Primary Study On The Status Of Germ Plasm Resource Of Four-naris' Carp Populations From Weishan Lake

Common carp (Cyprinus carpio L.) is an important economic species of freshwater fish, widely distributed in China. It has a long history of being cultured, and the economic profit from aquaculture is enormous. Wild four-naris'carp is endemic to Weishan Lake, This species has many special characters such as widely adaptability, fast growth and disease-resistant. It was widely distributed in Weishan Lake, but now the resource is dropped sharply because of over fishing and environmental deterioration from 1990s. In our study, the genetic diversity of four common carp populations was researched using morphological marker and microsatellite DNA marker, and we analysed the muscle nutrition composition of four-naris'carp in Weishan Lake and we expect to provide some necessary basic genetic database for their resource protection.1 Morphological Marker Research of Four Common Carp PopulationsTraditional morphological data and truss network data were combined to conduct a multivariate analysis to study the morphological variations and phylogenesis of four strains in common carp populations: Yellow River common carp population, Wild Four-naris'common carp population, Farmed Four-naris'common carp population and Suzhou wild common carp population. The results indicated that: (1) In the aspect of meristic characters, there were no significant differences(P>0.05) among the four strains; (2) Discriminate analysis showed the single discriminating accuracy is 87.5%,78.1%,73.5% and 96.8% respectively in the four populations and the synthetic discriminating accuracy is 83.7%; (3) Cluster analysis showed YR population and WF population cluster together, then FF population and SZ population cluster together; (4) Principal component analysis indicated morphological variations of the four populations mainly came from the head, tail and the change of fish's axis.2 Microsatellite DNA Marker Analysis of Genetic Diversity in Four Common Carp (Cyprinus carpio L.) PopulationsCommon carp (Cyprinus carpio L.) is an important economic species of freshwater fish, widely distributed in China. Its genetic diversity was studied among four populations of Yellow River carp (YR), wild four-naris carp (WF) and farmed four-naris carp(FF) from Weishan Lake, and wild carp from Suzhou Rojiang River(SZ). Sixteen microsatellite loci were used to investigate genetic diversity and population structure. Observed (Ho) and expected (He) heterozygosity values, polymorphic information content (PIC), and number of effective alleles (Ne) were all detected. Genetic similarity index and genetic distance were estimated based on the allele frequency. The Hardy-Weinberg Equilibrium was checked according to the test ofχ2. Genetic differentiation and hierarchical partition of genetic diversity were evaluated by FST and Nm. A clustering dendrogram was made based on the results of UPGMA methods using the MEGA software package (version4.0).The results showed that: (1) there were totally 2500 fragments ranging from 70bp to 329bp in length, One to five alleles were amplified in 16 loci and 176 alleles were detected in all four populations. The average number of alleles in each locus was 2.75. (2) The level of genetic variability was moderate in the four populations, polymorphic information contents of the four populations were 0.441, 0.412, 0.440 and 0.387 respectively, and the effective alleles were 2.141, 2.125, 2.170 and 2.063 respectively. The average expected heterozygosity values were 0.521, 0.497, 0.523 and 0.462. (3) Genetic differentiation between the four populations was obvious, the average number of FST was 0.140, and the average number of Nm was 1.544. (4) The genetic similarity coefficient was from 0.759 to 0.831; the clustering result showed that population WF and YR shared the nearest relationship which indicated that it was possible that WF was a branch of YR population.3 The Analysis of Muscle Nutrition Composition in Wild and Cultured Carps in Weishan LakeThe muscle nutrition composition of 10 wild carps and 10 cultured carps in Weishan Lake in Jiangsu province were analyzed. The results showed that the contents of crude protein (18.05%) and calcium (0.69mg/g) of wild fish were higher than those of cultured fish. The levels of crude fatty acid of wild fish (1.02%) were lower than cultured ones (1.86%), the contents of water content, crude ash and phosphor were not significantly different between wild carps and farmed carps. The composition of amino acids of wild and cultured carp was basically the same, containing 18 amino acids. Total contents of 4 flavor amino acids of wild and cultured carps were respectively 6.71 and 6.07 (fresh sample percent). The essential amino acid index(EAAI)were 73.35 and 67.44 respectively, and their composition ratio accorded with the standers of FAO/WHO.