completely randomized design was used in a growth trial for using thirty male lambs in three similar groups (ten lambs/ group). Animals were 7 months of age with an average body weight of 28.2kg ± 0.72). Body weights of lambs in a 98-day trial were recorded at the beginning of the experiment and biweekly through the experimental period. Animals were fed a basal diet (control, C) including concentrate feed mixture at level of 60% of total requirement of growth and Berseem hay at level of 40%. The control ration was offered to the first group without additives, while the other two groups received the control ration supplemented with Nano zinc oxide either 1g/head/day, T1 or 2g/head/day, T2. A digestibility trial was carried out at the end of the growth trial on 15 rams (5rams/rations). Ruminal contents were sampled at zero, 2, 4 and 6 h post-morning feeding via stomach tube to record the pH and determine concentration of NH3-N, and volatile fatty acid (VFA). Blood serum metabolites determined were total protein, albumin, globulin, urea, creatinine, blood glucose, AST and ALT.
Data revealed that adding nZnO in both levels lead to an increase in body weight. Total gain and ADG followed the same pattern. Digestibility of all nutrients was not significantly different between the experimental groups. Nutritive value as TDN improved due to nZnO supplementation. No significant differences between the three experimental groups for all N balance data. All the animals were in positive N balance.