1 Alternatives to antibiotics in animal agriculture
Antibiotics (as well as anti-parasiticides, GMOs, and hormones) are prohibited on organic livestock operations and may or may not be used on operations that consider themselves alternative. The debate on the use of antibiotics in livestock is a complicated mix of concerns related to food safety (e.g., appropriate use to prevent antibiotic residues and pathogens in food), food security (i.e., ensuring enough food for a growing population), and the growing global threat of antimicrobial resistance.
General considerations when using alternatives to antibiotics
Using alternative treatments is not just swapping out a natural product for an antibiotic or pesticide. Below are some important considerations when using alternative products. Alternatives to antibiotics are promising, especially ones that prevent infection while enhancing productivity. This is something that appeals to livestock producers. Many alternative products are already available or under development.
These alternative products act in three general ways, often overlapping and difficult to tease out. They can:
- Improve performance (e.g., growth rates, egg production, etc.)
- Prevent infection (sometimes simultaneously with growth promotion), and
- Act as treatments (Pew Trust 2017).
More on-farm research is urgently needed to test use and efficacy while gathering data on cost-effectiveness and potential side effects. Outcomes and lessons learned must be shared through extension and veterinarians for alternatives already being used successfully. The mechanisms of action for many alternative products are not well known. In the past, natural substances significantly contributed to developing treatments for cancer and infectious diseases. New technologies are revitalizing the investigation of these medications, especially for antimicrobial resistance. (Atanasov 2021). It will be important for these studies to collect and report on the same outcomes to make comparisons between studies straightforward.
Explore each of the sections below to learn about how alternatives to antibiotics are different from traditional antibiotics.
Spectrum of action
Alternative products may have a narrower spectrum of action, killing fewer organisms with possibly fewer side effects.
Efficacy against AMR
Alternative products are not usually affected by antimicrobial resistance and may be effective against multidrug-resistant pathogens.
Timing of administration
Alternatives differ in when they are used. Vaccines must be given before exposure; others, like bacteriophages, only work when bacteria are present, so they must be given at the time of infection.
Specific pathogen targeting
Some alternatives target specific pathogens, e.g., bacteriophages and antibacterial peptides.
Mechanisms of action
Prebiotics and probiotics indirectly inhibit pathogens by favoring beneficial bacteria resulting in the pathogens being outcompeted. Vaccines and immune modulators have different strategies by priming the animal’s immune system to better control the infection.
Compatibility between products
Compatibility between alternative products is an important consideration. For example, probiotics modulate the immune system and enhance the efficacy of certain vaccines. On the other hand, probiotics can also compete with bacterial vaccine strains and be antagonistic to them.
Some alternatives to antibiotics are being successfully used in commercial food animal production in the beef, dairy, and poultry industries. Data from the 2011 USDA NAHMS study shows that probiotics were used on up to 30 percent of US feedlots to increase production efficacy. Probiotics are also used more on dairy farms to prevent disease in cows and calves. Probiotics are also used in poultry to enhance performance and reduce the need for antibiotics (Hume, 2011).
