Are there alternatives to antibiotics in husbandry?
The first steps towards reducing antibiotic use in husbandry are improving hygiene and making changes to animal housing and other husbandry practices (WHO, 2017). Otherwise, there are a number of alternatives to antibiotics; these include vaccines, prebiotics, pro-biotics, in-feed enzymes, antimicrobial peptides, bacteriophages, heavy metals, and more. All of these alternatives have different levels of efficacy and target growth promotion and/or disease prevention and/or disease treatment (PEW, 2017).
Vaccines are the most prominent and widely used alternative to antibiotics as they pre-emptively introduce either an attenuated or killed version of the bacteria to the animal. In turn, the animal develops resistance and will be able to prevent later infection by itself (Frontiers in Microbiology, 2014).
Bacteriophages are viruses that act as parasites to bacteria by infiltrating them and then replicating once inside; in time, this kills the bacteria. This method has a number of advantages; for instance, it is highly specific to particular bacteria and will not harm helpful local bacteria in animals. Additionally it replicates inside the target bacteria meaning the injected dose is low (Frontiers in Microbiology, 2014).
Another alternative includes improving the immune system of the animal to encourage a more effective response against bacterial infection. This can also be used in conjunction with antibiotics to increase the treatment’s efficacy. At the moment, only a few bacteriophages are allowed on the market and only as post-slaughter decontaminants. One example is a phage that kills Listeria in food post-slaughter (Frontiers in Microbiology, 2014).