Resumo

KOZLOSKI, G.V. et al. Levels of neutral detergent fiber in lambs diets: intake, digestibility and ruminal fermentation. Arq. Bras. Med. Vet. Zootec. [online]. 2006, vol.58, n.5, pp. 893-900. ISSN 0102-0935.  http://dx.doi.org/10.1590/S0102-09352006000500027.

Eight 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.

Palavras-chave : concentrate; lambs; feeding eficiency; fibre level; roughage.