Fatty Acid Composition and Nutritional Value of Fresh Eggs, from Large- and Small-Scale Farms

Abstract

This paper supplies new data on the fatty acid composition of eggs, with special emphasis on polyunsaturated fatty acids (PUFA). A total of 29 fatty acids were identified and determined by capillary gas chromatography. Remarkable n-3 PUFA levels were 0.6% linolenic acid and 1.2% docosahexaenoic acid, and n-6 PUFA levels were 17.0% linoleic and 2.0% arachidonic. The polyunsaturated/saturated ratio and the n-6/n-3 ratio could be considered good for human diets. There were significant differences in total cis-monounsaturated fatty acids (cis-MUFA) and total n-6 PUFA, and in C20:5 and C22:5 n-3 contents, between eggs from large-scale production centers and eggs from small-scale producers. These differences exist also for the n-6/n-3 ratio, which was more favorable in small-scale producer eggs than in large scale-producer eggs. The study on the influence of hens′ diet shows that higher dietary contents of linoleic acid and trans-MUFA were directly correlated with higher proportions of commercial feed in the hens′ diet and that total saturated fatty acids content was independent of this intake. We also observed that increasing contents of C18:2 n-6 were associated with decreasing contents of MUFA and C20/22 n-3 PUFA.