Sex Modifications in Hens’ Eggs Following Immersion in Diethylstilbestrol Solutions

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Abstract
An account is given of the effects of a single 10-second immersion of fertile eggs (hens’) into solutions of diethylstilbestrol (DES) before incubation and between the ends of the 1st and the 5th days of incubation. The solvents used were 100 % and 50% isopropanol, 95% ethanol and 2% Tween 80 in distilled water. Evaluation of the modification of the reproductive structures was made with regard to genital papilla, morphology of the left gonad and retention of mullerian duct rudiments. The purposes of the study were: 1) to determine the time when treatment with low concentrations of stilbestrol would give a high percentage of modified sex differentiation without significantly lowering hatchability, 2) to determine the value of using the genital papilla of the male as an indicator of extensive modification of the internal structures of the reproductive system, and 3) to compare the results of the Seltzer method with other methods of introducing such substances into the embryonic environment. Both 100% isopropyl alcohol and 95 % ethanol served satisfactorily as vehicles for DES on eggs treated at 96 hours’ incubation time. The genital papilla served as a sensitive index of DES activity. Modification of the papilla to yield a vent of the female type was paralleled by the occurrence of modified left testes. A high correlation existed between the incidence of ovotestes (the most extreme modification of the left testis) and the frequency of retention of rudiments of the mullerian ducts. The effectiveness of the solvents is related to the volume that penetrates the intact shell. The results obtained by this technique are in general agreement with those reported by investigators using other techniques both with regard to time of treatment and to approximate amounts of effective agent reaching the embryo. The technique is valuable for mass treatment of eggs, providing the substance being studied is available in amounts adequate for preparing large volumes of solution.