Dietary vitamin E modulates the hypothalamic-pituitary-gonadal (HPG) axis and antioxidant capacity during early gonadal development in juvenile Chinese sturgeon (Acipenser sinensis)

A two-month feeding trial was conducted to investigate the effects of dietary vitamin E on the hypothalamic-pituitary-gonadal (HPG) axis and antioxidant capacity during early gonadal development in juvenile Chinese sturgeon. Three experimental diets were formulated: a basal commercial diet as the control (Con), and two diets supplemented with 0.2 % (VE2) and 0.4 % (VE4) vitamin E, respectively. The results showed that a 0.2 % dietary vitamin E level significantly enhanced final body weight (FBW), weight gain rate (WGR), and specific growth rate (SGR). Although H&E staining showed no morphological differences among the three groups, vitamin E supplementation significantly increased gonadotropin-releasing hormone (GnRH) concentrations in males, as well as testosterone and 11-keto testosterone (11-KT) levels in females. Additionally, the transcriptional levels of key genes in the HPG axis, including gnrh2 , kiss1 , kissr1 , kissr2 , ar , and fshr were markedly up-regulated in both sexes. Transcriptome analysis identified 892 and 1210 differentially expressed genes (DEGs) in males from the VE2 and VE4 groups, respectively, compared to the control. In females, 1431 and 655 DEGs were identified in the VE2 and VE4 groups, respectively. KEGG pathway analysis indicated that vitamin E could modulate multiple biological pathways in Chinese sturgeon, including Cortisol synthesis and secretion, Cell adhesion molecules, PPAR signaling pathway, Cholesterol metabolism, and ECM-receptor interaction. Furthermore, vitamin E supplementation significantly improved catalase (CAT) activity in males and superoxide dismutase (SOD) activity in females. Females fed the 0.2 % vitamin E diet exhibited the highest peroxidase (POD) activity and total antioxidant capacity (T-AOC), while those fed the 0.4 % vitamin E diet showed the lowest malondialdehyde (MDA) concentration. Vitamin E supplementation also significantly up-regulated the expression of gonadal antioxidant-related genes in both males and females. Based on the observed functional benefits in growth and physiological parameters, a dietary inclusion of 0.2 % vitamin E is recommended for juvenile Chinese sturgeon. • Vitamin E supplementation significantly elevated GnRH in males, as well as testosterone and 11-KT in females. • Dietary vitamin E markedly increased key HPG axis-related genes ( gnrh2 , kiss1 , kissr1 , kissr2 , ar , and fshr ) in both sexes. • Vitamin E improved antioxidant enzyme activities, such as CAT in males and SOD in females.