Ewes fed high-concentrate diets containing flint corn and increasing levels of exogenous amylolytic enzyme: effects on nutrient intake and digestibility

The aim was to evaluate if the inclusion of exogenous amylolytic enzyme affect the nutrient intake and digestibility in ewes fed high-concentrate diets containing flint corn. Five Santa Ines x Dorper crossbred ewes (54.04 +/- 4.5 kg and aged 8 months) were used in a 5 x 5 Latin square design. All animals were housed in individual metabolic cages for 60 days. The treatments consisted of a control diet (without amylolytic enzyme) and four inclusion levels of an amylolytic enzyme (3,000, 6,000, 9,000, and 12,000 a-amylase dextrinizing units [DU] kg(-1) dry matter [DM]). The enzyme was mixed into the feed at the time of supply to the animals. Data were analyzed by ANOVA, and orthogonal polynomial contrasts were used. Nutrient intake was not influenced by amylolytic enzyme inclusion. The digestibility of DM, organic matter, neutral detergent fiber, total carbohydrates, non-fibrous carbohydrates, and gross energy showed a quadratic increase with enzyme inclusion (P<0.05), with maximum values at levels of 7,600, 7,500, 6,300, 7,500, 7,400, and 7,800 DU kg(-1) DM, respectively. Total digestible nutrients of diets also showed a quadratic increase, with a maximum value of 894 g kg(-1) at a level of a-amylase activity of 7,786 DU kg(-1) DM. The inclusion of the exogenous amylolytic enzyme from 6,300 to 7,800 DU kg(-1) DM doesn't alter nutrient intake and improves the digestibility in ewes fed high-concentrate diets. Key words: Alpha-amylase. Nutrition. Sheep. Starch.