When visitors step through the door of the turkey house, excitement spreads through the well-lit hall. The previously gentle peeping of individual poults swells into an orchestra of twittering; fluffy yellow baby turkeys with beady black eyes stretch their necks curiously towards the door. They run towards the visitors from all sides, fearlessly examining their rubber shoes with their beaks. The air is as warm and humid as before a summer thunderstorm, it smells of wood shavings and feed.
With all the hustle and bustle, it’s impossible to estimate the number of animals, some of which head for the red drinking troughs while others gather around the yellow feed dispensers. But Corinna Wilke knows exactly how many animals she moved into the brood house eight days ago: 4,800 hens and 8,800 toms, all freshly hatched, were delivered to the farm. The farm that Wilke, a veterinarian, runs with her husband is located in the district of Oldenburg, where half-timbered houses are thatched, wind turbines stand on the horizon, and people greet each other with the North German greeting “Moin.” The Wilkes have specialized in turkey rearing: They raise the poults, which initially weigh around 60 grams, for six weeks. When the young animals weigh more than two kilos, they are passed on to the grow-out farm, where they remain for four months until slaughter.
Losing birds to disease not only means animal suffering; it is also bad for business. This is why hygiene regulations are strict. Anyone entering Wilke’s barn has to slip plastic covers over their feet and lower legs, put on rubber shoes and a blue disposable overall, disinfect their hands, and change their shoes again before taking their first step into the sawdust. “Keeping all the animals healthy at all times is not that easy,” she explains. “If you notice an infection too late, the entire rafter could be put at risk in the worst case.” That’s why she checks on her “turkey kindergarten” four to six times a day, cleans the drinking troughs, takes water samples, monitors the birds’ behavior, and examines their droppings in the laboratory of the veterinary practice where she is employed. “Diarrhea is a common problem,” says Wilke. “Young turkeys are particularly susceptible, as their intestinal flora quickly gets mixed up.”
Strict government regulations
Livestock farmers have been using antibiotics both therapeutically and metaphylactically to combat infections in barns for decades. While only sick animals are treated during therapy, metaphylaxis allows administering medication to healthy animals in the poultry house where cases of illness have occurred. However, it is now clear that antibiotic use urgently needs to be reduced. The problems caused by resistant germs have become too extensive worldwide. The veterinary office’s guidelines for antibiotic use in livestock barns have therefore become more restrictive over the past 20 years.
For example, Corinna Wilke is now required to take samples beforehand in order to clarify which pathogen she is dealing with. Distributing a broad-spectrum antibiotic as a precaution has been severely restricted in animal husbandry since 2022. In addition, using such antibiotics to compensate for poor husbandry conditions is now prohibited. “I also have to document exactly how many turkeys were given which quantities of a medication on which days,” Wilke says. If the same disease occurs twice in succession among the animals in the same poultry house, a resistance test with pathogen identification is required. Moreover, anyone who uses an above-average amount of antibiotics has been required to work out countermeasures with their vet since 2014. Using the drugs as growth promoters—which used to be common practice and is still done in some countries because animals then put on more meat—has been banned throughout the EU since 2006.
Less antibiotics, more health
The Wilkes’s records show that they have needed less antibiotics than before for about a year now. Since their turkeys started regularly receiving Ecobiol® Fizz, they are no longer sick as often as they were before. The effervescent tablets, which are dissolved in water, contain a probiotic from Evonik that is also available as a feed additive. The product has now been optimized and Ecobiol® Pro is being launched on the market. Regardless of whether livestock owners and feed mills add it to drinking water as a tablet or to feed pellets as a powder, the principle is the same: Among other things, the product stabilizes the intestinal microbiome of poultry and inhibits the spread of dangerous intestinal pathogens such as Clostridium perfringens. This bacterium often leads to infections in chickens. It not only causes diarrhea but also severe damage to the intestinal mucosa, which adversely affects the animal’s well-being and growth and can also be fatal. Droppings from infected birds can quickly infect other birds as well. Farmers suffer considerable economic damage due to intestinal diseases in their livestock. Experts estimate that this damage amounts to up to six billion US dollars a year worldwide.
Thanks to a modified production process, the effectiveness of Ecobiol® has now been increased. According to a feeding study conducted by Oklahoma State University, Ecobiol® Pro improves the survival rate of broilers by 50 percent compared to a commercially available product. Wilke reports that she noticed the effect in her barn from the very first use: “Turkeys are very sensitive and react to changes in the weather or feed, for example. Since we started giving them Ecobiol®, everything has become more relaxed. Our animals are healthier and even reach a higher weight.”
