Enzimas fibroliticas em dietas de novilhas leiteiras: metabolismo nitrogenado

Abstract

This study aimed to evaluate the nitrogen balance and microbial protein synthesis according to the experimental diets of Jersey heifers supplemented with cellulolytic enzymes (xylanase) corn silage or sugarcane silage. Eight Jersey heifers with initial average weight of 160±15 kg, and age of 8±2,5 months were used.The animals were randomly distributed into two latin square design 4 x 4, balanced and contemporary, 2 x 2 factorial arrangement. The experimental period was 20 days, and 14 days for the adaptation to the experimental diets and 6 days for data collection. The experimental diets were: 1 - Corn silage (SM); 2 - Sugarcane silage cane (SC); 3 - Corn Silage + fibrozyme (SME) and 4 - Sugarcane silage + fibrozyme (SCE). The diets were formulated to be isonitrogenous according to NRC (2001), aiming a daily gain of 800 to 900 g. The cellulolytic enzyme addition (Fibrozyme®) did not affect dry matter intake (P < 0.05). However, the digestibility of dry matter, organic, and crude protein of the sugar cane silage increased (P < 0.05) by the supplementation of the cellulolytic enzyme.