Divergent selection for ω3:ω6 polyunsaturated fatty acid ratio in quail eggs

Abstract. It is well known, that the ω6:ω3 PUFA (polyunsaturated fatty acids) ratio of the egg yolk can be changed by modifying the hen's diet. Information on genetic effects on PUFA in egg yolks is limited. Therefore four generations of divergent selection of high and low ω6:ω3 PUFA ratio were performed with quails as model animals to estimate genetic effects on the fatty acid profile of eggs. Heritability and correlated response to selection were analysed. Generation 4 consisted of 125 hens in the HIGH and 114 hens in the LOW line and 40 sires per line. Fatty acid profiles of the eggs were measured on pools of 3 yolks per hen, two times per hen. After four generations of selection ω6:ω3 PUFA ratio was significantly different in the LOW (12.4) and HIGH line (14.9), i.e. a difference of 1.6 phenotypic standard units. Heritability for ω6:ω3 PUFA ratio was estimated at 0.45 (SE 0.05). Selection tended to be asymmetric in the way that response to selection in the LOW line was higher. Fertility and hatchability of fertile, age at first egg, laying intensity, egg weight and fat percentage were not significantly different between selected lines, but yolk weight, yolk proportion and fat content were significantly higher in the Low line. Moderate heritability of ω6:ω3 PUFA ratio in egg yolks and lack of correlated responses to selection in major production and reproduction traits indicate that breeding for a lower ω6:ω3 PUFA ratio in eggs is promising.