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(63-03) Two candidate methods for early detection of a toxic impact on male fertility in birds . Niemann, L.*,1, Fathi, M.1, Woelffel, B.2, Selzsam, B.2, Chahoud, I.2, 1 Federal Institute for Consumers Health Protection and Veterinary Medicine, Berlin, Germany2 Benjamin Franklin Medical Center, Berlin, Germany ABSTRACT- An impact of endocrine disruptors on male fertility in birds might be elucidated by monitoring spermatogenesis. However, in ecotoxicology, no validated methods are available so far. In our reproduction studies in the Japanese quail, spermatide count is visually evaluated immediately following sacrifice. Preliminary results suggest that high doses of two pesticides on study caused a decrease in the average amount of mature spermatides. In-depth clarification of such an effect can be provided by flow cytometric differentiation of testicular cell populations according to their differing DNA content. As previously shown, this technique which is common in humans and laboratory mammals is also applicable to birds. Cell suspensions are obtained from the testis by physical and enzymatic separation. Following fixation, freezing and thawing, samples are labelled with the fluorochrome propidium iodide and 10,000 cells per run analysed on a flow cytometer for DNA concentration. The quantitative ratio between the different populations (e.g., haploid vs. diploid) in the treated and control groups is compared and may indicate alterations in spermatogenesis. Differentiation between somatic and germ cells is possible by an immunological method and might show a general depression of spermatogenesis if occurring. For an organophosphorous compound, a delay in spermatide maturation was noticed. However, although the difference was statistically significant, it was much less pronounced than age-related changes and fertility was not impaired. Our preliminary data also suggest a strong dietary influence on spermatogenesis. Surprisingly, with regard to the quantitiative amount of the different cell populations, the values obtained from the left and right testis of the same drake may differ by about 10-20% and, thus, results must considered with care. Results of a new study on the fungicide vinclozolin are not available so far but will be shown during the platform presentation. Key words: birds, impact on spermatogenesis, spermatide count, flow cytometry |
