Effect of carbohydrase supplementation of wheat- and canola-meal-based diets on growth performance and nutrient digestibility in group-housed weaned pigs

Fibrous components in canola meal and wheat limit their effective use in diets for weaned pigs. Effects of supplementing a carbohydrase (845 and 327 Units g(-1) xylanase and beta-glucanase) to a wheat-canola meal diet on growth performance, small intestine nutrient digestibility and digesta viscosity were investigated. Ninety-six weaned pigs (7.2 +/- 1.2 kg) had free access to control diet [65% wheat, 25% canola meal; 3.15 Mcal digestible energy (DE) kg(-1), 10.6 g digestible lysine kg(-1)] or control diet supplemented with carbohydrase at three inclusion rates (1, 2, or 4 g kg(-1)) for 28 d. Four pigs were housed per pen for six pens per diet. On days 19 to 21, six pigs per diet were euthanised to collect small intestine digesta. Carbohydrase increased average daily feed intake (ADFI) and average daily gain (ADG) quadratically (P < 0.01) for days 1 to 28, resulting in 16% higher ADFI and 13% higher ADG for 2 g kg(-1) carbohydrase compared to control. Carbohydrase did not affect feed efficiency (P > 0.10). The ADG was positively correlated to ADFI (r = 0.94; P < 0.01), but not to feed efficiency (P > 0.10). Carbohydrase did not affect digestibility of dry matter (DM) and energy (P > 0.10). Carbohydrase at 4 g kg(-1) only reduced digesta viscosity 30% in the distal small intestine compared to control (P < 0.05). Carbohydrase supplementation increased ADFI and thereby ADG, but not feed efficiency and nutrient digestibility, suggesting that reduction of dietary fibrous components using carbohydrase may stimulate voluntary feed intake of pigs fed diets limiting in DE.