Fibra em detergente neutro em dietas para ovinos confinados

Abstract

he objective of this study was to evaluate the effect of neutral detergent fiber (NDF) on nutrient intake and digestibility, ingestive behavior, consumption, ruminal pH and production of short chain fatty acids (SCFA) in fistulated sheep. Four male Santa Inês sheep, uncastrated, rumen fistulated, with a mean live weight of approximately 40 kg were used. The experimental treatments consisted of five diets containing neutral detergent fiber (NDF) levels in the diet (28%; 40%); %, 52%, 64% and 76%). The animals were confined for 105 days, with the first 15 days of each experimental period adapting to the diets, and 6 days of data collection, where total leftover samples were collected for consumption evaluation, total collection of feces for evaluation of apparent digestibility , evaluation of ingestive behavior and collection of ruminal liquid samples for determination of pH, concentrations of ammoniacal nitrogen and short chain fatty acids. The data obtained were submitted to analysis of variance using the software Statistical Analysis System - SAS (version 9.2). The intakes of all nutritional components evaluated had a quadratic effect with a maximum point between inclusion levels of 40% and 52%, with NDF consumption being the only one to be deferred, having a maximum point at 70.5%. The digestibilities of the nutritional components reduced linearly according to the increase of NDF in the diet, whereas the fiber, as well as the production of AGVs, was more digestible in the level of inclusion close to 52%. Ruminal pH presented higher decreases in diets with lower NDF contents, but negatively affecting intake and digestibility only in diets with NDF inclusion below 40%. The neutral detergent fiber content between 40 and 64% in the confined sheep diet optimized the consumption of the nutritional components, allowing its greater utilization and greater energy efficiency, without causing negative effects on its metabolic-ruminal health.