Biodiversity of Aflatoxigenic Aspergillus Species in Dairy Feeds in Bulawayo, Zimbabwe

Abstract

The presence of molds, especially certain species of Aspergillus, in food commodities may contribute to aflatoxin contamination. The aim of this study was to determine the biodiversity of Aspergillus species in dairy feeds from farms in select locations in Zimbabwe and assess their aflatoxin production potential using a polyphasic approach. A total of 96 feed samples were collected, which consisted of dairy feed concentrate, mixed ration, brewers’ spent grain, and grass from 13 farms during the dry season (August–October, 2016) and the following rainy season (January–March, 2017). A total of 199 presumptive isolates representing four sections from genus Aspergillus (Nigri, Fumigati, Flavi, and Circumdati) were recovered from the feeds. Section Flavi, which includes several aflatoxin producers, constituted 23% (n = 46) of the isolates. Species from this section were A. flavus, A. nomius, A. oryzae, A. parasiticus, and A. parvisclerotigenus, and 39 (84.4%) of these showed evidence of aflatoxin production in plate assays. Of the 46 section Flavi isolates examined, some lacked one or more of the five targeted aflatoxin cluster genes (aflD, aflR, aflS, aflM, and aflP). The presence of the five genes was as follows: aflD (76.9%), aflR (48.7%), aflS (74.4%), aflM (64.1%), and aflP (79.5%). This study highlights the species diversity of aflatoxigenic fungi that have the potential to contaminate different types of feed for dairy cows. Our findings underscore the importance of preventing contamination of feedstuffs by these fungi so that aflatoxins do not end up in the diets of consumers.

Evaluation of Cytotoxicity and Antimicrobial Activity of Flavipin Against Acinetobacter baumannii, Methicillin-Resistant Staphylococcus aureus, and Candida albicans

“…The sequence of A. flavus showed the highest sequence similarity with A. flavus strain ND36, and its "Expect value" (E-value) was 0.0. This strain (ND36) was submitted by Nleya et al (2021). 34 Calibration curves were initially made by estimating the synthesis of flavipin using its serial dilutions (standard).…”

“…This strain (ND36) was submitted by Nleya et al (2021). 34 Calibration curves were initially made by estimating the synthesis of flavipin using its serial dilutions (standard). These results agree with Ye et al's study in 2013, which used a standard curve to detect the production of flavipin.…”

Development of a real-time PCR and multiplex PCR assay for the detection and identification of mycotoxigenic fungi in stored maize grains

“…The five genes were present as follows: aflD (100%) and aflS (100%), aflR (66.6%), aflM (60%), and aflP (80%). Two genes, aflD and aflS , were significantly associated with aflatoxigenic A. flavus isolates (Nleya et al 2021 ).…”

Aspergillus species contamination in concentrate feeds collected from specialized dairy farms and local markets in selected urban centers of eastern Ethiopia

“…Aspergillus, Penicillium, and Fusarium are among the fungal genera that frequently contaminate dairy feeds and feed ingredients globally (Adelusi et al, 2022). A. flavus, A. parasiticus, and A. niger are among the genera of Aspergillus species that are predominantly contaminate feedstuffs destined to dairy cattle (Fusseini et al, 2016;Gherbawy et al, 2020;Nleya et al, 2021). In particular, A. flavus and A. parasiticus are a primary producer of aflatoxins, such as AFB 1 , AFB 2 , AFG 1 , and AFG 2 (Variane et al, 2018;Bouti et al, 2020), while certain strains of A. niger produces Ochratoxin A (El-Hamaky et al, 2016).…”