# Egg yolk-derived phosvitin as a natural chelator: In vivo mitigation of mercury toxicity in rats

## TL;DR

This study shows that a protein from egg yolks can reduce mercury toxicity in rats, suggesting it could be a natural treatment for mercury exposure.

## Contribution

The first in vivo evaluation of egg yolk-derived phosvitin as a mercury chelator in rats.

## Key findings

- Phosvitin reduced mercury-induced immune activation and liver damage in rats.
- Brain mercury levels decreased in rats treated with 10 and 20 ppm phosvitin.
- Phosvitin at 20 ppm showed the most effective mitigation of mercury toxicity.

## Abstract

Mercury (hydrargyrum, Hg) exposure poses significant risks to human, animal, and environmental health due to its persistence and toxicity. Conventional chelating agents, though effective, are limited by adverse side effects and reduced efficacy in chronic exposure. Phosvitin (PSV), a highly phosphorylated protein from egg yolk with strong metal-binding capacity, offers potential as a natural detoxifying agent. This study aimed to evaluate, for the first time in vivo, the chelating efficacy of egg yolk-derived PSV against Hg toxicity in rats.

PSV was isolated from Isa Brown hen egg yolks through ethanol precipitation and characterized for purity and antioxidant activity using Fourier Transform Infrared Spectroscopy, Sodium Dodecyl Sulfate–Polyacrylamide Gel Electrophoresis, Kjeldahl analysis, and the 2,2-diphenyl-1-picrylhydrazyl assay. Twenty-five male rats were exposed to Hg-contaminated fish feed (0.17 ppm for 14 days) and subsequently treated with commercial or isolated PSV at 10, 20, or 30 ppm for 4 weeks. Hematological indices, liver and kidney histopathology, and Hg accumulation in brain tissue were assessed. Data were analyzed using R software (v4.4.0), with p < 0.05 considered statistically significant.

The isolated PSV exhibited moderate antioxidant activity, comparable to that of commercial standards, with a purity of 51.68%. Hg exposure significantly increased white blood cell (WBC) and basophil counts, indicating immune activation. PSV administration, particularly at 20 ppm, markedly reduced WBC and basophil levels, reflecting immunomodulatory activity. Histopathological analysis revealed reduced hepatic necrosis and milder liver damage in treated groups, with modest improvement in renal structure, though not statistically significant. Brain analysis showed decreased Hg accumulation in the 10 and 20 ppm PSV groups, while the 30 ppm group exhibited inconsistent effects.

Egg yolk-derived PSV, especially at 20 ppm, effectively mitigated Hg-induced hematological, hepatic, and neural toxicity, supporting its role as a safe natural chelator. These findings highlight its potential as a dietary intervention in Hg-exposed populations. Optimization of extraction methods, larger-scale studies, and long-term safety assessments are needed to advance its translational application in toxicology and public health.