| Coregomts peled is a kind of whitefish genus which lived in cold-water, and generally distribute in the rivers and lakes of Siberia, Russia latitude50°, which is also the large breeding varieties of Russia. The fish acquires high economic value because of its strong adaptability, rapid growth, tasty meat, easy to salvage and it’s a typical fish to feed on the zooplankton species. Currently, the United States, France, Poland, Japan and many other countries have already started to transplant these types of whitefish, and achieved significant results in the breeding. Since the year1998, the whitefish eyed eggs have been introduced to Xinjiang for six straight years and have been out in Sailimu after being hatched. In June2000, Bozhou invested3.4million yuan to build the only whitefish breeding base in Wenquan province of China, which covers an area of100acres.However, with the expansion of the scale of breeding, the degree of intensification and yield improvement, a series of problems have to be solved in the actual production. For instance, only in the condition of annual lake frozen and the temperature drops below3℃, we can get better sexually mature male and female individuals. Further more, because of it’s fast transformation to mature reproductive organs, short breeding season in a group, it’s hard to judge when is the proper time to collect eggs, it’s also not easy to get functional male and female brood stock at the same time, which cause great problem in seeding production. Another problem is that the climate conditions of Sailimu cause the low natural reproduction rate of whitefish, and most whitefish self reproduce off-springs, so after years of reproductive isolation and multiple generations of inbreeding, degrees of degradation of breeding will be caused such as sexual precocity; small entity and low resistance. Restrained by production condition and scale, the supply of seeds is inadequate, many small and independent breeding groups are also affected. The whitefish produced from Salimu are seriously in short supply, the main reason is that much fewer little fish were put in the lake. Whitefish, as a newly introduced species to Xinjiang for a relatively short time, is still in an exploratory stage. Specific performance of this stage:1. The rate of fertilized eggs made by artificial propagation is very low. Eyed eggs are very low ((17.5%to20%), which lags far behind from Russia (70%).2. It’s the first time for Salimu, such a large water area, to proliferate cold water fish, so it has to continuously proliferate in order to achieve the production scale.3. Fewer commercial whitefish are caught, so it’s difficult to further promote to the market. Therefore, it’s urgent to study the whitefish. So we can get sexually mature male and female individuals.GnRH, as an important factor to control the pituitary luteinizing hormone (LH) and follicle-stimulating hormone (FSH) release in fish, plays an important role in the reproductive process. During the process of vertebrates’growth and development, the process of pregnancy and childbirth breeding, GnRH has mainly involved in the activities regulating steroid production, cell proliferation, fertilization, adhesion cells, extracellular matrix and cell migration and so on.For the reason of it’s potential application in the production of fish, GnRH becomes one of the hotpots of Reproductive Endocrinology. In order to further understand the role of GnRH in fish breeding process, it’s necessary to know the best time of oxytocin, to improve oxytocin effect, to overcome the current situation of artificial propagation.1. The tissue studies with Coregonus Peled’gonadThe Coregonus Peled gonad histological structure in Xinjiang Sailimu were studied by optical microscopy. The results show that the Coregonus Peled lobular type testes spermatogonial cells are found in the inner wall of the fine lobular, the spermatocyte and immature sperm cells in the fine small sac, sperm maturation fine small capsule rupture release sperm into the lobular cavity and completion of the developmental process, there are a lot of fine interlobular interstitial cells, capillaries and fibroblasts. The Coregonus Peled ovarian development period IV ovarian oocytes of ovarian memory at different developmental phase.2. The Localization of GnRH in nervous system and gonad of the mature Coregonus PeledUsing immunohistochemistry, we systematic observed the distribution of GnRH in the nervous system and gonad of mature Coregonus peled. The results show that, GnRH has immunopositive reaction at the brain, the cerebellum, the brain, spinal cord, medulla oblongata and mainly distributed in neurons. GnRH immunoreactive cells in the ovaries and testes were distributed, and its positive parts in ovarian mainly distributed in small growth stage oocytes; mainly distributed in the interstitial cells and spermatogonia in testis, This article discusses the GnRH directly or indirectly involved in gonad regulation with yellow catfish and catfish. The results will provide new morphological basis for the hypothalamus-pituitary-gonadal axis, nerve-endocrine and GnRH function.3. The Cloning and Expression of GnRH in sexual maturity Coregonus PeledWe design the PCR primers for real-time quantitative is based on the cloning and sequencing of GnRH in Coregonus Peled o using relative quantitative PCR, We analysis the mRNA expression of cGnRH-Ⅱ gene by the method of ΔΔCt,and lay the P-actin as the reference gene, To set up real-time quantitative PCR method for detection relative transcript levels of cGnRH-Ⅱ gene mRNA in in different organs and tissues of sexually mature Coregonus Peled,. The results show that cGnRH-Ⅱ genes have different levels of expression in various tissues; and higher expression in brain, heart and ovarian, compare with the muscle tissue,the times is317.86times,122.79times and71.01times.The data prove the results of the statistical analysis, SYBR Green Ⅰ real-time fluorescence quantitative PCR technology can determine the relative content of cGnRH-Ⅱ mRNA in Coregonus Peled. |
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