17α-甲基睾酮对钝吻黄盖鲽生长和性腺发育的影响OA

The marbled flounder(Pseudopleuronectes yokohamae),characterized by significant female growth superiority,presents a compelling case for all-female aquaculture to address industry constraints in growth performance.Capitalizing on the well-documented XX/XY sex determination system,this study focused on developing an optimized pseudo-male(XX♂)induction protocol using 17α-methyltestosterone(MT)to establish monosex female populations for commercial-scale cultivation.Through a 120-day feeding trial with 60-day post hatching diploid juveniles(initial biometrics:1.48±0.27 cm body length,0.07±0.04 g body weight),we systematically evaluated five MT dosage regimens(0-4 mg/kg diet)for their sexual manipulation efficacy and associated biological impacts.Notably,all MT-treated groups achieved complete masculinization(100％),contrasting with the natural 50.0％±6.7％male ratio in the controls(MT0:7.61±0.72 cm,14.22±4.71 g).Growth metrics at 240 days revealed dose-dependent responses:Low-dose groups(MT0.5,and MT1)maintained growth and survival rates(64.0％±2.0％)comparable to those of the controls(P＞0.05),whereas high-dose treatments(MT2/MT4)significantly suppressed growth(P＜0.05).Histological analyses demonstrated preserved testicular microstructure in the MT0.5/MT1 groups,featuring distinct spermatogenic lobules and diverse spermatocyte stages,whereas high-dose groups exhibited structural disorganization with diminished spermatocyte populations.Molecular profiling of the meiosis marker sycp3 validated this dichotomy,showing peak expression in the MT1 group and significant downregulation in the MT2/MT4 groups relative to the controls(P＜0.05),confirming dose-mediated meiotic inhibition.These integrated findings establish 0.5 mg/kg MT as the optimal dosage,successfully reconciling complete sex reversal(100％masculinization)with uncompromised growth performance.This protocol provides a scientifically validated framework for industrial-scale all-female seedling production,effectively addressing zootechnical and reproductive management challenges in marbled flounder aquaculture.