137 Dietary Supplementations of Ethanolamine and Serine Enhance Docosahexaenoic Acid Deposition in Eggs of Laying Hens

Abstract

Abstract Enrichment of docosahexaenoic-acid (DHA) into eggs of laying-hens may be limited by the availability phospholipids as a deposition sink. The present study was to determine if dietary supplementations of phospholipid-component molecules or synthesis-enhancers: choline, serine, and ethanolamine could elevate phospholipid and DHA enrichment in the eggs and tissues of hens. A total of 50-White-Leghorn-Shavers (42-wk old) were individually caged and divided into 5 groups (n = 10/group). The 5 groups of hens were fed the following diets for 3 wk: Diet-1 = a corn soybean-meal basal-diet, Diet-2 = Diet-1 + 4%-microalgae (Aurantiochytrium, Heliae, Gibert, AZ, 1.81 g-DHA/kg) + choline-chloride (26.3 g/kg diet, 60% purity, DSM-Co., Basel, Switzerland), Diet-3 = Diet-2 + 1.41% of L-serine (100% purity, Ajinomoto-Co., Inc., Kawasaki, Japan), Diet-4 = Diet-2 + 100 mg of ethanolamine/kg (99% purity, Sigma-Aldirch-Co., St Loius, MO), and Diet-5 = Diet-3 + 100 mg of ethanolamine/kg. At the end of study, eggs, liver, ovary, and adipose samples were collected from 6 hens/group for biochemical analysis. Data were analyzed by one-way ANOVA. Compared with Diet-1, Diet-2 enhanced (P < 0.05) DHA concentrations in egg yolk and liver by 213 mg/egg and 2.98 mg/g tissue, respectively, but decreased (P < 0.05) total phospholipid-concentrations of yolk and liver by 50%, and hepatic-mRNA levels of elongases-2/5 and desaturases-4/6 by 25–50%. Compared with Diet-2, Diet-5 enhanced (P < 0.05) DHA (by 20%) and phospholipid (by 40%) concentrations in the egg yolk, and upregulated (P < 0.05) lipid-metabolism genes involved in the citicoline (CDP, up-to-3-fold) and CDP-ethanolamine (up-to-2.5-fold) pathways in the liver and ovary-tissue. In comparison, Diets-3 and 4 resulted in only 3–11% higher (P < 0.05) DHA-concentrations in the liver over Diet-2. In conclusion, feeding hens a high DHA and choline diet enriched DHA in the egg yolk and down-regulated lipogenesis-gene-expression in the tissues. Supplementing the diet with extra-serine and ethanolamine further-enhanced the DHA enrichment in the egg yolk and restored the high DHA-mediated changes in the gene-expression. (Supported in part by DOE-MAGIC-grant DE-EE0007091, USDA-grant 2019-69012-29905, and Cornell-University-Hatch-grants NYC-127419/127302).