Growth performance, carcass characteristics and plasma urea nitrogen concentration of nursery pigs fed low-protein diets supplemented with glucomannans or protease

Abstract

Two experiments were conducted to evaluate the effect of glucomannans (GM; 0.0, 0.5, 1.0 and 1.5 kg ton−1) as mycotoxins binders (Exp. 1), or protease (0.00, 0.25, 0.50 and 0.75 kg ton−1; Exp. 2) added to sorghum-soybean meal, standard crude protein (CP) (20.5% CP) or low protein (14.5% CP) diets fed to 80 (five replicates per treatment per experiment) nursery barrows in a 2×4 factorial arrangement, on growth performance, carcass characteristics and plasma urea nitrogen concentration. In Exp. 1, average daily gain (ADG), feed:gain ratio (FGR), fat free lean gain and plasma urea nitrogen (PUN) were reduced in pigs fed low-protein diets. The level of GM and the interaction of CP×GM tended to affect FGR. In Exp. 2, there was no effect of protein or protease level on all variables, except for ADG and PUN that were reduced as CP was lowered in the diet. These results indicate that the addition of glucomannans as mycotoxins binders or protease to standard- and low-protein, sorghum-soybean meal, amino acid supplemented diets, does not improve growth performance nor had a negative effect on carcass characteristics of nursery pigs. Dietary CP concentration does not affect the carcass characteristics, but the PUN is lowered when dietary protein is reduced.