RESUMO
This study was aimed at determining the effects of two phytogenic antioxidants, namely, cinnamaldehyde and 1,8-cineole, and an antibiotic added to laying hen feed on the fatty acid profile of egg yolk and the weight loss and lipid peroxidation levels of eggs stored for different periods. Ninety-six 48-week-old Bovans White hens were randomly assigned to four groups, each with four replicates of six hens per replicate. The four groups were provided with the following feeds: maize and soybean-based laying hen feed, basal ration (control group); basal ration added 500 mg/kg of an antibiotic; basal ration added 100 mg/kg of cinnamaldehyde; and basal ration added 100 mg/kg of 1,8-cineole. At the end of an eight-week feeding schedule, 48 eggs, including 12 from each group, were used for yolk fatty acid analysis. In total, 240 eggs, including 48 eggs for each of the five different storage periods tested (1, 14, 28, 42, and 56 days), were collected for the detection of egg weight loss and yolk malondialdehyde (MDA) levels. The feed supplements cinnamaldehyde and 1,8-cineole were determined to have significantly reduced lipid peroxidation in the yolk of eggs stored for 14, 28, 42, and 56 days, when compared with the results of the control group and antibiotic-treated group. Furthermore, dietary cinnamaldehyde supplementation was determined to have decreased the yolk level of myristic acid, a saturated fatty acid, and to have increased the yolk level of oleic acid, the major unsaturated fatty acid found in egg yolk (46.28%) in comparison with the levels measured in the other three groups. Cinnamaldehyde and 1,8-cineole were determined to extend the shelf life of eggs by providing protection against free oxygen radicals. Cinnamaldehyde could be used as an alternative feed supplement to enrich the yolk fatty acid profile in unsaturated fatty acids.(AU)