The occurrence of mycotoxigenic fungi in abalone feed in South Africa

Abstract

Abalone feed in South Africa is mainly produced from locally sourced grains  and has soy or fishmeal as a protein source. Contamination with fungal species associated with grain-based animal feed is, therefore, a predictable risk. Various Fusarium, Penicillium and Aspergillus species are known to produce mycotoxins when colonising grains. The aim of this study was to investigate the occurrence of toxigenic fungal species in the ingredients of compound abalone feeds as well as in final abalone-feed products. In this study, 248 fungal isolates were obtained from feed ingredients and  compound abalone feeds collected from three different South African abalone farms and one feed supplier. Morphological and multigene  phylogenetic analyses were used to identify the fungi isolated. Fusarium, Penicillium and Aspergillus  species were consistently isolated. The presence of these species does not always result in mycotoxin contamination.

Keywords: aquafeeds, Aspergillus, fungal isolates, Fusarium, molecular identification, multigene phylogenetic analysis, mycotoxins, Penicillium