Study On The Developmental Process Of Female Reproductive System Of Procambarus Clarkii And The Factor That Affect Its Reproductive Performance

With the rapid increase in the scale of Procambarus clarkii,the demand for high-quality shrimp is growing rapidly every day,Traditional breeding methods of Pond and rice fields have many problems,leading to breed failure frequently.Such as irregular postlarvae specifications,poor quality,difficult fishing,transportation difficult and Low stocking survival rate,Therefore,this study adopted the appearance of anatomical observation,histological methods and orthogonal experiments,comparative experimental methods,carring out the research of reproductive system development and artificial induction on reproductive performance of Procambarus clarkii.1.The development of female reproductive system and histological study of Procambarus clarkii was performed by appearance anatomy and histological method.The results showed that the female reproductive system consists of ovaries and oviduct,ovaries were Y-shaped.Oogenesis experiences four phases,respectively for oocytes,pre-oval synthesis oocytes,yolk oocytes and mature oocytes.The ovary development could be divided into five stages,respectively for stage Ⅰ,stage Ⅱ,stag Ⅲ,stageⅣ and stage Ⅴ.the slurry endoplasmic reticulum,dense small particle material and mitochondria involved in the synthesis of yolk granules.The characteristics of black ovaries,filling egg yolk in oocytes,the nucleus disappearing,the oocyte and follicular cell separation were used as mature signs of the crayfish mature.Procambarus clarkii individual spawn once per year,gonadal development of Procambarus clarkii was not synchronized,the population had two periods of spawn ing peaks each year,September and October,April and May in the next year,respectively.2.According to design principle of Orthogonal experiment,Choosing the Orthogonal table of L9(3^4)without considering the interaction,researching the effection of parents shrimp sizes,shelter,illuminance and density on the survival rate of parents shrimp,egg-holding rate and number of eggs.the experimental result indicated,The artificial induction combination of parents shrimp sizes of 35～50g,shelter of "the Aquatic+asbestos tiles+brick",illuminance of 50～500Lux and density level of 20 Tails per m2 help to improve reproductive effect of Procambarus clarkii.Through this combination,the average survival rate of the parental shrimp reached 96.25%,the average rate of holding eggs was 85.71%,the average number of holding eggs was 436.6 pieces each tail.3.Setting up 7 induction way by random combination of the illuminance<100Lux、single-eyestalk ablation and salinity level of 8‰,the inducing experiment of Procambarus clarkii breeding was conducted.The comparative experimental results showed that,There was no significant difference in the survival rate of experimental parents(p>0.05),the spawning time of the group of illumination<100Lux,the group of single-eyestalk ablation and the group of illumination<100Lux+single-eyestalk ablation is respectively earlier than the control group 15～18d,the average rate of holding eggs was respectively 2.5 times that of the control group,2.75-fold and 2-fold.4.Choosing 7 groups of experimental feed,including only basic diet(Group1 as control),and basic diet supplemented with 0.5%vitamin C(VC),0.02%vitamin E(VE)and 8%highly unsaturated fatty acid(HUFA)(6%Peruvian fish oil and 2%soybean lecithin)(Group 2),0.5%VC and 0.02%VE(Group 3),8%HUFA(Group 4),0.02%VE(Group 5),and 0.5%VC(Group 6)and shrimp pelleted feed(Group 7)for 76 days indoors.A feeding trial was conducted to research the influence of dietary vitamin E,vitamin C and highly unsaturated fatty acid on survival,percent of egg-holding females,number of eggs per female and hatching rate of Procambarus clarkii.The fodder of supplementing VC,VE and HUFA was the maximal percent of egg-holding females and hatching rate in diet 2,which reached 75%and 82.8%,respectively,By feeding the diet 3 supplementing VE and VC,the amount of spawning of parents shrimp were highest,The average amount of spawning are 18 eggs per gram.the synergistic effect of VC,VE and HUFA leads to improvement of reproductive performance in Procambarus clarkii.5.The test was carried out about breeding,hatching shrimp and the tolerance of juvenile shrimp to low temperature in winter by Outdoor glass tanks and cement pool in plastic greenhouse.by the test of intensive breeding in Procambarus clarkii,the research shows,the survival rate of parents shrimp was 73.59%,the rate of holding eggs was 76.11%,breeding 2300 tailings of seedlings of 1～2 cm in size per m2.the recovery rate of Parents shrimp reach 97.3%.The seedlings body length of 1～2cm and 2～3cm in size had a strong ability to cold,it was safe to cross the winter in the habitat of the Outdoor cement pool or pond.