Supplementation of barley-based diets with β-glucanase for pigs: energy and amino acid digestibility response.

An experiment was conducted to determine the effect of graded levels of β-glucanase supplementation to barley (Hordeum vulgare)-based diets on the digestibility of DM, GE, N, and AA for growing-finishing pigs. Eight pigs (initial BW: 53.3 ± 3.2 kg) were each fitted with a simple T-cannula at the distal ileum and allotted to a replicated 4 × 4 Latin square design with 4 diets and 4 periods in each square. Diets were based on a barley-soybean (Glycine max) meal (SBM) basal diet (BD) containing 199 g CP and 3286 kcal DE per kilogram of diet. Treatments consisted of the BD and the BD supplemented with 10,000 (10K), 20,000 (20K), or 30,000 (30K) units of β-glucanase per kilogram at the expense of corn (Zea mays). Chromic oxide (0.5%) was included as an indigestible marker. Each experimental period consisted of 4 d of adaptation, 1 d of feces collection, and 2 d of ileal digesta collection. Apparent total tract digestibility (ATTD) of DM ranged from 81.0 to 82.5% and was not affected by β-glucanase supplementation. In the BD, ATTD of GE and N was 83.1 and 83.3%, respectively, and was not different in the BD supplemented with up to 30K units of β-glucanase per kilogram at 83.4 and 83%, respectively. Increasing levels of β-glucanase supplementation to the barley-SBM-based diet did not affect the ATTD of any criteria measured. Apparent ileal digestibility (AID) for DM, GE, and N ranged from 60.6, 65.4, and 70.8% (10K) to 66.4, 71.0, and 74.9% (20K), respectively. For indispensable AA, AID for Lys (79.9%) and Met (78.1%) was lowest in the BD supplemented with 20K and 10K units of β-glucanase per kilogram, respectively, and was not different from the digestibility of Lys and Met in the diet with added 30K units of β-glucanase per kilogram at 80.8 and 80.4%, respectively. There were neither significant linear nor quadratic effects of β-glucanase supplementation to barley-SBM-based diets on the AID of DM, GE, N, and AA. In conclusion, β-glucanase supplementation did not affect apparent ileal and total tract nutrient digestibility in grow-finish pigs fed a barley-SBM-based diet.