EFFECT OF FREE-RANGE FEEDING ON N-3 FATTY-ACID AND ALPHA-TOCOPHEROL CONTENT AND OXIDATIVE STABILITY OF EGGS

This study was carried out to compare the fatty acid and alpha-tocophe rol composition and the susceptibility to oxidation of egg yolks from hens fed grass and a commercial mixed diet under free-range conditions or in cages with only the commercial diet. Grass had a relative high proportion of alpha-linolenic acid (534 g kg(-1) total fatty acids) an d alpha-tocopherol (162.3 mg kg(-1) DM), Eggs from hens fed under free -range conditions had a higher concentration of total (n-3) fatty acid s than eggs from hens fed the commercial diet (P < 0.05). Eggs from la yers on free-range had a higher concentration of alpha-tocopherol than those of hens maintained in cages and fed the commercial diet (P < 0. 01). No differences in initial values or rate of oxidation were observ ed between treatments. This research suggests that some constituents o f grass may be of interest for the production of eggs rich in (n-3) fa tty acids, without adverse oxidative effects. (C) 1998 Elsevier Scienc e B.V.