Effects of a fungicide (VITAVAX 200 FF) on the reproductive-endocrine functions in mallards
✍ Scribed by P�czely, P. ;Kov�cs, K.
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 339 KB
- Volume
- 13
- Category
- Article
- ISSN
- 1053-4725
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✦ Synopsis
The effects of a fungicide VITAVAX 200 FF were studied on the reproduction of captive mallards living in an outdoor environment.
( ) In the first experiment, the fungicide was fed 2.5 g / kg duck food during the sexually inactive period ( ) ( ) October-November and in a second group at the beginning of reproduction February-March . The ( ) ( ) ( ) plasma levels of testosterone T , progesterone P and 17--estradiol E were measured and egg 4 2 production and sexual behavior were studied in both groups.
In the autumn-treated group, only males showed a decrease in T level in the spring and in P during 4 the molting period. T levels in spring-treated drakes and E levels in females were lower than in the 2 control during the peak of reproduction. P decreased only in males during molting. Egg production was 4 lower in both the autumn-and spring-treated groups. ( ) In the second experiment, the treatment was applied at the peak of egg laying March . Sexual steroids, gonadal weights, egg production, and sexual behavior were studied. The steroid levels showed only a slight tendency of change, but atretic follicles and decreased weights of ovaries and oviducts were observed.
The weight of testicles, phallus, and liver was higher in treated drakes. On the basis of these results, it is possible that VITAVAX's damaging effect manifests itself as a decrease in the oogenetic function of the ovary, which is not always or immediately related to the decline of sexual steroid levels. To interpret the increase in the weight of testicles and liver in drakes needs further histological and steroid receptor studies.