Sixteen Ossimi male lambs weighed 21.69 kg on average and aged 5 months were used in a 204 days feeding trial. Animals were randomly divided into four equal groups (4 animals each ) to study the effect of feeding corn stover silage with different feed additives on nutrients digestibility. performance. carcass characteristics and feed efficiency in growing lambs. The experimental lambs were randomly assigned into four experimental rations with or without feed additives. The first grOUp was considered as control (A) and fed at 1% of live body weight ( LBW) CFM (concentrate feed mixture) plus 1% of LBW corn stover silage and rice straw ad lib without feed additive. While. the other three groups received the control ration plus 59 l h! at More —- yeast (MY). 5g ihld Dina-fen'n (DF) and 59 (hid Biodian (BO) for B. C and D groups,   respectively.   Results showed that MY.DF and BO supplementation with lambs rations did not show any Affect on nutrients digestibility of DM, OM. CP. EE and NFE . On the other hand. the CF digestibility was significantly (P<0.05) higher with MY,DF and BO supplementation compared with the control ration. TDN values ranged between 60.33 and 61.68%.The lowest value was recorded with both rations of C and A (control) ; while. D and B rations had the highest value . DCP percentage tended to decreased with rations supplemented with MY,DF and BO than that in the control ration. However. TDN and DCP values did not significantly influence by the supplementations. Supplemented MY, DF and BO rations had lower ruminal pH at zero. 3 and 6 hrs. in all groUps (except with those fed D ration at 6 hrs.) compared with the control group. Supplemented rations with MY and DF had significantly (Ps0.05) lower NHg-N concentration at 3 hrs. than those fed the control ration. Also, ration D gave lower NHa-N concentration. but with no significant difference. compared with the control ration. Whereas.NH3-N concentrations at 6 hrs. post feeding were significantly (Ps0.05) decreased with C and D rations compared with those fed both the control (A) and B rations. Although, ruminal TVFA's values at 3 hrs post feeding were significantly (P< 0.05) higher for ration C supplemented with DF and significantly (P< 0.05) lower for ration B than the control (A) and D rations. Moreover. ruminal TVFA's values at 6 hrs. post feeding were significantly (P: 0.05) higher for ration D and significantly lower for ration B then the control and C rations . Results showed no significantly differences between the tested groups and the control group in blood serum total protein ,globulin and urea concentration .While. animals fed B and C rations recorded significant (ps0.05) decrease in concentration of serum albumin (3.72 and 3.30 gidl .respectively) compared to the control group < /p> (4.83 gidl ) and insignificant decrease with those fed D ration (4.33 gidl). . The decreases in DM intake (kgfhid) recorded with lambs fed C and D rations were 7. 40 and 2.61% .respectiveiy compared with those fed A ration (control) . TDN intake (kgrhld) was needy similar in all groups : while. DCP intake ( kgihid) was higher