Microbial Flora of Fish Feeds Sold in Asaba, Southern Nigeria

The microbial flora of fish feeds was investigated in this study. Commercially available fish feed samples were procured from sales outlets in Asaba, southern Nigeria. Three common fish feeds of three different particle sizes each, Coppens (6mm, 4.5 and 3mm), Dizengolf (10mm, 4.5mm and 2mm) and Durante (6mm, 3mm and 2mm) were cultured under laboratory conditions for bacteria and fungi growth. Serial dilutions of the fish feeds were made. The sub-cultured and pure cultures of samples were obtained. Bacteria isolates were characterized and identified. Bacterial count was determined using spread plate count. Isolated and identified bacteria were Escherichia coli and Staphylococcus aureus. Out of the nine sizes of cultured fish feed samples examined, E. coli was found in eight while one had S. aureus. Four of the samples had both E. coli and S. aureus. Bacterial counts from Coppens feed was significantly higher (P<0.05) than bacterial counts from Dizengolf and Durante fish feeds which had counts not significantly different (P>0.05) from each other. No fungus was found. Results obtained show that fish feeds sold in Asaba may have microbial flora with bacteria as the dominant microorganism. Storage conditions and unhygienic handling during storage, probably introduced bacterial flora in the fish feeds. Long duration of storage and scooping of feeds in small quantities during sales should be discouraged. Also, improved storage conditions to prevent fish feed contamination by microorganisms are recommended.