There is no additive, not of a medicinal nature, that can replace the role of antibiotics for therapeutic purposes. Sick animals requiring antibiotic treatment under veterinarian care should receive appropriate antibiotics at proper dosages to ensure their health and welfare. What happens to such animals raised under no-antibiotics-ever production is a matter that has to do with the marketing/commercial aspects of such business.
What concerns us here is the preventive and growth-promoting action of certain non-medicinal feed additives that can be used to deter bacterial outbreaks, or at least help toward this direction, and those that can increase overall animal immune status. These are additives that can replace the growth-promoting effects of low dosages of in-feed antibiotics as used in the past and are now being banned worldwide with an increasing pace.
Although this is not a new field of research, and antibiotic-free feeds for healthy animals are already the norm in several regions worldwide, there is an increasing pressure to further decrease even therapeutic use of antibiotics and discontinue their growth-promoting use in even more regions. As such, research is often repeated under several excuses or reasons, some of which are valid, whereas others have to do with politics, commercialism, marketing and even survival of traditional research institutions. Regardless of one’s position toward such modern pressures unrelated to animal or even human health and welfare, we have to cope with what we are asked for and find a way to remove those antibiotics denied to us and our animals for any reason.
The following list of in-feed products/additives is not exhaustive. Each nutritionist may have a different opinion or list, and such is the privilege of having a university degree, especially a Ph.D. degree. Those who make their living from such or similar products naturally emphasize the importance of their products, but as it will be shown, no single additive can replace antibiotics entirely and effectively. Thus, most nutritionists agree that a mix of products is required. And, not only that, but feed formulation and farm biosecurity changes also are needed to make this something more than an another failed attempt to catch up with modern times.
1. Organic acids
There is a plethora of organic acids that have been proven effective against a host of microorganisms, especially against bacteria, the targets of antibiotics. Here, we will distinguish coccidiostatic products from traditional antibiotics and refer to antibiotics only as non-coccidiostatics. The main reason organic acids are not used as much as they should be is because they are commodities and as such they do not present a fertile ground for extensive marketing and differentiation. As such, their inclusion level is always below required levels and this gives the impression that such acids are ineffective. When used at the right amounts and at the right profile, they can become very powerful tools against most bacteria. It should be noted that most nutritionists agree that we require more than one organic acid per feed, and some even have evidence of the need for a different profile depending on basic feed formulation. Inorganic acids also work well, but these require a slightly different approach, and they remain largely ignored, to the benefit of those who know how to use them. At any rate, the research on organic acids replacing antibiotics goes back several decades and it is rather surprising to see new research repeating basic treatment protocols where research should be directed toward other areas of organic acid nutrition.
2. Phytogenic compounds
Today, there are myriad such products, most of them as effective as nothing. The few select products that work do so under the right circumstances and dosage. Here, we have the problem that we cannot exceed certain dosage levels or animals will refuse eating. As such, we are restricted to low dosages that are often inadequate. To this end, combining the right blend of photogenic compounds with certain organic acids has been shown to confer a synergetic effect, meaning their combination is working very effectively – and this is backed up with sufficient commercial experience throughout the past decade. Lamentably, the market abounds with non-effective proprietary blends of photogenic compounds that target the low-cost-minded feed producer, especially those who market feeds and nutritional supplements instead of raising their own animals. For this category of products, even institutional research can often be inadequate for several reasons and, thus, the best advice is to test promising products at own facilities under commercial conditions.
3. Zinc and copper
Besides their basic nutritional role, these minerals have been used also as gut health additives for many decades, first copper and then zinc. Certain products containing zinc or copper have been shown to replicate the end effects of in-feed antibiotics with relative success. The mode of action remains obscure and rather complicated. Today, there is a great number of products, as is to be expected. Some are organic forms, others inorganic; even within these two major categories there are several distinct or similar products. The point is that the original research was based on copper sulphate and zinc oxide as sources of pharmacological levels of these two minerals. The success of other forms/products has been from negative to almost successful. The real problem is not finding which product works, but that governments have started banning their use altogether, for reasons that have to do with soil quality preservation, as the excesses being fed are spread as manure into crop fields. Thus, even this effective tool is being removed from our arsenal of powerful antibiotic replacements. The fact that such products have had little lobbying support at major decision centers did not help reaching a reasonable conclusion on how to protect soil fertility without decreasing animal health.
4. Fiber
Fiber is a word that includes so many and such diverse compounds that is rather confusing, but it is the word that we are left from the early years of nutritional research and we keep using it no matter how much we advocate its redefinition. Adding extra fiber in diets that previously benefited from low-dosage levels of antibiotics appears to help animals establish a better gut microbiota that copes better with pathogenic organisms. The amount and profile of fiber to be used depends on species, other additives and a host of other variables. What most authorities agree is that more fiber is needed when antibiotics are not needed, and here stops any consensus in fiber nutrition. Nevertheless, it is still a new field of research for pigs and poultry and, apart from breaking away from traditional thinking, the very same complex nature of fiber makes research even more difficult. But, if ruminant nutritionists who feed microbes before they feed the animals have managed to understand fiber, then with a simpler animal as a monogastric, one might expect research to be quicker and more conclusive.
Lack of coordinated and trustworthy research
If the above appears generic and of little practical use is an intentional effort to demonstrate the lack of coordinated and trustworthy research as opposed to the plethora of available products, and the difficulty in using such products that require farm-specific application as opposed to the blanket application of old-fashioned antibiotics. Of course, this list is but a fragment of what is commercially available. But it is not difficult to realize the difficulties faced with all other products when one is already in half-dark with such well-established products.