What makes Ecobiol® products special is that this probiotic, which supports a healthy intestinal flora with beneficial bacteria, contains spores rather than active cells. Bacteria of the genus Bacillus produce these so-called endospores when nutrients become scarce. The spores are resistant to heat and cold and can withstand acid, radiation, and high pressure. In short, they can survive for millions of years under the most adverse conditions and wait for better times. Only when living conditions become suitable do the spores outgrow and develop back into active bacteria that can multiply.
Evonik made use of the microorganisms’ survival strategy when developing Ecobiol® Pro, whereby the spores of the Bacillus velezensis CECT 5940 strain of beneficial intestinal bacteria are not supposed to become active when the pellets are pressed, during feed storage, in the feed trough or the upper gastrointestinal tract of a chicken; instead they should become active only after they reach the small intestine. But things have to move quickly there: Depending on the age of the animal, feed passes through the entire intestinal tract in three to five hours, and the spores outgrow in the duodenum within one hour. The timing is crucial in order to ensure that the probiotic can work there effectively.
Tests in the poultry intestine model
Stefan Pelzer, Head of Microbiome Research at Evonik, and his team investigated what Ecobiol® does in the chicken intestine. At the chemical company’s Biotech Hub in Halle-Künsebeck, Westphalia, scientists have been working for several years with the “Dynamic Avian Intestine in vitro System” (DAISy) poultry intestine simulation model, which has already proven its value in the development of other products. The conditions in each of the system’s glass vessels are the same as those in the respective sections of a chicken’s digestive tract—the pH, oxygen content, enzyme activity, and microbial composition correspond to the conditions in the animal. “We can put in different feed mixtures and let DAISy digest them,” Pelzer explains. “The model also enables us to take samples from each section of the gut, which would otherwise require us to euthanize a chicken.”
A pipetting robot does some of the lab work for the humans and dilutes the semi-digested feed residues from DAISy to the desired concentration. “The spores survive the crop and then pass through the proventriculus and gizzard,” Pelzer explains. “In the small intestine, enzymes break down the feed further, producing amino acids and sugar.” Both of these serve as a signal for the spores to start outgrowth. By the time the digesta has finally reached the lower part of the small intestine, almost all the spores have turned into active cells.
Ecobiol® Pro is not the only probiotic feed additive on the market. However, the experiments using the DAISy model showed that many other products never become active bacteria at all in chicken intestines. Instead, the birds excrete the spores unused because they do not outgrow in time. This means there can be no effect. “In other words, it’s not enough to count the spores in the feed to determine the effectiveness of a product,” says Pelzer, who has been carrying out research for Evonik for 14 years and teaches at the University of Tübingen. “The decisive factor for the probiotic effect is that the spores outgrow in the right place in the intestine at the right time.”
Fermentation as the key to success
Like many successful Evonik products, the spores for Ecobiol® Pro are produced by fermentation, one of the company’s specialties. This biotechnological process utilizing selected bacteria on an industrial scale initially provides perfect living conditions for the microorganisms. The temperature, pH, pressure, oxygen content and nutrient supply are all optimized in such a manner that the bacteria multiply within a short time. Only when large amounts of biomass have been produced and the nutrients have been fully consumed does sporulation begin: The bacteria form their persistent dormant form, the endospore. “We discovered that we can use the production conditions in the fermenter to influence the memory of the spores and thus the outgrowth kinetics in the intestine,” says Pelzer. “With this knowledge, we optimized the manufacturing process and the effect of our probiotic without having to change the bacterial strain.” Compared to the average of the competing products tested, the new Ecobiol® Pro outgrows significantly faster. “This puts Ecobiol® in the top league of probiotic products,” says Stella Molck, a microbiologist in Pelzer’s team.
Since Ecobiol® Pro is added to different types of feed all over the world, the team in Halle-Künsebeck also used the DAISy model to test how the spores behave in different mixtures, for example with maize, soybean meal or wheat. “Not all feeds are the same,” Pelzer points out. “The quality of the raw materials constantly varies and the formulations differ from region to region.” Still, laboratory tests have shown that the outgrowth rate of Ecobiol® Pro is amazingly stable. “It works consistently well with all feed mixtures, while the competitor products display greater variations,” Pelzer explains.
»The world has a huge problem with antibiotic resistance«
Stefan Pelzer Head of Microbiome Research at Evonik
Pelzer also believes it is important to point out that probiotic feed additives benefit not only broilers and turkeys: “Humanity has a huge problem with antibiotic resistance, and if we don’t address it, the number of deaths that result will continue to rise tremendously.” Livestock farming accounts for 73 percent of the antibiotics used worldwide—far too much, Pelzer believes: “In line with the World Health Organization’s One Health concept, which sees health risks for humans, animals, and the environment as being closely linked, we should not be indifferent to the massive use of antibiotics in animals. After all, this also affects our lives.”
