Enzyme Supplementation to Increase Value of Soyhulls Fed to Finishing Pigs

Abstract Text: Soybean hulls are a byproduct of soybean processing, and are widely available throughout the U.S.  However, the high concentration of nonstarch polysaccharides in soyhulls limit a pig’s ability to digest this feedstuff and thus decreases their value to pork producers.  Current feeding recommendations for finishing pigs suggest limiting inclusion of soyhulls in late finishing pig diets to 10%.  Exogenous enzymes with protease and carbohydrase activity are commercially available for use in pig production and the addition of these enzymes to diets containing soyhulls may enhance the utilization of otherwise wasted nutrient components.  The purpose of this preliminary trial was to evaluate the individual and combined effects of feeding soyhulls and exogenous enzymes to finishing pigs. Ninety-six pigs (61.2 ±1.4 kg) were blocked by gender (48 barrows and 48 gilts) and allotted to 8 pens (4.2 ´ 2.8 m) such that initial pen weight was similar. Within gender block, pens were randomly assigned to 1 of 4 dietary treatments. Experimental design was a 2 ´ 2 factorial with two levels of soyhull (0 or 20%) combined with two levels of exogenous carbohydrase and protease enzyme supplementation (0 or 1,000 ppm).  Every 14 d, pigs, feed, and feeders were weighed to determine ADG, ADFI, and G:F.  Pigs were marketed after 49 days of feeding. Treatments were arranged as a 2 ´ 2 factorial and data were subjected to ANOVA using JMP 11.0 (SAS Inst. Inc. Cary, NC). For all parameters a pen of 12 pigs was considered the experimental unit. Results were considered significant at P ≤ 0.05. In this preliminary experiment, ADG, ADFI, and G:F were not impacted by dietary treatment (P ≥ 0.05). This pre-trial was limited to a small sample size, but numeric differences between dietary treatments suggest further examination is warranted (table 1).  Increasing the nutrient utilization of soyhull inclusive diets will decrease the amount of nutrients lost to the environment while supporting growth. 

Table 1. Summary of finishing pig performance by dietary treatment
	Dietary Treatment
Soy hull, g/kg	200	200	0	0
Enzyme, ppm	0	1000	0	1000	SEM	P-value
ADG kg/d	0.72	0.78	0.79	0.85	0.13	0.97
ADFI kg/d	2.04	2.05	1.94	1.99	0.52	0.97
G:F g:g	0.36	0.38	0.41	0.43	0.03	0.98

Keywords: nonstarch polysaccharides, soyhulls, exogenous carbohydrases, protease enzymes