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| Zohar, Y.; Billard, R.. |
| Some recent findings concerning hormonal treatments inducing or accelerating final stages of gametogenesis in some teleost fish are reviewed. In the rainbow trout and northern pike detailed research using in vivo and in vitro techniques led to a better understanding of the endocrine control of final stages of oogenesis. As a result, exogenous hormonal treatments, composed of a piscine gonadotropin administered alone or followed by 17a-hydroxy-20?-dihydroprogesterone injection were found to be effective inducers of precocious oocyte maturation and ovulation in the carq trout and pike. In all species fertilization rates of ovulated oocytes were high (more than 75 %). In the males of the trout, the pike and the goldfish, treatment with fish gonadotropin or... |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1978 |
URL: http://archimer.ifremer.fr/doc/1978/publication-6026.pdf |
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| Breton, B.; Billard, R.. |
| The use of hormonal factors in the induction of artificial egg laying was introduced in fish farming following the first works by Houssay in 1929. Since then, this technique has not evolved much. Pickford and Atz in 1957 have reviewed, exhaustively, most of the attempts carried out to date. This approach is still widely used, and in this way numerous hormonal concoctions have been put into use: mammalian hormones LH, FSH, HCG, PMS... and some fish hypophyseal extracts (mostly carp) often in a raw state. The hypophysation technique can be considered as finalized in the carp, through the use of homologous concoctions. However, in other species, success is more unpredictable and variable, depending on the nature of the hormones used. |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1973 |
URL: http://archimer.ifremer.fr/doc/1973/publication-5990.pdf |
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| Billard, R.. |
| Gametes preservation is usually short (several hours to several days) at temperature above O°C. At subzero temperature sperm fertilizing ability may be kept for several weeks while egg fecondability does not exceed one week. Techniques of sperm cryopreservation in liquid nitrogen are now established for some marine fish species but have to be improved for salmonids. |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1978 |
URL: http://archimer.ifremer.fr/doc/1978/publication-6021.pdf |
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| Billard, R.; Chevassus, B.; Jalabert, B.; Escaffre, Anne-marie; Carpentier, M.. |
| In some gonochoristic Teleosts, the sexual phenotype seems likely to be inverted in relation to the genotype, in some specific experimental conditions (cf. review by T. Yamamoto, 1969). Up to now, the best way to obtain such a result has been the administration of exogenous steroid sexual hormones in the fries' diet, before the normal gonad differentiation period. This way, T. Yamamoto (1953, 1958) obtained some total sexual inversions for the first time, either in the male direction, or in the female one, through the action of methyltestosterone and estrone in the Medaka (Japanese Killifish) Oryzias Latipes, then in the goldfish Carassius auratus (T. Yamamoto and T. Kajishima, 1968). |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1973 |
URL: http://archimer.ifremer.fr/doc/1973/publication-5992.pdf |
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