Table_1_Liver Transcriptomic Analysis of the Effects of Dietary Fish Oil Revealed a Regulated Expression Pattern of Genes in Adult Female Spotted Scat (Scatophagus argus).DOCX

Despite the significance of n-3 long-chain polyunsaturated fatty acid (n-3 LC-PUFA) in fish oil in promoting the maturation of female broodstocks, the detailed mechanism of the effect on the expression of hepatic reproduction-related genes is still unclear. In this study, transcriptome sequencing was used to analyze the effect of the higher dietary n-3 LC-PUFA level on gene expression in the liver of adult females spotted scat. Two-year-old female spotted scat (average weight, 242.83 ± 50.90 g) were fed with diets containing 8% fish oil (FO) or 8% soybean oil (SO) for 40 days. The fatty acid profile in the serum, liver, and ovary was analyzed, and high proportions of n-3 LC-PUFA were observed in the FO group. The final average fish body weight and gonadosomatic index were similar between the FO and SO groups. The serum vitellogenin (Vtg) and hepatosomatic index (HSI) of the FO group were significantly higher and lower than that of the SO group, respectively. Comparatively, the liver transcriptome analysis showed 497 upregulated and 267 downregulated genes in the FO group. Among them, the expression levels of three estrogen-regulated genes (i.e., Vtga, Vtgb, and Zp4) were significantly higher in the FO than in the SO group. This expression pattern could be related to the upregulation of Hsd17b7 (the key gene for the synthesis of liver steroid hormone) and the downregulation of the Hsp90 (the estrogen receptor chaperone). The expression levels of Foxo1a and Lep, which are involved in the lipid metabolism, decreased significantly in the FO group, which may be related to the lower level of HSI in the FO group. The genes related to liver LC-PUFA absorption and transport, Fabp2 and Mfsd2ab, were significantly upregulated in the FO group, indicating that fish actively adapt to high-fish-oil diets. In brief, high-fish-oil diets can influence the expression of genes related to liver n-3 LC-PUFA metabolism and reproduction, inhibit the accumulation of liver fat, and promote the liver health and gonad development. This study will contribute to clarifying the mechanism of dietary n-3 LC-PUFA on promoting reproductive development in teleost fish.

尽管鱼油中n-3长链多不饱和脂肪酸（n-3长链多不饱和脂肪酸）在促进雌性亲鱼成熟方面具有重要意义，但其对肝脏生殖相关基因表达影响的具体机制尚不明确。本研究采用转录组测序技术，分析了高膳食n-3长链多不饱和脂肪酸水平对成年雌性斑点鲟肝脏基因表达的影响。两年龄雌性斑点鲟（平均体重242.83±50.90克）被喂养含8%鱼油（FO）或8%大豆油（SO）的饲料40天。血清、肝脏和卵巢中的脂肪酸谱被分析，结果显示FO组中n-3长链多不饱和脂肪酸的比例较高。FO组和SO组之间的最终平均鱼体重和性腺体重指数相似。FO组的血清蛋黄蛋白（Vtg）和肝脏体重指数（HSI）显著高于SO组，而HSI则显著低于SO组。相对而言，肝脏转录组分析显示FO组中上调基因497个，下调基因267个。其中，三种雌激素调节基因（即Vtga、Vtgb和Zp4）的表达水平在FO组中显著高于SO组。这种表达模式可能与Hsd17b7（肝脏类固醇激素合成的关键基因）的上调和Hsp90（雌激素受体伴侣蛋白）的下调有关。涉及脂质代谢的Foxo1a和Lep在FO组中的表达水平显著下降，这可能与FO组中较低的HSI水平相关。与肝脏LC-PUFA吸收和转运相关的基因Fabp2和Mfsd2ab在FO组中显著上调，表明鱼类能够积极适应高鱼油饮食。简而言之，高鱼油饮食可以影响与肝脏n-3长链多不饱和脂肪酸代谢和生殖相关的基因表达，抑制肝脏脂肪积累，并促进肝脏健康和性腺发育。本研究将有助于阐明膳食n-3长链多不饱和脂肪酸促进硬骨鱼类生殖发育的机制。