Digestibilidade dos nutrientes em ovinos Santa Inês recebendo dietas com diferentes fontes de carboidratos associadas à ureia

Abstract

The objective of this study was to evaluate the digestibility of diets based on different sources of carbohydrates associated with high urea levels, replacing soybean in diets for sheeps. Four diets were tested with Tifton-85 hay (580 g/kg dry matter) as forage and corn+soybean; corn+urea; cassava scraping+urea and cactus pear+urea as concentrated ingredients. The experiment was carried out at the Animal Science Department of UFRPE. 40 male uncastrated sheep were used, distributed in random blocks, with four treatments and ten replications, housed in individual wooden stalls, equipped with feeder and drinking fountain. The duration of the experiment was 76 days, 20 of adaptation and 56 for data collection. The apparent digestibility (AD) assay was performed by the total fecal collection method. During the period of the digestibility test the feces were collected daily to determine the digestibility coefficients of dry matter, organic matter, crude protein, ethereal extract, neutral detergent fiber, total carbohydrates and non-fibrous carbohydrates. The apparent digestibility coefficients (ADC) were obtained by the relationship between the amount of ingested and excreted nutrients. The data were submitted to analysis of variance and the averages were compared by the Tukey test (P <0,05) procedure using the General Linear Models (GLM) of the Statistical Analysis System (SAS) program. The dry matter digestibility coefficients did not vary among the treatments, except for the animals that were fed with cactus pear+urea (59,66). The diet that contained cactus pear in its composition also provided lower digestibility of organic matter (62,92) and total carbohydrates (63,75), compared to corn+urea (69,50; 69,97) or cassava scraping+urea diets (70,47; 71,91). The crude protein digestibility coefficients were similar for the corn+urea, cassava scraping+urea and cactus pear+urea diets (78,54), being higher than the control diet (74,46). The digestibility coefficients of the ethereal extract were similar to each other in treatments corn+soybean and corn+urea (72,21) and similar to each other in the treatments cassava scraping+urea and cactus pear+urea (60,68). The digestibility coefficient of the non-fibrous carbohydrates was higher for the cassava scraping+urea diet (86,26). It is possible the total replacement of soybean by urea in the experimental diets, especially in the diet composed by the association of manioc and urea, which presented better overall response in the variables evaluated in relation to the apparent digestibility.