How can we transition from antibiotics growth promoters to feed additives?

Antibiotics growth promoters: useful or dangerous tools?

Since animals are reared in intensive conditions, antibiotics are needed to treat bacterial infections, but they are also very well known because of their effect on animal feed conversion, growth, and performance. These effects are related to the antimicrobial activity of these molecules in the intestinal tract of animals: it was shown already in the eighties that germ-free chickens grow better than chickens with a physiological commensal intestinal microflora, as well as they do not respond to the action of antibiotics used as growth promoters. At the same time, chickens treated with AGP have live performance similar to germ-free birds. AGP help in different ways the animal during its productive life. Since they reduce the microbial load in the intestine, nutrients are more available for the host and there are also fewer growth-depressing metabolites produced by bacteria. Secondly, antibiotics reduce pathogens, with fewer subclinical pathologies, lower toxins production, and a lower metabolic cost for the innate immune system. Furthermore, the reduction in microbial load leads to a thinner intestinal wall with an improvement of nutrient uptake by the host. Another action of AGP, studied in recent years, is their anti-inflammatory effect. AGP, as well as antibiotics used for therapeutic purposes, inhibit different functions of inflammatory cells, in particular the production of proinflammatory cytokines, limiting their catabolic effect. All the explained effects of AGP are positive for the host and the farmer. The flip side is that AGP also promote antimicrobial resistance. The prolonged administration of low dosages of antibiotics, not completely effective in eliminating all pathogens, leads to the selection of those bacteria able to survive and, subsequently, to proliferate in the presence of these molecules. This is why, after decades of AGP use, there is an alarming increase in multi-drug resistant pathogens and untreatable bacterial infections. And this is also the reason for the global tendency to reduce the use of AGP.

What happens when we eliminate the AGPs?

The sudden halting of AGP use necessarily has implications in animal farming: intestinal inflammation and dysmicrobisms occur, with systemic infections (frequently difficult to treat), lower growth, and worse performance. AGP cannot be only eliminated, they must be replaced and the zootechnical practice ad biosecurity measures must be revised: prevention is the keyword. The most important and simple measures to put in action are: 1) restricted permission to enter the farm only to a few, necessary, people/vehicles; 2) shoes disinfection before the entrance; 3) clothes dedicated to a single farm; 4) accurate cleaning and disinfection of all the environment and rearing tools between two rearing cycles; 5) an adequate period of time without any animal in the pens after this disinfection and before the introduction of the new animals. Furthermore, prevention includes, of course, vaccinations against the most important pathologies, that vary depending on the geographical region.

We can also give a plus to animals

AGP have many positive effects for the host: something similar is needed to replace them. In this case, nutrition and feed additives are the most important tools. At the intestinal level is important to modulate microflora, reducing pathogens. The antimicrobial activity of organic acids is well known: they passively enter pathogenic bacterial cells and have both bacteriostatic and bactericidal activity. Other useful antimicrobial agents are nature identical compounds: these molecules form pores in the bacterial cell wall with strong bactericidal activity. Organic acids and nature identical compounds are good antimicrobial agents alone, but they are more powerful when in combination: pores formed by nature identical compounds favor the entrance of organic acids into pathogens, enhancing their activity. At the same time, these molecules in combination have also an anti-inflammatory effect on the intestinal epithelium, improving its barrier function, reducing the passage of toxins and bacterial cells, and lowering inflammatory cytokines production. So this combination of molecules has all the positive effects of AGP, without being antibiotics. The only problem is that organic acids and nature identical compounds are degraded within the first tract of the small intestine, so they cannot exploit their activity where it is most needed.

AviPlus®P is the solution to this problem: the synergistic combination of sorbic and citric acid and nature identical compounds as thymol and vanillin is ensured by the microencapsulation technology. First of all, it prevents the quick degradation of the active ingredients and brings them to the intestine. At the same time, it allows the slow release of organic acids and nature identical compounds along the whole intestine, due to the species-specific granulometry of the product. When other zootechnical and veterinary preventive measures are there and the diet is correctly balanced, but higher life performance is requested, AviPlus®P can give the needed boost to reach the goal even without AGP.For more information: