| Amur grayling is a kind of typical cold-water fishe lived in the mountain brook and stream. Its meat is delicious and is a kind of valuable Edible fish.Catching excessively and the changes of natural condition for existence make Amur grayling exist difficultly.To develop and make full use of the valuble autochthon fish and provide a great quantity of fish seeds for the development of artificial breeding,we make the study to protect Amur grayling efficiently.We study on the structure of genitical gland, gametogenesis, azoospermia, embryo and postembryonic development about Amur grayling by the method of histology,breeding biology and cyemology .We want to find the optimal method to artificialy propagate Amur grayling and establish the base for profound research.We observe the structure and developmental capacity of spermary and ovaries by fixing with Bouin's and paraffin section.The result showed that its spermary is microphyll type.It grows intoⅡ+ stage after about 10 months.At this time the spermary is barred and translucent.In the spermary there are mostly androgonial cells. It grows into V++ stage after about 3 years . The genitical gland is ivory and its cross section is oval or round. On the surface the blood vessels increase and it is mostly made up of spermatozoas.Then the bursula full of spermatozoas breaks and spermatozoas are full of folial cavity. When the abdomen is pressed, the white ejaculum will spill. Its ovaries is close type and grows intoⅡstage after 10 months. The genitical gland is opaque, flat and pallide-flavens.There are mostly egg mother cells ofⅡstage in it. A small quantity of egg mother cells begin transitting to the III stage.When the ovaries of 2+ stage grows into III stage, female and male fishes can be identified easily. The ovaries expands and is covered with gross blood vessels. It is buff. Ovum pills begin to deposit yolk.In the ovaries most of egg mother cells are III stage and some are Iistage.The sperm motility of Amur grayling were measured by BSS and water in temperature of 4℃and 14℃(room temperature), preserved the sperm and diluted sperm by ASP for experiment. The results showed that the spermatozoa of Amur grayling could be activated by BSS and water, the motility rate were 100%和98% respectively. At 14℃, the average life of the spermatozoa of Amur grayling was 72.1s, the average movement time of A degree (quick movement) was 14.1s by BSS; the average life of the spermatozoa of Amur grayling was 67.2s, the average movement time of A degree was 12.5s by water. The spermatozoa that conserved in different temperature had significant deviation in average life and quick movement time: the sperms which were preserved for 2 hours in 4℃have lost A degree movement and motility rate was more than 70%; the motility rate of sperms which were preserved for 6 hours was less than 20%. The sperms preserved in 14℃, would lost A degree movement after 1.5 hours and the motility rate was more than 70%, 4 hours later, the motility rate was less than 20%. Preserved in ASP(pH was 7.0,7.8,8.0,8.5,9.0), under the temperature of 4℃and 14℃, the motility rate of sperms which was either activited by BSS or water was less than 20%, and the spermatozoa showed the movement of C and D degree, the motility rate of every preserving group was 0 after 1.5 hours. The results indicated that, BSS had a better activing effect than water on the Amur graying; Preserving effect in 4℃was significant better than in 14℃, in order to get a ideal effect the sperm which was not diluted were preserved in 4℃and used within 2 hours. ASP was not suitable to store the spermatozoa of Amur graying.Different methods were used to artificial propagation of Amur Grayling. Parent fish were divided into Sixty groups and the sex ratio was 1︰1.47. DOM+LRH-A2,HCG and S-GnRH-A were used simultaneously to induce ovulation and injected at the base of pectoral fin at one time. Eggs and sperm we re picked up by means of squeezing the abdomen of Grayling, and both the dry and solvent methods are used for fertilization. Hatching was carried out by spring water and well water individualy. The results showed that the maturity of parent fish was pretty well; the effect of promoting spawning was ideal and the promoting spawning rate was 95%, the average spawning number of eggs was 1948(884～3504)per fish and fecundity of female is 2435 (1024~3721); water temperature maintained 7.5±1℃during incubation, eyed eggs appeared when cumulative temperature reached 90～95℃·d, and they were obvious during 100～110℃·d; fry began hatching at 120～130℃·d and finished at 190～200℃·d; larvae became floating at 240℃·d and first feeding at 260℃·d. The results indicated that fertilization with solvent method was significantly better than that of dry; the average eyed eggs rate was 63.89%, the average hatching rate was 78.26%, and average floating rate was 78.14%; the hatching results with spring water were significantly better than that with well water, the average eyed egg rate was 65.49%, the average hatching rate was 80.13%, and the average floating rate was 78.23%.We observe embryonic development and the condition of saccus vitellinus absorption in young fishes hatched by fixing with Bouin's and peeling egg envelope.At the same time we measure the length and body weight of the young and immature fishes within 70 days age and observe the growth condition.The result shows the roes of Amur grayling are typical anisolecithal eggs. The modus of cleavage is discoidal cleavage. The archoplasm concentrate at the animal pole after postfertilization and yolk seize the most part of the roe. The embryonic development can be divided into 23 stages, zygote(archoplasm assembling and blastoderm bulging),2 cell stage,4 cell stage,8 cell stage,16 cell stage,32 cell stage,64 cell stage,multi-cell stage,blastula earlier period,blastula intermediate stage,low blastula stage,blastula advanced stage,archigaster earlier period,archigaster intermediate stage,archigaster advanced stage,neurula stage,archistome close stage,capsula optica appearing stage,pectoral fin fundamentstage,crystal appearing stage,eyeball pigment depositing stage,circulating stage and appearing membrane stage.The saccus vitellinus of the young fishes hatched diminish gradually with the volume of the saccus vitellinus increasing.The absorption is comparatively fast before 4 days age and slow after 4 days age.When the cumulative temperature achieves 384.3℃·d (20 days age),the saccus vitellinu is absorbed completl.The length and body weight of young fishes achieve 1.540±0.131cm and 0.01081g respectively.They grows comparatively slowly before 36 days age and fast after 36 days age. |
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