(P06-048-23) Changes in the Fatty Acid and Antioxidant Profile of Eggs Across the Grazing Season in a Southern Ohio-Based Pasture-Raising System for Layer Hens

Objectives: There is growing interest in regenerative egg farming with a focus on soil health, increased biodiversity, and symbiosis between chickens and the environment. Foraging allows poultry access to nutrient-rich and biodiverse feed, producing eggs with a more favorable nutrient profile for human health. However, throughout the seasons, the quality and composition of the feed vary. This study aims to investigate the impact of seasonal changes on the nutrient profile of eggs in a Southern Ohio-based pasture-raising system for layer hens.

Methods: Twenty-four egg samples were collected monthly from May to December and pooled to form n = 12 replicates per month. Egg yolk fatty acids profiles were determined using gas chromatography-mass spectrometry analysis. Carotenoid content was assessed colorimetrically. Vitamin content was assessed in a commercial laboratory.

Results: Egg characteristics differed by month. Vitamin A content was higher in the late summer months (p < 0.001), while vitamin E content gradually increased over the season and was highest in November (118.1 ± 24.0 ug/g fresh weight; p< 0.001). Carotenoid content was higher in mid-summer and late fall (p < 0.001). Total fatty acids were highest in May (20.1 ± 3.9 g per 100 g fresh yolk) and decreased over the year (p < 0.001). Total saturated, monounsaturated, and polyunsaturated fatty acids were significantly different by month (p < 0.001). Total omega-3 fatty acids were higher in May compared to the mid-summer and late fall months, and the n-6:n-3 ratio was lower in the early summer and fall compared to July (p < 0.001). Oleic acid content was highest in the month of May (8.1 ± 1.7 g per 100 g fresh yolk; p<0.001). Finally, ALA and DHA content were higher in the early summer, decreased over the summer months, increased again in the late fall, and then decreased in December (p < 0.001).

Conclusions: This study demonstrates significant changes in the fatty acid and antioxidant profile of pasture-raised eggs across the growing season relevant to consumers purchasing pasture-raised eggs in this region. Future analyses will associate the egg nutrient profile with forage and soil composition along with weather across the season.

Funding Sources: The Greenacres Foundation provided funding for this study.