Study On Reproductive Biology Of Poecilia Reticulata

The guppy Poecilia reticulata is a popular aquarium species, with the male commending much higher price due to its long and colorful tail. In this study, we tested the feasibility of producing higher proportions of male fish by increasing rearing temperature. When the fry produced from the female broodstock that gave birth a week prior (the females can use stored sperm to fertilize the eggs) and cultured under 19, 21, 23, 25, 29, 32 and 35℃, respectively, % male of the fry produced increased from 21.58 to 77.36% with increasing temperature. Although the death rate was higher at the two highest temperature levels (32 and 35℃). On the other hand, when the fry produced from the female broodstock that were about to give birth and subjected to the same temperature treatments as above, % male of the fry produced was similar (48.57 to 53.78%) among the temperature treatments, confirming that thermal treatment must begin at an early development stage to influence the sex change in the species.To further clarify the changes of guppy gonads' development, and the structure of guppy gonads, we observed the microscopic and ultra-microstructure of different stages of their gonads, found that the oocyte can be divided into six phases. In addition to the development of ovarian the corresponding period of six, also in accordance with the development of embryos, add a gravid period after the V period, so the development of ovary divided into seven period. Anatomizing found there is only one ovary in guppy's, surface of the ovary was composed of the film, body cavity wall and reproductive epithelium. the mature oocyte with much oil sphere, oil sphere dispersed below the egg membrane, yolk particles liquefied, invisible. Microscopic observation of the guppy ovarian showed that the accumulation of yolk is not first began in the region which surrounding of the membrane or the nucleus, but in the middle part of the cell membrane and the nucleus, and arounding for a ring, and then gradually dispersed to both sides of the nucleus and the of cell membrane.According to the characteristics of guppy's germ cells in the testes, confirming their testes are tubular type. Guppy mature testis was composed of Spermatogonium, Primary spermatocyte, Secondary spermatocyte, Spermatid and Sperm.The basic unit of the guppy was Spermato-genic cyst. Spermato-genic cyst developing into the unique structure of Livebears fish- Spermatophore, mature sperm expeled from the testis in this structure. We observed the spermatophore ultra-structure with scanning electron microscopy and transmission electron microscopy, found their shape and appearance much like Cocoon, wrapped film, in which mature sperm are arranged in actinomorphy.Colligating the above research and breeding experience, after a year study we worked out a set of high-grade guppy breeding system, applies not only to the families of small-scale aquaculture, also apply to the expansion of factory farming, help the transition of industrial restructuring of fisheries and laid-off workers.