Body-Form And Ovary Genesis And Follicular Histochemistry In Goat

Studies on the genesis and development of the goat embryos are very important to the goat reproduction and breeding. It also have great significance for providing the essential contents of the embryology and the developmental biology. Now there is a little materials about the goat development. So, we study the process of the development by light—microscope and electronmicroscope and his-tochemical methods. ① the cleavage stage and formation of the blastula of the Guan Zhong dairy goat; ② the ultrastructure of the early embryo of the dairy goat; ③ the formation of the blastoderm of the dairy goat ; ④ the systematic morphological genesis of the dairy goat embryos at the age of 17 days and 18 hours; ⑤ the development of the body form of the dairy goat embryos; ⑥ the location and migration of the primordial germ cells of the goat; ⑦ the histological and ultrastructural Changes in the process of genesis and development of the goat ovary; (8) the histochemical changes of glycoconjugates in the oocytes of the goat ovarian follicles.The main results of this experiment can be summerized as following :1. After coitus 1. 5 days, 2. 0 days, 2. 5 days, 3. 5 days, 4. 0 days, 5. 5 days and 6. 5 days, the goat embryos were found to be pronucleus, 2-cell, 4-cell, 8-cell,16-cell, morula and blastocyst stages respectively.2. The goat embryos become compact in the morula stage.3. The inner cell mass of blastocyst of the goat is not covered by the flat tro-phoblasts. The outer cells of the inner cell mass are cuboid or columned. It's different from the flat blastocyst epithelium in shape, but it is similar in function.4. With the merogenesis and the formation of the blastula, the number of microvillus of the plasma membrane which is near to the zona pellucida is in-creased more and more. These microvillus can increase the outer areas of the blastula, it is very helpful to assimilate nutriment.5. The shape of mitochondria is changed greatly with the occuring of cleavage. Before morula stage, it's hooded. From the blastocyst stage, the large mitochondria with traverse crista appeared and the hooded mitochondria disappeared.6. After the later stage of pronucleus and 2-cell stage, many balstomeres form evaginations of the inner or outer leaflet of the nuclear evelope. These e-vaginations projected into the cytoplasma or to the nucleoplasm and formed tubes or bubbles which usually contain many granular substance in it. The evagination is most in 8-cell stage, and in this stage, the nucleopore is not enough. After 16-cell stage, because the nucleopore is sufficient, many nuclear substance is transported into cytoplasm by the nucleopores? therefore, the evegination is decreased , it is a kind of forms of transportion between cytoplasm and nucleoplasm also.7. At the late stage of pronucleus, the vacuols nucleoli can be found in the thelykaryon. The circular nucleoli can be found in 2-cell stage. The reticulated nucleoli start at the 4-cell stage and increase during the following stage. This indicates that the RNA synthesis probably began at the later pronucleus stage or 2-cell stage.8. The gap junctions and tight junctions formed at 4-cell stage, while the desmosomes appered at morula.9. About 9 days and 10 hours after coitus,the surface of the goat embryo is covered by the trophoblast, the outer of the inner cell mass of the goat embryos are the degenerated trophoblastic cells. These cells were probably come from the outer cuboidal cells of the inner cell mass of blastocyst. We call this kind of cell: the para—trophoblast cell. The embryonic disc is exposed to the surface of the embryo after para—trophoblast cells disppeared.10. About 9 days and 10 hours after coitus, the lower surface of the inner cell mass of the goat embryos has differentiated into the endoderm. It will forms primitive gut cavity along the inner surface of the trophoblast, by the time, 9 days and 10 hours, it has not become a complete primitive gut cavity-11. It is about 12 days after coitus the complete primitive gut cavity ot the goat embryos come into being.12. About 13 days and 18 hours after coitus, the goat embyo's mesoderm has generated from the cauda node. Therefore it comes from the ectoderm.13. The trophoblast cells of the goat embryo are flat and with a dark—dyeing nucleus which are spherical. After mesoderm formation, these cells turn into the cuboid epithelium.14. About 17 days and 18 hours after coitus, the goat embryo has 4 pairs somites, and has formated the embryo-axial organ.15. The whole development of goat embryos can be divided into 5 stages; the first stage is the stage of branchial arch; the secondary stage is the stage of thumb-web; the third stage is the stage of artiodactyla; the fourth stage is the stage of formation; the fifth stage is the stage of fetus.16. In the process of development of the goat embryo; the fetus grows fast —grow slowly—grow fast again—grow slowly again; it's circulative. There are five stage of growing fast in the total process. That is ;from 26 to 33 days; 39 to 47 days; 51 to 67 days; 85 to 91 days; 106 to 122 days.17. About 13 days and 18 hours after coitus, the ectoderm cells coming from the inner of the cauda node go throw the mesoderm and reach in the endoderm. These cells finally become a part of the cells of primitive gut wall. It's probably the primodial germ cells (PGCs).18. Before the genesis of the genital ridge, the PGCs has reached at the place where the genital ridge will generate beside the mesonephron. About 23 days after coitus, the genital ridge is generated in the goat embryo. Therefore, the PGCs reach at there is earlier than the genesis of the genital ridge. The genesis of genital ridge is probably the total result of the function of mesonephron and the PGCs.19. The migratory path of the goat PGCs runs preferentially along the wall of the yolk sac, the wall of the hind gut, the mesenterium dorsale, the celomic cavity epithelia, the mesonchym around the celomic cavity epithelia and finally settle in genital ridges.20. About 35 days after coitus, the goat embryo begin sex differentiation, the male embryo differentiate earier than the female does, the sex gland then begin to produce testicular code.21. About 42~49 days after coitus, the oogonia develope rapidly and the symplast can be found in this stage.22. The oogonia proliferation stage is about 35-^91 days. The prophase of the meiophase I stage last from 49 to 105 days. About 73 days after coitus, the fetus' ovary has many primodial follicles, but they all be degenerated. Only about 91 days the real primodial follicles are found in the fetus' ovary and the primary follicles are also be found. About 106 days after coitus, the secondary follicles which have no antrum in it are found. About 122 days after coitus, the antral follicles are found in fetus' ovary.23. About 73 days after coitus, the primary cortex and the primary medulla can be found in the fetus' ovary.24. The process of genesis of the primary oocyte in the primary follicle is that:PGCs—Oogonia—symplast—syncytium— The mass of the diplotene primary oocytes—The singe primary oocyte in the primodial follicle.25. The goat's PGCs are bigger and the organelles get together beside the nucleus.26. With the development of the goat's ovary, the junction(desmosome) between the oocytes and the peripheral profollicle cells increase, and the relation between them is more intimate.27. During the differentiation of the PGCs, the mitochondria changes from mitochondria which display columnar-shaped cristae to vesicular mitochondria which display small round cristae; then to mitochondria which display arc-shaped cristae.28. In the symplast of the oogonia, it could been observed that several oogonia share the same plasma or there are intercellular bridge among them, which has important function at the development; differentiation, degeneration as well as the death of the oogonia.29. It is dicovered that the nuclear membrane break and produce a larger amounts of membrane layers which are winding the chromosome in pachytene of primary oocyte. This probably indicats the degeneration of PGSc30. About 106 days after coitus,On the day of 106, it is obeserved that the plasma membrame of the oocyte in primary follicle projects special circular process to the flat follicle cells, these processes increase the gap between oocytes and follicle cells, which is very helpful to the prodcution of the zona pellucida between the oocytes and the follicle cells, and also promotes the changes of the materials .31. In the plasma of the PGCs and all the varied phase of the oocytes, thereare a few of membrane layers which are especially abounden in the pachytene, it is probably the earlier stage of endoplasmic reticulum(ER). It probably indicats the degeneration of the cells also.32. The follicle cells come from the sexual cord cells which are produced by germinal epithelium. During the differetiation, the shape of the cells are changed from cubic to polugonic, then to flat. The founction of the cells probably also be varied.33. There are a larger amounts of the sexual cord cells and the germ cells degenerated during the genesis and development in the ovary.34. The oocyte in the primodial follicle or in the primary follicle contains a few carbohydrates in the cytoplasm. But with the oocytes increase in the cytoplasm , the carbohydrates are increased in proportion to the growth of the ooplasm in the secondary follicle.35. The cytoplasm of the oocyte in the primodial follicle, in the primary follicle and in the preantral follicle is devoid of sulfated acidic glycosaminoglycans, the neutral glycosaminoglycans is also smaller in it, but the non-sulfated acidic glycosaminoglycans is more as compared with others.36. With the follicular development, the quantity of the neutral glycosaminoglycans in the cytoplasm of the oocyte is more than the quantity of the acidic glycosaminoglycans.37.Three layers could be distinguished in the zona pellucida, the middle layer contains neutral carbohydrate,the acidic carbohydrate is contained in the outer and inner layers.38. The six kinds of lectins included in this experiment, GS- 1 , ConA, UEA- I , LPA, SBA, RCA- I . These lectin receptors (special sugar residues) are distributed in throughout ooplasm. But in the ooplasm of the primodial follicle and the primary follicle, the quantity of the receptors are smaller than the quantity in the ooplasm in the secondary follicle and the antral follicle. The inner and outer layers of the zona pellucida contains more lectin receptors than the middle layer. The middle layer of the zona pellucida is usually devoid of the lectin receptors , and also if the animal is different, the distribution of the lectin receptor site in the zona pellucida is not same.