IP03 Avian Endocrine Test Protocols
B113 & B114
1:20 PM - 4:40 PM, Monday
(IP021) The Influence of the Inclusion of Additional Endpoints on the Outcome of Reproduction Studies in Japanese Quail and a Comparison with Results Obtained in the Bobwhite.
Niemann, L1, Selzsam, B1, Gericke, C2, Haider, W3, Chahoud, I2, 1 Federal Institute for Risk Assessment, Berlin, Germany2 Charité School of Medicine, Campus "Benjamin Franklin", Institute for Clinical Pharmacology and Toxicology, Berlin, Germany3 Institute for Animal Pathology, Berlin, Germany
ABSTRACT- A number of one-generation studies in Japanese quail (Coturnix coturnix japonica) was performed with the main objective to investigate the suitability of additional methods to detect and characterize primarily hormone-mediated effects on reproduction. Here, the NOECs and LOECs from these experiments as based on "classical" reproduction parameters are compared with those obtained when additional endpoints such as histology (liver, gonads), testicular spermatid count, certain serum hormone concentrations (estradiol, testosterone, T4), eggshell strength or sex ratio in 14-day chicks were included. Furthermore, we compare the outcome of our trials with results from regulatory studies in the Bobwhite quail (Colinus virginianus) on the test substances dimethoate, epoxiconazole, fentin-hydroxide, and vinclozolin. Our data suggest that histology and spermatid count might be particularly sensitive endpoints although the relevance even of significant findings at dietary levels well below those causing overt reproductive impairment still remains to be discussed. Although possible treatment-related differences in eggshell strength were observed only when a vertical comparison of pre-treatment and administration period was performed, it is recommended to determine this parameter in addition to shell thickness since a rather poor correlation between both endpoints was seen. Moreover, our studies confirm a similar sensitivity of the Japanese quail and the Bobwhite but the relevant effects in studies on the same compound may be different for the two species. The NOECs obtained were generally the same but in the Japanese quail were sometimes based on additional parameters. Because of the much shorter duration of our studies it may be hypothesised that the inclusion of new endpoints allows for detection of effects that would be otherwise displayed only after long-lasting substance administration.
Key words: Japanese quail, Endocrine disrupture, Reproduction, Additional test parameters