Estimation of genetic parameters for disease‐resistance traits in Cynoglossus semilaevis (Günther, 1873). (29th April 2016)

• Record Type: Journal Article
• Authors: Liu, F.; Li, Y. Z.; Wang, X. X.; Liu, X. F.; Xing, H. F.; Wu, Y. H.; Xiu, W. S.; Shao, C. W.; Chen, S. L.
• Is Part Of: Journal of applied ichthyology. Volume 32:Number 4(2016:Aug.)
• Page Start: 643
• Page End: 651
• Publication Date: 2016-04-29
• Subjects: Fishes -- Periodicals; Fish culture -- Periodicals; Fisheries -- Periodicals; Ichthyology -- Periodicals; 597
• DOI: 10.1111/jai.13067
• Languages: English
• ISSNs: 0175-8659

Abstract

Summary: The objective of this study was to estimate genetic parameters for three traits based on 28 Cynoglossus semilaevis families approximately 6 months of age (at least 5 cm total length), including trait_1 (survival of 26 families, 3434 individuals in total subjected to challenge tests with Edwardsiella tarda ), trait_2 (survival of 20 families, 2016 individuals in total subjected to challenge tests with Vibrio anguillarum ) and trait_3 (survival of 27 families, 9340 individuals tagged at circa 180 days of age and reared in indoor ponds for circa another 5 months). The result showed that there were large differences in the survival of the families after challenge (11.11–65.31% for E. tarda and 9.18–70.54% for V. anguillarum ). Additionally, the survival of families reared in indoor ponds was also different, varying from 21.00% to 73.67%. Heritabilities of the three traits varied from 0.14 to 0.26, as estimated by the linear model (LM) and the threshold model (TM). The trait_1 heritabilities (0.26 and 0.19 estimated by LM and TM) were higher than those of the others (0.20 and 0.23 estimated by LM, 0.14 and 0.19 estimated by TM). The estimates of heritabilities using LM were consistently higher than those of TM in this study. There were significant medium genetic correlations of 0.44 and 0.42 between trait_1 and trait_2 obtained from LM and TM (P < 0.05). However, very low and non‐significant genetic correlations of trait_1 and trait_3 (−0.10 for LM, −0.05 for TM), as well as those of trait_2 and trait_3 (0.05 for LM, 0.04 for TM) were obtained. Therefore, indirect selection for trait_1 and trait_2 was effective, but almost ineffectual for trait_1 and trait_3 as well as trait_2 and trait_3. Otherwise, there was no significant difference in the predictive abilities of LM and TM. Two families resistant to both Edwardsiella tarda and Vibrio anguillarum were selected plus one family resistant to both Vibrio anguillarum and naturally infected by unknown pathogens through family selection. As there was very low and non‐significant genetic correlation of trait_3 and trait_1 as well as trait_2, superior strains are anticipated with the ability to resist two or more kinds of diseases, through the crossing of families selected for the three traits described above. The results support the hypothesis that genetic variation exists for disease survival, which could be used to design a breeding program for selecting strains of Cynoglossus semilaevis with high disease resistance.