A survey of fungi and mycotoxins adulteration in South African small scale poultry farms.

Submitted in partial fulfilment of the requirements for the degree Magister Technologiae: Agriculture in the Department of Animal Sciences, Faculty of Science at the Tshwane University of Technology.

Mycotoxins are secondary metabolites produced by a wide-range of filamentous fungi that contaminate products and present significant hazards in the food-chain. This study was conducted to determine fungal and mycotoxin contamination of poultry feeds on South African farms. Eighty-two composite feed samples were collected from feeders and storage on 41 farms in Mpumalanga (40 samples), Gauteng (24 samples) and Limpopo (18 samples) provinces in the year 2016. Fungal isolation and identification were done using molecular analyses, and mycotoxins extraction was performed using an immune-affinity column. High-performance liquid chromatography (HPLC), thin layer chromatography (TLC) and Enzyme Linked Immunosorbent-Assays (ELISA) were used to determine and quantify mycotoxins. Results show the incidence of several fungal genera as follows: Aspergillus (51.2%), Fusarium (46.3%) and Penicillium (18.35%). Mpumalanga had the highest incidence of Aspergillus contamination (75.5%) compared to other provinces. Fusarium verticilliodes (39%), A. flavus (28%) and A. Niger (21%) were the most common contaminants. Fumonisin, aflatoxins, zearalenone and ochratoxin A were the most common mycotoxins detected, with 100%; 89.02%; 89.02% and 97.56% incidence rates respectively. The concentration of the mycotoxins ranged from 388.34 parts per billion (ppb) to 8519.35ppb; from 15.35ppb to 1846.75 ppb; from 0.36 ppb to 26.09 ppb and from 2 ppb to 40 ppb respectively fumonisin, aflatoxins, zearalenone and ochratoxin A. Though the mycotoxin concentration in the feed samples seems to be below the maximum acceptable levels for poultry, cumulative effects could be expected in humans consuming poultry products. Therefore, further studies on the contamination in live chickens and poultry products, monitoring and awareness on fungi and mycotoxin contamination in small-scale farms are recommended for food safety.