What is the heritable component of spinal deformities in the European sea bass (Dicentrarchus labrax)?

Abstract

Malformations in farmed fish are a prime research topic as it has a major impact on fish welfare and on the economical value of the product. In this study, the genetic component of spine deformities was estimated in European sea bass, a major species of Mediterranean aquaculture, with the use of a posteriori reconstruction of pedigree with microsatellites. Our population exhibited a very high malformation rate (81%), probably due to intense swimming of fish during pre-growing. The heritability of global spine deformities was evaluated to be 0.21 ± 0.04 on the underlying scale (0.33 ± 0.06 for lordosis, 0.13 ± 0.04 for scoliosis). Deformities scored by an internal or external examination turned out to be genetically the same trait (genetic correlations > 0.9), although phenotypic correlations were moderate to high (0.45 ± 0.04 to 0.92 ± 0.01) due to difficulties in scoring the less severe deformities. Along time (from 100 to 800 g mean weight), lordosis had a constant heritability, with very high genetic correlations between stages (> 0.9). Its incidence increased from 39 to 53% indicating that the malformation was probably present from the beginning of the rearing period but that its expression increased over time. A positive linkage between spine deformities and growth rate was demonstrated both by the higher early weight of affected fish and by the positive genetic correlation between weight and malformation (from 0.21 ± 0.15 to 0.40 ± 0.14), although deformities have a negative phenotypic impact on growth. However, heritabilities of malformation traits calculated here are only estimates that may indirectly describe the sensitivity of fish to the particular pre-growing environment as a function of different body weight genotypes. A quantification of realised heritability would therefore be necessary before concluding on the existence of a genetic basis for spinal malformations such as lordosis and scoliosis. Nevertheless and by precaution, selection for fast growth rate needs careful monitoring of deformities, and selection against malformations may counteract impacts of selection for fast growth

Evaluation of environmental impact on natural populations of the Mediterranean killifish Aphanius fasciatus by quantitative RNA biomarkers

“…Spinal deformities have been reported in natural fish populations (Ayed et al, 2008;Kessabi et al, 2009;Messaoudi et al, 2009a;Messaoudi et al, 2009b;Sun et al, 2009;Tutman et al, 2000) as well as in farmed fish (Aunsmo et al, 2008;Aunsmo et al, 2009;Bardon et al, 2009;Silverstone and Hammell, 2002). Whereas skeletal malformations in aquaculture appear to be related to a complex interaction of genetic, procedural and infectious/immunological factors (Aunsmo et al, 2008;Aunsmo et al, 2009;Bardon et al, 2009;Lall and Lewis-McCrea, 2007), the presence of deformities in natural populations are most likely related to pollution (Kessabi et al, 2009;Lemly, 2002;Messaoudi et al, 2009a).…”

“…Whereas skeletal malformations in aquaculture appear to be related to a complex interaction of genetic, procedural and infectious/immunological factors (Aunsmo et al, 2008;Aunsmo et al, 2009;Bardon et al, 2009;Lall and Lewis-McCrea, 2007), the presence of deformities in natural populations are most likely related to pollution (Kessabi et al, 2009;Lemly, 2002;Messaoudi et al, 2009a). Spinal deformities can be experimentally induced in fish upon exposure to different organic and inorganic substances, including metals, metalloids and organic substances like PAHs, OC and dioxins (Cachot et al, 2007;Gagnon and Rawson, 2009;Holth et al, 2008;Miller et al, 2007;Yamauchi et al, 2006).…”

Spinal deformities in a wild line of Poecilia wingei bred in captivity: report of cases and review of the literature

“…Finally, a genetic basis has also been proposed for spinal malformations [50][51][52][53][54][55] , since spontaneous spinal curvature mutants exist. Particularly, the so-called Mutant Guppy (P. reticulata) Syndrome Curveback, characterized by a primary sagittal lordosis with some individual exhibiting posterior kyphosis and /or coronal deviation, appears to be a possible animal model to study the pathogenesis of human idiopathic scoliosis.…”

Are trunk lateral line anomalies and disoriented scale patterns in European seabass (Dicentrarchus labrax) influenced by genetics?

“…One interesting observation from our data is that there is a negative genetic correlation between growth and the disoriented scales. This shows that for this type of defect, faster growing fish are not more sensitive to impaired development, a feature commonly observed in farmed animals (Rauw et al, 1998) and for spine anomalies in fish (Bardon et al, 2009;Boglione et al, 2013;Karahan et al, 2013;Kolstad et al, 2006). On the other hand, it could also be that affected fish have slower growth rates, as the observed scale anomalies are the most evident effect of some hidden impaired developmental process.…”