ABSTRACT
Digestibility and feeding trials were conducted to investigate the effect of partial replacement of ground date seeds (GDS)to ground maize (GM) on nutritive values, nitrogen metabolism, and lambs growth performance. Four mature Ossimi rams of 40 ± 1.45 kg live body weight (LBW) were used in digestibility trial and sixteen Ossimi growing male lambs had LBW averaged 19.88 ± 0.86 kg were used in group feeding experiment for 120 days. The basal diets used in both experiments formed of concentrate feed mixture (CFM) + wheat straw (WS) where it represent 3% and 1% of LBW, respectively in the control group (D1). In experimental groups,15, 30 and 45% of ground maize (GM) in (CFM) were substituted by ground date seeds (GDS) for diet 2 (D2), diet 3 (D3) and diet 4 (D4), respectively. The results of the digestibility trial revealed that all replacing rates of GM with GDS was associated with significant increases in CP, EE, CF and NFE digestibilities. The corresponding nutritive value expressed as total digestible nutrients (TDN) and digestible crude protein (DCP) were increased significantly (P≤0.05) with GDS inclusion in the diets.  There was significant (P≤0.05) increase in nitrogen balance (NB) with GDS treatments compared to the control group. Also nitrogen absorption (NA) was increased significantly (P ≤0.05) in the diets containing GDS, being 11.90, 12.13, 12.14 and 12.23 g/day for D1, D2, D3 and D4, respectively.
Significant increases (P≤0.01) were recorded in total body gain and daily gain of lambs fed all diets containing GDS. Total dry matter consumed during the whole feeding period was significantly differed (P≤0.01) among groups, being 129.84, 135.91, 139.39 and 143.51 kg for D1, D2, D3 and D4, respectively. Feed conversion efficiency expressed as kg feed / kg gain was in favor to lambs fed D3 (6.49) than those fed either D2 (6.71), D1 (6.83)or D4 (7.18), respectively. The economic evaluation showed improvement (P≤0.01) due to GDS inclusion in the diets. Accordingly, results indicates that ground date seeds could replace up to 30% of the ground maize in concentrate feeds of sheep without any adverse effects.