Before buying meat, many consumers are concerned about the conditions in which the animals have lived. As part of a process of continuous improvement in animal welfare, practices have been put in place on farms to protect animals from stress and better prevent disease. While vaccination helps to contain the spread of disease, the use of advanced fermentation nutritional solutions can also help to strengthen their intestinal flora of animals and optimise the effectiveness of their immune system. We spoke with Alain Riggi, veterinarian and technical director of the poultry sector of the Phileo Business Unit at Lesaffre, for an update.
In order to prevent the development of pathogen-related diseases in poultry farms, sanitary measures can be put in place. Good site hygiene, controlled animal density, full periodic disinfection downtimes, and good water and feed quality are the basic ingredients. “The regular use of antibiotics, given as a preventive measure in the drinking water of chicks, is a bad idea,” warns Alain Riggi, technical director of the poultry sector of the Phileo Business Unit at Lesaffre. “This results in the destruction of most intestinal bacteria, even non-pathogens. This antibiotic intake therefore delays the balance of the young chicks’ flora by several days, even though it should play its role as a barrier against pathogens and be balanced after 15 days to 3 weeks.” Repeated use of antibiotics also promotes the emergence of resistant bacteria, currently a global public health problem. As a result, the health rules that used to govern livestock farming are now undergoing a major change. The focus is now on natural processes that support the biological defence mechanisms of animals and preserve the integrity of the food chain.
Balance and diversity of intestinal flora, assets against external aggressions
In poultry, there are several barriers that allow the body to limit infections before the immune system is activated. Mechanical barriers, physical-chemical barriers and microbiological barriers. Present in the skin, digestive tract, respiratory and reproductive systems, epithelial cells are at the heart of immunity. “The walls of the trachea and bronchi are lined with epithelial cells with vibrating hairs to expel dust. They secrete mucus, capable of trapping and evacuating many pathogenic bacteria.” These cells also secrete antibacterial substances, or defensins.
On the intestinal side, the microflora, which in poultry consists of, among other things, non-pathogenic Lactobacilli, Firmicutes and Clostridiums, produces lactic and butyric acids. It thus modifies the local pH and creates an environment that is unfavourable for pathogens. This intestinal microbiota, naturally present in the mucous membranes, also helps to protect these farm animals against pathogens via the barrier effect: “By adhering to the intestinal mucosa, the commensal – i.e. beneficial – bacteria of the intestinal flora prevent, by competition, other pathogenic micro-organisms from colonising the intestine.” There is therefore a close relationship between the intestinal flora and the immunity of the intestinal tract. Thus, the more diverse and balanced the commensal flora is in poultry, the less likely they are to contract diseases. “And to keep poultry farms in good health, this diversity must be present in the largest number of animals in a batch,” says Alain Riggi.
Yeast fractions, part of postbiotics, to prevent possible infections
Administered directly as powders in complete feed or in premixes for poultry feed, “yeast fractions from advanced fermentation can positively modulate the composition of the intestinal microbiota and reinforce its barrier effect,” Alain Riggi reveals. Several modes of action exist for postbiotics: yeast fractions can “stimulate the growth of the cells that produce intestinal mucus, promote the growth in height of intestinal villi, or act on keeping tight junctions between intestinal cells to prevent the passage of pathogenic bacteria.” This improves the function of the intestinal barrier.
These yeast fractions can also capture pathogenic bacteria, such as Salmonella, which have fimbriae, or pili, on their surface and bind with them via one of their main components – mannan. They then form complexes which will subsequently be evacuated thanks to the peristaltic movements of the intestine. “This mechanism reduces the amount of these intestinal pathogenic bacteria by 1 to 2 log (90 to 99%),” says Riggi. Advanced fermentation solutions also help in the fight against other bacteria, such as Clostridium perfringens, responsible for necrotic enteritis, a common bacterial disease in chickens.
Postbiotic yeast fractions to boost the immune system
If, despite all these barriers, a pathogen enters the poultry body, the cells of the immune system will take over. In both chickens and mammals, the immune response has two components: the non-specific (innate) response that occurs upon first contact with a potential pathogen, and the adaptive (cellular or humoral) response that takes over from the innate immunity, with lymphocytes coming from two specific organs, among others: the thymus and the Fabricius bursa.
Yeast fractions are likely to interact with the immune system: their main components (mannans and beta-glucans), thanks to their chemical structure, are recognised by receptors present on the surface of immune cells such as macrophages (large cells derived from a blood monocyte, endowed with the power to absorb foreign particles) and dendritic cells. These are present under the intestinal epithelium and are capable of developing evaginations (exit of an organ from its natural cavity) through this epithelium to detect pathogens in the intestinal lumen. This is then a specific alert of the immune system. This interaction with the immune system allows the immune system to stay alert and respond more effectively and quickly to a viral or bacterial infection.
In this context, yeast fractions can also be used to “strengthen the vaccine response and obtain better protection for the animals.” On these farms, vaccination has a proven usefulness: it limits the economic consequences of infectious diseases by allowing the prevention and control of certain highly pathogenic viruses. By reducing the viral load in the environment, it avoids the risk of serious disease in poultry and reduces the likelihood of zoonotic disease and the risk of human exposure. Improving the vaccine response using yeast fractions thus directly improves the performance of the farm and ensures consumer health safety.
Lesaffre works alongside farmers to meet their needs
“In the Phileo Business Unit at Lesaffre, we are first and foremost trying to understand what farmers need, in order to develop tailor-made solutions for them in terms of preventive care,” Alain Riggi stresses. “Whether their chickens are stressed by bacteria in drinking water, by poor quality feed with too abrasive raw materials, or suffer from intestinal disorders, we offer a global approach based on a risk study to make their animals more resistant and resilient.”
This approach also helps to solve farm animal stress problems and thereby improve feed efficiency. “Thanks to our products, farmers can reach their poultry’s target weight by giving them less feed, which reduces the food footprint of their poultry farms, and ensures a gain in production costs, but also reduces the resources used for farming, and therefore its environmental impact.”
With over 170 years of research and industrial expertise in micro-organisms, Lesaffre offers a diverse range of beneficial products, from yeast fractions (mainly used in poultry), to live yeasts (in ruminants and pigs), as well as mixed solutions of bacteria and yeast. Immune system, intestinal health, stress, meat and milk production, fertility, prevention of salmonella, pre-weaning… These are all criteria that Lesaffre employees work on within the Loos research and innovation platforms, in order to ensure animal welfare and consumer food safety, while helping to reduce antibiotic resistance and the carbon footprint of livestock farms.
To find out more, watch this video to discover the link between an animal’s microbiome and its immunity and how in vitro models are now advancing research in this field.