Astaxanthin Boosts Egg Yolk Color, Alters Carotenoids - Study

study PMID: 40646766

Quick Summary: Researchers found that adding astaxanthin and lutein to hen feed made egg yolks more colorful. However, it also changed the levels of other important nutrients (carotenoids) in the eggs.

What The Research Found

Adding extra astaxanthin and lutein to chicken feed made the egg yolks more vibrant. The study found that while the egg yolks became more colorful, the levels of other beneficial nutrients (carotenoids) in the yolks changed. Specifically, adding lutein lowered the amount of zeaxanthin, and adding astaxanthin lowered the levels of lutein, zeaxanthin, and another carotenoid called 5,6 epoxy-lutein-caprate-palmitate.

Study Details

Who was studied: Laying hens (chickens that lay eggs).

How long: The summary doesn't say how long the study lasted.

What they took: Hens were fed diets with added lutein or astaxanthin at different doses (100, 200, or 400 mg per kilogram of feed).

What This Means For You

This study is about how to make eggs with more nutrients. It shows that adding astaxanthin can change the levels of other nutrients in the egg yolk. If you eat eggs, this means that the nutritional content of the egg can be affected by what the chickens eat.

Study Limitations

The study summary doesn't provide all the details, such as how many chickens were used or how long the study lasted. Also, this study was done on chickens, so we can't be sure if the same effects would happen in humans.

Key Findings

High-dose lutein and astaxanthin supplementation (100–400 mg/kg) in hen diets significantly improved yolk color but induced competitive inhibition of endogenous carotenoid deposition. Lutein supplementation reduced yolk zeaxanthin levels, while astaxanthin decreased yolk concentrations of lutein, zeaxanthin, and 5,6 epoxy-lutein-caprate-palmitate. No significant effects were observed on laying rates or standard egg quality parameters. LC-MS analysis detected 26 carotenoids in yolk, with 14 exceeding 0.1 µg/g. The study concludes that carotenoid interactions must be considered when producing lutein/astaxanthin-enriched functional eggs.

Study Design

This was an animal feeding trial using laying hens. The methodology involved supplementing basal diets with additional lutein (100, 200, 400 mg/kg) or astaxanthin (100, 200, 400 mg/kg) across experimental groups. Carotenoid profiles were quantified via liquid chromatography-mass spectrometry (LC-MS). The provided summary does not specify sample size (number of hens/group), breed, study duration, or statistical methods beyond noting "significant" effects.

Dosage & Administration

Lutein and astaxanthin were administered separately at three dose levels: 100 mg/kg, 200 mg/kg, and 400 mg/kg of feed. Supplements were added directly to the hens' standard diets. No co-administration of lutein and astaxanthin in the same group was described in the summary.

Results & Efficacy

Yolk color improved markedly with supplementation (quantitative color metrics not provided in summary). LC-MS confirmed 26 carotenoids in yolk, 14 at >0.1 µg/g. Dose-dependent competitive inhibition occurred:
- Lutein supplementation reduced yolk zeaxanthin (specific concentrations not quantified).
- Astaxanthin supplementation reduced yolk lutein, zeaxanthin, and 5,6 epoxy-lutein-caprate-palmitate.
No statistical values (p-values, confidence intervals) or effect sizes were reported in the provided summary. Egg production and quality parameters (e.g., weight, shell strength) showed no significant changes.

Limitations

Critical methodological details were omitted in the summary, including sample size, hen demographics (breed, age), study duration, and statistical reporting (p-values). The absence of dose-response curves or quantitative reduction percentages for inhibited carotenoids limits interpretation. As an animal study, direct applicability to human supplementation is unsupported. No discussion of potential mechanisms for competitive inhibition was included.

Clinical Relevance

This research is relevant for egg producers creating carotenoid-enriched functional foods, not direct human supplementation. It demonstrates that high-dose astaxanthin (≥100 mg/kg feed) effectively enhances yolk color but disrupts natural carotenoid profiles. Producers must balance enrichment goals with unintended reductions in beneficial carotenoids like zeaxanthin. For human astaxanthin supplement users, these findings highlight potential nutrient interaction complexities but do not translate to direct physiological effects in people. Formulators of functional eggs should optimize carotenoid combinations to minimize competitive inhibition.