Abstract Chicken eggs are one of the most consumed foods worldwide. However, the practice of chicken culling in the poultry industry involves unnecessary animal suffering and finding a way to put an end to this has become a societal priority. One approach that has been propagated as acceptable is based on the selection of female eggs early in the incubation process and the devitalization of the male eggs. It is with this objective in mind that we searched for a biomarker for early gender screening in eggs. Applying an untargeted mass spectrometry approach, we profiled allantoic fluid of different day-old eggs and identified the feature 3-[(2-aminoethyl)sulfanyl]butanoic acid (ASBA) as a strong biomarker for in-ovo gender prediction for day-9 old embryos. After validation using LC-APCI-MRM with an internal standard, we found ASBA can predict the female gender with a sensitivity and specificity well above 95% in our experiments. Highlights Discovery of a biomarker of chicken embryo gender in allantoic fluid from eggs Day 9 after laying was determined as optimum for sex prediction and animal welfare 3-[(2-aminoethyl)sulfanyl]butanoic acid was identified using mass spectrometry The biomarker was validated on large cohorts of different chicken species Graphical abstract

How to prevent chick culling in the poultry industry? Discovery of a new biomarker forin ovogender screening