Adelusi Oluwasola Abayomi, Gbashi Sefater, Adebiyi Janet Adeyinka, Makhuvele Rhulani, Aasa Adeola Oluwakemi, Oladeji Oluwaseun Mary, Khoza Minenhle, Okoth Sheila, Njobeh Patrick Berka
Department of Biotechnology and Food Technology, Faculty of Science, University of Johannesburg, Doornfontein Campus, Johannesburg P.O. Box 17011, South Africa.
Department of Biological sciences, University of Nairobi, Nairobi P.O. Box 30197-00100, Kenya.
J Fungi (Basel). 2022 Nov 11;8(11):1192. doi: 10.3390/jof8111192.
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.
本研究调查了2018年至2019年从南非自由邦和林波波省采集的65份（夏季35份，冬季30份）小农户奶牛饲料的真菌污染情况，并评估了季节变化对真菌污染水平、分离频率和多样性的影响。采用宏观和微观方法对样本进行真菌污染检测，并通过分子手段确认其身份。从两个季节的饲料中总共分离出217株真菌，分属14个属，包括曲霉属、镰刀菌属和青霉属。分离出的最常见真菌种类是烟曲霉和硬皮青霉。真菌学分析表明，97%的样本被一种或多种真菌分离株污染，夏季饲料的真菌平均水平（6.1×10³至3.0×10⁶CFU/g）高于冬季采集的饲料（平均水平：1.1×10³至4.1×10⁵CFU/g）。独立样本t检验显示，曲霉属和镰刀菌属的分离频率夏季显著高于冬季（p≤0.05），而青霉属在两个季节的流行率无统计学差异（p>0.05）。此外，香农-韦纳多样性指数（H′）显示夏季真菌多样性（H′=2.8）高于冬季（H′=2.1）。这项关于真菌污染的研究可用于南非未来的真菌控制和霉菌毒素风险管理。
