The aim of this study was to investigate the effects of supplementing commercial diets with rapeseed, hempseed and camelina seed cakes on the yolk and albumen colour and nutritional value of yolk lipids in Estonian quail eggs. A total of 585 eggs were used to evaluate egg weight, yolk and albumen pH and colour, proximate yolk composition, cholesterol content and fatty acid composition in the yolk lipids of three Estonian quail groups each fed a diet supplemented with 10% rapeseed, hemp or camelina seed cakes. The higher (p < 0.01 and p < 0.05, respectively) lightness (L*) of the yolk was detected in the group of quail fed the diet supplemented with rapeseed and camelina cakes compared to the hempseed addition. Meanwhile, the albumen lightness in the rapeseed group was higher (p < 0.01) in comparison to the camelina group. A lower (p < 0.001) yolk negative a* value was estimated in the hemp group than in the groups fed rapeseed and camelina seed cake supplements, while the rapeseed group demonstrated lower (p < 0.001) albumen yellowness (b*) and colour saturation (C) in comparison to the other groups. The highest and lowest proportions of total saturated (SFAs)and monounsaturated (MUFAs) fatty acids, respectively, were found in the yolk lipids of quails fed a mixture supplemented by hemp cake. A higher (p < 0.05) proportion of polyunsaturated fatty acids (PUFAs) was only found in the hemp group compared to the camelina group. The highest and lowest (p < 0.001) n-6/n-3 PUFA ratios were found in the yolk lipids of quail receiving mixtures supplemented with rapeseed and camelina cakes, respectively. The yolk of the quail from the rapeseed group showed more favourable lower and higher (p < 0.01 and p < 0.05, respectively) atherogenic index (AI) and hypocholesterolemic/hypercholesterolemic (h/H) ratio compared to the hemp and camelina groups. The lower yolk cholesterol content was found in the eggs of the quail fed the diet supplemented with rapeseed cake compared to the eggs of the quail which were fed the diets containing more n-3 PUFAs from the addition of hemp and camelina cakes (p < 0.05 and p < 0.01, respectively).
Keywords: cholesterol; colour; egg; fatty acids; lipid indices; quail; yolk.