Effect of Habitat Locations on the Bacterial and Water Quality Changes in Freshwater Tilapia (Oreochromis niloticus) Using Small Scale Depuration

Abstract

Aim: The aim of the study was to investigate the effect of habitat locations on the bacteriological and physicochemical assessment of aquaculture freshwater Nile Tilapia (Oreochromis niloticus) using a small scale depuration system. Methodology: Nile Tilapia samples were harvested from two different locations Michael Okpara University of Agriculture (MOUAU) and Umugbalu fish farm. The Nile Tilapia sample was subjected to depuration for a period of 48 h. The total bacteria count (TBC) of the Tilapia samples were determined and isolates characterized before and after depuration. The total bacteria count (TBC) and other selected pathogenic bacteria in water and different fish organs differed significantly              (p < 0.05) with TBC being the highest (1.80 x 106 cfuml-1) in water from Umugbalu habitat. The TBC and other pathogenic bacteria from different fish organs (gill, muscle and gut) differed, being 1.41 x 106, 1.10 x 106, 1.50 x 106 cfug-1 (TBC); 8.3 x 105, 7.4 x 105, 9.5 x 105 cfug-1 (Coliform); 1.4 x 105, <101, <101 cfug-1 (Listeria spp); 2.7 x 105, 2.3 x 105, 3.9 x 106 cfug-1 (Salmonella spp) respectively as typically observed in samples from MOUAU habitat. For pH, temperature, salinity and turbidity, water sample from Umugbalu location had the highest values of 6.80, 30.9°C, 6.50 ppt and 26.0NTU and 7.00 ml/g respectively. Conclusion: Small scale depuration system was adequate for the assessment of bacterial quality of the water and freshwater Tilapia organs. Furthermore, habitats as investigated in this study revealed that the water sample was grossly contaminated with pathogenic bacteria and as such could affect fish cultivation and the consumers.