Microsatellites Analysis, Growth Comparation, Correlation Analysis Of Morphometric Traits And Body Weight And Ecological Culture For Selective Populations Of Trachinotus Ovatus

In order to empolder the excellent varieties of Trachinotus ovatus and promote the healthy, stable, sustainable development of aquaculture, molecular and morphological markers were applied on the selective breeding program for T. ovatus, and healthy cultivation of T. ovatus was also carried out in this research. The results were showed as follows:1 Genetic polymorphism of cultured populations of Trachinotus ovatus as revealed by microsatellitesAmplifications with 6 pairs of microsatellite primers we determined the genetic polymorphism of genomic DNA in three cultured populations of goldern pompano(T. ovatus), which were collected from Hainan,Shenzheng and Fujian province respectively. POPGEN ver.32 software package was used to analyze the data and phylogenetic trees were also constructed in MEGA ver.4.0. The result showed that in all three populations the value of average number of allele(sN_a)was 3.67³.83, the value of average effective number of alleles(N_e) was 2.43³.03, the oberved value of mean heterozygosity(H_o) varied from 48% to 66% and the expected value of mean heterozygosity(H_e) varied from 56% to 64%, the value of average polymorphism information content(PIC) was 0.49⁰.55, a high genetic diversity among three populations could be concluded from the datas mentioned above. Additionally, we computed the Hardy-Weinberg index to access the distribution of genotypes, and the values in Hainan,Shenzhen and Fujian population were 0.10, 0.12 and -0.08, respectively. The Bonferroni Correction test showed that all the loci reflected no significant genetic disequilibrium in three populations(p>0.05). Cluster analysis was also applied based on the Nei's genetic identity and genetic distance. The result revealed that the phylogenetic relationship between the population FJ and SZ was closer, and the resource of these populations may request further studies.2 Correlation analysis of morphometric traits and body weight on base population of T. ovatusMorphometric traits of T. ovatus at 1-month-old stage, 4-month-old stage, 7-month-old stage, 10-month-old stage and 13-month-old stage were measured, including total length(x₁), body length(x₂), body height(x₃) and weight(y). Correlation coefficients, path coefficients and determination coefficients of each trait to body weight were calculated through path analysis and multiple linear regression. Effects of each morphometric trait on body weight were also dissected and then the optimal regression equation was established. The results showed that the Pearson correlations among 4 traits ranged from 0.017 to 0.960, and all reached significant level(p< 0.01) at different stages except that at 4-month-old stage. At 1-month-old stage and 4-month old stage, the trait with strongest direct effect on body weight was the total length, but that at other stages was body height. The result of determinant coefficients analysis was consistent with that of path analysis, and the fitness of equations at different stages were good(86.9%-90.6%). It indicated that the main morphometric traits affecting body weight were found and traits for selection should be thoroughly considered at different stages, which provided theoretical evidence for selective breeding for T. ovatus.3 Growth comparation of three cultured populations of Trachinotus ovatusBase population for selective breeding of T. ovatus had been constructed by three cultured populations, which were collected form Hainan, Shenzhen and Fujian respectively. And the total length, body length, body height and body weight of T. ovatus in each group were measured too. Variance analysis of the growth rate in different stages, growth variation, absolute growth rate, specific growth rate, and the correlation relationship between main morphological traits and body weight were also conducted. The results showed that growth rate in each experiment group was significantly higher than that in control group after beening selected for 6 months. The absolute growth rate and specific growth rate in Fujian group was 0.23g/d and 2.79% higher than that in Hainan group respectively, 0.49g/d and 9.41% higher than that in Shenzhen group(p<0.05). In the earlier stage(2-month-old), the largest weight variation was found in Fujian group, followed by Shenzhen group, and that in Hainan group was placid. With the same weight variation(6-month-old), the distribution of weight in Hainan group was wider(200g-600g), and that in Fujian group was concentrate, 43.33% of T. ovatus were weighted between 450-500 gram. It could be concluded that the selection effect was initially reflected, and Fujian group had a greater growth advantage than Hainan and Shenzhen group, it was a good candidate for further studies.4 Foundational studies on integrated multi-trophic aquaculture(IMTA) in intertidal zoneIntertidal mudflat integrated aquaculture has been drawing reasearchers'interests in China for its controllability, sustainable management and flexible operation. The study was conducted to mearsure the potential environmental and economic efficiency of integrated multi-trophic aquaculture (IMTA) in intertidal zone by testing the effects of what on growth, survival and yield of T. ovatus, Penaeus vannamei Boone, Scylla serrata and Crassostrea in the IMTA system in Changsha Bay, Shanwei, Guangdong Province, China. Two culture modes were applied in the experiment. T.ovatus was polycultured with P. vannamei Boone and S. serrata in all the ponds at a ratio of 1.2 fish:90 shrimp:1.3 crab / m2, where oyster was monocultured in the channel and enclosure at the same density of 2.3 individuals / m2. Water in the system flowed and transferred with the change of tide to recycle waste nutrients from higher trophic-level species into production of lower trophic-level species of commercial value. Three ponds for polyculture of T.ovatus, P. vannamei Boone and S. serrata, and enclosures for oyster monoculture were set as control groups. No significant differences in temperature, salinity and pH were obeserved among all the treatments throughout the trial (p>0.05), where other water parameters were not the same case. There were also no significant differences in all the water parameters between infall and outfall of the IMTA system. The mean reduction efficiency of total ammonia nitrogen and reactive orthophosphate in the IMTA system were 53.38% and 58.02%, respectively. The yields of T.ovatus, shrimp, Scylla serrata, oyster in control groups were significantly lower than those in IMTA system(T.ovatus: 3943.4kg/ha vs 4236.2kg/ha, p<0.05). Total costs in IMTA system were slightly lower than that in controls, but benefits and net incomes was very higher by 48.97% and 123.48% respectively. It may be concluded that adopting an IMTA configuration in intertidal zone can not only mitigate the pollution to coastal waters from ponds, but also save energy and improve the economic efficiency.