大菱鲆卵子排放后在卵巢腔内老化特征初探

Study on characteristics of post-ovulation aging in ovarian cavity of turbot

为了探明大菱鲆(Scophthalmus maximus)卵子在卵巢腔内老化的原因及特征,采用连续跟踪采卵的方式,通过荧光染色、生理生化指标测定,对不同采卵时间(0,3,6,9,12 h)的卵子活性氧和脂质过氧化情况(氧化产物丙二醛MDA)、抗氧化系统(超氧化物歧化酶SOD,还原型谷胱甘肽GSH)、卵巢液pH值及受精率和孵化率进行对比研究。结果表明,随着卵子在体内老化时间的延长,其活性氧含量及脂质过氧化程度逐渐升高,活性氧含量及过氧化程度与排卵后卵子老化呈正相关;SOD酶活力,GSH酶活力均显著下降,MDA含量显著提高;受精率和孵化率均显著下降。排卵后6 h,孵化率降到2.87%~10.60%,此时的卵质已经极度恶化,不能再继续用于后续的生产中。综上,在卵巢腔中,卵子排放后,随着时间的延长,活性氧含量显著升高,抗氧化能力逐渐下降,受精率和孵化率显著降低,老化逐渐加剧。

Using fluorescence staining,physiological,and biochemical methods,we investigated the characteristics of postovulatory aging in ovarian cavity of turbot.Lipid peroxidation and antioxidant system(superoxide dismutase(SOD),reducing glutathione(GSH),and oxidation product malondialdehyde(MDA)),ovarian fluid pH,and fertilization and hatching rates were detected.Five time points(0,3,6,9,and 12 h)were set for the artificial collection of eggs and fertilization.The results showed that with delayed fertilization of eggs in ovarian cavity,the ROS content and degree of lipid peroxidation gradually increased.ROS and peroxidation were positively correlated with postovulation aging.The concentrations of antioxidant enzyme SOD and GSH decreased,whereas that of MDA significantly increased.Fertilization rate and hatchability significantly declined.At 6 h postovulation,the hatchability dropped to 2.87%to 10.60%,and the eggs cannot be used at this point.In summary,in ovarian cavity,after ovulation,ROS content significantly increases with the extension of time,whereas fertilization rate and hatchability considerably decrease.ROS mainly causes postovulation aging.The present study revealed the basic characteristics of postovulation aging of turbot,determined the optimal time for egg collection,and bears importance in the cultivation of high-quality turbot larva.