2017 年 52 巻 1 号 p. 23-30
In this study, we evaluated the red sea bream iridoviral disease-resistant (RSIVD-resistant) trait of broodstock of red sea bream used in a commercial production based on DNA parentage analysis. We compared family structures of two groups from the same production lot and cultured at two different farms: a population without any outbreak of diseases (farm A) and a high mortality population after an RSIVD outbreak (farm B). The survival percentage of the fish at the farm A and farm B were 86.4% and 20.5%, respectively. Pedigree tracing was conducted on 200 individuals from each farm using eight microsatellite DNA markers among 22 potential breeders (20 dams and 2 sires), and parental pairs at farm A and B were successfully assigned with 93.0 and 90.5%, respectively. After allocating parentage information to each specimen collected from both farms, the estimated survival percentages of each family were calculated. The estimated survival of offspring from a male was 82.3%, and this survival was higher than that from the other male (estimated survival was 2.5%). Also, offspring from a female showed a high survival. These results suggest that some broodstock have resistant traits against RSIVD and shows the potential for developing an RSIVD-resistant strain of red sea bream.
