Supplementation of protease and different nutrient density diets in growing-finishing pigs

This study was conducted to investigate the effects of protease supplementation and different nutrient density of diets in growing-finishing pigs. A total of one hundred-eight crossbred growing pigs ([Landrace x Yorkshire] x Duroc) with an initial body weight (BW; 18.74 +/- 3.46 kg) were used for 15 weeks. Pigs were randomly assigned to six dietary treatments with 6 replicates of 3 pigs per pen in a 3 x 2 factorial through the following arrangement: Three groups of protease (1, Basal diets; 2, Protease A: 125 mg/kg protease derived from Streptomyces sps; 3, Protease B: 100 mg/kg protease derived from Bacillus licheniformis) at two different nutrient density diets (1, Basal requirement; 2, 0.94%-0.98% higher than requirement in dietary protein and 50 kcal/kg in energy). High nutrient (HN) diets showed higher average daily gain (ADG) (p < 0.05) and apparent total tract digestibility (ATTD) of crude protein (CP) (p < .0001) compared to basal nutrient (BN) diets during growing periods. Supplementation of protease showed higher BW (p < 0.05) and ADG (p < 0.05) compared to non-supplementation of protease during growing periods. Also, supplementation of protease showed higher ATTD of CP (p < 0.01), ATTD of gross energy (p < 0.05) and decreased blood urea nitrogen (BUN) level (p = 0.001) compared to non-supplementation of protease during finishing periods. Pigs which fed the protease showed decreased ammonia (NH3) emissions (p < 0.05) during experiment periods and decreased hydrogen sulfide (H2S) emissions (p < 0.01) during finishing periods. Interactions between nutrient density and protease were observed, which decreased the feed conversion ratio (p < 0.05) in HN diets without protease compared to BN diets without protease during weeks 4 to 6. Also, interaction between nutrient density and protease was observed, which resulted in improved ATTD of CP (p < 0.01) in response to PTA supplementation with HN diets during the finishing period. In conclusion, supplementagrowth performance and nutrient digestibility in growing periods.