The Expression Analysis Of Na~+/K~+-atpase ?1Gene And Cultivation Evaluation Of Breeding Strains In Chinese Mitten Crab(Eriocheir Sinensis)

Chinese mitten crab (Eriocheir sinensis), commonly known as rivercrabs, naturally distributes in the most part of the coastally eastern waterssystems of our country. This crab belongs to migratory aquatic economicanimals and undergoes two salinity changes during its lifetime. Therefore,Chinese mitten crab needs to have reasonable adjustment mechanism tomaintain the osmotic balance in the body in the process of migration. Onthe other hand, Chinese mitten crab industry has been hugely developedand this crab has been considered as the highest value species in thefreshwater crabs, but its breeding works have been weakly conducted insupporting the industry development, consequently, the excellent bredhave been made a little contribution to the aquaculture of the crab. As aresult, the breeding of Chinese mitten crab is imperative. In this paper,based on the basic biological characteristics and the actual demand of itsindustrial development, and integrated molecular biology, reproductivebiology and biostatistics, the molecular structure of Na~+/K~+-ATPase ?1gene and expression characteristics were studied, the growth performance evaluation of the breeding strains of this crab was conducted in severaldifferent regions, meanwhile, the ecological reproduction and larvaculturing effects was investigated from the different size of parental crabsin earthen ponds. The main results were presented as follows:1. Molecular cloning and expression analysis of Na~+/K~+-ATPase ?1gene in Chinese mitten crab, Eriocheir sinensisNa~+/K~+-ATPase ?1is a key enzyme in regulating the osmoticpressure of aquatic animals. In this study, the cDNA of Na~+/K~+-ATPase?1gene was first cloned from Chinese mitten crab (Eriocheir sinensis)using RT-PCR and RACE. The full length of cDNA was3805bp(GenBank No. KC691291.1), containing a306bp5' UTR and388bp3'UTR, and a3111bp open reading frame encoding1037amino acids. Theamino acid sequence shared as high as91.9%-98.5%homology withother aquatic crustaceans, indicating its high conservation in crustaceans.Quantitative RT-PCR indicated the highest expression level in thehepatopancreas, followed by the gill, the intestines and stomach, and thenthe muscle and heart. Na~+/K~+-ATPase ?1expression was detected at theeight developmental stages of Eriocheir sinensis, in which, the lowexpression was found in the five zoea stages (zoea I to zoea ?).Surprisingly, the expression reached the highest level at the megalopastage and then significantly decreased at the larva and juvenile stages(P<0.05). Culturing the adult crabs in brackish water (Salinity21) andfresh water for30days yielded the following results: Expression in themuscle and hepatopancreas of crabs reared in brackish water wassignificantly higher (P<0.05) than that of crabs reared in fresh water,expression in the gill in fresh water was significantly higher (P<0.05)than that in brackish water; and finally, expression in the gonad did notsignificantly differ between brackish and fresh waters (P>0.05). Theresults showed that the hepatopancreas and gill were the dominant organs of Na~+/K~+-ATPase ?1gene expression in Eriocheir sinensis, indicatingthat this gene played an important role in regulating the osmotic pressureof this species. This study provides based dates for research on suitablesalinity control in reproduction, zoea production, and parentalconservation of crab.2. The growth performance evaluation of the breeding strains ofChinese mitten carbIn this section, the growth performance were evaluated in thebreeding strains of Chinese mitten crab producing reared in the9regionsof4provinces(Shanghai, Jiangsu, Anhui and Guangxi)?and the relativegrowth parameters, such as body weight (BW), carapace length (CL),carapace width (CW) and condition factor (CF) were statisticallyanalyzed for the crabs which have finished the last molting (reproductivemolting). The results indicated that the growth performance wereexcellent in the all investigated regions. The individual BW ranged from182.90g to218.24g for male crabs and from125.39g to165.54g forfemale crabs, the condition factor was0.53-0.65, and the percentages oflarge size crab (male?150g, female?200g) was32.1%. thecoefficient of variation of BW ranged from16.9to24.8. The powerfunction relationship were found between BW and CL, CW in eachinvestigated region. Multiple analysis of variance (MANOVA) showedthat environment, block and sex effects played significant roles on BW,CL, CW and CF (P <0.01). The significant interaction effects fromenvironment-block, environment-sex were found on BW, CL, CW andCF (P <0.01), while the interaction effects form block-sex on the abovetraits was not significant (P>0.05). The interaction effects fromenvironment-block-sex on the growth traits was extremely significant (P<0.01) except for CF. These results provided valuable data forapplication and extension of the selective strains of Chinese mitten crabin Shanghai. 3. Assessment of ecological reproduction in earthen pond fordifferent size of parental crabsIn this study, the ecological reproduction in earthen pond wasassessed for five sizes (A, B, C, D, E) of parental Chinese mitten crabs atSheyang county of Jiangsu province, including A: Female100-125g,Male125-150g; B: Female125-140g, Male150-175g; C: Female140-150g, Male175-200g; D: Female150-175g, Male200-225g; E:Female150-175g, Male225-250g. The results showed that the larvaproduction for each acre was listed as A:28.37kg; B:25.05kg; C:22.37kg; D:46.05kg; E:39.00kg. indicating the higher of the larva, thehigher of acre production. The larva production for each female crab werepresented as A:0.62kg; B:0.59kg; C:0.61kg; D:0.92kg; E:1.56kg,indicating the higher of the larva, the higher of seed production. Theseresults gave insight into the ecological reproduction in earthen pond forChinese mitten crab.