Frequently Asked Questions
Probiotics, by concept, are products containing live microorganisms that favor the health of the host. In the market, there are some products containing a single strain, and others containing multiple strains of the same species or different species, specific for birds or not.
Competitive Exclusion (EC) refers to a term used to describe the protective effect of the microbial flora that comes from the bird`s gut and limits the colonization from pathogenic bacteria, especially Salmonella spp. (OIE 2010).
EC products, therefore, are a “pool” of friendly intestinal microorganisms from the gut of adult birds. Counting the number of species of the natural microbial flora of adult birds can create an estimation as high as a thousand different types of bacteria, 90% of those still unidentified.
Products manufactured through anaerobic fermentation (or microaerophilic) are capable of colonizing several parts of the Gastrointestinal Tract (GIT), including the ceca. Products of aerobic fermentation that colonize the prior GIT (small intestine), are almost never found on the ceca of birds, where the oxygen levels are close to zero.
The probiotics (defined or undefined) can be covered by one or several layers of polymers. These polymers are externally adhered to microorganisms in order to protect them from the acid environment of the stomach and favoring their release on the medium portion of the GIT. The coverage also makes microorganisms more resistant (Kabir, 2009).
? Breakage of complex molecules ingested by the bird, favoring digestion;
? Vitamin production;
? Production of antimicrobial substances, mainly organic acids and bacteriocins;
? Competition for adhesion sites, since probiotic bacteria adhere to the enterocytes on connection sites for pathogenic bacteria;
? Competition for nutrients, reminding that probiotic bacteria do not compete against the bird for nutrients, but against other bacteria present in the GIT. Probiotic bacteria normally use nutrients of low availability or unavailable for the birds, such as the non-starchy polysaccharides, which negatively affect the performance of the birds;
? Immune system stimulation. The largest and the most important immune structure in birds is the gut;
? Gut health promotion through improving the integrity of the mucous membranes including the length of the villousness and depth of ceca crypts, with rounder and more defined cells showing better cell differentiation;
? Reduction of pathogenic bacteria, highlights to Salmonella spp.
? Improvement on weight gain with reduction of feed conversion and mortality;
? Maintenance of zootechnical performance in birds that starved severely after birth;
? Reduction on carcass condemnation at the slaughterhouse, especially because of cellulitis and pododermatitis.
Through these mechanisms, defined and undefined probiotics (EC) are capable of reducing or eliminating pathogenic bacteria, promoting zootechnical performance and the integrity of the gut of birds (Houssain, et al., 2014; Agazzi, 2015).
In nature, when chicks are incubated and hatch under the chicken, they swallow the feces present in the nest. These microorganisms act as inoculum by establishing a protective gut flora similar to the one of the adult birds. The connection between the different bacterial strains is highly complex and depends on an specific interaction, which is not yet fully understood, but the more natural it is, the better it is for the bird (Cisek & Binek, 2014; Ribet & Cossart, 2015).
The most common application routes are: cabinet spray, drinking water and feed, as well as providing mini pellets, as is Colostrum Plus® (Mansoub et al., 2011). New studies proved the possibility of using “in ovo” as an administration route for defined flora probiotics (Colostrum Bio 21 Líquido®), associated to vaccines against viral infections, at the moment of transferring the eggs. “In ovo” administering Colostrum Bio 21 Liquido® was tested in more than 40 hatches of two different Brazilian companies and the results were favorable to this possibility.
The earlier the better, since the gut flora is poor on birds artificially hatched, having in mind that the first bacteria to reach the gut are those that tend to colonize and stay there. The use of probiotics is highly recommended for young birds and adults when there is an unbalance of the gut microflora due to enteritis and coccidiosis, changes on the microbial flora due to transportation stress, management, vaccination, forced changes, temperature stress, or after receiving antimicrobial medication. Considering that the gut flora of commercial birds is always dynamic and responds to continuous challenges due to several factors, by using probiotics the birds is protected because of the friendly microbial flora established there, which avoids the colonization by pathogenic bacteria.
These products are classified according to their ingredients, and they can either be just called probiotics or defined probiotics- when their formula contains identified microbial species or strains; internationally, they are known as DFM (“Direct-Fed Microbial”). Products that contain uncountable species are called competitive exclusion or undefined probiotics – those are internationally known as NAGF (“Normal Avian Gut Flora”) (OIE 2015).