Comparative studies of bacteria load in fish species of commercial importance at the Aquaculture Unit and Lagoon Front of the University of Lagos

Abstract

Bacteria diseases are widespread and can be of particular importance in fish farming. Bacteria exist as micro flora in water until certain environmental conditions such as poor water quality occur, which could impose a stress on fish, thereby making them vulnerable to infection, most especially by pathogenic bacteria. This study was carried out to assess and compare the bacteria diversities and population in Clarias gariepinus, Sarotherodon melanotheron and Oreochromis niloticus, in the three grow out ponds of the aquaculture unit of the Department of Marine Science and Lagoon Front of the University of Lagos. It also aims at determining their public health significance. The experiment was carried out between May-September 2013. Water samples were collected from the three grows out ponds in the Department of Marine Sciences and from Lagos lagoon Front of the University of Lagos. In each case, water samples were analysed for the possible indicator organisms of faecal and industrial pollutions such as Escherichia coli, Staphylococcus aureus, Salmonella spp., feacal streptococcus, Vibrio spp., and Clostridium spp. From the result obtained, all the bacteria listed above were first seen as common bacteria in all the samples of water analysed. Further studies (biochemical tests) also reveal bacteria such as Klebsiella spp., Proteus spp., Enterobacter aerogenes, Citrobacter spp. and Pseudomonas aeroginosa. Moreover, the same indicator bacteria seen in water samples were also detected in the different body parts (flesh, mouth, gill and gut) of each of the fish species analysed, both from the Departmental ponds and Lagoon front, except Clostridium perfringes (C. welchii), Vibrio cholera and Salmonella typii which were found in the gut of those fish species from the departmental ponds A-C and in the mouth, gill and gut of the fishes from lagoon front. The population of each of these bacteria was found to be highest in the gut region, followed by the gill, the mouth and least in the flesh. There was no significant difference in the population of each of the bacterial across pond water (P>0.05). Same is the case with each bacteria analysed across body parts of the fish species (skin, mouth, gill and gut) in the Departmental ponds, that is, no significant difference (P>0.05). But, when compared with the lagoon front (both for water and fish samples) the difference was highly significant (P<0.05). None of the population of the bacteria in the ponds exceeds the limit for human consumption. The bacteria load in the lagoon fish (skin, mouth, gill and gut) was higher than the recommended limit for human consumption. Therefore, they are not fit for consumption most especially samples from the mouth, gill and gut, except effective processing treatment is employed before consumption. Due policy should also be taken by the government to curtail the tradition of indiscriminate discharge of untreated effluent into the lagoon.

Bacteriological Assessment of African Catfish (Clarias gariepinus) Isolated from Earthen and Concrete Fish Pond

“…The highly infected part of the examined° C. gariepinus used for bacteriological studies was the skin compared to the intestine, this may be due to the fact that the skin is always in contact with the surrounding water and also, the skin may get contaminated with bacteria during handling. This observation agrees with the work of [17] who recorded high bacterial loads on the skin of fresh Tilapia fish (Oreochromis niloticus) when compared with the intestines and gills; Adebayo -Tayo et al [18] also made similar observation but this observation was in contrary to the work of Olugbojo et al [19] who reported high population of bacteria in the gut of three fish species sampled in Lagos State; likewise [20] and [21], also reported high bacterial loads in the intestine part of African Catfish.…”

Bacterial Content in Gut For Different Species of Fish Collecting From Tigris River in Baghdad City, Iraq

“…The total bacteria count load in the gut of G. elegans fish was higher than in the gut of A. marmid and other types of fish as shown in Table (4). [13] explained that the total bacteria count in fish that exceeds 8 91 making them unfit for consumption therefore, the results of the present study can not be considered as a risk to the consumer. The contamination observed may result from rupturing fish gut during poor processing or inadequate washing agent for food spoilage [14].…”

Non-Selectivity of R-S Media for Aeromonas hydrophila and TCBS Media for Vibrio Species Isolated from Diseased Oreochromis niloticus

“…and Enterococcus spp. as recorded by Aboyadak et al [4], Zhang et al [5], Olugbojo and Ayoola [6], Darak and Barde [7], Thune et al [8].…”