The fatty acid profile in the yolk and yolk sac from incubated goose eggs depends on the breeder age and laying period.

1. The study analysed the content of fatty acids in the lipids of the yolk and yolk sac of hatching eggs obtained from geese in four reproductive flocks and three laying periods at different incubation dates.2. A total of 1080 hatching eggs were used in the study (90 eggs from each age group in three laying periods). The geese were kept on one farm under the same conditions.3. On days 0, 16, 22, and 28 of incubation, the yolk/yolk sac was sampled. Saturated and unsaturated (mono- and poly-) fatty acids were determined, including myristic acid, palmitic acid, palmitoleic acid, margaric acid, stearic acid, oleic acid, linoleic acid, α-linolenic acid, behenic acid, eicosapentaenoic acid. The ratio of unsaturated to saturated fatty acids was calculated.4. Embryo fatty acid utilisation in eggs from different age groups of geese was similar. The fatty acid profile depended mostly on the laying period. The different proportions of fatty acids in the yolk during incubation indicated changes in the activity of various enzymatic processes in the membrane of the yolk sac of embryos from the beginning and at the end of the laying period.5. When analysing the interactions between the age of the parent flock and the laying period, the most significant effect on the fatty acid composition was found in fresh eggs. On d 16 of lay the myristic, stearic, linoleic, and behenic acids and PUFA; on d 22 of lay linolenic acid, and on day 28th palmitoleic and margaric acids were involved in this interaction.