Replacement of part of yellow corn by dried sugar beet pulp untreated or biologically treated by Saccharomyces cerevisiae, Trichoderma viride or Cellulomonas cellulasea to represent 40% of the concentrate feed mixture had done in the present study to investigate its effect on rumen fermentations and microbes, blood parameters, nutrients digestibility, nutritive value, rate of passage in the rumen, nitrogen and water balances and lambs performance. Twenty five weaned Barki ewes lambs were randomly divided into five groups to conduct growth trail followed by digestibility trail. Lambs fed on five rations: R (1): Concentrate feed mixture (CFM) + berseem hay (BH) (control), R (2): CFM contained untreated SBP + BH, R (3): CFM contained SBP treated with S. cerevisiae + BH, R (4): CFM contained SBP treated with T. viride + BH. R (5): CFM contained SBP treated with C. cellulasea + BH. The ratio of CFM to BH was 60%: 40% in all rations. The main results indicated that biological treatments for SBP significantly increased (P≤0.01) ruminal pH values, total ruminal VFA's, microbial protein, ammonia nitrogen, non-protein nitrogen, true protein, total nitrogen concentrations and ruminal protozoa numbers. Also, R3, R4 and R5 increased the concentrations of blood serum glucose, total proteins, albumin and creatinine. Also, these treatments achieved the highest (P≤0.01) feed intake digestion coefficients, nutritive values, rate of passage in the rumen, nitrogen and water utilization comparing with untreated group, which reversed on lambs performance as increasing body weight, average daily gain, feed efficiency and economic efficiency comparing to R2.  Results of rations contained biological treated SBP were near to those of control.