塑膜大棚内中华鳖发育过程血清性激素与性腺发育的研究

以塑膜大棚内养殖的不同龄的中华鳖为试验材料,观察其性腺形态学和组织学的变化,并用酶联免疫吸附法测定血清中睾酮和雌二醇的含量。研究发现,塑膜大棚内中华鳖不仅生长速度加快,而且性腺发育也提前。大棚内养殖的中华鳖的性腺质量和性腺指数明显大于露天池塘养殖的同等鳖龄的中华鳖的性腺质量和性腺指数。半年龄鳖精巢的曲细精管中填塞精原细胞;1龄鳖的精巢,曲细精管中精原细胞2～3层,分布较散;2龄鳖的精巢,生精上皮层数很多,包括精原细胞、初级与次级精母细胞、精子细胞,并且已见圆形精子细胞和拉长的精子出现在管腔中;3龄鳖的精巢,管腔明显增大,生精上皮比2龄鳖的生精上皮层数少,可见靠近基膜的极少量精原细胞、初级与次级精母细胞,变态后的精子细胞的数量最多。半年龄鳖的卵巢内卵泡已经发育至初级卵泡期,1龄鳖的卵泡处于生长卵泡期,2龄鳖的卵巢处于卵黄发生期,3龄鳖处于排卵期。雄性鳖的睾酮的峰值出现于2龄鳖,即生精活动的旺盛期;雌性鳖的睾酮峰值出现于1龄时,即卵泡的生长期;而2龄、3龄的雌鳖的睾酮含量明显降低,即在卵黄形成期和排卵期,睾酮含量是降低的。雌性鳖的雌二醇,在3龄时即卵黄的沉积期和成熟卵的形成期达到最高值。雄性鳖的雌二醇,在2龄时出现最高值,此时生精活动最为旺盛。

Serum Sex Hormonal Levels and Gonadal Development in Broodstock Soft-Shelled Turtle Trionyx sinensis in a Green House

The morphological and histological changes were observed and the serum testosterone and estradiol concentrations were determined in different age soft-shelled turtle Trionyx sinensis cultured in a plastic green house by ELISA.The turtles were found to grow more rapidly and to mature much earlier in the green house than in the outdoor ponds.There were larger gonad weight and gonado-somatic index in the same size turtles in the green house than those in the outdoor ponds.Spermatogonia were filled in the seminiferous tubules of the testes in the 6 month old turtles,and two or three layers of spermatogonia were scattered in the seminiferous tubules of testes in one-year-old turtle.For two-year-old turtles,there were many layers of seminiferous epithelia containing spermatogonia,primary spermatocytes,secondary,spermatocytes,even round spermatids and elongated spermatozoa in the seminiferous tubules.The seminiferous tubules of the testes in three-year-old turtles were increased obviously in number,but the seminiferous epithelium was thinner than that in the two-year-old turtles.A few spermatogonia,primary spermatocytes,and secondary spermatocytes were observed near the basement membrane with large amount of metamorphic spermatozoa.The ovarian follicles were observed in the 6 month old turtles with the follicular phase in the one-year-old turtles.The ovary of two-year-old turtles was found to be at the vitellogenesis and to be at ovulation in the three-year-old turtles.The peak testosterone levels were observed in one-year-old turtles with the follicular phase.In two-and three-year-old females,however,the testosterone levels were decreased significantly,indicating that the testosterone levels were decreased during vitellogenesis and ovulation.The peak plasma estradiol levels was found in the three-year-old females with yolk deposition and maturation,and the peak estradiol levels were occurred in two-year-old males with spermatogeniesis.