| The Japanese flounder is marine precious economical fishes in China, the artificial cultivation of Japanese flounder began from the 1990s, nowadays it has been the the most important breeding species throughout the north and FuJian coastal areas. Despite this, most of the production is carried out using unselected breed. The broodstock mainly come from wild fish captured in the sea or under several generations cultured. The offspring take on slow growth rate, poor resistance to disease and weak ability of adap to intensive breeding. Therefore the development of genetic improvement study and the cultivation of excellent family of Japanese flounder of good economic traits such as fast growth have very important meaning to protect the natural resource and meet the current needs of aquaculture industry. Samples were obtained from BeiDaiHe center lab station of the Chinese Academy of Fishery Science, based on the selection and breeding families of Japanese flounder, and used derivative free restricted maximum likelihood (DFREML) to compare the difference of genetic parameters of growth traits including body weight (BW), body length (BL), body depth (BD) and body shape (BS) estimated by different animal models. Single trait and integrative breeding value of different day-age BW, BL and BD were estimated by animal model best linear unbiased prediction (BLUP), furthermore different families were compared. Gynogenesis families of Japanese flounder were studied by microsatellite DNA marker, analyzed its correlation with BW, BL and BD. Primers were designed on the basis of Japanese flounder growth hormone gene sequence. Single nucleotide polymorphisms (SNPs) were detected by direct sequencing for Japanese flounder growth hormone gene, furthermore analyzed its correlation with BW, BL and BD. The results showed:(1) The analytic results of fixed effect showed that the family year had extremely significant effect on different day-age BW, BL, BD and BS (P<0.01). Reproduction method had significant effect on 180 day-age BW, BL, BD, BS, 240 day-age BL, BS and 360 day-age BW, BL, BS (P<0.05), but had no significant effect on 240 day-age BW, BD and 360 day-age BD (P>0.05). The differences of genetic parameters of different day-age BW, BL, BD, BS estimated by 4 animal models were compared. The results showed that modelâ…£was fit to estimate genetic parameters of BW, BL and BD, modelâ…¢was fit to estimate that of BS.(2) Heritabilities for 180 day-age BW, BL, BD and BS were 0.35, 0.30, 0.35 and 0.25. Heritabilities for 240 day-age BW, BL, BD and BS were 0.30, 0.32, 0.39 and 0.25. Heritabilities for 360 day-age BW, BL, BD and BS were 0.13, 0.29, 0.37 and 0.30. The range of different day-age high positive correlations between BW and BL, BW and BD, BW and BS was 0.80-0.96, 0.89-0.97, 0.76-0.89, respectively. The different range of very high positive correlations between BL and BD, BL and BS was 0.88-0.94, 0.95-0.99, respectively. The different range of high negative genetic correlations between BD and BS was -0.69--0.76.(3) There was no difference in the results of genetic evaluation according to single trait and integrative breeding value of 180, 240 day-age BW, BL, BD and 360 day-age BL and BD in families. There was a little difference in the results of genetic evaluation according to single trait and integrative breeding value of 360 day-age BW in families. Rank correlation analysis of four methods of genetic evaluation reached extremely significant level (P<0.01). Phenotypic and genetic trend at different day-age for BW, BL and BD showed rising trend.(4) The comparison of selection efficiency based on breeding value or phenotypic value showed that there was significant difference in the selection based on breeding value or phenotypic value for different day-age growth traits. The minimum difference in both selection methods was observed in the 360 day-age. The efficiency of breeding value selection was found to be 93.92% and 28.97% of BW, 465.22% and 124.49% of BL, 176.00% and 157.80% of BD higher than that of phenotypic value selection for family or individual, the efficiency of breeding value based selection was significant higher than that of the phenotypic selection.(5) The results of microsatellite analysis showed that 8 microsatellite markers were significant correlation with BW, BL and BD. The poli6TUF, poli30TUF, poli116TUF and poli145TUF had significant correlation with BW and BL (P<0.05), poli107TUF, poli108TUF, poli123TUF had significant correlation with BL (P<0.05), poli9-8TUF had significant correlation with BW, BL and BD (P<0.05). Different genotypes of the same marker were multi-ply compared and found correlation with traits.(6) The materials were from Japanese flouner gynogenesis families. 14 pairs of primer were designed according to Japanese flounder growth hormone gene sequence, in which six pairs of could be useful and the total of 1736bp sequence was amplified. SNPs were detected in coding and promoter region by direct sequencing. 10 SNPs was identified in a fragment of the growth hormone gene spanning 1736bp and the correlation analysis with growth traits was carried out. The results showed: the effect of 2067T/-del and C477T loci on the BW, BL and BD reached significant level (P<0.05). The other SNPs loci have no significant effect on growth traits (P>0.05).
|
PDF Full Text Request