DataSheet_1_Ovary transcriptomic analysis reveals regulation effects of dietary fish oil on hormone, lipid, and glucose metabolism in female adult spotted scat (Scatophagus argus).docx

In the aquaculture industry, fish oil is widely used as a nutritional supplement to promote the gonadal maturation of broodstocks, while the mechanism of fish oil on ovary development remain unclear. Herein, female adult spotted scat (Scatophagus argus) with most ovaries at phase II were fed with diets containing 8% soybean oil (SO) or 8% fish oil (FO) for 60 days. The final average fish body weight was similar between FO and SO groups. The average gonadosomatic index (GSI) of FO group was higher (non-significant) than that of SO group. Finally, the phase IV ovary of the FO and SO groups were 7 and 5 out of 10, respectively. The serum estradiol (E2) level of the FO group was significantly higher than that of the SO group. The proportions of n-3 long-chain polyunsaturated fatty acids (LC-PUFA, such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA)) in the ovaries were much higher in the FO group than in the SO group. These results suggest that the maturity level of the FO group is relatively higher than that of the SO group. Transcriptome sequencing was used to detect the ovary gene expression. Comparatively, the ovary transcriptome analysis showed 68 up-regulated and 193 down-regulated genes in the FO group. The expression levels of Jund and Jun necessary for the ovary maturation were up-regulated in the FO group, while Pparγ and Cxcl12, which could inhibit the ovary development, were down-regulated in the FO group. Cyp3a27 coding the enzyme for degrading the estrogen was significantly down-regulated in the FO group and coincided with the increase of its serum E2. Kif5b which could regulate the glucose metabolism was up-regulated in the FO group. Serum insulin level was also increased in the FO group. Additionally, Aldh3a2 and Plin2 related to lipid metabolism were significantly down-regulated in the FO group. Briefly, dietary fish oil can influence the expression of genes related to steroid hormone, glucose and lipid metabolism. This study will clarify the mechanism of dietary fish oil in promoting ovary development in teleost fish.

水产养殖业中，鱼油（fish oil）被广泛用作营养补充剂，以促进亲鱼的性腺成熟，但其调控卵巢发育的分子机制尚不明确。本研究选取卵巢大多处于II期的雌性成年斑石鲷（Scatophagus argus），分别饲喂添加8%大豆油（soybean oil, SO）或8%鱼油（fish oil, FO）的基础日粮，持续60天。两组试验鱼的最终平均体质量无显著差异。FO组的平均性腺指数（gonadosomatic index, GSI）略高于SO组，但差异无统计学意义。试验结束后，FO组与SO组中卵巢处于IV期的个体数分别为10尾中的7尾与5尾。FO组的血清雌二醇（estradiol, E2）水平显著高于SO组。FO组卵巢组织中n-3长链多不饱和脂肪酸（n-3 long-chain polyunsaturated fatty acids, LC-PUFA，如二十二碳六烯酸（docosahexaenoic acid, DHA）与二十碳五烯酸（eicosapentaenoic acid, EPA））的占比显著高于SO组。上述结果表明，FO组的卵巢成熟水平相对更高。本研究采用转录组测序（transcriptome sequencing）检测卵巢的基因表达情况，转录组分析显示，FO组相较于SO组共有68个上调基因与193个下调基因。卵巢成熟必需的Jund与Jun基因在FO组中表达上调；而可抑制卵巢发育的Pparγ与Cxcl12基因则在FO组中表达下调。编码雌激素降解酶的Cyp3a2基因在FO组中显著下调，与血清E2水平的升高相吻合。调控糖代谢的Kif5b基因在FO组中表达上调，该组的血清胰岛素水平也有所升高。此外，与脂代谢相关的Aldh3a2与Plin2基因在FO组中显著下调。简言之，日粮鱼油可通过影响类固醇激素、糖代谢与脂代谢相关基因的表达发挥调控作用；本研究将阐明日粮鱼油促进硬骨鱼类卵巢发育的分子机制。