Effects of supplementing diets containing hulless barley varieties having different levels of non-starch polysaccharides with β-glucanase and xylanase on the physiological status of the gastrointestinal tract and nutrient digestibility of weaned pigs

Pigs (n=78), weaned at 21 days, were used for determining the effects of β-glucanase and xylanase inclusion, in feeds containing hulless barley, on performance and nutrient utilization in different parts of the gastrointestinal tract (GIT). The hulless barley varieties, Buck and Falcon, having high and low concentrations of β-glucan and xylose, respectively were used with or without β-glucanase (600 units/kg diet) and xylanase (745 units/kg diet) inclusions. Diets were provided for ad libitum consumption and blood samples were taken from the jugular vein. Weight gain and feed consumption were recorded on days 5, 10 and 15. Six pigs per treatment were euthanised on days 0, 5, 10 and 15, and digestive tracts were rapidly removed and divided by ligature into the stomach, three equal parts (proximal, medial and distal) of the small intestine, caecum and colon. The digesta from each section were analyzed for viscosity, energy, non-starch polysaccharide (NSP) and amino acids. Enzyme inclusion improved growth performance particularly for Buck. Enzyme treatment decreased (P<0.05) the viscosity in the distal part of the small intestine for pigs at days 5 and 10. Enzyme treatment also reduced (P<0.05) the plasma urea nitrogen concentration at day 10 and increased the apparent ileal digestibility of energy and some amino acids. These results suggest that NSP degrading enzymes are of benefit to early-weaned pigs fed diets based on hulless barley with high β-glucan content.