7 questions about antibiotics in animal feed

7 questions you wanted to know about antibiotics in animal feed:

7 questions you wanted to know about antibiotics in animal feed
7 questions you wanted to know about antibiotics in animal feed

Question 1: Why are antibiotics in animal feed in the first place?

Antibiotics have been good for the world. They have been instrumental in allowing humanity to enjoy a standard and quality of life unimagined prior to their discovery. Initially, antibiotics allowed us to control life altering and fatal diseases in humans.

Secondarily, they have facilitated the development of a modern, safe and efficient agricultural system which produces food economically, affordably and plentifully to the most of the 7 billion people on the planet. 

When farmers began putting antibiotics in the feed of animals in the 1950s they did so initially because it resulted in lower mortalities but quickly they also noted their animals grew faster, requiring less feed. Veterinarians later observed better intestinal health and less inflammation during autopsies and surmised that the improved animal performance was most likely due to the more efficient absorption of nutrients in the intestine of those animals.

Question 2: Where does resistance come from?

The simple definition of resistance is “the ability of microbes to resist the effect of antibiotic drugs” and the mechanisms by which bacteria become resistant and pass on that resistance to other bacteria are relatively well known. Bacteria adapt very quickly to the environment, so when antibiotics are used continuously, the bacteria they are meant to kill can adapt, survive and replicate making it extremely difficult to kill the remaining bacteria. Resistance can develop through selective pressure (that is, when antibiotics kill some but not all of a bacterial group); mutation and gene transfer. These three mechanisms can also combine, as when bacteria not only become resistant to antibiotics, but also start to pass that characteristic on to other bacteria present in the gut. 

There are many sources of resistance with examples in humans and animals, including the inappropriate use of drugs or inadequate diagnostics in hospitals or veterinarian situations, the use of antimicrobial soap in bathrooms, the use of zinc oxide or copper sulfate in the diets of animals, and the use of chlorine in water of humans and animals alike. Scientists have demonstrated that these and any substances that create pressure on a microbial population lead to changes similar to the passage of resistance. 

Overall, humans are the main source of resistance, due to the misuse of antibiotics, not using them for the time period recommended by their doctors, or not using the recommended dose. Hospitals and homes for the elderly have become hot spots of resistance, which puts older people, very young people and immune comprised people who are the least capable of fighting off infection without antibiotics at the highest risk.

It is clear that antibiotic use in humans is not uniform. For example, looking at a map of the U.S., antibiotic misuse per 1000 people tends to be concentrated in the eastern part of the country rather than the west, with over-prescription particularly prevalent in the south and mid-west. Recent studies indicate that an average of 506 antibiotic prescriptions are administered per 1000 doctor visits, while experts concluded that just only slightly more than half of these prescriptions were actually necessary or appropriate.

In animals, resistance works the same way, and the passage of resistance from animals to humans can occur through contact with live animals or environmental contamination. (In 2005, the CDDEP found that when antibiotics are fed to animals 90% go through urine and 75% were found in feces; more recently antibiotic resistant bacteria have been found in water systems, waste treatment and in dust carried by air.) It also seems to be possible for resistance to be passed through the consumption of meat, milk and eggs from contaminated animals (for example, a U.S. study found that 53% of grocery chicken contained antibiotic resistant E. coli). 

Farmers are often irritated that activists focus on antibiotics in animal food, when the majority of resistance come from human misuse/overuse/abuse, but the general public finds it easy to agree with Prince Charles (speaking to the Royal Society in London) when he said, “I find it difficult to understand how we can continue to allow most of the antibiotics used in farming, many of which are also used in human medicine, to be administered to healthy animals.”

Q.3 How serious a problem is resistance, really?

Very. In Thailand, doctors have warned about the collapse of the modern medical system due to an increasing number of antibiotic-resistant infections. The Economist estimates that superbugs will kill one person every three seconds, and antibiotic resistant infections will lead to 10 million additional deaths annually by the year 2050. Doctors are warning that it could make routine procedures such as appendectomies or caesarean sections potentially life-threatening decisions. And foremost in everyone’s mind are apocalyptic stories of hospital infections such as vancomycin-resistant E. coli MRSA (multi-resistant), along with a myriad of other resistant pathogens now being found in hospital environments. Antibiotic resistance is now accepted as one of the biggest challenges facing the human race.

