Antimicrobial Action of Epidermal Mucus Extract of Clarias gariepinus (Burchell, 1822) Juveniles-Fed Ginger Inclusion in Diet

The antimicrobial activity of epidermal mucus extract of C. gariepinus juveniles-fed ginger inclusion in diet was investigated and compared with the activity of epidermal mucus extract of C. gariepinus juveniles (control) without ginger in diet. This study demonstrates the antimicrobial role of ginger in improving protection of fish against bacterial infection as shown by the higher zones of inhibition observed for epidermal mucus extract of fish-fed ginger in diet as compared with control. Zones of inhibition for epidermal mucus of treatment fish were 30.7 mm, 29.8 mm, 26.3 mm and 19.3 mm for Bacillus, Escherichia, Staphylococcus and Streptococcus species respectively. Though these values were not significantly (P > 0.05) higher than those obtained for the control fish with zones of inhibition of 25 mm, 11.2 mm, 9.0 mm and 7.3 mm for Bacillus, Escherichia, Staphylococcus and Streptococcus species respectively, the higher values recorded for the treatment fish shows that ginger inclusion in fish diet had an antibiotic effect against isolates of bacteria in fish samples from cultured ponds. The addition of ginger in C. gariepinus diet is encouraged as its action is indicative of the potentials of ginger in preventing emergence of resistant bacteria and improving the antimicrobial role of fish mucus and therefore the quality of C. gariepinus.