Study On Artificial Propagation Techniques Of Erythroculter Ilishaeformis (Bleeker)

Bleeker (Erythroculter ilishaeformis), one of Chinese precious large-size upper formation ominous fierce economical fish, classifies subordinates to Cypriniformes , Cyprinidae, Culterinae, Culter. Because bleeker has the characteristic of larger size, rapid growth rate, pure white and delicate meat, tasty flavor and high nutritional value, its artificial bred receives the widespread value. Because of reduction of wild stocks, it is pivotal to adopt artificial propagation on large scale to resolve the problem.Juvenile bleeker, captured from the nature stocks of Lake Taihu and Qiantang River, was reared in the pond of fingerling base in Zhejiang Ocean College. The average initial weight of fingerlings was 100~150g and achieved autumn by artificially culture. The sex gonads were dissected timely in order to analysis the mature condition of gonad, the coefficient of sexual maturity of female and male and fertility. The experiment of hatching fingerling adopted measures of the different combination and dosage of artificial egg parturition chemicals, one-off injection in pectoral fin, the dosage of male fish half, naturally spawning in the pond, hatching the fertilized egg in the incubation circuit or vat and so on. Through this study, the technology of total artificial cultivation and artificial propagation was established. And idioplasm characteristic is also analyzed, from which the information characteristic of DNA atlas and cytochrome B gene sequence are attained by RAPD, all of them provide basic dates for protecting excellent breed.The major results were: 1) bleeker, captured from natural water area, can achieve sexual maturity in the pond by artificially cultivation and the rate of maturity is 100%. The maturity time of gonad of female and male respectively is IV and V, when the size of fish is 1-2.9g. 2) The change coefficient of the mature period of female and male is consistent. The mature peak is achieved from the end of June to the beginning of July, the reproduction period is from the middle of June to the beginning of July and sexual mature is 3 years old. 3) The mature coefficient of ovary in female is 14.46% and relative yield of ovum is 30.28 X 104/kg per fish, which is the same with mature fish captured from natural water area. 4) The individual absolute fertility and relative fertility are positive correlation with the length and body weight:Fi=1.76241L31039, r=0.9866898 (PO.05); Fw=313W"15214, r=0.994748, ro.oi=O.515,r>ro.oi (p<0.05).The results of treatment with different medication and dosage were: 1 )The optimal combination group and dosage were: LRH-A 21.2 u g + DOM 5mg or LRH-A 21.2 u g + HCG 1000IU + PG 0.8mg, which based on the measurement of one-off injection in pectoral fin, the dosage of male half and naturally spawning. 2) The effect time of oxytocin with water temperature is negative correlation. 3) The proportion of female and male broodstock should be lower than 3:1 is higher than 1:1. 4) The hatching effect of the fertilized egg in the circuit is obviously good.In order to realize the genetic variations at the molecular level and provide foundation for management of breed, RAPD technique was applied to assess community genetic variations in 20 bleeker with 14 random primer (lObp) given 121 units locus, in which the polymorphic locus was 40 and it accounts for 33.06%. Amplification with 14 primer checks out 5-14 bands, average 8.6. The scope of genetic similarity variations was 0.8878 ~ 0.9600, average 0.9201, the heredity variation degree is 0.0799. Shannon variations exponential of the community is 10.8824, the Shannon variations value is 0.0899. Compared with other fish, the level of genetic variations is quite higher.In order to expound the blood relationship relations of bleeker and otherCulterinae fish, PCR technique was used to expand cytochrome b gene fragment and then analyzed its sequence. Amplification sequence in 4 bleeker gave 4l4bp with alkali base: A 29.5%; T 27.5%; G 14.7%; C 28.3%. Compared with cytochrome b gene sequence of 4 breed of Culterinae in Genbank, homology of bleeker and Culterinae is highest with 93.48%; while homology of bleeker with Guangdong bream, bream and masou separately is respectively 90.58%, 90.82% and 91.30%. Based on common carp as the outside group, two same molecular phylogenetic trees were attained through analyzing the data showed above with MP and NJ. The analysis indicated a close genetic relationship between bleeker with bream, both of the two clustered are sister groups, bleeker were clustered as paraphyletic groups with the sister groups composed by Guangdong bream, the bream as well as masou.