Poster Topical Area: Energy and Macronutrient Metabolism
Location: Hall D
Poster Board Number: 502
Objective: The objective of the current study was to determine the effect of rearing system, strain and hen age on fatty acid and carotenoid content of whole raw egg. We hypothesized that levels of unsaturated fatty acids and carotenoids are higher in eggs from free-range hens than in all other environments. We did not expect egg fatty acid or carotenoid levels to vary between strains or by hen age.
Methods: Eggs from white egg layers (TA Tetra White) and brown egg layers (Hy-Line Brown) aged 44, 68 and 88 weeks were evaluated for hens reared in 1) conventional battery cages 2) enrichable cage systems 3) enriched colony housing 4) cage free (HB hens only) and 5) free range rearing systems. Six randomly selected eggs from each set were homogenized for analysis. Lipids were extracted using a modified Folch method and fatty acid methyl ester analysis for common SFA, MUFA and PUFA species were performed by GC-FID. The extract also analyzed for carotenoid and retinol content by HPLC-MS/MS.
Results: Eggs from enriched colony and free range hens had higher MUFA and SFA content than eggs from conventional hens. Total PUFA content of eggs from free range hens was higher than that of eggs from conventional hens. However, arachidonic acid (20:4n-6) content was higher in eggs from enriched colony and free-range hens. Total carotenoid content of eggs from free range hens was almost twice that of eggs from conventional hens. Retinol content was lower in eggs from 88 wk hens than in eggs from 68, but not 44 wk hens. Strain by age interaction effects were detected for egg content of alpha-linolenic acid (18:3n-3). Interaction effects among age, strain and environment were detected for egg content α- and β- carotene, lutein/ zeaxanthin, and total carotenoids.
Conclusions: In our study, rearing condition, strain, and age were associated with differences in fatty acid, retinol and carotenoid content of eggs. With the exception of 20:4n-6, differences in fatty acid, retinol and carotenoid are most likely not relevant to human nutrition at the current level of egg consumption.
This research was supported by the North Carolina Layer Performance and Management Program, Raleigh, NC., the USDA, ARS project 3062-51000-053-00D (SR, LH-M), and a grant from the Egg Nutrition Center, (Park Ridge, IL (SR, LH-M)).
Grand Forks, North Dakota