从江香猪生精上皮周期及睾丸发育的形态学分析

Morphological Analysis of Spermatogenic Epithelial Cycle and Testicular Development in Congjiang Xiang Pigs

试验旨在探究初情期前后生精上皮周期差异及睾丸发育过程中的形态学变化。通过测定15、30、60和90 d睾丸相关指数,结合睾丸组织形态学特征,判断香猪初情期,划分从江香猪生精上皮周期。结果显示,30 d的睾丸指数较15 d极显著升高(P<0.01),睾丸重、长轴及短轴的增长率分别为298.05%、66.42%和65.45%,60和90 d两个阶段睾丸重增长率相对稳定。形态学观察表明,从江香猪30 d时生精小管出现游离精子,完成第一次生精并进入初情期;与15 d相比,30 d生精小管面积和生精上皮厚度极显著增加(P<0.01),增长率分别为136.12%和40.19%,在60和90 d均处于稳定增长状态。睾丸细胞数统计显示,日龄增加不影响支持细胞(setoli cells,SC)数量(P>0.05),而30 d生殖细胞数(germ cells,GC)较15 d极显著增加(P<0.01)。相关分析结果发现,生殖细胞数量增加与生精小管面积增大、生精上皮厚度变化之间呈明显正相关(r=0.994;0.96)。根据生殖细胞组合形式差异,将初情期前后生精上皮分为3和8个阶段。初情期前生殖细胞以第一次减数分裂前期为主,A、B型精原细胞、SC、初级精母细胞(primary spermatocyte,Ps)、前细线期(preleptotene,PI)、细线期(leptotene,L)等生殖细胞在初情期前后生精上皮中均存在,而圆形精子(round spermatids,R)、延伸精子(elongating spermatid,E)、精子细胞(spermatozoa,S)仅存在于初情期后的生精上皮。本研究结果表明,从江香猪30 d初情,睾丸发育以生殖细胞和生精小管面积的迅速增加为主,该结果对从江香猪早熟性状挖掘、种猪选育及开发利用等有重要的指导意义。

This study was aimed to investigate the difference of spermatogenic epithelial cycle and the morphological changes during testicular development before and after puberty.The testicular correlation indexes at 15,30,60 and 90 d were measured,and the morphology of testicular tissue was observed to judge the puberty,and divided the spermatogenic epithelial cycle in Congjiang Xiang pigs.The results showed that the testicular index at 30 d was extremely significantly higher than that of 15 d(P<0.01).The growth rates of testicular weight,long axis and short axis were 298.05%,66.42% and 65.45%,respectively,the testicular weight growth rate was relatively stable at the two stages of 60 and 90 d.Morphological observation showed that the dissociative sperm appeared in the seminiferous tubules at 30 d of Congjiang Xiang pigs,completing the first spermatogenesis and entering the puberty phase.The seminiferous tubules area and seminiferous epithelium thickness at 30 d were extremely significantly increased relative to 15 d(P<0.01),the growth rate were 136.12% and 40.19%,respectively,it was in a stable growth state at 60 and 90 d.Statistical analysis result of the testicular cells showed that the number of setoli cells(SC) was not affected by the increase of age(P>0.05),but the number of germ cells(GC) at 30 d extremely significantly increased compared with that of 15 d(P<0.01).Correlation analysis result showed that there was a significant positive correlation between the increase of germ cell number and the increase of the seminiferous tubule area and spermatogenic epithelium thickness(r=0.994;0.96).The spermatogenic epithelium was divided into 3 and 8 stages before and after the puberty stage by the difference in the combination of germ cells.Germ cells in the first meiotic period were mainly at the first stage of meiosis,there were A and B types spermatogonia,SC,primary spermatocyte(Ps),preleptotene(PI) and leptotene(L) in the spermatogenic epithelium before and after puberty,but the round spermatids(R),elongating spermatid(E) and spermatozoa(S) were only found in the spermatogenic epithelium after puberty.This study found that Congjiang Xiang pigs reached the puberty when it was 30 days old,the testicular development was dominated by the rapid increase in the area of germ cells and seminiferous tubules.This results had important guiding significance for excavating early-maturing traits,breeding pigs,development and utilization in Congjiang Xiang pigs.