Black soldier fly larvae meal influences the growth, reproduction and related gene expression in farm-raised and growth-trait-selected Clarias magur brooders

A 120-day feeding trial was conducted to evaluate the effects of Black Soldier Fly Larvae (BSFL) meal on gonadal development, reproductive performance, and gene expression in two populations of Clarias magur: Farm-raised stock (FR) and genetically selected stock (GS), Maha Magur. Two diets, FM (14.65% fishmeal) and IM (20% BSFL, 0% fishmeal), were employed in a 2 × 2 factorial design. A total of 168 brooders were fed respective diets on a satiation basis. GS showed significantly better growth and nutrient utilization (final weight, weight gain %, SGR, PER) than FR (p < 0.05). Conversely, FR showed superior reproductive indices (GSI, Relative fecundity), reproductive performances (fertilization %, hatching % and larval survival %) (p < 0.05). Hormonal profiles varied among stocks, with FR having higher serum 17α20βDHP and GS females having increased estradiol. Serum 11-Keto-testosterone was increased in FR females and GS males. Gene expression indicated upregulation of fshr, cyp19a1a, and vtg in GS females, which correlated with increased estradiol, while increased lhr expression, correlating with serum 17α20β-DHP found in FR females. Histology indicated mature oocytes and numerous spermatozoa in FR, with GS females having vitellogenic oocytes. BSFL addition had little effect on the reproductive characters of either stock. In general, FR exhibited better reproductive performance and maturity irrespective of GS exhibiting improved growth.