The Chinese sturgeon (Acipenser sinensis) is a critically endangered species whose conservation depends on hatchery releases, yet most captive females fail to mature past ovarian stage II. To reveal the metabolic basis of this sexual dimorphism and improve breeding protocols, we compared serum physiology, steroid hormones and lipid metabolites between 11-year-old male and female sturgeons at stage II, then tested whether a two-year diet supplemented with the marine fish Setipinna taty accelerates ovarian development.
Males displayed significantly higher testosterone, dihydrotestosterone, 7α,25-dihydroxycholesterol, polar lipids, cholesterol esters, PGE2, C18:1n9c, MUFA, SOD and glucose, but lower LDL, C18:3n3 and n-6 PUFA than females (P < 0.05). Of 1,469 lipid species, 65 differed between sexes and mapped to bile secretion, steroid and ovarian steroidogenesis pathways. PCA linked female yolk-forming indicators with cholesterol, HDL and LDL.
In the feeding trial, fish receiving 50 % marine fish for 24 months outgrew controls in length, weight and girth (P < 0.05); ovarian mass and thickness reached stage III criteria while controls remained stage II. Serum SOD, CAT, TP, HDL, LDL, cholesterol and 17β-estradiol rose (P < 0.05), n-3 PUFA (EPA, DHA) and n-3/n-6 ratio doubled, and glycerophospholipid metabolites (lyso-PC, lyso-PE) were up-regulated, indicating enhanced antioxidant capacity and lipid-driven steroid synthesis.
These results demonstrate pronounced metabolic sexual dimorphism in Chinese sturgeon and show that marine-fish supplementation can overcome the female maturation bottleneck by supplying n-3 PUFA that fuel E2 production and ovarian growth. The findings furnish biochemical markers for sex identification and a practical dietary intervention to optimize artificial propagation and recovery of this flagship species.

Chinese sturgeon, feeding strategy, biochemical indices, fatty acids, metabolomics, ovarian development