青虾幼虾发育时期性腺发育组织学研究

Histological Observation of Gonadal Development During Post-larva in Oriental River Prawn,Macrobrachium nipponense

采用组织切片及类固醇激素含量测定等方法,研究青虾Macrobrachium nipponense幼虾发育第1~31d的精巢、卵巢及促雄腺发育的起始时间、发育过程及成熟时间。结果表明：青虾幼虾发育到第10d（PL10）时促雄腺呈索状结构开始发育,随后经历增殖期（PL10）、合成期（PL13）和分泌期（PL19）3个发育阶段发育成熟,形成完整的促雄腺。青虾精巢和卵巢均在幼虾发育第13d（PL13）开始发育,精巢形成不规则排列的精原细胞,而卵巢生殖上皮开始分化为椭圆或多边形的卵原细胞。精巢经精原细胞期（PL13）、精母细胞期（PL16）、精细胞期（PL19）和精子期（PL22）4个发育阶段成熟,此时成熟的精巢生精小管内充满成熟的精子。卵巢经卵原细胞期（PL13）、初级卵母细胞期（PL16）、次级卵母细胞期（PL16）和卵子期（PL19）4个时期发育成熟,此时卵巢充满成熟卵子。从PL1到PL22,睾酮分泌量逐渐增加,维持在稳定水平至PL25后逐渐下降;从PL1到PL19,17β-雌二醇的分泌量逐渐增加,维持在稳定水平至PL25后逐渐下降。本研究显示：促雄腺与精巢发育过程均持续10d,但促雄腺早于精巢3d开始发育和成熟,这可为性别和生殖相关基因的筛选及性别调控机制的研究提供参考。

In this study, histological method and steroid hormone detection were used to analyze the beginning period, developmental process and mature period of gonad including testes, ovary, and androgenic gland during post-larvae of oriental river prawn（Macrobrachium nipponense）. The histological analysis revealed that the initial development of funicular androgenic gland with a few androgenic gland cells was observed at post-larval stage of 10 days（PL10）. The androgenic gland development was divided into 3 developmental stages： proliferating phase at PL10, synthesis phase at PL13 and secretary phase PL19, full maturity at PL19. Both small testes and ovary were found to begin to develop at PL13 when the spermatogonia with irregular arrangement were the first time observed.Oogonia differentiated from germinal epithelia were oval or polygon in shape. The testis development was divided into 4 stages including spermatogonium stage, spermatocyte stage, sperm cell stage and sperm stage and matured at PL22 when the seminiferous tubule of matured testis was filled with mature spermatozoa. The ovary development was divided into 4 stages including oogonia stage, primary oocyte stage, secondary oocyte stage and ovum stage, matured at PL19 when the matured ovary was full of ovum. The 17β-E2 levelwas shown to be gradually increased from 10.26 pg/prawn at PL1 to 19.77 pg/prawn at PL19, constant until PL25, and then the17β-E2 level was gradually decreased. The level of 17α-T, however, was gradually increased from 33.69 pg/prawn at PL1 to 69.27pg/prawn at PL22, constant until PL25, and then gradually decreased. Both androgenic gland and gonad were developed in 10 days, 3days earlier in development and maturity of androgenic gland than those in gonad. The findings provide information for the screening of the genes related to sexual differentiation and reproduction and for the mechanism of sex control during the developmental process.