Association of the FADS2 Gene with ω-6 and ω-3 PUFA Concentration in the Egg Yolk of Japanese Quail

Abstract

This study focused on the association of polymorphisms of the FADS2 gene with fatty acid profiles in egg yolk of eight Japanese quail lines selected for high and low ω-6:ω-3 PUFA ratio (h2 = 0.36–0.38). For the identification of polymorphisms within the FADS2 gene 1350 bp of cDNA sequence were obtained encoding 404 amino acids. Five synonymous SNPs were found by comparative sequencing of animals of the high and low lines. These SNPs were genotyped by single base extension on 160 Japanese quail. The association analysis, comprising analysis of variance and family based association test (FBAT), revealed significant effects of SNP3 and SNP4 genotypes on the egg yolk fatty acid profiles, especially the ω-6 and ω-3 PUFAs (P < 0.05). No effects of the other SNPs were found—indicating that these are not in linkage disequilibrium with the causal polymorphism. The results of this study promote FADS2 as a functional candidate gene for traits related to ω-6 and ω-3 PUFA concentration in the egg yolk.

Keywords:

• Δ
• 6-desaturas
• Coturnix japonica
• DHA
• Divergent selection
• Omega3
• Omega6
• SNP

The authors thank Mrs. Helga Brodeßer and Ms. Nadja Wahl for their effort in collecting the phenotypic data. We also thank Mr. Heinz Biörnsen for taking care of the birds and Mr. Heiko Buschbell for valuable discussions regarding statistical analysis. This project was supported by the Federal Ministry of Education and Research (BMBF), Germany.

Notes

TD: Touch down.

∑ SFA, total saturated fatty acids including C14:0, C16:0, and C18:0. ∑ MUFA, total unsaturated fatty acids including C16:1 and C18:1. ∑ PUFA ω-3, total ω-3 polyunsaturated fatty acids including C18:3 ω-3 and C22:6 ω-3. ∑ PUFA ω-6, total ω-6 polyunsaturated fatty acids including C18:2 and C20:4, ω-6. The ω-6:ω-3 PUFA ratio is given by (C18:2 ω-6 + C20:4 ω-6):(C18:3 ω-3 + C22:6 ω-3); na: not analyzed; Pooled SEM: standard error of mean; F-Test p: significance of line effect; ∗significantlydifferent (P < f0.05); ∗∗significantly different (P < 0.01); ns: not significant.

p-value of chi square test for deviation from Hardy-Weinberg equilibrium.

Results are expressed as means±SD

^a,b significantly different at P < 0.05

∗significantly different (P < 0.05);

∗∗significantly different (P < 0.01); ns: not significant.