Changes in the intestinal bacterial profile and serum biochemical parameters of Nile Catfish Clarias lazera after feeding with probiotic.

Abstract

In this study, the experimental set-up was based on fed Clarias lazera commercial diet with probiotic for 45 days either 1 time/week (W 1 ) all over the experiment or 3 times/week for the 1 st two weeks then 1 time/week till the end of the experiment (W 3 ). Bacteriological and biochemical examinations were done on intestinal tract and serum respectively.Bacteriological investigation revealed the presence of Escherichia coli and Klebsiella spp. in all groups and Pseudomonas aeruginosa failed to be isolated from W 1 and W 3 . Bacterial isolates proved to be pathogenic for mice, positive for Congo red binding activity and toxigenic in infant mice. The intestinal total aerobic bacterial count; Enterobactereacae count and coliform count in males and females of both W 1 and W 3 fish groups were significantly lower than the respective values in control group. Significant low values were detected in W 3 group compared to W 1 group. Significant sex differences in the three counts were detected in the three groups of fish except the Enterobactereacae count in W 3 group.Concentrations of serum ammonia and urea were significantly decreased in both treated groups compared to the control group. Both serum items were significantly lower in W 3 group than that in W 1 group. Significant sex difference was recorded in serum creatinine of the three groups (females lower than males).The activities of serum alkaline phosphatase; alanine aminotransferase and aspartate aminotransferase enzymes significantly differed according to sex with a general trend that these enzymes were significantly higher in W 3 group than that of W 1 group. Serum total protein, albumin, globulin and A/G ratio in fish of W 1 group were more affected by probiotic administration than that in W 3 group. These serum protein items in all groups were significantly affected by sex. Serum IgM level in both sexes of W 1 group was significantly higher than that in both control and W 3 groups.A correlation analysis was conducted to determine the strength of the association between serum biochemical parameters and viable total bacterial count; Enterobactereacae and coliform counts in the guts of fish. Male fish showed similarity of the correlations analysis between the three bacterial counts and the different serum biochemical parameters, while female fish detected some variations according to the type of bacterial count.