Can sound alter layer gene expression?

At present, 7.5 billion chicks a year are culled after they hatch, costing farms billions in losses and raising ethics questions. Countries such as France, Germany, Italy, Austria and Luxembourg have either banned the practice or are in the process of doing so.

Many of the technologies being scrutinised and piloted are around the detection of the embryo sex before hatching, leading to their destruction much earlier in the embryo’s development process.

Exposing hens to increased lighting is known to stimulate egg production, but researchers are now looking to see if sound waves could increase the number of egg laying hens.

Sound waves to alter gene expression

Scientists at Syracuse University and Soos Technology believe sound waves could resolve one of the age-old ethical and economic concerns within the egg industry – culling of day-old male chicks.

The proposed technology equips incubators with devices that introduce sound waves to fertilised eggs to alter gene expression. The result is genetically male chicks that express female physical traits, which will mean these chicks will lay eggs.

Sound waves have been used in the past to alter gene response in plants and they can also alter gene expression in the fertilised chicken embryos. This is both non-intrusive and does not involve any form of genetic modification or hormonal intervention.

The researchers control the environmental conditions in the incubator during embryonic development using sound energy produced by vibration. By altering the sound frequencies and volumes, along with temperature and humidity, Soos Technology claims they can increase the odds of hatching a female chick from 50-80%.

Soos Technology has been awarded a US$1 million grant through the Gow-New-York competition and have formed a collaboration with a commercial fam at Auburn, New York, close to Syracuse University.

Triggering female genes

James Crill, professor of practice in the Forensic Science Institute at Syracuse, said: “In our labs we have a large experiment in place looking at genomic and RNA expression to find out what’s happening inside of the chicken during embryonic development that actually tells it to be a female but also have all the male genetics in place. We are looking to determine how the sound waves are triggering certain female genes to be expressed over the male genes.”

So far, around 61% of the hatched chicks that have undergone the Soos treatment have been female.

Efrat Petel, Soos US general manager, said the most significant discovery so far had been that exposure to sound treatment at certain frequencies and intensities significantly affected the sex change process, especially when it is performed from day 0-16.

One experiment found a 69% female ratio in one set and a 63% in another: “Our technology can influence the embryo to develop into a female, which is eventually able to lay eggs,” he added.