The Quality Evaluation And Genetic Diversity Of The Typical Crustacean Released Seedlings

Crustaceans are ideal for proliferation and release because of their fast growth,good taste and high economic value.Among them,Fenneropenaeus chinensisandPortzrnus trituberculatusas a traditional fishery resource in China,is a representative stock enhancement species.However,with the expansion of the scale of stock enhancement,the release effect could not meet the expected standards,and even caused genetic damage to wild populations.In this study,two typical crustacean specieswere used as research objects to compare the quality differences and explore the genetic relationship between the released seedsand their parents,in order to provide scientific guidance and technical support for future work.1.Analysis of the quality of Fenneropenaeus chinensisjuveniles for stock enhancementThe basic nutrients,amino acids,fatty acids,immunoenzyme activities and digestive enzyme activities of the Fenneropenaeus chinensisjuveniles in the Panjin,Yingkou and Jinzhou laboratories in Liaoning were analyzed.The results showed that(1)the difference of crude protein and crude fat content of shrimp juveniles in different producing areas was statistically significant,and the content of Jinzhou group was the lowest.In addition,from the content and composition of amino acids and fatty acids,there are also large differences among the three groups of shrimps;(2)SOD,CAT,POD from high to low was Panjin group,Yingkou group and Jinzhou group,and the difference was statistically significant,but the activities of ACP,AKP in Jinzhou group were significantly higher than those in other groups.(3)The activities of a AMS from high to low were Jinzhou group,Panjin group and Yingkou group,while the activities of LPS and PEP were from Panjin,Yingkou to Jinzhou.There were differences in the growth,immunity and digestibility of the three groups of Chinese shrimp prawn.The quality of the shrimp seedlings in the Jinzhou was still lower than that of the Panjin and Yingkou.2.Comparativeanalysisof genetic diversity between broodstock and offsprings in Swimming Crab forstock enhancement.Releasing and stock enhancement of swimming crabhas been carried out since 2012 in Liaoning Province as the wild resources is decreased significantly.There has been no comprehensive study on the genetic effects of using a smaller number of female crabs as breeding parents in the releasing.The present study traced the crab population enhancement in Yingkou.To address possible genetic effects from the hatchery stock,we compared the genetic characteristic among 5 female broodstock and 169 offsprings population based on ten microsatellite markers.The results showed that(1)The 10 microsatellite markers used in this study have achieved an ideal identification success rate in the phylogenetic identification of P.trituberculatus,which can provide technical support for the estimation of genetic parameters in the later stage.(2)The genetic contribution of P.trituberculatus used for breeding was unbalanced,and the effective population size of their offspring showed a downward trend.(3)Ne,Ho,He,uHe and Ar of the offspring lower than the female parent involved in reproduction.There were no significant differences in the number of effective alleles,observed heterozygosity,and expected heterozygosity between the parent and the released progeny,but there was a significant difference between the allele richness and the unbiased expected heterozygosity.The offspring have a lower Fis than the parent.The genetic diversity of the released swimming crab is lower than that of the parents.The current proliferation and release work may cause genetic damage to natural sea populations.(4)The mating strategy of the three-spotted crab is multi-mating,and there is a multi-parental mating system.In order to ensure the sustainable development of thestock enhancement,the quality of the released seed and its potential genetic risk should be evaluated before release.Therefore,we should put the focus of the release work on the scientific development and release strategy to eliminate economic and ecological problems caused by unscientific release.