Due to the buildup of antibiotic resistant bacteria, the increasing incidence of multi resistant bacterial infections, and the decreasing efficacy of existing antibiotics, the use of antibiotics in livestock animal feed has been questioned. This has led to the search to find alternative methods, or rather additives to match the improvement in animal health and performance which resulted from feeding antibiotic growth promoters (AGP’S) to livestock animals.
Antibiotics were first discovered by Alexander Fleming in 1928 and once its biochemistry and efficacy was proven by Ernst Chain and Howard Florey, together they released “penicillin” as a medicine to the world. This resulted in a population growth with human life expectancy jumping by 8 years in less than three decades. With this, came the demand for more food, more protein. Certain foods were in short supply and the government turned to scientist to help. In the 1950’s scientists discovered that feeding production animals low doses of antibiotics resulted in healthier livestock, which grew faster and lived longer. This provided the population with more milk, eggs and meat at a lower cost. However, Fleming did warn that if the dose is too small, the microbes would not be killed and resist the antibiotics.
From the 1970’s onwards there was an increase in the concern of antibiotic resistance bacteria. Sweden and Denmark were the first to make voluntary bans on AGP’S in the 1980’s – 1990’s respectively, in an attempt to decrease the build up antibiotic resistant bacteria in human health perceived to be related to antibiotic use in livestock animal feed. By 2006 the EU had decided to ban all nontherapeutic antibiotic use in livestock animals, and by 2013 there were regulations in place for AGP’S in 46 countries around the world.
A large percentage of administered antibiotics pass through the animal and into the environment. It is estimated that up to 90% of an antibiotic dose can be excreted in the urine and 75% in their faeces. The FDA estimated that 80% of antibiotics produced in the US are used in livestock. Due to this large quantity of antibiotics being used in the animal production industry and what we know is excreted by the animal, as well as the increase in antibiotic resistant bacteria and its possible link to antibiotic resistant disease in humans – it is evident that the role agriculture plays in the antibiotic resistance cycle needs to be reduced or eliminated.
The threat of antimicrobial resistant disease is a relevant concern, with the World Health Organization warning that antibiotic resistance could cause more deaths than cancer in the years to come. An estimated 23 000 people in the Unites States, 38 000 people in Thailand and 25 000 people in the European Union, die each year as a result of antibiotic resistant disease (CDC, ECDC). In a review on Antimicrobial resistance done in 2014 it was estimated that the global impact of antimicrobial resistance by 2050 will result in a mortality of 9 million people in Africa and Asia alone (Figure 1).
In a nutrition and feed survey conducted by Jackie Roembke (editor of Feed Management and Feed International), it was clear that the poultry industry is taking a proactive approach to moving production towards being antibiotic free. Of the 286 respondents, 17% reported a production system running at 100% antibiotic free, while a further 26% reported running at 50% or more of the production system antibiotic free (Table 1). Collectively this gave an impressive 43% of the respondents across the world running at 50% or more of their poultry production