Influence of technical and commercial decamethrin, a new synthetic pyrethroid, on the gonadic germ population in Quail embryos.

Contamination of Quail eggs with the synthetic pyrethroid decamethrin significantly reduced the gonadic germ population in 5 day-old embryos. Technical grade and commercially formulated pesticides were used, the commercial excipient and its main hydrocarbon constituent (xylene) were also tested. Eggs were treated either directly by intravitelline injection (1.25 mg, 0.80 mg or 0.30 mg of active substance by egg) or spraying of the shell (with a 2% aqueous suspension of pesticide) or indirectly through repeated ingestion by the parental birds of feed contaminated with 100 ppm of pyrethroid. Reduction in germ potential was primarily due to the excipient used in the formulation of the commercial product. The xylene, main constituent of the matrix, was responsible of this reductive effect. These chemicals (excipient and xylene) were also chiefly responsible for the high embryo mortality rate observed after injection. Both excipient alone and formulated decamethrin were distinctly less embryolethal when sprayed onto eggs or added to feed.