Probiotics refer to microorganisms that exhibit a beneficial effect on the animals’ health through intestinal microbial balance. This investigation intends to identify and define the probiotic characteristics of Lactobacillus strains isolated from the digestive systems of ruminants. Bacterial strains were isolated purified and characterized based on morphological and biochemical characteristics. The isolates were identified using the 16S rRNA gene partial sequencing method. Most of the strains exhibited a decrease in the growth by increasing the concentration of the bile salt, NaCl, increasing the temperature over 37oC, and moving toward neutrality and alkalinity of the media. Strain Lactobacillus farraginis MD_A11 revealed the lowest decrease in the growth percentage when subjected to different bile salt concentrations of 5.96, 6.61, 6.85, 7.40, 7.53, and 7.64%, NaCl% concentrations of 1.40, 5.62, 6.48, 7.36, 7.39, 7.41, 7.42, 7.28, and 13.76%, raising the temperature over 37oC being 4.19 & 3.945%, different pH levels as compared to control, and it recorded the lowest medium pH after the third day being 4.20 with titrable acidity of 0.32%. Strain Lactobacillus farraginis MD_A11 could be recommended as a probiotic feed additive for ruminants to improve their growth performance and productivity.

The effect of two probiotic products with Palm Kernel Cake (PKC) as source of dietary protein and/or energy in ruminant diets on the growth performance and some blood parame-ters of Barki lamps were evaluated. Two com-mercial probiotic formulas (ZAD and ICEC-Trol) were administrated directly with theirap-plications: P1 (without probiotic), P2 (ZAD), P3 (ZAD + ICEC-Trol), the combination of four different rations: R1 (control), R2 (PKC as source of energy), R3 (PKC as source of en-ergy and protein) and R4 (PKC as source of protein). Barki lambs (n=96, 35kg average body weight) were randomly assigned to 12 experimental groups in a completely random-ized block design. (8 lambs for each group) and fed for 47 days. ZAD probiotic was ap-plied at 2 ml/head/day and ICEC-TROL was applied at 3 g/head/day. Animals weight gain and average daily gain were measured and Glucose, total protein, albumin, calcium and phosphorus were measured. Results showed that animals fed control ration (R1) with P2, R2 with P3 and R4 with P3 showed highest (P<0.05) total weight gain (10.75, 10.88 and 10.56, respectively) and average daily gain (0.229, 0.231 and 0.225, respectively). ZAD probiotic improved serum total protein, globu-lin, glucose when using with PKC in lambs’ rations. In conclusion, using PKC as a source of energy or protein, with two sources of pro-biotics in lambs’ rations showed to be more ef-fective in weight gain, while using one probi-otic (ZAD) is enough for fattening with tradi-tional rations.