Journal of Pure and Applied MicrobiologyVol. 9 No. Special Edition Nov. 2015

Screening of Bacterial Pathogens Attached to Invertebrate Bodies and Biocontrol of Pathogenic Aermonas hydrophila in Marsupenaeus japonicus Culture

Sahar W.M. Hassan1, Hanan Abd-Elnaby1 and Ragia M. Moussa2*

1Microbiology Laboratory, Environmental Division, National Institute of Oceanography and Fisheries, Alexandria, Egypt. 2Invertebrate Aquaculture Laboratory, Aquaculture Division, National Institute of Oceanography and Fisheries, Alexandria, Egypt.

Received on 30 June 2015 and accepted on 15 September 2015

 

ABSTRACT

Microbes play crucial role in aquaculture systems. In the present study, screening of the bacterial communities of Aeromonas sp. Vibrio sp. Staphylococcus sp., E. coli sp. and Salmonella sp. associated with shrimp, bivalves and sea cucumber revealed that Aeromonas sp. was the dominant pathogen in shrimp representing 6.33% and 11.25% of the total heterotrophic bacteria associated with shrimp surface and body, respectively. Antibacterial activity of different extracts of the invertebrate bodies and chitosan in addition to eleven attached bacterial isolates were tested. The marine bacterial isolate which was identified as Vibrio alginoticus by using 16S rRNA sequence analysis. Vibrio alginoticus, was superior in its Antibacterial activity, recording the highest activity unit of 10.24 ? 3.15 AU against A. hydrophila. The impact of probiotic V. alginoticus in improving the water quality of A. hydrophila infected Marsupenaeus japonicus culture was investigated. The histopathological study of M. japonicus tissues showed limited tissue damages observed in treatments using probiotic bacteria. Three stages of infection have been defined in infected hepatopancreas according to vacuolation, and hemolytic aggregation while intensity of infections in muscle and heart tissues was determined according to bacterial doses and hemolytic aggregation.

Keywords : Vibrio alginoticus, Aeromonas sp., Antibacterial, Probiotic, Marsupenaeus?japonicus, Histopathology.