Laboratory of Fish and Shellfish Nutrition, School of Marine Sciences, Ningbo University, Ningbo315211, People's Republic of China.
Key Laboratory of Aquaculture Biotechnology Ministry of Education, Ningbo University, Ningbo315211, People's Republic of China.
Br J Nutr. 2024 Oct 14;132(7):835-850. doi: 10.1017/S0007114524001193. Epub 2024 Oct 11.
Female crabs enter a stage of rapid ovarian development after mating, and cholesterol is a substrate for steroid hormone synthesis. Therefore, in this experiment, an 8-week feeding trial was conducted to investigate the effects of mating treatments (mated crab and unmated crab) and three dietary cholesterol levels (0·09 %, 0·79 % and 1·40 %) on ovarian development, cholesterol metabolism and steroid hormones metabolism of adult female swimming crab (). The results indicated that crabs fed the diet with 0·79 % cholesterol significantly increased gonadosomatic index (GSI) and vitellogenin (VTG) content than other treatments in the same mating status. Moreover, mated crabs had markedly increased GSI and VTG content in the ovary and hepatopancreas than unmated crabs. The histological observation found that exogenous vitellogenic oocytes appeared in the mated crabs, while previtellogenic oocytes and endogenous vitellogenic oocytes were the primary oocytes in unmated crabs. The transmission electron microscopy analysis showed that when fed diet with 0·79 % cholesterol, the unmated crabs contained more rough endoplasmic reticulum and mated crabs had higher yolk content than other treatments. Furthermore, mating treatment and dietary 0·79 % cholesterol level both promoted cholesterol deposition by up-regulation of the mRNA and protein expression levels of class B scavenger receptors 1 (Srb1), while stimulating the secretion of steroid hormones by up-regulation of the mRNA and protein expression of steroidogenic acute regulatory protein (Star). Overall, the present results indicated that mating behaviour plays a leading role in promoting ovarian development, and dietary 0·79 % cholesterol level can further promote ovarian development after mating.
雌蟹交配后进入卵巢快速发育阶段，胆固醇是甾体激素合成的底物。因此，本实验进行了 8 周的饲养试验，研究了交配处理（交配蟹和未交配蟹）和三种膳食胆固醇水平（0.09%、0.79%和 1.40%）对成年游泳蟹（）卵巢发育、胆固醇代谢和甾体激素代谢的影响。结果表明，摄食 0.79%胆固醇组的性腺指数（GSI）和卵黄蛋白原（VTG）含量显著高于同交配状态的其他处理组。此外，交配蟹的卵巢和肝胰腺中的 GSI 和 VTG 含量明显高于未交配蟹。组织学观察发现，外源性卵黄发生卵母细胞出现在交配蟹中，而未交配蟹中存在前卵黄发生卵母细胞和内源性卵黄发生卵母细胞。透射电子显微镜分析表明，摄食 0.79%胆固醇时，未交配蟹的内质网更粗糙，而交配蟹的卵黄含量高于其他处理组。此外，交配处理和膳食 0.79%胆固醇水平均通过上调 B 类清道夫受体 1（Srb1）的 mRNA 和蛋白表达水平促进胆固醇沉积，同时通过上调类固醇生成急性调节蛋白（Star）的 mRNA 和蛋白表达促进类固醇激素的分泌。总之，本研究结果表明，交配行为在促进卵巢发育中起主导作用，膳食 0.79%胆固醇水平可进一步促进交配后的卵巢发育。
