饲料磷脂对已交配和未交配雌性三疣梭子蟹卵巢发育、组织学和卵黄蛋白原表达的影响

为探讨饲料磷脂对已交配和未交配雌性三疣梭子蟹卵巢发育、组织学结构和卵黄蛋白原基因表达的影响,本研究采用2×2双因子随机区组设计(日粮类型:0%和4%大豆卵磷脂;三疣梭子蟹交配处理:已交配和未交配),共4个处理组,以大豆卵磷脂0%和4%两种人工配合饲料分别投喂交配和未交配两组三疣梭子蟹雌蟹,进行了为期12周的饲养实验。结果显示,无论三疣梭子蟹是否交配,饲料中添加4%大豆卵磷脂可显著增加三疣梭子蟹的卵巢指数,提高血清中卵黄蛋白原、孕酮和雌二醇的浓度,增大卵母细胞直径;同时上调肝胰腺卵黄蛋白原m RNA相对表达量,但无显著性差异,肝胰腺指数呈现出和卵巢指数相反的趋势;交配后的三疣梭子蟹卵巢指数、肝胰腺卵黄蛋白原m RNA表达量显著高于未交配组。组织学观察显示,交配使得三疣梭子蟹卵母细胞沉积更丰富的卵黄颗粒,促进卵母细胞成熟,交配处理对肝胰腺指数和血清中卵黄蛋白原及孕酮的水平无显著性影响。此外,饲料磷脂水平和交配处理的交互作用显著影响了三疣梭子蟹血清中类固醇激素孕酮和雌二醇的浓度。本实验结果显示,饲料中大豆磷脂和交配处理均能促进雌性三疣梭子蟹的卵巢发育,交配处理对卵母细胞成熟的促进作用更为明显。

Effects of dietary soy lecithin on the ovary development, histology and vitellogenin gene expression in mated and unmated female swimming crab (Portunus trituberculatus)

A 12-week experiment with 2×2 factorial arrangement (0% or 4% soy lecithin and mated or unmated female swimming crab) was conducted to evaluate the effects of dietary soy lecithin on ovary development, gonadal histology and vitellogenin mRNA expression of swimming crab. The results indicated that crab fed the diets containing soy lecithin supplementation had significantly higher gonadosomatic index (GSI), oocyte diameter, the levels of serum vitellogenin and sex steroids than those fed the unsupplemented soy lecithin diets (P<0.05). Hepatopancreatic vitellogenin mRNA expression showed a increasesing trend with increasing levels of dietary soy lecithin (P>0.05). The results of hepatosomatic index (HSI) showed a reverse trend with GSI. Mated female crabs yielded higher hepatopancreatic vitellogenin mRNA expression than unmated female crabs (P<0.05). Furthermore, the mated female crabs had higher the ovarian yolk granules in number and size than those unmated female crabs. Mating treatment did not affect HSI, serum vitellogenin (VG) and progesterone (PG) contents (P>0.05). The interaction of dietary soy lecithin and mating on serum progesterone (PG) and estradiol (E2) contents was identified (P<0.05). In conclusion, the dietary soy lecithin and mating stimulated had a positive effect on ovarian development in swimming crab broodstock, and mating stimulated had a more beneficial effect on promoting oocyte maturation.