【摘要】 本文对鲢、鲤、团头鲂和草鱼四种鱼精液的低温生物学特性及冷冻保存技术进行了研究。筛选出适合这些鱼类精液冷冻保存的理想稀释液配方。查明了冷冻处理导致精子膜破损、使精子谷草转氨酶及其它蛋白质大量逸出进入精浆的原因,而二甲亚砜通过升高精子渗透压和降低冰点可以明显减轻这种冷冻损伤效应。确定了有效的二甲亚砜浓度为8—12％。比较了玻璃安瓿法和塑料管法对精子冷冻保存效果的影响。筛选出了能提高冻精活力和延长运动时间的激活—授精溶液。探讨了精卵授精量比与冻精受精率之间的关系,确定了获得高受精率(80％)所需的最低冻精密度为0.5×10~6精子/卵。获得了短期(几天)和长期(1年)冷冻保存的草鱼和鲢冻精活力稳定在60—75％,受精率稳定在80—90％,鲤和团头鲂冻精活力稳定在55—65％、受精率稳定在70—80％,冻精授精鱼苗的孵化率稳定在75—95％的结果。更多还原

【Abstract】 This paper deals with the cryopreservation of spermatozoa from four species of Chinese carps (Ctenopharyngodon idella, Hypophthalmichthys molitrix, Cyprinus carpio and Megalo-brama amblycephala). A series of experiments was carried out to develop a satisfactory, repea-table and easy technique for the cryopreservation of the sperms of Chinese carps (1) Effects of the compositions of diluents on sperm motility before freezing and after thawing were studied. It showed that the slightly acidic diluents containing only NaCl, KCl and glucose yielded higher post-thaw motility and fertility of the sperms than the slightly basic diluents. Among the NaCl/ KCl/glucose diluents, D-15 gave the best results for the sperms of grass carp and silver carp, while D-16 and D-17 appeared to be more appropriate for the sperm of common carp and blunt snout bream. (2) Cryoprotection nf DMSO for the sperms was examined. It demonstrated that freezing of sperms resulted in marked increase of GOT enzyme activity and other protein levels in seminal plasma, and the addition of DMSO to the diluted sperm mixture before freezing can significantly reduce the effect of freezing damage by increasing the osmotic pressure and droping the freezing point of sperms. (3) The effects of DMSO concentrations on the motility and duration of post-thaw sperms were observed. DMSO of 6-18% always provided cryoprotection. 10-12% DMSO gave the highest post-thaw motility, and 8% DMSO gave the longest duration of motility. (4) Comparison of the effects of different freezing containers on sperm survival and fertility indicated that plasti tube method was superior to glass ampoule freezing method for cryogenic storage of carp sperms. (5) The effect of osmotic pressure of activator solution on sperm survival was studied. The result demonstrated that solutions with osmotic pressure of 256-510 mOsm/l were most suitable for the reactivation of frozen sperms and solutions with 170-256 mOsm gave longer duration of sperm motility. Fertility of frozen-thawed sperms was higher when ova were inseminated in the above solution than in freshwater. (6) The efficiency of the cryopreserved sperms can only be estimated when the sperm-ova ratio is known. Therefore, the effect of the sperm-ova ratio on fertility was studied. The lowest density of frozen sperm cells required to obtain satisfactory fertilization rate (over 80%) was determined to be 0.5×106 sperm/egg. (7) The present study demonstrated that the sperms of the Chinese carps could be stored in liquid nitrog en for 2 days to 1 year with high post-thaw motility (60-70%) when the sperms were preserved in D-15, D-16 or D-17 diluents. Frozen Sperm could fertilize ova almost as effectively as fresh sperm, and the fertilization rate was between 80-94%. The hatching rate of frozen sperm group was the same as the control group.更多还原