Aflatoxins and aflatoxigenic fungal contamination of common poultry feed products in Katsina State, Nigeria

Abstract

This study was conducted to screen the common poultry feed products sold within Katsina State, Nigeria, for the presence of aflatoxigenic fungi and aflatoxins. A total of 15 poultry feed samples from 3 major producing companies were purchased from retailers, and then cultured for fungal isolation on potato dextrose agar (PDA) supplemented with Cycloheximide. Fungal colonies were identified using standard mycological techniques. The samples were further extracted using a methanol-water solvent (v/v) 1:2, and the extracts were analyzed for the presence of aflatoxins using Fourier Transform Infrared Spectroscopy (FTIR). A total of 30 fungal isolates comprising Aspergillus spp. (30%), Mucor spp. (30%), Rhodotorula spp. (13.3%), Rhizopus spp. (10%), Saccharomyces spp. (10%), Geotrichum spp. (3.3%) and Endomyces spp. (3.3%) were recovered. The FTIR results showed that 10% of the samples were contaminated by aflatoxins as evidenced by the presence of peaks/wavenumbers specific for aflatoxins’ functional groups in their FTIR spectra (2850 to 3100 cm-1, 1650 to 2000 cm-1, 1670 to 1820 cm-1, 1400 to 1600 cm-1, 1364 to 1369 cm-1 and 1040 to 1050 cm-1, for aromatic –C–H and CH2, in-plane aromatic –CH bending, Carbonyl C=O, aromatic C=C, –CH3 adjacent to epoxy ring, and symmetric stretching of =C–O–C, respectively). The poultry feeds analyzed were contaminated by aflatoxigenic fungi and aflatoxins, in addition to other potentially pathogenic fungi. Therefore, more stringent prevention and control methods are required to reduce the contamination levels, to avoid loss of poultry lives and possible transfer of carcinogenic mycotoxins to humans along the food chain.