Xylanase effects on apparent total tract digestibility of energy and dry matter with or without DDGS at 46, 54 and 70 kg bodyweight

Abstract Text: The objective of this study was to evaluate the impact of xylanase supplementation on the digestibility of dietary energy with or without DDGS over three time points in growing pigs. Two groups of sixteen individually housed gilts (37.3 ± 0.33 kg) were randomly allotted to one of four dietary treatments (n=8) arranged as a 2 x 2 factorial with xylanase added at 0% vs 0.4% and reduced-oil DDGS (6.83% fat, 24.54% NDF) included at 0% vs 30% of the diet. Pigs remained on the same treatment throughout the trial. Pigs were fed 90% of estimated ad libitum intake, re-calculated after d12 and d22. Chromic oxide was added to the diets (0.4%) as an indigestible marker. Dietary treatments started d0 and fecal samples were collected via grab sampling at three different time points: d8 – 9 (T1), d18 – 19 (T2), and d38 – 39 (T3), corresponding to body weights 46.0 ± 0.39, 54.1 ± 0.40, and 70.3 ± 0.49 kg respectively. Data were analyzed using PROC MIXED procedure of SAS with pig as the experimental unit, inclusion of xylanase and DDGS as fixed effects, and group as a random effect. DDGS decreased dry matter (DM) digestibility in all three time points, from 79.9 to 75.0%, 83.5 to 74.0%, and 84.9 to 78.5% for T1, T2, and T3 respectively (P ≤ 0.049). Xylanase inclusion did not significantly impact DM digestibility (77.4%) or digestible energy (DE) value (3.28 Mcal/kg) of the diet at 46 kg BW (P = 0.9047). There was an interaction between enzyme inclusion and DDGS inclusion at 54 kg BW with xylanase inclusion decreasing DM digestibility from 76.9 to 71.0% and DE values from 3.37 to 3.09 Mcal/kg in 30% DDGS diets, and increasing DM digestibility from 81.7 to 85.2% and DE values from 3.38 to 3.54 Mcal/kg in diets with no DDGS (DM: P = 0.047) (DE: P = 0.044). At 70 kg, xylanase inclusion increased DM digestibility from 80.0% to 83.4% (P = 0.017) and increased dietary DE from 3.42 Mcal/kg to 3.57 Mcal/kg (P = 0.013). In conclusion, xylanase did not affect DM digestibility or DE in the smallest pigs, had mixed effects depending on diet composition at the intermediate weight and improved both in the heaviest pigs.  The improvement at 70 kg was equal to 4.25%. The differing responses across BW provide further insight into the function and most effective use of xylanase.

Keywords: xylanase, DDGS-RO, digestibility