A computational model for asynchronous oocyte growth dynamics in a batch-spawning fish

A computational model of oocyte growth dynamics (i.e., oocyte recruitment, growth, and spawning) in a batch-spawning fish, fathead minnow (FHM, Pimephales promelas), has been developed. The model provides a quantitative link between oocyte growth dynamics and biochemical processes in FHMs through the absorption of vitellogenin (a lipoprotein precursor of egg yolk proteins) into oocytes, which contributes significantly to oocyte growth in fish. The model simulates the number and volume of oocytes in different batches within a FHM ovary. Model-predicted clutch sizes and spawning intervals matched the experimental data well for both unexposed FHMs and FHMs exposed to 17b-trenbolone (a relatively stable metabolite of trenbolone acetate, a synthetic androgen used as a growth promoter in livestock). Overall, the model presents a novel approach to simulating oocyte growth dynamics in a batch-spawning fish and meets an urgent need in ecotoxicological studies to link the effects of endocrine disrupting chemicals at a biochemical level to adverse effects upon reproduction.