PSV-15 - Effects of supplementation of protease to different nutrient density of diets on growth performance, nutrient digestibility, blood profile, gas emission, fecal microflora in growing-finishing pig

Abstract: This study was conducted to investigate the effects of protease supplementation and different nutrient density of diets on growth performance, nutrient digestibility, blood profiles, gas emissions, and fecal microflora in growing-finishing pigs. A total of one hundred-eight crossbred growing pigs ([Landrace × 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: 125mg/kg protease derived from Streptomyces spp; 3, Protease B: 100mg/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 50kcal/kg in energy).

Supplementation of protease was significantly increased (p < 0.05) in BW at weeks 4 and 6. Also, supplementation of protease significantly increased (p < 0.05) in ADG at grower periods and weeks 13 to 15. In addition, improvement (p < 0.05) of ADG was observed in pigs fed a high nutrient density diet (HN) compared with basal nutrient density diet (BN) at grower periods and weeks 13 to 15. In the apparent total track digestibility (ATTD) of crude protein (CP), there was significantly increased (p < 0.05) in supplementation of protease at weeks 6 and 13. The HN showed a significantly increased (p < .0001) ATTD of CP at 6 weeks. BN showed a significantly increased (p < 0.01) in the ATTD of CP at weeks 13. Also, there was interaction (p < 0.05) between nutrient density of diets and supplementation of protease. In the ATTD of gross energy, supplementation of protease showed a significantly increased (p < 0.05) at weeks 13. The supplementation of protease in diets significantly decreased (p < 0.05) the concentration of blood urea nitrogen (BUN) at weeks 13. The supplementation of protease in diets significantly decreased (p < 0.05) the emission of NH₃ at weeks 6 and 13. Also, H₂S showed a significantly decreased (p < 0.05) due to the supplementation of Protease A in diets. At weeks 6 to 9, average daily feed intake showed a tendency to increase (p < 0.10) when the BN diets were fed. Also, during the entire period, the feed conversion ratio showed a tendency to increase (p < 0.10) when the BN diets were fed.

In conclusion, supplementation of protease reduces NH₃ in feces and BUN in whole blood by increasing the digestibility of CP and improved growth performance. Also, diets with high nutrient density improved growth performance and nutrient digestibility in grower periods.