Comparison of antimicrobial activity in the epidermal mucus extracts of fishes

Objective: The mucus layer on the surface of fish consists of the several antimicrobial agents that provide a first line of defense against pathogens. However, today, little is known about the antimicrobial properties of the mucus of hagfish (Myxine glutinosa) and brook trout (S. fontinalis). The goal of this research is the comparison of antimicrobial response in the epidermal mucus extracts of this two species of fishes. Method & Materials: The epidermal mucus samples from these fish were extracted with acidic, organic, and aqueous solvents to identify potential antimicrobial agents including basic peptides, secondary metabolites, aquenous and acid soluble compounds. The initial screening was the comparison of antimicrobial activity of this extracts against a susceptible strain of Salmonella enterica C610. Results & Conclusion: The acidic mucus extracts of both brook trout and hagfish exhibited bactericidal activity. The organic mucus extracts of brook trout showed bacteriostatic activity. There was no detectable activity in the aquenous mucus extracts. Further investigation of the activity of acidic mucus extracts of both brook trout and hagfish showed that theses species had specific activity for fish and human pathogens, demonstrating the role of fish mucus in antimicrobial protection. In comparison to brook trout the minimum bacterial concentrations of hagfish acidic mucus extracts were found to be approximately 1.5 to 3.0 lower against fish pathogens and 1.6 to6.6 folds lower for human pathogens. This preliminary information suggests that the mucus from these species may be a source of novel antimicrobial agents for fish and human health related applications.

Keywords:

brook tout , hagfish , Salmonella enterica