MCFA’s and fight against antimicrobial resistance

MCFA's and fight against antimicrobial resistance. Photo: Ronald Hissink
MCFA's and fight against antimicrobial resistance. Photo: Ronald Hissink

There is a global concern and even demand to reduce the antibiotic use in poultry and in this way reduce the risk for antimicrobial resistance. Medium chain fatty acids (MCFA’s) make it possible to reduce the use of antibiotics without compromising bird performance and food safety.

Antimicrobial resistance is a global problem. New resistance mechanisms emerge and spread globally threatening our ability to treat common infectious diseases, resulting in death and disability of individuals who until recently could continue a normal course of life. With the increasing resistance, many standard medical treatments will fail. Antimicrobial resistance also increases health care costs because of more expensive therapies, in case first-line antibiotics don’t work.

Infections caused by resistant microorganisms often even fail to respond to the standard treatment, and can result in death. According to the ‘Review on Antimicrobial Resistance’, published in 2014, 700,000 people per year die from antimicrobial resistance nowadays. If the global feed industry would continue the current usage of antibiotics, it is estimated that the number of deaths could increase to 10 million per year by 2050. In that case, antimicrobial resistance would be the leading cause of death in the world (Figure 1).

Figure 1 – Prediction of antimicrobial resistance deaths in 2050 compared to other causes of death.

Antimicrobial growth promotion

Antibiotic use in animal production has been practiced for about 50 years. Most of this use of antibiotics is as antibiotic growth promoters (AGP’s). AGP’s are the antibiotics that are continuously used in poultry feed at a low level to improve growth and feed conversion and not for the purpose of any therapeutic reasons. One of the major current benefits of AGP use may be maintaining animal health in older facilities, where hygiene management is less efficient. Farms that produce broilers with AGP’s tend to have older houses, with less modern equipment, and are less likely to follow a plan for managing food safety hazards. AGP’s may have smaller benefits when production conditions are optimised: researchers demonstrated significantly smaller response in chicks to AGP’s in new environments compared to previously used environments.

Controlling AGP’s in poultry production

An EU-wide ban on the use of antibiotics as growth promoters in animal feed was entered into effect on January 1st, 2006. The ban was the final step in the phasing out of antibiotics used for non-medicinal purposes. In Europe, people had to take action to accomplish the challenge: building new adapted poultry houses with sufficient climate control, proper hygiene and biosecurity at the farm, and also nutrition and additives are adapted. In the US, AGP’s are not banned, but the FDA recently issued guidelines for the industry to voluntarily withdraw medically important antibiotics from growth promotion. For policy makers, the challenge is to evaluate the benefits and costs of animal antibiotics to society. What is the economic value of antibiotics to the livestock industry versus the potential health cost of increasing resistance levels? What are the potential productivity and economic effects of a ban on AGP’s for US meat producers and consumers? All these questions should be solved first, but nonetheless a ban on AGP’s is expected in the US in 2017.

Medium chain fatty acids as antibiotic alternative

Medium chain fatty acids (MCFA’s) have been used for many years as an alternative to antibiotics in poultry nutrition. Thanks to its broad antimicrobial and immune supporting activity, Aromabiotic Poultry has become one of the leading feed additives to reduce the use of preventive and growth promoting antibiotics.

In the low pH environment of the stomach, undissociated MCFA molecules are capable of penetrating the phospholipid bilayer of the bacterial cell membrane, thereby destabilising it. Inside the bacterial cell, MCFA’s encounter a near-neutral environment resulting in accumulation of dissociated MCFA molecules and protons in the bacterial cytoplasm. Intracellular acidification will eventually lead to the killing of the bacterium. Aromabiotic MCFA’s not only show lower minimal inhibitory concentrations when compared to SCFA and LCFA, the free MCFA provide an early pathogen barrier already in the stomach of the animal, compared to MCFA esters and fat coated butyrates which only release their active components in the intestinal tract by gut lipases. The combination of these antibacterial actions will result in a beneficial microbial ecosystem and thus a higher villus/crypt ratio favouring the digestive and absorptive capacities of the intestines.

MCFA’s positive effect of a chicken’s immunity

In addition to the antimicrobial effect, MCFA also have a positive effect on the animal’s immunity. The first line of defence against the pathogens are the neutrophils. These white blood cells will attack the pathogens and protect the animals from getting ill. In times of stress the white blood cells will suffer, and have a very short lifetime. By adding MCFA’s to the feed, research showed that MCFA could prolong the lifetime of the white blood cells which means that the blood will contain more viable white blood cells and consequently the animals will be better protected.

MCFA’s preformed well in Clostridium challenge

A recent trial confirmed again that MCFA’s are the perfect alternative of AGP’s. In a challenge trial, 900 ‘Cobb 500’ birds (10 repetitions over 3 treatments, 30 birds per cage) were challenged with Clostridium perfringens. It is clear that the trial set up was successful since the performance of the birds is low and the mortality of the negative control group is around 9%. That means that there was a clear induction of the Clostridium in the birds. In a second and third treatment the effect of respectively AGP and MCFA was tested. Both treatments significantly restored body weight and feed conversion. Mortality was reduced below 4% with AGP and even below 3% using MCFA. The resulting European production efficiency factor (EPEF) of the birds who received Aromabiotic MCFA’s was exactly the same as the EPEF of the birds who received the AGP programme. Next to the zootechnical performances also the lesion scores were measured at day 21. Again a comparable and significantly lower lesion score was obtained with both AGP and MCFA (Table 1). With MCFA’s poultry performances can be improved, while the risk for antimicrobial resistance can be reduced.

Author: Manu De Laet

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