Prevalence and Characterization of Moulds Associated with Fish Feeds Sold in Kisii County, Kenya

Abstract

There is an increase in aquaculture in Kenya due to increased demand for fish as a source of white meat and increased population growth. Most fish farmers use plant-based ingredients such as peanuts, cottonseed, soybeans, maize bran and wheat as sources of protein for the fish feeds. These ingredients are very susceptible to attack by aflatoxigenic fungi. In humid climatic conditions like those found in Kisii County, growth of such fungi on fish feeds is accelerated due to absorption of moisture from the environment as a result of poor storage and sometimes improper drying. This study was conducted to determine the moulds associated with fish feeds sold in Kisii. Commercial fish feeds from five main outlets in Kisii County were sampled and analysed. Home-made fish feeds were obtained from three groups. Fungi were isolated using various media and percentage isolation determined. The results show that fifteen fungal species were associated with fish feeds sold in Kisii County. They include Mucor spp, Penicillium glabrum, Fusarium oxysporium, Aspergillus oryzae, Aspergillus flavus, Aspergillus parasiticus, Alternaria spp, Penicillium citrinum, Stachybotrys spp, Cladosporium spp, Aureobasibium spp, Eurotium spp, Aspergillus versicolor, Aspergillus fumigatus and Aspergillus niger. The aflatoxigenic fungi comprising of A. flavus, A. parasiticus and A. niger were most prevalent in fish feeds obtained from Egetuki outlet (29 %) and least prevalent in Dombetty (16.6 %). The mean differences of fungal species were statistically significant (P<0.05) in four outlets. This shows that fish feeds sold in Kisii county are contaminated with aflatoxigenic fungi.