The effect of different carbohydrase and protease supplementation on apparent (ileal and overall) digestibility of nutrients of five hulless barley varieties in young pigs

Two experiments were conducted to investigate the effect of β-glucanase, xylanase, or an enzyme cocktail (β-glucanase, xylanase and protease) on nutrient and energy digestibilities at ileal and total tract levels on five diets for young pigs based on hulless barley. In experiment 1, twelve Cotswold male pigs of approximately 15 kg initial body weight, which were surgically fitted with a post-valve "T" caecum cannula (PVTC), were used to study the effects of various feed enzyme additions on nutrient digestibility of hulless barley-variety Falcon. In experiment 2, twenty pigs with similar weight and cannulation as experiment 1 were used to investigate the effect of adding a cocktail of various enzymes on nutrient digestibility of diets having one of each of five hulless barley varieties, i.e., Phoenix, Falcon, Silky, Condor or Buck, as an energy source (774 g/kg) and cano la meal as protein supplement (200 g/kg). The results from experiment 1 showed that the supplementation of single β-glucanase or enzyme cocktail significantly (P<0.05) improved apparent ileal digestibility of dry matter (DM), gross energy (GE), crude protein (CP), amino acids (AA), neutral detergent fibre (NDF) and total non-starch polysaccharide (NSP). Xylanase supplementation significantly (P<0.05) increased apparent ileal digestibility of NDF, cystine, isoleucine, lysine, methonine and tyrosine. In experiment 2, positive (P<0.05) effects of enzyme cocktail addition were observed for apparent ileal digestibility of DM, GE, CP and most of the AA with the magnitude greater for Buck and Condor. Apparent fecal digestibilities of DM, GE and NDF were also improved (P<0.05) by the enzyme cocktail addition. Reduction in hindgut fermentation was observed probably due to the improved ileal absorption of nutrients.