Seasonal variation of mycotoxin levels in poultry feeds and feed ingredients in Oyo State, Nigeria

Mycotoxins pose a major problem to poultry production as a result of feed contamination which has deleterious consequences such as production losses and human health risks. A total of 158 chicken feed samples were randomly collected from 46 consenting poultry farms in Oyo State throughout the wet season (April-October; 91 samples) and the dry season (November-March; 67 samples), including compounded feed (n = 129) and feed ingredients (n = 29). Samples were promptly transported to the laboratory in sterile plastic vials for lateral flow assay for mycotoxins using six different commercial mycotoxin test kits each for aflatoxin B1, zearalenone, deoxynivalenol, ochratoxin A, fumonisin, and T-2 toxin/HT-2 toxin. Summary values of mycotoxin levels (mu g/kg) in the feedstuffs were represented as frequency or median (and range). Fisher exact or Mann-Whitney U tests were carried out where appropriate at alpha = 0.05. Every sample contained at least four mycotoxins. Aflatoxins and fumonisin co-occurred in 80% of the samples. Aflatoxin and fumonisin concentrations were above the permissible limits in 32.9% and 18.4% respectively in feedstuff sampled in the dry season while the values were 17.1% and 6.3% respectively during the wet season. Among feed ingredients, peanut cake and maize had the highest median concentration of aflatoxin and fumonisin, respectively. Median aflatoxin concentration in the feedstuff was significantly higher than the permissible limit irrespective of season. There is a need to frequently monitor mycotoxin levels of feed and feed ingredients and improve storage system for feed ingredients in order to reduce the risk associated with high mycotoxin intake in poultry.