Influence of Protease Supplementation to Corn-Soybean Meal Based High and Low Energy Diets on Growth Performance, Nutrient Digestibility, Blood Profiles, and Gas Emission in Growing Pigs

A total of 140 growing pigs [Duroc × (Yorkshire × Landrace)] with an average body weight (BW) of 24.10 ± 1.66 kg were used in a 6-wk trial to determine the effect dietary protease supplementation in different energy diets in growing pigs. Pigs were randomly allotted to one of four dietary treatments in a 2×2 factorial design, with 2 levels of nutrient density (low or high nutrient density) and protease (0 or 125 g protease/ton) according to their sex and BW (7 pens with 3 barrows and 2 gilts/pen). Individual pig BW and pen feed consumption were recorded at the end of sixth week to calculate average daily gain (ADG), average daily feed intake (ADFI), and gain to feed ratio (G:F). Fresh fecal samples were collected at the sixth week for calculation of dry matter (DM) and nitrogen (N) digestibility. All data were subjected to the mixed procedure of SAS for a randomized complete block design with a 2 × 2 factorial arrangement. Pigs fed the high density diets increased (P < 0.05) ADG, G:F, and energy digestibility compared with the low density diets during 6 weeks. The supplementation of protease in the diet did not have significant effect on BW, ADG, and digestibility of DM and N. However, at week 6, pigs fed the diet with protease supplementation increased energy digestibility (P < 0.05). In addition, trends in increased DM digestibility and G:F) (P = 0.08, P = 0.09 respectively) were observed. With regards to blood profiles, a significant increase in the level of creatinine at the 6th week and trends in increased blood urea nitrogen (BUN) (P = 0.06) and reduction in nor-epinephrine levels (P = 0.07) were also observed. Further more, ammonia gas emission, tended (P = 0.06) to reduce in the faeces of pigs fed protease supplemented diets. In conclusion, these results suggest that supplementation of growing pigs diet with protease significantly increased energy digestibility and creatinine levels, tended to increase G:F, DM digestibility, BUN, and decreased ammonia gas emission and norepinephrine levels.

Key words: digestibility; growth performance; pigs; protease.

Table. Effect of different energy diet supplementations of protease on growth performance in growing pigs, wk 0 to 6
Item	Low			High		SEM	P-value
	˗ Prot	+ Prot		˗ Prot	+ Prot		Density	Prot	Density × Prot
ADG, g	692	716		735	758	20.24	0.045	0.254	0.981
ADFI, g	1573	1564		1565	1546	21.90	0.565	0.539	0.824
G:F	0.440	0.458		0.470	0.490	0.01	0.005	0.08	0.924