Comparison of testicular development in traditional pond, lotus pond and rice paddy of hybrid crucian carp
Currently, traditional pond aquaculture is the main aquaculture method in WR, and non-mainstream aquaculture methods of lotus-fish and rice-fish co-culture also exist. To investigate the effects of lotus pond and rice paddy aquaculture on the development of WR testis, this study constructed traditional pond (TP), lotus pond (LP) and rice paddy (RP) WR aquaculture modes and compared the differences in the development of WR testis among the three aquaculture modes.Comparison of the histologic features of the WR testis showed that the morphology of the testis in the group RP was fuller and contained a large number of spermatid and spermatozoa, whereas the group LP had a large number of spermatocytes in the testis and the smallest number of spermatocytes. Comparison of steroid hormone levels in plasma showed that the concentration of testosterone was lowest in the group RP, and the concentration of luteinizing hormone was higher in the group LP than in the group TP. Labeling of spermatogonia (cyclin a, vasa), spermatocytes (vasa), and supporting cells (sox9) in the testis using immunofluorescent markers showed that all types of germ cells were present in all groups of testis, and that most of the germ cells were undergoing meiosis or mitosis. Comparison of the expression of genes related to testis development showed that the expression of spermatogonial stem cell genes (nanog, gpr125, gfra1), spermatogonial genes (dnd, ccna1, vasa), spermatocyte genes (vasa), and Sertoli cell genes (sox9, dmrt1) was generally higher in the group TP than in the group LP, and that of nanog was higher than that of the group RP. The expression of meiosis-related gene sycp3 was higher in the group LP than in the other groups.In summary, this evidence showed that the testis of WR developed normally in all aquaculture modes, with the testis of WR aquacultured in rice paddy developing faster and those in lotus ponds slower. This study provides a theoretical reference for the preservation and continuation