Comparison of the composition and color characteristics of haploid and diploid rainbow trout (Oncorhynchus mykiss) eggs produced under different rearing conditions

Abstract

This study investigated the biochemical composition and color characteristics of haploid (n) and diploid (2n) eggs from rainbow trout (Oncorhynchus mykiss) broodstock reared at two farms in Seydikemer, Muğla. Four-year-old females and three-year-old males were used, and eggs were analyzed for proximate composition, fatty acid profile, and colorimetric parameters. While no significant differences were observed in dry matter, crude protein, crude fat, or ash content (p>0.05), diploid eggs exhibited higher total saturated and monounsaturated fatty acids, greater omega-3 levels, and higher EPA+DHA content. Haploid eggs showed higher omega-6 levels, DHA/EPA ratio, and hypocholesterolemic/hypercholesterolemic (HH) ratio (p<0.05). Color analysis revealed that diploid eggs had higher L* (lightness) and b* (yellowness), whereas haploid eggs were redder (higher a*, p<0.05). These results indicate that ploidy affects egg fatty acid composition and color, which may influence embryonic development and selective breeding programs.