Effects of Grass-Fed Beef Suet and Liver Supplementation on Fatty Acid and Nutrient Profile of Chicken Eggs

Abstract

ObjectivesThe nutrient composition of chicken eggs can be manipulated by altering the composition of layer hen feeds and adding supplements to chicken diets. Current nutrition guidelines recommend consuming diets with less saturated fatty acids (SFAs) and a lower omega-6: omega-3 (n-6: n-3) ratio to mitigate the risk of cardiovascular disease. There has been interest in utilizing the byproducts of grass-fed systems to reduce the SFA content and n-6: n-3 ratio of eggs in a sustainable manner. The objective of this study was to quantify and compare the FA and nutrient profile of pasture-raised chicken eggs supplemented with grass-fed beef suet and liver (n = 6) to pasture-raised chicken eggs fed a standard non-GMO layer hen feed (n = 6) and cage-free chicken eggs from a local grocery store (n = 6). MethodsEgg samples were collected and lyophilized prior to analysis. FA profiles were determined by microwave-assisted lipid extraction, acid-base methylation, and gas chromatography-mass spectrometry analysis. Total carotenoids were measured using UV-Vis spectrophotometry and total phenolic content was measured using a microplate reader and compared to a gallic acid standard. Vitamin and mineral content were assessed by a commercial laboratory. FA profiles of the layer hen feeds and the grass-fed beef suet and liver were also quantified. ResultsThere was no significant difference in total SFA among the three groups of eggs (P = 0.787). Conjugated linoleic acid (CLA) was significantly greater (P < 0.001) and the n-6: n-3 ratio was significantly lower (P < 0.001) in the chicken eggs supplemented with grass-fed beef suet and liver. Total carotenoid content was significantly greater in eggs supplemented with grass-fed beef suet and liver compared to the eggs from the grocery store (P < 0.001), but total phenolic content was significantly lower (P = 0.012). Vitamin B1, B3, B5, B12, and K1 content were significantly different among groups (P < 0.05). ConclusionsThese results indicate that supplementing chicken diets with grass-fed beef suet and liver increases the CLA content and decreases the n-6: n-3 ratio in eggs without influencing the SFA content. In addition, the diet also influenced egg nutrient and phenolic profile. Funding SourcesThe Cure AMD Foundation provided funding for the vitamin and mineral analysis.