Pathogenic Bacteria in Oreochromis niloticus var. Stirling Tilapia Culture

摘要

Tilapia Oreochromis niloticus is an aquaculture resource that represents one of the most popular crops in theworld. However, species cultivation presents health problems, which are associated with the presence of pathogenicbacteria and causes high economic losses. The aim of this study was to determine the diversity of these bacteria atthe genus level in the species O. niloticus var. Styrling during growing stage in the fattening and pre-fatteningphases. Tilapia samples were collected and analyzed; each sample was subjected to a macroscopic external andinternal observation of organs and tissues. Subsequently, samples were evaluated by microbiological tests usingTrypticase Soy Agar (TSA), Thiosulfate Citrate Bile Salts Sucrose Agar (TCBS) and selective media (Pseudomonassp. Group), and conventional biochemical tests aimed at the production of glucose, sucrose, lactose, oxidase,catalase, indole, ornithine and Gram staining. External analysis revealed clinical signs of disease such as skinbleeding, body ulceration, corneal opacity, and intestine and vesicle inflammation. Microbiological and biochemicalanalysis showed the presence of eleven bacterial genera known as Arthrobacter sp., Enterococcus sp.,Staphylococcus sp., Micrococcus sp., Streptococcus sp., Aeromonas sp., Pseudomonas sp., Edwardsiella sp.,Flexibacter sp. and Flavobacterium sp., with a predominance of 55% Gram-negative bacilli in tilapia crops.According to the results, it is necessary to take preventive and corrective measures in order to avoid possible risksduring production cycles, mainly when handling organisms. It is also important to promote good crop managementpractices and quality systems in production units to benefit the aquaculture sector.