Abstract
Olive tree by-products (OTB) were examined to be used as an alternative feed for ruminants after improving their chemical composition through urea and Phanerochaete chrysosporium treatments. Twenty eight lactating Barki ewes were randomly assigned to four groups ( seven animals each) using the complete random design. Ewes were fed 70% concentrate feed mixture (CFM) + 30% Berssem hay (R1), 70% CFM + 30% untreated OTB (R2), 70% CFM+30% OTB treated with urea (R3), and 70% CFM+30% OTB treated with Phanerochaete chrysosporium (R4).Chemical and biological treatments were so effective in fiber decomposition of OTB and improve its nutritive value. Ruminal total volatile fatty acids, NH3-N concentrations and microbial protein synthesis were higher in treated groups R3and R4 than R2 group. Urea treatment was superior over biological treatment (p < 0.05) for improvement of all nutrients digestibility, blood serum glucose, protein and albumin, milk yield and milk composition. Inclusion of chemically and biologically treated OTB in lactating ewes's rations improved their productive performance with no deleterious effects on the health.