Fertilised chicken eggs can be sexed by ‘sniffing’ chemicals emitted through the shell – a discovery that could help the global poultry industry improve welfare, cut costs and reduce its environmental footprint.
Scientists in America found volatile organic chemicals released early-on during incubation can indicate the sex of an embryo. And by developing technology that ‘sniffs’ the air, they can identify if an egg is male with 80% accuracy.
In research published in PLOS ONE, researchers at UC Davis said about 7bn day-old male chicks are culled each year in broiler (egg laying) production systems — a procedure that is banned in some European countries.
If hatcheries could identify the sex of an egg early on, those male eggs could be put to other uses, the scientists said, improving welfare, reducing waste and limiting the industry’s environmental impact.
Current technology available to sex eggs involves making a tiny hole in a shell to obtain an embryo sample that is sexed through DNA markers. Another method is to use imaging technology through the egg shell – a procedure that is more accurate with older eggs.
Faster and simpler
However, scientists at UC Davis believed they could simplify and speed up the process by analysing the biological information that’s encoded in volatile organic compounds, which are emitted through porous egg shells.
To analyse if there was a reliable difference in the sex-specific chemicals given off by male and female embryos, UC Davis’ department of mechanical and aerospace engineering first developed a sensor chip to collect and analyse organic chemicals in the air.
Using suction cups already used for industrial handling of eggs, the researchers adapted them so they could ‘sniff’ air from the eggs without breaking the shells.
After analysing the samples taken randomly from male and female eggs, researchers discovered they could identify male embryos at 8 days of incubations with 80% accuracy.
“There are abundant egg-derived [volatile organic chemicals] that be used to statistically classify embryos by sex, non-invasively, early in incubation with high confidence,” the researchers said.
While future work needed to look at the amount of time taken to collect samples, as well as the temperature of eggs, the results could pave the way for chemical sensor microchips to test large numbers of eggs at once, making the hardware simple to integrate into hatcheries, they added.
