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| Analyzing of Heritability and Breeding Value of Disease Resistance for Edwardsiella tarda in Japanese Flounder (Paralichthys olivaceus) |
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Abstract The Japanese flounder (Paralichthys olivaceus) culture industry faces unprecedented crisis, due to the high density of factory farming, water pollution and other reasons. In the research, 57 families were established in April 2015, based on stock with disease-resistance and fast-growing families followed by our previous study, including 11 F3 families and 46 F4 families, F4 families were firstly established in China. Disease resistance was investigated using 46 families, tail number is more than 150, through 2 intraperitoneal injection challenged with Edwardsiella tarda, and the paired sample t test showed that there no significant difference between two experiments (P＞0.05), besides, pearson correlation analysis demonstrated that there was a very significant linear correlation (P＜0.01) between the survival rate of the two experiments. Analysis of survival rate demonstrated that there were significant differences in different families on resistance to E. tarda infection. Among 46 families, 5 families were identified as strong disease resistance, the survival rate were over 70% (F1551, F1503, F1501, F1550, F1505), 15 families with a survival rate of 50%~70% were identified as disease-resistance families, 23 families with a survival rate of 20% ~50% were identified as normal disease resistance families, and 3 families with a survival rate of less than 20% were identified as susceptible families. According to the comparison of daily weight gain rate of 46 families, 4 fast-growth families were identified which daily weight gain rate was up to 0.225 0 g/d (F1533, F1551, F1514, F1502), 12 secondly fast-growth families were identified, 24 normal growth families were identified and 6 slow-growth families were identified. The heritability of disease-resistance was 0.177±0.020, which was low heritability and fit for selection and breeding in families. The breeding value of parents for disease-resistance range from (-1.962±0.646) to (2.110±0.546). The breeding value of F1551 and F1550 in female breeding value was higher than in the other families and the breeding value of F1551 in male breeding value was higher than in the other families. By the variance analysis, correlation analysis and analysis of breeding value. A F4 family (F1551) with excellent breeding performance has picked out, such as disease-resistance, fast-growing, and high breeding value. Our study finds that descendant enhance disease resistance inherited from their parents, indicating that the establishment of a disease-resistant strain based on these families is suitable for aquaculture.
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Received: 02 March 2016
Published: 01 July 2016
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