Embryos Culture In Vitro And Larvae Studies On Postembryonal Development Of Sebastes Schlegelii Hilgendorf

Sebastes schlegelii is an important farming economic fingerling in northern China and mainly distributed in the Yellow and the Bohai Sea. In this paper, the ovarian collected from the Sebastes schlegelii breeding females and access the fertilized eggs and embryos. Morphological observation and description of its early development in vitro culture. Collected larvae from Muping factory farming, explore its features of postembryonal development on perspective of the morphology and histology, in order to create a theoretical foundation for embryos and larvae real-time access,and provide technical support for the realization of Sebastes schlegelii artificial breeding1. Biological research of Sebastes schlegelii embryos fertilized in vitro cultureEmbryonic and early larval of Sebastes schlegelii develop in the matrix ovary, the necessary nutrients of embryonic development provided by their own yolk. In this study, vitro culture found in seawater teleost saline at temperature 15-16℃, pH 7.4-7.8, salinity 21-23, inflated condition in 24 hour, Sebastes schlegelii embryos can develop to hatch. The embryonic development can be divided into 27 periods, from the fertilized egg to larvae hatched at least 200h over time.By setting culture fluid containing different additives,we find the cultures with Sebastes schlegelii serum and ovarian tissue has a certain role in promoting development. It was found that the salinity change important implications in vitro culture, and high salinity will lead fetal death.2. Larvae morphology of Sebastes schlegeliiIn this study, the development of Sebastes schlegelii larvae were continuous observation and description, and the results showed that preterm fish larvae length is 4mm, body transparent, can be observed in the light microscope to each tissues and organs, including the closure of the original digestive tract, the beating heart and blood flow in the artery, dendritic and chrysanthemum melanocytes on the top of the brain, the up side of abdomen and both sides of the trunk. The length of ldpb larvae is 4.8-6mm,and the mouth is already opening. The melanin is much more than preterm fish.8dpb larval appear the ventral and dorsal fin primordia, gill cover and occipital spine obviously, feeding capacity and significantly improved exercise, then the fish larvac development turn into the juvenile stage.45dpb, fish total length is 30.4 35.5mm, body length is 25.5-30.4mm, in this time the melanocytes subsided, and the whole fish takes the shape of golden yellow,4-5 stripes appear on trunk, opercular spine developed. The fish body, fin-type, and all part is basically the same proportion of adult fish, metamorphosis is complete.Now the larvae development into the juvenile stage, the avoid predators and swim ability have greatly enhanced.The larvae began to turn into lower water.3. The histological observation of postembryonal development in Sebastes schlegeliiIn this study, histological study is used to observe the larvae organ development of Sebastes schlegelii. The results showed that the newly hatched larva is no differentiation. The difference of esophagus, stomach, intestines is not obvious,the liver is observed between the yolk sac and digestive tract, liver blood sinus and the early pancreatic cells is occurrence. 1dpb larval digestive tract have differentiation, gastric cavity size began to exceed the intestinal lumen. Mucosal fold is appared in hindgut,and the liver is still connected to the yolk sac.12dpb Juveniles can clearly be divided into cardia, stomach and pylorus. Gastric cells is appeared in the stomach submucosa, intestines muscle layer. The volume of liver is futher increased.29dpb larvae, a large number of gastric gland is formed in gastric, muscle layer thickness. The structure of gastric is obviously, intestinal cavity expanding significantly and longitudinal fold increase. liver cells tightly packed, pancreatic cells arranged in groups, this time close to the body’s digestive system. Liver cells arranged closely, pancreatic cell arrange cluster. The digestive system is close to adult.The visual organ development is not perfect in preterm larvae, the lens size is small, retina differentiation is not perfect. Development of 1dpb larvae eye has more perfect.16dpb larvae appeared muscle fibers outside of eye, eye movement is more sensitive, every part of the 24dpb eye is close to the Juvenile.Respiratory organ development is mainly included the growth and differentiation of branchial arch, gill filaments and gill lamella.