Endocrine Control of Oogenesis in Rainbow Trout
Captive female fish broodstock frequently exhibit an array of reproductive problems including precocious or delayed puberty, failure to initiate or complete oocyte development, and production of low numbers of eggs (reduced fecundity). Understanding the control of the development of oocytes into fertilizable eggs is necessary to overcome some of these reproductive problems yet little is known about the early phases of oocyte development, despite the fact that this is when fecundity is largely determined. The purpose of this project is to understand the hormonal mechanisms controlling the critical early events in the development of oocytes of fishes that lead to the production of primary oocytes which can be recruited into the growth pathway and accumulate yolk. The project will focus on the role of pituitary follicle-stimulating hormone, sex
steroids, and insulin-like growth factor I in regulating the early stages of oogenesis in rainbow trout, including proliferation of oogonia, their entry into meiosis and growth of the resulting primary oocytes. The results will potentially be of use in the development of methods to manipulate fecundity and the timing of puberty onset, and thus increase reproductive efficiency both in commercial aquaculture and in captive broodstock programs for endangered species.