Dry residue of cassava on slow-growing broiler diets, with or without the addition of carbohydrases

Abstract

Dry residue of cassava was studied on the digestibility, performance, intestinal measurements, with or without inclusion of carbohydrases, of slow-growing broilers. 160 Label Rouge broiler chickens, 21-d-old, were distributed in a randomized, 2x5 factorial arrangement (male and female x 0, 10, 20, 30 and 40% residue) (metabolism trial). 1,100 male chicks were distributed in a 2x5 factorial arrangement (with/without carbohydrases x 0; 2.5; 5.0; 7.5; and 10.0% residue), with five replicates (performance trial). Increasing residue levels led to increases in energetic values. Feed intake from 1-21-d-old and 1-63-d-old decreased linearly. At 42 d-old, feed intake and weight gain levels exhibited a quadratic response, which predicted a highest value at 3.32% and 4.77%, respectively, for diets without carbohydrases. For 21- and 42-d-old chickens, the inclusion of carbohydrases reduced the weight and length of the small intestine. The energetic values of the diets were positively influenced by the residue and had similar digestibility values for both sexes. Inclusion of up to 10% of residue in slow-growing broiler diets does not impaired performance and intestinal morphology. The addition of carbohydrases reduced the viscosity of the digesta but it was not enough to improve the performance of the birds.