Effects of dietary conjugated linoleic acid in broiler breeders and egg storage time on the fatty acid profile, lipid oxidation and internal egg quality

Context. The need for the storage of fertile eggs is a reality in the poultry industry. At the same time, prolonged storage periods decrease the quality of egg components that are essential for embryo development, and can compromise hatchability and chick quality; thus, the high content of unsaturated fatty acids in embryo tissues increase the susceptibility to peroxidation. Aims. The objective of this study was to evaluate the addition of cis-9, trans-11, trans-10 and cis-12 isomers of conjugated linoleic acid (CLA) to the broiler-breeder diet and the storage time on the internal egg quality, composition and lipid oxidation. Methods. In total, 22 000 Cobb female broiler breeders of 58 weeks of age were fed with diets containing 0 or 0.024% CLA and fertile eggs were stored 3, 6 or 9 days prior to incubation. In total, 6912 hatching eggs were used in a completely randomised experimental design in a 2 x 3 factorial arrangement (CLA inclusion x egg storage time). At the end of each storage period, 30 eggs per dietary treatment were sampled to analyse yolk and albumen height, percentage and pH, yolk:albumen ratio, yolk diameter and index, Haugh unit (HU), yolk lipid oxidation, acidity and fatty acid profile. Key results. The progression of storage negatively affected the internal quality of the eggs; however, inclusion of CLA minimised these effects up to Day 6, especially for yolk diameter, HU, height and albumen pH. The total lipid content was not affected by the dietary treatments; however, CLA inclusion resulted in a higher proportion of stearic acid and a lower concentration of linoleic acid in yolks. Conclusions. The changes observed in fatty acid profile of the eggs may have favoured the reduction of lipid oxidation, as shown by the decrease in the acidity index and thiobarbituric acid-reactive substance (TBARS) values at shorter storage periods. Implications. The dietary addition of CLA to broiler breeders may be used to preserve the egg internal quality during a short-term storage period.