| The grouper as the typical androgynous females their reproductive regulationmechanism is quite complex. In this paper, grouper reproductive biology, themechanism of sex determination and sex reversal induced by a brief summary of thetechnical methods, focusing on artificially induced sex reversal in reproductive biology,sexual reversal of related gene the progress made, and its development prospects, inorder to obtain for the proportion of matching male and female broodstock to addressthe male and female synchronization mature to provide a theoretical basis. Blackseabass is one of groupers which has nuptial colcration during the spawning season. Theobject of experiments was to find the connection, such as, the study of PGCs andovarian, the technology of sex reveral of black seabass. The results were brieflysummarized as follow:1the migration of primordial germ cell of Centropristis striataWith the method of histology and morphology, the migration of PGCs of blackseabass was preliminary studied. The result showed that, PGCs of black seabass wasfound in the other place of body, and they translocated to the genital ridges somaticthrough the somatic.2The annual change of ovarian development in female of Centropristis striataWith the method of anatomy and morphology, the annual changes of ovarian werestudied. The study found that the ovarian of black seabass obviously changed withtemperature,and the optimum spawning temperature is19-22℃:from March to April,the ovary begin to develop followed with the increase of volume and the accumulationof yolk,it changed from Ⅲ period to Ⅳ period; from May to June, black seabassbegan to breed, it was Ⅴperiod, In July, the ovary developed to Ⅵ period since itspawned out; from Augest to September,the ovary developed into Ⅲ period, and itwould developed until next year in March. GSI、HIS and CF has some relevance duringthe spawning season,we could accurately predict the spawning time by measure the CFof black seabass. The peak of GSI emergenced in the annual May, and the fish onlyspawning once a year in short term.3Effects of17α-methyltestosterone and aromatase inhibitors on sex reveral of Centropristis striataCentropristis striata were buried drugs which including17α-methyl testosteroneor aromatase inhibitors in the back muscles to induce the change of sexuality during thespawning season. It was buried once every four weeks and three times in total. Theresults of experiments show that, The ovary of black seabass can be reveral tofunctional spermary with active sperms after the bury of twelve weeks. We wouldknown that17α-methyl testosterone could induce sex reveral of Centropristis striata.And testosterone,11-ketotestosterone and estradiol are promoted by17α-MT. Theelevation of brain aromatase activities was also increased by17α-MT. Aromataseinhibitors can significantly increase concentration of testosterone,11-ketotestosteronein brood but reduce concentration of estradiol. It also reduce the elevation of aromataseactivities of brain and gonadal. So we could known that17α-MT and aromataseinhibitors could induce sex reveral obviously. Effect of common use of17α-MT andaromatase inhibitors is higher than the effect of single-handed. The sex reversal processof black seabass can be divided into four phases: ovary period, ovary period with littlesperm, spermary period with little ovary, and spermary period(sex reversal completionperiod).4Electronic microscopic observations on the spermatozoon,egg and fertilization processof Centropristis striataThe ultrastructure of spermatozoon and egg，together with the fertilization processof Centropristis striata were observed using scanning electron microscope (SEM) andtransmission electron microscope (TEM). The results showed that the sperm ofCentropristis striata was mainly composed of the following3parts. The first part wasalluded to as the head, mainly composed of nucleus. The acrosomal structure hadn’tbeen found in the head. The second part was named midpiece, consisted ofmitochondrion, centriolar complex (including proximal centriole and matrix) andsleeve structure. The third part was called tail, composed of axoneme, which issurrounded by plasma membrane. The axoneme of Centropristis striata was consistentwith the typical “9+2” structure in most of fishes. The eggs were spherical, colorlessand transparent,0.950±0.039mm in diameter. They belonged to pelagic eggs. A biggrain of oil ball (0.182±0.011mm in diameter) was observed in the egg. Overlappingcurves were observed on the surface of the egg, and among them, tiny holes ofdifferent sizes (0.246±0.103μm) were evenly distributed. A completely openedfertilization hole was in the central part of the funneled area at the animal pole. Theshell of the egg was composed of plasma membrane, vitelline membrane and shell membrane. The shell was filled with cytoplasm. The fertilization process ofCentropristis striata was short. The sperm was found to have swimed into the eggthrough micropyle only about10seconds after insemination. The morphologicalfeature of the fertilized egg then changed, and the fertilization cone and fertilizationplug appeared one after another. Finally, about60s after insemination, the fertilizationhole closed to keep other sperms outside the egg. |
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