The golden era of antibiotics occurred during the 1940s and 1950s when a seemingly endless stream of antibiotics were discovered. Since then the pipeline has slowed dramatically, with only Cephalosporins and Fluoroquinolones added this century. At the same time, antibiotic resistance development has accelerated. The drug of last resort, Colistin, has been critical for treating humans with resistant infections but a recent study in Shanghai found that 15% of bacteria found in pork and chicken were resistant to Colistin. 21% of the pigs in a sample of slaughterhouses tested positive, and when the study looked at human patients who had consumed the same meat, 1% tested positive for Colistin-resistant bacteria. 

The scale of the problem has prompted initiatives such as the Global Antibiotic Resistance Partnership (GARP), and even the Horizon Prize, a €1m prize for developing a rapid test to tell whether or not antibiotics are needed to treat a patient. Both the U.S. president and the UK prime minister have set up commissions to develop national action plans for combating antibiotic resistant bacteria.

Q.4 Can we reverse resistance?

Many governments are actively working to reverse antibiotic resistance in animals. For example, Denmark, has created the DANMAP report, which maps antibiotic use and resistance in the milk, meat and eggs of animals. The Danes have found the levels of resistance dropped since antibiotics were removed from the diets of animals. This decline happened in spite of the use of therapeutic antibiotic drugs (drugs used to treat specific diseases). The Danish government is taking the project to the next level through a new initiative called DANVET, with the intent to reduce the overall amount of antimicrobials on the farm including therapeutics. Adopting a "name and shame" approach, they publish annual lists of the top farms and veterinarians by the number of antibiotics used and prescribed per animal. 

Building on the Danish success, Finland, Norway, Sweden, The Netherlands, Canada and the UK have all put in place similar monitoring programs and a focus on how to reduce overall levels. In January 2017, the U.S. will implement the Veterinarian Feed Directive. The intent of this directive is to stop the wholesale use of antibiotics in feed and to require veterinarian prescriptions for antibiotic use. Notably, the veterinarian must confirm that animal is sick and fill out a specific prescription for that animal. Undoubtedly this will result in a reduction (though not elimination) in the use of antibiotics.

However, there is also evidence that resistance is persistent. In a study undertaken at the University of Kentucky, generations of pigs were not fed antibiotics for 22 years, and yet antibiotic resistance in the pigs hardly changed, demonstrating that once resistant bacteria exists, it is extremely difficult to remove. Moreover, once resistant bacteria are in the general environment they can be found anywhere. For example, studies with wild feral pigs off the coast of South Carolina found antibiotic resistant bacteria in their stomachs, which was attributed to tannins in the nuts and fruits they consumed. Antibiotic resistance has also been found in organic pigs. In both cases, the levels and range of antibiotic resistant bacteria were notably lower than those that occurred in conventionally reared or farmed pigs, but their presence demonstrates how pervasive resistant pathogens are in the larger environment.

 Q.5 So how do we solve the problem?

It is probable that by 2021 there will be a global ban on growth promoting antibiotics in animal nutrition, along with severe restrictions on therapeutics, though the specific rules, and more importantly the enforcement of the rules, are likely to vary from country to country. Restrictions on use in humans will be less rigorous and implemented more slowly, largely because it is so hard to get people to change their behavior. 

New techniques and technologies will emerge to deal with pathogenic bacteria in humans (it is unlikely that manufacturers will go through the costs of getting approval for animal nutrition). These technologies will include the passive identification of infections, strategies to interfere with inter-bacterial communication, quorum-sensing inhibitors to also interfere with bacterial cross-talk and the creation of an inhospitable environment through the use of peptides. Overall the focus will be on favoring antibiotic sensitive populations, such that when drugs are used, they become more effective.

