The occurrence of mycotoxigenic fungi in abalone feed in South Africa

Greeff-Laubscher, Mariska Riana; Beukes, Ilze; Marais, Gert Johannes; Jacobs, Karin

doi:10.2989/1814232x.2018.1534699

Cited by 3 publications

(6 citation statements)

References 65 publications

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“…To our knowledge, the only modern studies reported 23 species isolated from house dust ( Visagie et al. 2014a ) and seven species from abalone feed collected in the Western Cape ( Greeff-Laubscher et al. 2018 ).…”

Section: Introductionmentioning

confidence: 99%

Updating the taxonomy of Aspergillus in South Africa

Visagie

Houbraken

2020

Studies in Mycology

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The taxonomy and nomenclature of the genus Aspergillus and its associated sexual (teleomorphic) genera have been greatly stabilised over the last decade. This was in large thanks to the accepted species list published in 2014 and associated metadata such as DNA reference sequences released at the time. It had a great impact on the community and it has never been easier to identify, publish and describe the missing Aspergillus diversity. To further stabilise its taxonomy, it is crucial to not only discover and publish new species but also to capture infraspecies variation in the form of DNA sequences. This data will help to better characterise and distinguish existing species and make future identifications more robust. South Africa has diverse fungal communities but remains largely unexplored in terms of Aspergillus with very few sequences available for local strains. In this paper, we re-identify Aspergillus previously accessioned in the PPRI and MRC culture collections using modern taxonomic approaches. In the process, we re-identify strains to 63 species, describe seven new species and release a large number of new DNA reference sequences.

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Section: Introductionmentioning

confidence: 99%

Updating the taxonomy of Aspergillus in South Africa

Visagie

Houbraken

2020

Studies in Mycology

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“…Although Aspergillus spp. isolated from abalone feed were able to produce aflatoxins when reinoculated onto abalone feed, no detectable levels of aflatoxins were measured on abalone feed and ingredients in a previous study (Greeff-Laubscher et al 2018). Therefore, when feed is kept fresh and stored correctly it lowers the risk of aflatoxin contamination.…”

Section: Discussionmentioning

confidence: 91%

“…The first part of this study aimed to assess the potential of fungal isolates to produce mycotoxins when re-inoculated onto abalone feed. Isolates used during this study were previously isolated from abalone feed and feed ingredients (Greeff-Laubscher et al 2018 ). In total 94 isolates were inoculated onto abalone feed to assess potential mycotoxin production at standardised temperatures over 6 weeks.…”

Section: Discussionmentioning

confidence: 99%

“…In total 94 isolates were inoculated onto abalone feed to assess potential mycotoxin production at standardised temperatures over 6 weeks. Formulated abalone feeds are made up of a mixture of grains together with protein, making it an ideal substrate, not only for fungal growth but also for mycotoxin production (Diener and Davis 1969 ; Burgess et al 1981 ; Cassini 1981 ; Greeff-Laubscher et al 2018 ). This was indeed the finding for the positive control strains in this study.…”

Section: Discussionmentioning

confidence: 99%

“…In South Africa, the abalone industry makes use of commercially produced feed, mainly produced from a protein source and locally sourced grains. This is a favourable medium for fungal growth (Greeff-Laubscher et al 2018 ). The feeding ratio for these cultured abalone is ±1 g feed/952.38 mL.…”

Section: Introductionmentioning

confidence: 99%

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Mycotoxin production by three different toxigenic fungi genera on formulated abalone feed and the effect of an aquatic environment on fumonisins

et al. 2019

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Mycotoxins are toxic secondary metabolites produced by various filamentous fungi, of which Fusarium, Aspergillus and Penicillium are the three main genera. Fusarium verticillioides is one of the most dominant toxigenic fungal species, associated with fumonisin contamination in grainbased feeds, such as compound abalone feed. Mycotoxin production is influenced by temperature and available nutrients. In this study the aims were: to determine if abalone feed as growth substrate favours mycotoxin production for toxigenic fungi; to determine the most effective temperature for fumonisin production by F. verticillioides on abalone feed; and to assess the effect of the aquatic environment on fumonisin-contaminated abalone feed. A total of 93 fungal isolates were inoculated onto abalone feed, including species belonging to the genera Fusarium, Aspergillus and Penicillium. Feed inoculated with F. verticillioides were incubated at two different temperatures and fumonisin-contaminated feed was submerged into seawater for 24 h. Results showed that mycotoxins were produced when abalone feed was inoculated with toxigenic fungi, and that F. verticillioides produced higher concentrations of fumonisins at a lower temperature. Submerging fumonisin-contaminated feed in seawater showed that this toxin leached into the seawater, lowering the risk of fumonisins to be consumed by abalone.

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Seasonal Diversity and Occurrence of Filamentous Fungi in Smallholder Dairy Cattle Feeds and Feedstuffs in South Africa

Adelusi

Gbashi

Adebiyi

et al. 2022

JoF

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This study investigated 65 (35 in summer and 30 in winter) smallholder dairy cattle feeds from Free State and Limpopo provinces in South Africa from 2018 to 2019 for fungal contamination and assessed the impacts of seasonal variation on fungal contamination levels, isolation frequency, and diversity. Samples were examined for fungal contamination using macro- and microscopic approaches, and their identities were confirmed by molecular means. A total of 217 fungal isolates from 14 genera, including Aspergillus, Fusarium, and Penicillium, were recovered from feeds from both seasons. The most prevalent fungal species recovered were A. fumigatus and P. crustosum. Mycological analyses showed that 97% of samples were contaminated with one or more fungal isolates, with the summer fungal mean level (6.1 × 103 to 3.0 × 106 CFU/g) higher than that of feeds sampled during winter (mean level: 1.1 × 103 to 4.1 × 105 CFU/g). Independent sample t-test revealed that the isolation frequencies of the genera Aspergillus and Fusarium were significantly (p ≤ 0.05) higher in summer than winter, while Penicillium prevalence in both seasons was not statistically (p > 0.05) different. Furthermore, the Shannon–Weiner diversity index (H′) revealed a higher fungal diversity in summer (H′ = 2.8) than in winter (H′ = 2.1). This study on fungal contamination could be used for future fungal control and mycotoxin risk management in South Africa.

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The occurrence of mycotoxigenic fungi in abalone feed in South Africa

Cited by 3 publications

References 65 publications

Updating the taxonomy of Aspergillus in South Africa

Updating the taxonomy of Aspergillus in South Africa

Mycotoxin production by three different toxigenic fungi genera on formulated abalone feed and the effect of an aquatic environment on fumonisins

Seasonal Diversity and Occurrence of Filamentous Fungi in Smallholder Dairy Cattle Feeds and Feedstuffs in South Africa

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