Inheritance of skeletal deformities in gilthead seabream (Sparus aurata) – lack of operculum, lordosis, vertebral fusion and LSK complex1

Abstract

Morphological abnormalities in farmed gilthead seabream (Sparus aurata) are a major problem as it entails significant economic losses. In this study, 3 large scale experiments under different conditions of spawning, offspring handling and breeders phenotype were performed to analyze the inheritance of 4 types of deformities in this species: lack of operculum, lordosis, vertebral fusion, which are 3 of the most important skeletal deformities, and LSK, which is a consecutive repetition of lordosis/scoliosis/kyphosis. In Exp. [1] (mass spawning and fingerling sorting), 900 fish were analyzed at 509 d post-hatching: 846 fish that had been on-grown in a farm and 54 LSK-deformed fish that had been reared separately after being selected during the fingerling sorting process. A total of 89 families were represented. A statistically significant association between 5 of these families (from 6 breeders) and LSK-deformed fish was found. In Exp. [2] (mass spawning and no fingerling sorting), 810 fish were analyzed at 2 ages: 179 and 689 d post-hatching. Significant relationships between 2 of the breeders and 2 of the families with the lack of operculum prevalence of their descendants were found at 689 d but not at 179 d. Heritabilities: 0.09 ± 0.09 at 179 d and 0.17 ± 0.08 at 689 d. Column deformities prevalence was low and no association with family was observed. Family relationships were determined by microsatellites multiplex PCR in both experiments. In Exp. [3] (designed mating), sires suffering from lordosis or lack of operculum or vertebral fusion deformities were mated with non-deformed dams and a mass-spawning mating was considered as a control. After analyzing 11,503 offspring at 159 d post-hatching, a significant relationship between each deformity prevalence and the mating of breeders suffering from the same deformity was observed. In addition, a significant prevalence of lack of operculum in offspring from lordotic matings was observed. Heritabilities ranged from 0.34 to 0.46 for the 3 deformities. The results of the present study suggest that these deformities have a genetic origin. They also suggest that the sorting process is not recommended and that producers should consider these deformities in genetic breeding programs to significantly improve their fish morphological quality and to minimize farmed fish deformities incidence.

Detection of QTL associated with three skeletal deformities in gilthead seabream (Sparus aurata L.): Lordosis, vertebral fusion and jaw abnormality

“…The present study identifies, for the first time, seven QTL for three of the most relevant and frequent skeletal deformities in gilthead seabream, what support the genetic component for this trait recently proposed by Lee-Montero et al (2014) and Negrín-Báez et al (2015). For vertebral fusion, one of the three QTL detected in this study was considered significant (QTLFV3), it was located in LG21.…”

“…In the context of PROGENSA® (a Spanish Breeding Program), heritability from 0.06 to 0.11 for lack of operculum and from 0.16 to 0.41 for any type of vertebral deformity were estimated in gilthead seabream that had been reared under different production systems in four Spanish regions . In addition, significant associations between determined families and prevalence of lordosis, vertebral fusion, lack of operculum and LSK complex (lordosis-scoliosis-kyphosis) under different breeding conditions, phenotype of breeders and offspring handling were found (Negrín-Báez et al, 2015). Moreover, this study provided really useful populations to search for quantitative trait loci (QTL) that were related to these deformities.…”

“…These breeders were descendants (F1) of two deformed sires and one normal dam, this mating is described in detail by Negrín-Báez et al (2015). Fish were cultured at the industrial-like facilities of the Marine Science and Technology Park of the University of Las Palmas de Gran Canaria (PCTM-ULPGC, Gran Canaria, Spain) under intensive rearing conditions, described by Roo et al (2009).…”

Skeletal Deformities in Seabreams. Understanding the Genetic Origin Can Improve Production?

“…Lack of operculum, lordosis and vertebral fusion have also a genetic origin. When sires suffering from lordosis or lack of operculum or vertebral fusion deformities mated with non-deformed dams, a significant relationship between each deformity prevalence and the mating of breeders suffering from the same deformity was observed (Negrín-Báez et al, 2015a). A significant prevalence of lack of operculum in offspring from lordotic matings was also observed by Negrín-Báez et al (2015a).…”

“…When sires suffering from lordosis or lack of operculum or vertebral fusion deformities mated with non-deformed dams, a significant relationship between each deformity prevalence and the mating of breeders suffering from the same deformity was observed (Negrín-Báez et al, 2015a). A significant prevalence of lack of operculum in offspring from lordotic matings was also observed by Negrín-Báez et al (2015a). Quantitative trait loci (QTL) were identified for lordosis, vertebral fusion and jaw deformity in gilthead seabream (Negrín-Báez et al, 2015b).…”