The aim of this study was to evaluate effect of different level of probiotic supplementation to ruminant rations, using in-vitro batch culture technique to determine degradation and fermentation parameters. In vitro experimental ration was formulated, the ration consisted of 40% alfalfa hay and 60% concentrate feed mixture. Three level of probiotic supplementation (106, 108, 1010 cfu/kg DM) were evaluated. DM and total gas production as well as fermentation parameters of the incubated samples were determined after 24 hrs. of fermentation. Slightly increases (P>0.05) in in-vitro dry matter degradability were observed for the ration supplemented with probiotics bacteria at different levels (106,108 and 1010 cfu/ kg DM) compared to control ration. Probiotics bacteria supplementation with different level (106,108 and 1010 cfu/ kg DM) led to significant (P<0.001) increases in organic matter degradability and total gas production per sample and per g DM, OM, NDF and ADF compared to the not supplemented ration (control ration), and no significant differences were observed among the different levels of probiotics supplementation. Significant increase in total volatile fatty acid concentration after 24 hours' incubation period compared to the not supplemented ration. On the other hand, the treatment supplemented with probiotic recorded lower ammonia concentration compared to the control group. It could be concluded that, adding 
probiotics bacteria supplementation to experimental ration resulted increase DM and OM degradability and using dose 106 CFU/kg DM feed is sufficient to induce improvement in degradability and fermentation parameters