The global shortage of fishmeal to use in the fomulated aquafeed and the need of producing high- nutrient density (HND) diet based on the plant proteins (PPs) are the most important challenges faced on the cost-benefit production of aquatic species [1]. In spite of reducing the cost of aquafeeds when to include PPs in the diets, PPs reduce the nutriet bioavailability and disrupt the levels of esteroid hormones (EHs) of fish fed the diets included with high levels of PPs. In this regard, Vitex Pseudo-Negundo (VPN) as a naturally regulating candidate of EHs was included at five levels (1, 10, 100, 1000 and 10000 mg/Kg basal diet) in the diet of one- year rainbow trout broodstocks (359 ± 9.6 g) for 126 days. The profile of EHs (esterogen, testosteron, -estradiol and progestrone) in the experimental fish (n=30) and fecundity were measured in the first and final days. Results showed that the use of 1000 mg VPN per Kg diet reduced significantly (P≤0.05) the ratios of EHs profiles (esterogen: progestrone; esterogen: -estradiol and testostrone: -estradiol). The normal ratios of EHs profiles with the least disturbance range is one of the most important external stimuli affecting on the reproduction of rainbow trout. The fecundity of broodstocks showed a significantly trend (P≤0.05; r2 = 72.3 %) with an increase in the VPN level in the diet. Based on the results, using 1000 mg/Kg VPN in the diet of rainbow trout broodstocks was practical.

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