The effect of substrate, season, and agroecological zone on mycoflora and aflatoxin contamination of poultry feed from Khyber Pakhtunkhwa, Pakistan.

To study the effects of and interactions among feed types, seasons, and agroecological zones on the total fungal viable count and aflatoxins B1 (AFB1), B2 (AFB2), G1 (AFG1), and G2 (AFG2) production in poultry feed, an experiment was conducted using three-factorial design. A total of 216 samples of poultry feed ingredients, viz. maize, wheat, rice, cotton seed meal (CSM), and finished products, that is, starter and finisher broilers' rations, were collected from Peshawar, Swat, and D. I. Khan districts of Khyber Pakhtunkhwa, Pakistan, during the winter, spring, summer, and autumn seasons of the year 2007/2008. Analysis of variance showed that there was a complex interaction among all these factors and that this influenced the total fungal viable count and relative concentrations of the aflatoxins produced. Minimum total culturable fungi (6.43 × 10³ CFUs/g) were counted in CSM from D. I. Khan region in winter season while maximum (26.68 × 10³ CFUs/g) in starter ration from Peshawar region in summer. Maximum concentrations of AFB1 (191.65 ng/g), AFB2 (86.85 ng/g), and AFG2 (89.90 ng/g) were examined during the summer season whereas the concentration of AFG1 was maximum (167.82 ng/g) in autumn in finisher ration from Peshawar region. Minimum aflatoxins were produced in the winter season across all the three agroecological zones.