The high informational value of the tests in the chicken intestine model enables the targeted evaluation of probiotic efficacy under customer-specific feed conditions. Stefan Pelzer and Stella Molck offer customers close cooperation on this basis. For example, customers can send in feed to have the outgrowth rates of various probiotics tested individually. “Firstly, we compare the outgrowth behavior of Ecobiol® Pro with other products in customer-specific feeds and give the customers tips on how they can improve the effectiveness of the probiotic,” Molck explains.
ELEMENTS-Newsletter
Gain exciting insights into Evonik's research and its societal relevance – conveniently delivered via email.
The aim here is to learn more about Evonik’s own product and better understand which factors influence the outgrowth of the spores. In the future, the company intends to use these findings to determine how the outgrowth behavior and thus the effectiveness of Ecobiol® Pro can be further improved.
Storage at minus 112 degrees
How Ecobiol® Pro is produced on an industrial scale can be seen in the northwestern part of Spain, where Molecular biologist Pilar Honrubia manages a small production facility in Onzonilla, south of León. Twenty-nine people are employed here; a long row of windows in the laboratory provides a view of the fermentation hall. Two new fermenters have been in place there for four years, with the largest tank holding 8,000 liters. The fermentation process for Ecobiol® Pro takes five days and begins every Monday as soon as an employee has carefully carried a fresh starter culture from the laboratory into the hall and added it to the first tank.
Each starter culture is prepared in a glass flask in the facility’s production laboratory on the basis of bacterial stem cell banks that were established in Halle-Künsebeck. After they have been delivered to Onzonilla, the bacterial cultures are stored in a freezer at minus 112 degrees Fahrenheit (minus 80 degrees Celsius). Several cultivation steps are required before the large fermenters can be inoculated. “The biggest enemy of successful fermentation is contamination with other microorganisms,” says Honrubia. “We therefore pay strict attention throughout the entire process to ensure there is no contamination. Otherwise, in the worst case, we would have to get rid of the entire batch.” The plan is to continue to ramp up production in Onzonilla and soon have it running around the clock in two fermenters simultaneously, including on weekends.
Sugar as a foundation
Pumps and engines roar in the hall and there is a malty smell. A forklift truck drives past, two men wearing safety goggles heave a thick blue hose upwards to an opening in the fermenter. The other end is submerged in a tank containing liquid glucose, which the men are now pumping into the fermentation vessel, which is around four meters high. Sugar is the most important ingredient in fermentation. It serves as the nutrient for the bacteria while they multiply behind the stainless-steel wall of the tank. Once the glucose has been used up, the lack of nutrient triggers sporulation. Once this is complete, the biomass consisting of the nutrient solution, water, and spores can be harvested.
After centrifugation, a thick brown pulp remains. The pulp is poured onto trays, shock-frozen at minus 31 degrees Fahrenheit (minus 35 degrees Celsius), and stored in the hall’s freezer container. The next step, drying, takes place just a few meters further on. The frozen water is removed by sublimation in two large freeze dryers, leaving behind dry slabs consisting mainly of spores. The boards are crushed and sieved, after which the powder is mechanically mixed with various excipients and filled into bags—Ecobiol® Pro is ready.
In order to ensure that each bag contains the specified amount of spores, the laboratory staff test up to 40 samples from ongoing production every day. Samples are taken from the nutrient solution several times during the entire incubation period; after they are dried, the concentration of the Ecobiol® biomass is determined. This is done because the end product must contain a defined concentration that is guaranteed to the customer. To count the spores, the biologists dilute the samples in the laboratory and spread them out on agar plates, where the spores outgrow again. Each one grows into a bacterial colony on the culture medium in the incubator; the colonies are then visible to the naked eye or can be digitally scanned and counted.
The employees in the Spanish laboratory also test finished pellets to which Ecobiol® Pro has been added in feed mills; a new delivery has just arrived. However, the facility doesn’t just employ humans, as a separate building on the site has space for 475 chickens on which feed mixtures are tested—under the strict supervision of two veterinarians.
Although the new Ecobiol® Pro has only just been launched on the market, one thing is already clear: It will help reduce the use of antibiotics in livestock farming. The animals will be the first to benefit—for example Corinna Wilke’s turkey poults, which are doing better with probiotics. Their owner is not only pleased in her role as operations manager: “As a veterinarian, it’s important to me that we can use antibiotics more responsibly thanks to products like these.” Because this will also help people all over the world.