The objective of this study was to evaluate the intake, apparent digestibility of nutrients and the nitrogen balance of diets containing babassu-mesocarp meal (BMM) as a replacement for elephant-grass silage (0, 21, 38, 62 and 78%). Twenty sheep were used, housed in individual metabolic cages and distributed in a completely randomized design with four replications. Food intake was noted and faeces and urine excretions were collected and recorded. Intake of dry matter, organic matter, crude protein, ash, neutral-detergent fibre, acid-detergent fibre, hemicellulose, and total carbohydrate was not affected by the experimental diets. Changes were observed in the non-fibrous carbohydrates intake (INFC) and a reduction in the intake of ether extract as a % of live weight (LW) and grams per unit of metabolic body size (g MBS-1). Total digestible nutrient intake (ITDN) presented quadratic behaviour, with maximum points at 37.3% and 37.9% of BMM expressed as %LW and g MBS-1 respectively. The apparent digestibility of organic matter, neutral-detergent fibre, acid-detergent fibre, crude protein and non-fibrous carbohydrate decreased with the increase in BBM in the diet. The apparent digestibility of dry matter (ADDM), ether extract and non-fibrous carbohydrates showed a quadratic response, with maximum ADDM estimated at 10% of BMM. The TDN decreased by 0.28% for each percentage point of BMM added to the diet. The addition of BMM reduced digestibility of the fibres and increased both INFC and ITDN, indicating that this byproduct can be used as an energy source in ruminant diets.