For producers, farmers and integrated food operations, the choices are stark. They can: 

Do nothing

Replace antibiotics with gut health programs

Take a holistic approach and reform their systems root and branch

Consumers may not understand all the subtleties of the situation, but they clearly believe that feeding antibiotics to animals is one of the reasons for antibiotic resistance, and 86% say they want meat without antibiotics (in response, the overall antibiotic-free chicken segment has grown rapidly, and in the US is now worth more than $1billion/per annum). Moreover, there is a new, more active group of consumers these “prosumers” not only take a proactive approach in how they choose products, but they have become product and brand advocates. Their purchases demonstrate their beliefs, ethics, standards and aspirations, and they express those views not just in what they buy in the supermarket, but in what they do online, through blogs and social media.

Governments are also stepping in. A recent study found that 47 countries have either already implemented or are in the process of implementing a ban on the use of antibiotics to promote growth in the diets of animals. The tobacco industry illustrates the perils of ignoring public opinion and trying to tough out government regulators. So, doing nothing does not look like a good plan.

Taking the path of least resistance- simply removing growth performing drugs and waiting to see what happens- also turns out to be a bad plan. Farms who made these changes report that performance does not get worse immediately, but does over time. For example, with chickens, the first three flocks post antibiotic removal perform strongly, but typically from flock four onwards things got steadily worse. Similar trends have been reported in other species. In such scenarios reversing these trends are extremely difficult. Looking for natural replacement (non-antibiotic) products is the logical alternative. 

Q.6 Can natural programs really deliver results as well as antibiotics?

Actually, farmers and producers all over the world and in all species are already embracing farming without antibiotics. Farmers raising broiler chickens, turkeys, pigs, and cattle have demonstrated that they can achieve similar levels of performance without the use of growth promoting antibiotics. This has led to the ‘Never-Ever-3’ concept: never use antibiotics, never use growth promoters and never use animal by-products when feeding animals. When benchmarking systems are used these companies perform at the top of their category even compared to companies who continue to use antibiotics. Examples from the world’s largest beef cattle feedlots, farms who specialize in raising calves, pork suppliers to companies such as Whole Foods, and chicken and egg farmers who put food on plates in food outlets from Chipotle and Panera Bread to Chick-fil-A and McDonalds have all shown that it is possible.

However, what these farmers have shown is that it takes more than just swapping out one product for another: to succeed it is necessary to truly embrace a root and branch, top to bottom holistic approach to farming. Everybody involved in the animal’s health and nutrition (nutritionists, farm management, veterinary and the farm itself) needs to work in tandem. Looking beyond the baseline post-antibiotic metrics (feed efficiency and livability/survival rate) is essential. The farmer needs to consider: 

Is it safe for animals and for humans?

Is it acceptable to the consumer?

Is the mode of action known?

Are responses to inclusion consistent?

Will it survive temperature treating such as pelleting?

Dr. Steve Collett from the University of Georgia developed a program he called “Seed, Feed & Weed.” It is an alternative approach to gut heath that seeds the gut with the right bacteria by introducing the proper microorganisms; feeds the good bacteria to maintain a proper environment for them to survive; and then weeds the unfavorable organisms before they colonize the intestinal tract.

In the same scenario mycotoxins become a critical control point and farmers can help their animals get the right start through nucleotide supplementation. Other concerns can included optimizing nutrient digestibility (undigested nutrients can support the proliferation of pathogens) and controlling protozoal diseases such as coccidiosis through the support of vaccines.

 Q.7 Can we really feed 9 billion people without using antibiotics in animal feed?

Yes, we can feed the world without antibiotics. From an agricultural perspective the main challenge is a change of mind-set. Better management, more use of technology, better use of veterinarian interventions on a more strategic level, and use of technologies to monitor, measure and inform those decisions will allow farmers to grow strong flocks and herds without growth promoting antibiotics. In turn, antibiotics can be reserved for treating animals that are suffering from disease.

Animal nutrition will evolve beyond the goal of just delivering the right nutrients. Farms will use nutrition as a tool to foster the right bacteria on the farm, to create a “probiotic environment.” In this way animals entering the farm for the first time immediately encounter the right bacteria at the right time and in the right way, allowing for optimal intestinal health, improving nutritional uptake, and minimizing disease. In turn this will allow farmers to grow enough food to meeting the needs of the 7 billion people who are on the planet now- and the 9 billion who will be here by 2050.

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