Ask a RIFM Scientist

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Headshot of Yax Thakkar

Can an egg save animal lives?

Yax Thakkar, MS

Everyone wants products that are safe to use without having to test them on animals. In a move toward developing animal alternatives, RIFM developed a set of safety assessment criteria in 2013, outlining a series of scientifically rigorous approaches to help avoid testing on animals.

In rare cases where these approaches are impossible, the chicken egg model offers a promising genotoxicity testing method that avoids in vivo (live animal) experiments.

The egg model uses fertilized eggs from white leghorn chickens. Fertilized leghorn eggs take 21 days to hatch. Therefore, RIFM conducts testing up to day 11, before the chicken embryo develops a fully formed nervous system, to avoid any possible discomfort.

When in vitro (in Petri dish) studies show results for DNA mutations (mutagenicity) or chromosome breaks and alterations (clastogenicity), an animal follow-up study was once necessary to confirm these results. However, RIFM can ensure the results with the egg model by following the same guidelines as confirmation animal studies. The sole exception is that they would be carried out in eggs rather than in animals.

In addition, the egg study can validate the biological relevance of the Petri dish study. For instance, Petri dish studies lack a liver detoxification pathway, which can lead to false-positive results. The egg model includes a liver and the enzymes required for the liver detoxification pathway.

RIFM is also looking into other animal-alternative genotoxicity strategies. For example, since the primary route of exposure to fragrance ingredients is via the skin, RIFM supports 3D skin models for mutagenicity and clastogenicity.

Senior Scientist Yax Thakkar, MS, leads RIFM’s genotoxicity safety assessment and research programs.