Parasites, nasty bacteria or infectious diseases, it would be great if livestock farmers could detect these diseases in their poultry before it’s too late. The e-nose should provide a solution.

Saxion University of Applied Sciences in Enschede and Utrecht University are starting a six-year study together with partners from science and industry to develop such an electronic nose. At the moment many poultry farmers suffer from infections with parasites and bacteria in their chickens. As a result, more chicken feed is needed and antibiotics and pesticides are sometimes used. The e-nose can detect poultry diseases earlier. That is not only better for the farmer, but also for the chicken and ultimately for humans.

Professor of Applied Nanotechnology at Saxion, Cas Damen, explains Scientias.nl explains how he got the idea for the e-nose from a vet with a sharp nose. “He said to me: ‘When a farmer calls me, I immediately smell what is going on: blood mite. It is a pity that a farmer does not have a method for detecting blood mites at an early stage by means of smell, so that he can intervene earlier.’ He asked me: can you not develop something like this?”

Sustainable food production

This red mite or red mite is a parasite that causes a lot of damage in poultry. The e-nose could be for this. And there are more applications. “We are now also looking at a method to measure disturbances of the gut bacteria by picking up the gases. That is not only better for animal welfare, but also for sustainable food production.”

Francisca Velkers, poultry specialist and epidemiologist at Utrecht University, explains why a healthy intestinal flora is so important from a sustainability point of view. “Brief chickens eat a lot of feed. That has to come all the way from South America, for example. When the gut is out of balance, digestion is bad. The food is badly digested and pooped out again. So you need a lot more food. Residues of proteins also remain in the faeces, which increases the harmful emissions.”

A blood mite under the microscope. Photo: Phototrip/Getty Images

The system

To solve these problems, the researchers want to develop a sensor system with a chip containing various plastic layers that absorb gases. Many sensors come together on the chip and each sensor layer contains a different polymer. This allows the system to detect various parasites, bacteria and other pathogens. The device sends out a signal when, for example, an infection with parasites is detected. Damen explains: “A pattern emerges that we can analyze. It works the same as with the human nose. It contains receptors, from which a pattern is created that is sent to the brain. They recognize it and say: this is coffee or this is a rose.”

User friendly

It seems obvious that farmers embrace this system, but it is not. Velkers: “It has to be user-friendly and not too complicated. And the costs must outweigh the benefits. Now a vet is doing an autopsy on dead animals and looking at the intestines to determine the cause of death. The new method has to be better than what you already have.”

In a barn with 30,000 chickens, it is also difficult to make a sensor that is sharp enough to recognize possible odor disorders. “In such a barn there is a lot of dust and there are many other odours. The technology must be able to recognize the pattern through that.”

What is unique about the e-nose is that the sensor knows which gas it has to detect and can be adjusted accordingly by choosing the polymers. Damen: “That went wrong with Covid. At that time, a system in the laboratory could distinguish healthy people from people with Covid, but it was unclear which gases were measured. Once outside the lab, other gases started playing in and it stopped working.”

Advantages

Ultimately, the benefits of an e-nose, which can detect a disturbed intestinal flora at an early stage, are numerous. “If the intestines are very out of balance, you can restore that by adjusting the feed,” says Velkers. “If you are too late, a lot of feed and growth have already been lost and sometimes you even have to use antibiotics. And you don’t really want that, because we are working on a sustainability campaign. Farmers get less money for their meat if the chickens have grown less well and sometimes also if they have used antibiotics.”

Velkers also talks about the transition to more organic farming: “The risk of diseases is greater if animals are outside more often. They then come into contact with bird droppings or dirty rainwater that is scalding the grass in the summer. For example, parasites and bacteria can be transferred much more easily than in a closed housing system.”

The e-nose can possibly ensure that this happens less. “Intestinal disease can be detected at an early stage, even before the disease has caused a lot of damage to many animals,” says Velkers. “But it may be possible to go a step further: if certain feed causes an imbalance in animals, you can provide feedback to the manufacturer. They can then adjust the feed slightly, for example by adding an enzyme, so that other farmers are prevented from being affected as well.”

It is not without reason that feed manufacturers have already shown interest, just like Philips and various agricultural organizations for example. “They want to help sell the product or see the benefits for the farmer.” This is partly because they anticipate the switch to circular agriculture. “If a chicken is then given a residual product as feed, you want to know what that does to its intestines. You can then adjust the feed accordingly.”

Forest fires and slaughterhouses

But the same measuring principle can be applied much more widely. It can also be useful, for example, to detect forest fires in southern Europe. “Now they only discover a fire when the smoke rises above the trees,” says Damen. “It can be useful to hang a device every few meters that detects the smell of smoldering material.” A sensor that measures abnormal odors can also play a role in the storage of agricultural crops, adds Velkers. “In slaughterhouses they are already using a sensor to detect meat that is no longer completely tasty. It can also be useful for farmers in third world countries where a vet is not always available. If our device is cost-effective, it can prevent many diseases in livestock in those countries.”

Velkers: “It is actually technically applicable to everything that produces gases. The advantage of the application in chickens is that the situation resembles that of pigs. The disturbance of the intestines in chickens is similar. If it goes well, it’s a matter of adapting.”

A chicken farm. Photo: Onyinye Photography

Confident

The scientists are very confident that the sensor will come. They focus on four measurement methods. The more experimental the methods are, the more sensitive they are. “The detection of red mite will probably be successful, measuring the imbalance in the intestines is more uncertain.”

Damen explains: “You have to be able to adapt the specific chemistry to the gases you want to absorb. You can use an infinite number of polymers and choose what you want to use them for. It is only suitable for large numbers, so applications that require many sensors.”

What should that device look like? It could simply be a sensor that a farmer hangs in his barn. Damen: “But I can also see that the farmer has the device hanging around his neck and can then measure the odors while he walks through the barn.” Velkers adds: “A farmer walks through the barn at least twice a day to check whether everything is in order and sometimes to pick up eggs from the ground.” So it hardly takes any extra time.

Potency

The electronic nose has a lot of potential. This is also apparent from the many partners and other stakeholders who are interested. If all goes well, every farmer may have an e-nose around his neck or in the barn in a few years’ time.