Screening of bioactive compound from soil mycoflora and its therapeutic effect on fish borne pathogens of grass carp, Ctenopharyngodon idella (Valenciennes)

Abstract

Soil samples were collected from diverse agricultural fields of Erode Taluk. There were 7 fungal genera which include 11 fungal species observed in composite soil sample in which 9 were identified and 2 of the Aspergillus species could not be identified. Among the fungal genera the genus Aspergillus was predominant in the test soil sample with five of its species. Total bacterial population in the gills and intestine of test fish were counted and recorded. The high percentage of occurrence was shown by E. coli and Aeromonas hydrophila (17.2%). There were 9 bacterial genera isolated from C. idella and identified as E. coli, K. pneumoniae, P. aeruginosa, B. cereus, E. faecalis, Salmonella, Vibrio, Aeromonas hydrophila and Proteus. The bacterial pathogens were tested against selected antibiotics. Biofilm was produced as black colonies. Trichoderma species 1 was found to exhibit high antimicrobial activity against all selected pathogens.