Aflatoxin deposition and clearance in the eggs of laying hens

Hens fed a diet containing 3310 μg of AFB₁ and 1680 μg of AFB₂ per kg feed for 28 days showed a significant decrease in egg production and egg weights by wk 3 and 4 of feeding, respectively. Transfer of aflatoxins to the eggs occurred rapidly, reaching maximum levels after 4–5 days, and remained relatively constant throughout aflatoxin feeding. The mean values for combined residue levels in eggs were less than 0.5 μg/kg. Levels of AFB₂, AFM₁ and AFM₂ were similar in yolk and albumen while levels of B₁ and B_2a were higher in the yolk. Upon removal of the aflatoxin-containing diet, residues in eggs decreased rapidly. Clearance of aflatoxin residues from the albumen occurred faster than from the yolk. Thus, no residues were detected in the albumen and in the yolk after 5 and 7 days of withdrawal, respectively. No aflatoxin residues could be recovered from whole eggs after feeding the aflatoxin-free diet for 4 days.