This experiment was conducted to evaluate of rumen cellulolytic bacteria activity of dromedary camels fed cultivable and pasture forage. Four fistulated dromedary camels were fed for 35 days in 2 periods as cross over design with cultivable and pasture forage (4 camels per forage). Then rumen fluid was collected after morning feeding. Inoculant of cellulolytic bacteria was prepared and in vitro gas production, digestibility and enzyme activity were measured (6 replicates). Treatments were including: rumen fluid of camels fed cultivable forage × wheat straw and or atriplex as a substrate and rumen fluid of camels fed pasture forage × wheat straw and or atriplex as a substrate. The result showed, after 96 hours incubation, the produced gas and actual digested organic matter for treatments 1 and 4 were higher (P≤0.01). However, the ammonia-N was affeted by treatments at 24 and 48 h incubation (P≤0.05). Digestibility of dry matter, organic matter and natural detergent fiber by bacteria were influenced by treatments (P≤0.01). The results revealed that the activity of endoglucanase and exoglucanase in treatments 1 and 3 at 48 h incubation (P≤0.01) and values of treatment 4 at 96 h was the highest (P≤0.01). Therefore, pasture forage such atriplex caused to a silent delay in starting bacteria fermentation activity in camels, then primary delay was compensated by adaptation to the substrate. Also feeding of C4 pasture forage to camels improved the fiber degradability and enzyme activity of rumen bacteria in compared with C3 cultivable forage. تفاصيل المقالة