Antibacterial activity of muscle wall extracts of sea cucumber (Stichopus horrens) from Chabahar coastal area, Iran, against pathogenic bacteria in rainbow trout (Oncorhynchus mykiss)

Abstract

The aim of this research was to evaluate the antibacterial activity of the muscle wall extracts of sea cucumber, Stichopus horrens, against Lactococcus garvieae, Streptococcus iniae, Aeromonas hydrophila, and Yersinia ruckeri bacteria in rainbow trout using the disk-diffusion and well-diffusion methods. In this study, nine sea cucumbers (with the mean weight of 1690 ± 12.18 g) were randomly obtained from two locations in Chabahar Bay, Iran in November 2018. The muscle wall of the body was extracted with each of the ethyl acetate, methanol, and acetone organic solvents. The antibacterial activities of extracts were determined. Only the ethyl acetate extracts of S. horrens in the concentrations at 8 and 12 mg/mL had an inhibitory effect on all the examined bacteria. Y. ruckeri and A .hydrophila bacteria were sensitive to the acetone extracts. The best property was recorded with the S.horrens ethyl acetate extracts, with the MIC value of 0.625 mg/mL against S. iniae and L. garvieae. The MIC values ranging from 0.626 to 1.25 mg/mL were also displayed with the acetone extracts against Y. ruckeri and A. hydrophila, respectively. In conclusion, the ethyl acetate extracts of S. horrens displayed the best spectrum of bactericidal effect obtained from four bacteria strains examined.