Penetration studies and residue determinations of 2,4-dichlorophenoxyacetic acid butyl ester in fertile hen eggs and chicks hatched from treated eggs.

Fertilized hen eggs were topically applied with 2,4-Dichlorophenoxyacetic acid butyl ester (3.1 mg/egg) before starting incubation. During the incubation time 20% of the compound applied on eggs was lost by volatilization. At different incubation times (0, 1, 5, 10 and 15 days) the wash-off technique was applied to fertile hen eggs and residue analyses of 2,4-D ester were determined and quantified by gas chromatography with an electron capture detector. We found that 2,4-D ester began to be detectable at the embryo from the 5th incubation day and the amount of the compound progressively increased during chick embryonic development. Furthermore chicks hatched from treated eggs showed the presence of the compound in all studied tissues and the highest levels were found in organs such as brain and kidney.

Nucleic acid content and residue determination in tissues of chicks born from 2,4-dichlorophenoxyacetic butyl ester treated eggs.

The effects of 2,4-dichlorophenoxyacetic butyl ester (2,4-D b.e.) on protein and nucleic acid contents of different tissues of chicks born from externally treated hen's eggs were studied. Residues of 2,4-D b.e. were also determined and quantified by gas liquid chromatography (GLC). A diminished DNA content was observed in skeletal muscle and stomach, an increased one was found in cerebrum and cerebellum, whereas no variations were observed in the other analysed tissues. Protein levels were found decreased in kidney, cerebrum and heart. Besides, the GLC determinations revealed the presence of the 2,4-D b.e. in all the studied tissues finding the highest concentrations in kidney. 2,4-D did not appear to be a significant metabolite of 2,4-D b.e. in this experimental system. The dissimilar effects of 2,4-D b.e. on protein and nucleic acid contents of the studied tissues would be related to a different tissue susceptibility to the drug and/or to drug distribution.