ronozyme^® ProAct, DSM Nutritional Products, Kaiseraugst, Switzerland) containing 75,000 protease units/g derived from Bacillus licheniformis. Pigs were fed their respective diets for 6 weeks. All pigs were housed in environmentally controlled pens with free access to diets and water throughout the entire experiment period. After 6 weeks, pigs were fasted with only free access to water for 4 h and final BW of pigs was recorded prior to transportation. Pigs were transferred to a local commercial slaughter facility with a conventional scalding-singeing process. Measurements were growth performance and carcass characteristics of finishing pigs. All data were analyzed using the PROC GLM procedure of SAS. The statistical model for every measurement included dietary effect and BW as a covariate. There was no difference in ADG between CON and PRO (0.891 vs. 0.929 kg/d). However, pigs fed PRO had lower ADFI (2.92 vs. 3.29 kg/d, P < 0.05) and higher G:F ratio (0.319 vs. 0. 271 kg/kg, P < 0.05) than those fed CON. No differences were found in hot carcass weight (83.55 vs. 82.81 kg), dressing percentage (76.94 vs. 77.07%), final backfat depth (17.20 vs. 16.73 mm), and fat free lean (58.13 vs. 57.99%) between CON and PRO. In conclusion, addition of protease in finisher pig diets increased feed efficiency but did not affect carcass characteristics.