Effect of dietary n−3 LC-PUFAs on plasma vitellogenin, sex steroids, and ovarian steroidogenesis during vitellogenesis in female silver pomfret (Pampus argenteus) broodstock

Abstract

We investigated the effects of dietary n − 3 LC-PUFAs on plasma vitellogenin (Vtg), sex steroids levels and ovarian steroidogenesis during vitellogenesis in female silver pomfret (Pampus argenteus) broodstock. Broodstock were fed four iso-nitrogenous, iso-energetic, and iso-lipidic experimental diets for 185 d: FO (100% fish oil), FSO (70% fish oil and 30% soybean oil), SFO (30% fish oil and 70% soybean oil), and SO (100% soybean oil) with n − 3 LC-PUFA levels of 5.18, 4.01, 3.02, and 2.22%, respectively. The results revealed that plasma FSH levels increased at vitellogenesis (P < 0.05) and slightly decreased at post-vitellogenesis in all four groups. However, plasma LH levels continuously increased during vitellogenesis and significantly increased at post-vitellogenesis (P < 0.05). The FO and FSO groups had significantly higher FSH and LH levels than the SO group at vitellogenesis and post-vitellogenesis. Plasma E2 and T levels continuously increased during vitellogenesis in all four groups. However, the SO group had the lowest plasma E2 and T levels during vitellogenesis. Plasma Vtg levels significantly increased at vitellogenesis and post-vitellogenesis (P < 0.05). FO and FSO had significantly higher Vtg levels than SO (P < 0.05) during vitellogenesis. Cyp19α1α and erα expression levels significantly increased at vitellogenesis and post-vitellogenesis (P < 0.05), with no significant differences between the vitellogenesis and post-vitellogenesis, except in the SO group. Cyp19α1α and erα expression levels decreased in SO at vitellogenesis. In conclusion, dietary n − 3 LC-PUFAs affect ovarian steroidogenesis in silver pomfret by altering plasma FSH and LH levels and ovarian Cyp19α1α gene expression levels during vitellogenesis. High dietary n − 3 LC-PUFAs promote ovarian development in silver pomfret, by increasing E2 secretion and Vtg synthesis.