中草药淫羊藿和菟丝子对日本鳗鲡卵巢发育的影响

Chinese herbs Epimedium brevicornum Maxim. and Cuscuta chinensis Lam. induced ovary development in Japanese eel Anguilla japonica

在水温(21±1)℃下,给体重(592.5±52.5) g的日本鳗鲡(Anguilla japonica)雌亲鱼投喂每千克体重含0.034 g淫羊藿和0.034 g菟丝子浸膏的饲料90 d,对照组投喂人工配合饲料,研究淫羊藿和菟丝子对卵巢发育的影响。结果显示,饲料中添加淫羊藿和菟丝子的雌鱼卵巢大部分卵母细胞属第Ⅱ时相,性腺指数和肝体比均显著高于对照组(P<0.05);卵母细胞油滴明显增多,部分卵母细胞胞质已充满油滴,核仁变小增多;血清雌二醇(E2)和11-酮基睾酮(11-KT)水平显著升高(P<0.05),实验组11-KT含量约为对照组的4倍;肝脏卵黄蛋白原基因vtg表达量升高,实验组和对照组卵巢cyp19a1仅微量表达,肝脏未检测到erα和erβ的表达;实验组肌肉总脂肪酸、饱和脂肪酸(SFA)、单不饱和脂肪酸(MUFA)和高度不饱和脂肪酸(HUFA)含量均显著高于对照组(P<0.05),最主要的高度不饱和脂肪酸花生四烯酸(AA)、二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)含量均显著高于对照组(P<0.05)。本研究表明,在亲鱼培育饲料中添加中草药淫羊藿和菟丝子促进了日本鳗鲡卵母细胞油滴和肝脏卵黄蛋白原增加,提高了肌肉高不饱和脂肪酸的积累,为卵黄生成和卵母细胞进一步发育做好更充分的准备。

In the present study, female Japanese eels(Anguilla japonica) with an average body weight of(592.5±52.5) g were fed with a commercial diet supplemented with two Chinese herbs Epimedium brevicornum Maxim. and Cuscuta chinensis Lam at a water temperature of(21±1)℃ for 90 d. Then, the histological structure of ovarian development;changes in serum 11-KT and E2 levels;mRNA expression levels of liver vitellogenin(vtg), estrogen receptors(erα, and erβ), and ovarian aromatase(cyp19 a1);, and the fatty acid composition were investigated by tissue section staining, immunoenzymatic assays, semi-quantitative PCR, and gas chromatography,respectively. The results showed that the gonadosomatic indices(GSIs) and the hepatosomatic indices(HISs) in the Japanese eels fed with diets containing E. brevicornum Maxim. and C. chinensis Lam. were significantly higher than those in the control group(P<0.05);the treated group also showed ovaries filled with advanced perinucleolar follicles and increased numbers of oil droplets, and significantly higher serum 11-KT and E2 levels(P<0.05). Expression of vtg mRNA was elevated in the liver of the treated group;however, cyp19 a1 mRNA levels were extremely low in the ovaries of both the control group and the treated group, and the expression of erα and erβ mRNA was not detected in the livers of the two groups. Total fatty acid levels, including saturated fatty acids(SFA), monounsaturated fatty acids(MUFA), and highly unsaturated fatty acids(HUFA), in muscle were significantly higher in the Japanese eels fed with diets containing E. brevicornum Maxim. and C. chinensis Lam than in the control group fish(P<0.05);particularly, the levels of arachidonic acid(AA), eicosapentaenoic acid(EPA),and docosahexaenoic acid(DHA) were higher in the treated group. These findings indicated that the two Chinese herbs, E. brevicornum Maxim. and C. chinensis Lam., induced early ovary development by increasing oil droplets of previtellogenic oocytes and promoted vitellogenin accumulation in the liver of parental female Japanese eels.Moreover, E. brevicornum Maxim. and C. chinensis Lam. accelerated absorption of fatty acids, particularly HUFA,from diets, and subsequently their accumulation in the muscle, to prepare for vitellogenesis and further development of oocytes.