Rolfe (Daniellia oliveri) seed meal as a protein source in locally produced concentrates for lambs fed low quality basal diet

Abstract

The objective of this study was to determine the effects of replacing different levels of toasted Daniellia oliveri seed meal (TDS) for groundnut cake (GNC) in the diets of fifteen growing 8-month-old ram-lambs (13 ± 0.25 kg body weight (BW)) on growth performance, nutrient digestibility, nitrogen utilization and ruminal fermentation. The animals were randomly assigned to one of three diets containing 0 g/kg TDS, 100 g/kg TDS and 200 g/kg TDS to replace 0, 50 and 100% of GNC (on dry matter basis) in a complete randomized design. Intakes of total dry matter (DM), digestible crude protein (DCP) and digestible organic matter (DOM), DOM, DCP, energy concentration, N retention, purine derivatives excretion, microbial protein synthesis (P < 0.01) and propionate (P < 0.05) increased linearly with increasing level of TDS. Intakes of fibre, feed conversion ratio, total N excretion, ruminal pH and NH3-N, total volatile fatty acids, acetate, acetate-to-propionate ratio and methane production progressively declined (P < 0.01), as the TDS level increased. Whereas, intakes of concentrate, non-fibre carbohydrates, condensed tannins and energy, digestibilities of DM, CP and OM, average daily gain, digestible organic matter fermented in the rumen (P < 0.01) and valerate (P < 0.05) increased linearly and quadratically, roughage intake and fibre digestibility decreased linearly and quadratically (P < 0.01). Results indicate that inclusion of 200 g/kg TDS (100% replacement of GNC) improved feed intake, nutrient digestibility, N utilization, ruminal fermentation and growth performance of lambs.