Níveis de fibra em detergente neutro na dieta de cordeiros: consumo, digestibilidade e fermentação ruminal Levels of neutral detergent fiber in lambs diets: intake, digestibility and ruminal fermentation

Abstract

Foram utilizados oito cordeiros castrados (35,0±6,0kg peso vivo) em um delineamento duplo quadrado latino 4 ´ 4 para avaliar o efeito de quatro níveis de fibra em detergente neutro (FDN) na dieta (25, 31, 37 e 43% da matéria seca (MS)) sobre o consumo e parâmetros digestivos. O consumo de nitrogênio (N) variou de forma quadrática; o de MS, matéria orgânica (MO) e energia diminuíram (PEight castrated raw lambs (35.0± 6.0kg live weight) were used in a replicated 4 ´ 4 latin square design to evaluate the effect of four neutral detergent fiber (NDF) levels (25, 31, 37 and 43% of dry matter (DM)) on intake and digestion traits. Nitrogen (N) intake varied quadratically; intake of DM, organic matter (OM) and energy decreased (P<0.05) and that of NDF increased (P<0.01) as fibre level increased. NDF and N digestibility, as well as pH and ruminal concentrations of peptides were similar for all treatments. Apparent digestibility of DM, OM and energy, as well as ruminal concentrations of sugars decreased (P<0.01) and, ruminal microbial protein synthesis and ruminal concentrations of ammonia and amino acids varied in a quadratic way (P<0.05) with increased levels of NDF. The effect of NDF in decreasing intake and digestibillity was more evident only at the highest level (43%). The inclusion of about 30% NDF represents the most adequate level for sorghum silage and concentrate based diets fed to feedlot lambs.

Keywords

• concentrado
• cordeiros
• eficiência alimentar
• nível de fibra
• volumoso
• concentrate
• lambs
• feeding eficiency
• fibre level
• roughage