Free Access
Reprod. Nutr. Dev.
Volume 45, Number 3, May-June 2005
SYMPOSIUM: Homage to Professor Charles Thibault
Page(s) 261 - 279
Reprod. Nutr. Dev. 45 (2005) 261-279
DOI: 10.1051/rnd:2005019

Particularities of reproduction and oogenesis in teleost fish compared to mammals

Bernard Jalabert

Groupe « Sexualité et Reproduction des Poissons », Institut National de la Recherche Agronomique, SCRIBE, Campus de Beaulieu, 35042 Rennes Cedex, France

Abstract - Compared to mammals, teleost reproduction presents many original features. Reproductive strategies of species are diversified into numerous adaptations to a large variety of aquatic environments. This diversity may concern sexuality, spawning and parental behaviour, sensitivity to environmental factors, and specific features of gametogenesis such as the duration of vitellogenesis, and egg morphology. Sexuality presents a variety of natural modalities, from gonochorism to hermaphrodism. The absence of definitive arrest of body growth in the adult of most species gives a particular interest to the practical control of growth-reproduction interactions. Vitellogenesis, which represents an important metabolic effort for the maternal organism, involves the synthesis of vitellogenin, a specific glycolipo-phosphoprotein produced in the liver under estradiol stimulation, and its incorporation into oocytes by a receptor mediated process. Both estradiol synthesis in follicle cells and vtg uptake by vitellogenic follicles appear to be mainly controlled by FSH. Oocyte maturation is directly triggered by a progestin, or MIS (maturation inducing steroid) synthesised in follicle cells mainly under LH control, and acting through the non-genomic activation of a membrane receptor. Practical applications of some of these particularities result mainly from the external character of the fertilisation process and of embryonic development, which allows manipulating respectively egg chromosome stocks and sex differentiation. Moreover, the sensitivity of sex differentiation to exogenous factors favours the development of practical methods to control the sex of farmed populations. Finally, the sensitivity of reproductive mechanisms to xenobiotics has led to various kinds of bioassays for putative pollutants.

Key words: reproductive strategies / sexuality / spawning / vitellogenesis / oocyte maturation / fertilisation

Corresponding author: Bernard Jalabert

© INRA, EDP Sciences 2005