Mineral content of eggs differs with hens strain, age and rearing environment

Authors: Heflin-Morgan, Laura; ANDERSON, KENNETH - North Carolina State University; JOHNSON, LUANN - University Of North Dakota; Raatz, Susan

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/26/2017
Publication Date: 2/16/2018
Publication URL: https://handle.nal.usda.gov/10113/6472282
Citation: Heflin-Morgan, L.E., Anderson, K.E., Johnson, L.K., Raatz, S.K. 2018. Mineral content of eggs differs with hens strain, age and rearing environment. Poultry Science. https://doi.org/10.3382/ps/pey025.

Interpretive Summary: The nutrient content of eggs is strongly influenced by hen diet but may be affected the raising system used, the breed of hen and the age of the hen. In this work, we determined the effect of five different rearing systems: 1) conventional battery cages 2) enrichable cage systems 3) enriched colony housing 4) cage free and 5) free range on mineral concentration of eggs from brown egg layers and white egg layers from hens at 44, 68 and 88 weeks of age. Rearing system, strain and age of hens influenced the mineral concentration of the eggs. However, the differences in egg mineral content in our study were small and are unlikely to be important in human nutrition at levels commonly consumed.

Technical Abstract: Egg nutrient quality is strongly influenced by hen diet but is also affected by rearing environment, hen strain and hen age. The objective of the current study was to determine the effect of: 1) conventional battery cages 2) enrichable cage systems 3) enriched colony housing 4) cage free and 5) free range rearing systems on mineral concentration of whole dried egg (yolk and albumen combined) from TA Tetra White (TW) and Hy-Line Brown (HB) hens at 44, 68 and 88wk of age. We hypothesized that mineral concentration of whole dried eggs would differ among rearing systems but not between strains or with hen age. Hens held in enriched colony housing systems produced eggs with 10% lower magnesium (Mg) and 11% lower manganese (Mn) levels than conventional hens. Concentrations of calcium (Ca) and copper (Cu) were higher (7 and 8%, respectively) in whole dried eggs from TW hens than from HB hens. Whole dried eggs from HB hens had 8% higher concentration of iron (Fe), 6% higher Mg and 5% higher Mn than TW hens. Mn was higher in whole dried eggs from 44wk hens than from 68wk and 88wk hens (16 and 11%, respectively). Interaction effects between rearing environment and hen age were observed for potassium (K) and Mn concentrations. Whole dried eggs from 68wk hens in conventional rearing systems contained 14- 21% more K than eggs from conventional hens at 44 and 88wk and 14- 18% more than eggs from 68wk hens in other rearing systems. At 88wk of age, hens in conventional rearing systems produced eggs with higher Mn concentration than hens in enrichable or enriched colony housing systems (22 and 23%, respectively). Interactions between rearing environment, hen strain and hen age were observed for egg Zn concentration among 44 and 68wk hens but were not detectable among 88wk hens regardless of rearing system or hen strain. Observed differences in egg mineral content in our study were small and are unlikely to have substantial impact on human nutrition.