On the other hand, content of the total lipids was low at the diet contained mixed bacteria (19.24%). The highest content of the total lipids was obtained in the control (23.5 %). Total lipid content in the fish groups which fed diet contained P. species and M. luteus were 20.93 and 22.31%, respectively. Ash content in whole fish body was significantly increased with diets containing P. species, mixed bacteria and M. luteus (25.90, 25.17 and 23.87%, respectively), while the least one was observed in the control (21.69 %).
Erythrocyte counts in fish fed diets containing M. luteus were significantly high (1.059 ± 0.043 million/mm3), while the decreased significantly in fish fed with diet containing Psuedomonas sp (0.626 ± 0.034 million/mm3). The erythrocyte count in fish fed diets containing mixed bacteria and control group were 0.821 ± 0.034 and 0.997 ± 0.067 million/mm3, respectively. Hemoglobin content was slightly increased in fish fed diet containing M. luteus (5.12 g/100 ml ). Also, the hemoglobin content decreased in fish fed diet containing Psuedomonas sp (3.29 g/100 ml). Hemoglobin content in fish fed diets containing mixed bacteria and control group were 4.115 and 4.57 g/100 ml, respectively. Haematocrit value (Hct) decreased at fish fed diets containing P. species (9.0%), while other treatments were approximately similar and ranged from 14.75% to 18.5% (Table 5).
The plasma glucose concentration of the fish control group was 85.72 ± 3.45 (mg%). Data presented in Table (6) indicated that fed of O niloticus with pro biotic induced an increase in the plasma glucose as compared to the control group. It was significantly increase in fish fed with diet containing Psuedomonas sp and mixture of M. luteus and Psuedomonas sp. On the other hand, as shown in table (6) the plasma total proteins were decreased significantly in fish fed with diet containing Psuedomonas sp and mixture of M. luteus and Psuedomonas sp (2.66 ± 0.136 and 2.75 ± 0.170 g/L, respectively) where the control group was 3.17 ± 0.118 (g/L). Also, the AST and ALT activities in plasma of O niloticus were significantly decreased in fish fed with diet containing Psuedomonas sp and mixture of M. luteus and Psuedomonas sp (Table 6) when compared to treatment fish fed with diet containing M. luteus only and the fish in control group. Same as the trend, the average level of plasma LDH activity in fish control group was ( 189.90 ± 8.16 IU/L). As shown in Table (6), the lactate dehydrogease was significantly decreased in fish fed with diet containing Psuedomonas sp and mixture of M. luteus and Psuedomonas sp.
Challenge test results:
Table (7) showed that M. luteus had a probiotic effect with fish. The mortality rate was 25% of O. nilotecus fed on a diet containing M. luteus for three months and challenged i.p. by pathogenic A. hydrophila (0.3 ml 0f 107 cells/ml) . The mortality rate of O. niloticus which fed on a diet containing Psuedomonas sp was 90% , this ratio was more than control. The fish which fed on diet contained Psuedomonas sp had external sings including ulceration and hemorrahges, and the fish becam sensitive to any infection. The mixed and the control groups had the same mortality rate (80%).