This study was conducted to investigate the effect of solanine in potato by - products as silage or hay on microorganisms activities and some another parameters in Rahmany rams . Nine adult rams with an average body weight of 70.35 kg and 3 years of age were randomly divided into three groups , assigned to three digestion trials with three experimental rations . The experimental diets were consists of 50 % concentrate feed mixture (CFM) + 50% roughage as well as berseem hay in control ration , potato by–products silage (PB-PS) and potato by–products hay (PB-PH) in second and third rations , respectively . The digestion trials was lasted for 4  weeks  .The obtained results showed that PB-PS diet was significantly lower ( p < 0.05 ) in crude fiber ,  and higher in crude protein (CP) and ether extract ( EE ) compared to the another treatments . On the other hand the higher values of crude fiber and solanine were found in PB-PH diet value of NDF, ADF, ADL , cellulose and  hemicelluloses were significantly ( p < 0.05 ) decreased in PB-PS , whereas this values were increased in PB-PH  and control diet .The higher values of acetate, Butrtate ,  Iso – Butratewere detected in PB-PH , whereas the PB-PS diet recorded highervalue of p < /strong>ropionate and valerate , and lower value of A : p ratio compaered to control treatment . Both of ammonia –N and VFAs in rumen liquor were higher significant (p < 0.05 ) in silage group followed by PB-PH and control group through different times .The total bacterial count and cellulebacterial and protozoal were significantly higher ( p < 0.05 ) . in PB-PS at  0 , 3 and  6 hrs after feeding . On the other hand PB-PH was lower in  RBC and Monocyte while it was higher in PB-PS     and control groups . Neutrophile , WBC, Eiosinophile , Lymphocyte . were significantly higher ( p < 0.05 ) for PB-PH compared with PB-PS and control groups .