Q: How relevant are probiotics and prebiotics in the poultry industry right now?
A: At this time, they are very important because they are alternatives to antibiotics. The worldwide situation, with the appearance of pathogenic strains of E. Coli, Salmonella, Campylobacter and other enteropathogens, is alarming in terms that these bacteria are appearing and have shown resistance to all antibiotics available for humans or animals. When we look at these situations, there are not many alternatives that the animal industry could use and, among those few alternatives, prebiotics and probiotics, along with other natural compounds like essential oils and enzymes, are going to be key elements as substitutes in the new legislation that is being established worldwide.
Europe was the first continent that banned or restricted the use of antibiotics growth promoters in January 2006 and that tendency is being followed very rapidly. As a matter of fact, for many years, United States was the number one chicken meat export producer, until seven years ago Brazil took the lead and became the main chicken export producer in the world, just by listening to the demands of Europe, Middle East and Asia, that were requiring a product with no residues of antibiotics.
This is a situation that is changing the perception of the consumers. The public in general, not only scientists, they are requesting every day products with alternatives to antibiotics. That is why prebiotics and probiotics are going to become part of those few tools that effectively could reduce the use of antibiotic growth promoters in the animal industry.
Q: In this situation, what are the advantages of Direct-Fed Microbials?
A: In the US, there are two categories where probiotics have been divided. One, the probiotics per se, are those live microbial microorganisms, defined products, not undefined products, that are administered in the drinking water. The difference between probiotics and DFM (Direct-Fed Microbials) is that probiotics go in the drinking water and DFM, which is also a probiotic, goes in the feed, in the ration of the animal.
In our experience, what we have seen in the development of more useful Direct-Fed Microbials, based on Bacillus subtilis strains that produce spores, is improved digestibility. We have selected several strains that have been able to produce exogenous enzymes, such as light-based proteases, carbohydrases among them cellulase, xylanase, amylase, beta galactolase and others, and these enzymes are secreted by these spores when they are consuming the feed, and the spores germinate in situ, inside the bird.
It is been amazing to see how the administration and the use of these DFM on chickens can significantly improve digestibility, particularly of diets of chickens and turkeys that use alternative grains to corn as a source of energy. For example, corn has been substituted as a source of energy with alternatives like wheat, rye, barley, oat, and DDGS, as a subproduct of the ethanol production in the US.
The DFM that we have selected and we have worked with in these diets have been able to reduce all the adverse effects of this kind of diet that are very high in NSP or Non-Starch Polysaccharides. The problem with these high fiber diets, which are basically high Non-Starch Polysaccharides, is that the monogastric animals -not only chicken but also pigs, fish and more, even other mammals as us, humans- do not have the enzymes to digest such high concentration of fiber in a specific diet. That kind of fiber, that kind of diet with high NSP can produce a mess in the gut in terms of inflammation and a lot of other severe effects; it increases viscosity, reduces dramatically the gastric transit time.
When you have high production of mucus and high viscosity in the GI tract, you have a dysbacteriosis, which increases the population of clostridium perfringens, for example, and this facilitates the apparition of necrotic enteritis. With the administration of these DFM, we have been able to reduce all this gut inflammation in chickens and turkeys that received diets with high NSP, so it has been very good. Some of these strains we have shown that they secrete antimicrobial compounds against Clostridium perfringens, and at this time we are going to start an experiment to see if DFM can ameliorate necrotic enteritis in a chicken model that we have here in the laboratory.
Q: What has been your experience so far researching prebiotics?
A: The inulin has been the prebiotic that has been more researched, not only in animals but also in humans. Inulin is a polysaccharide that we find in products like onions, bananas, asparagus, artichoke, for example. The two leader producers are in China, they extract inulin from artichoke, and in Belgium, they extract it from chicory root.
Inulin as a prebiotic is a fiber, a very good fiber that increases the population of beneficial bacteria in the gastrointestinal tract. When we hear a combination of a probiotic with a prebiotic, is like giving a fertilizer and the seed together, combined, because the prebiotic is going to increase the population of these beneficial bacteria.
In our experience, many years ago we worked with lactose, chickens since they are not mammals, they do not have the enzyme lactase, and we have shown, in some of our published work, that concentration in the diet of 0.1 per cent of lactose is a very effective prebiotic, is a source of a carbohydrate that will increase population of beneficial bacteria, like bifidobacteria and lactobacilli, in the GI tract of chickens and turkeys, without causing diarrhea.
The problem is that China basically is consuming all the lactose in the world. At the time we started working with lactose, it was a commodity, nobody wanted it until China started using it and buying it for their milk products. Since then, we have worked with other prebiotics, particularly Aspergillus meal. There are several companies that produce commercially this prebiotic and is a fantastic source of fiber. The problem with inulin is that is so good and it has so many benefits that is very expensive. And it has been used mostly in humans; so for animals, it would be prohibitive to try to use inulin as a prebiotic.
An alternative has been the use of nopal or agave. Mexican agave is a cactus where tequila is used for fermentation and it contains a high concentration of inulin. Aspergillus meal, as I mentioned, is an alternative. Aspergillus meal is a sub product of the citric acid industry. The advantage of Aspergillus meal is the fungi that grow. The mycelium contains not only MOS, FOS, and chitosan, which is again another polysaccharide, that is a very good source of food or prebiotic for beneficial bacteria.
Q: What are the benefits of lactic acid bacteria?
A: Lactic acid bacteria is a probiotic and it is an incredible group of bacteria. Since 1908, it has been studied, it started with Élie Metchnikoff, who is considered the father of probiotics because he analyzed lactobacillus from yogurt in Bulgaria, in people that were consuming high quantities of this fermented milk or yogurts, and he found that these people in Europe at that time had the highest rate of longevity and health in the continent.
Lactobacillus, or lactic acid bacteria in general, are an incredible source of probiotics, but they are temperature sensitive. That is why they have to be administered in the drinking water and they cannot be added in the feed, especially if it is going to be pelletized because the temperature and the pressure in the process will kill them. That is also the difference with DFM's because spores from bacillus species they are so tough that they will receive the benefits.
Also, the benefits are different. You can have incredible resistance and treatment of flocks without cases of salmonella, for example, with lactobacillus. In our experience, we have not had such good results with DFM's. But the benefits that you get in terms of digestibility of high NSP diets you cannot get them with a lactic acid bacteria, you get them using a bacillus that produces the enzyme. What I am saying is that perhaps the combination -and we will start looking into this and evaluating it- of both, lactobacillus in the drinking water and DFM in the feed, could give us the best of both worlds that could have benefits in terms of health and digestibility for the poultry industry.
As a matter of fact, there are publications that indicate that lactobacillus increases the population of bacillus when they are administered together. So this is an exciting opportunity for us to do some research after having years of experience working with both groups of bacteria separately.