A plant cocktail may replace antibiotics, zink and copper in pig production

A mixture of antibacterial plants may be able to replace antibiotics, zinc and copper for pigs with diarrhoea, according to scientists at Aarhus University.

A mixture of, for example, wild garlic, horseradish, cranberries and other plants that have a documented effect on bacteria may in the future become the recommended remedy for treatment or prevention of diarrhoea in young piglets in organic productions. This is the theory of a group of scientists from Aarhus University who have just received 2m Danish kroner from the Green Development and Demonstration Programme for the research project MAFFRA.

The MAFFRA project will investigate the possibility of developing new multi-component, plant-based remedies against stomach and intestinal problems in weaning piglets, and there is reason to believe that it will be successful, according to Senior Researcher Martin Jensen who is the project leader.

- In earlier research projects we have found a number of plant species that have an antibacterial effect on the pathogens in question and we will use this knowledge in the new project, says Martin Jensen.

Plants replace antibiotics

Gastrointestinal infections in pigs – which the plant remedies are intended to prevent or cure – are a serious problem both in organic and conventional herds. The infections affect animal welfare, increase mortality and result in large consumptions of antibiotics, zinc and copper for treatment and prevention.

A high consumption of antibiotics can cause problems with the development of resistant pathogens that are dangerous to humans. Danish pigs consume 91 tonnes of antibiotics per year (2013) and one of the negative consequences is a rise in the incidence of resistant bacteria.

Although the organic pig production in Denmark is quite small and subject to tougher regulations than the conventional one, antibiotics may also be used in organic production, and likewise zinc and copper to prevent diarrhoea in young pigs. Excess heavy metals end up in the slurry and subsequently in the fields where they accumulate and pose a growing problem for the environment.

Martin Jensen therefore expects that there will be significant interest in the MAFFRA results.

- We expect that organic farmers, at whom the project is primarily directed, will have a very positive attitude towards a plant-based solution for diarrhoea. But if we succeed in developing a product with a good and well-documented effect, I also believe that it will be equally interesting for conventional pig farmers, he says.

Wild garlic and horseradish

Martin Jensen has worked with antibacterial substances from plants in previous research, including the BERRYMEAT project. This project studied the preservation of meat products using antibacterial plants instead of nitrite. The antibacterial substances found in the plants include phenols, essential oils, acids, isothiocyanate and allicin.

In BERRYMEAT the researchers found a number of plant species that were particularly interesting because of their anti-bacterial properties. These include wild garlic, horseradish, cranberries, red currants, summer savory and sage. These were shown to inhibit E. coli, Salmonella and Listeria bacteria, which is why the work was continued in the MAFFRA project. In an earlier EU project the project partners likewise identified a number of antibacterial plant species that inhibit  Campylobacter or Clostridium, and these will also be included in the project.

- We will test them in various mixtures and concentrations, and we expect to end up with three different combinations that we will continue our work on, he says.

Positive cocktail effect  

By mixing selected plant species with differing antibacterial mechanisms, the researchers expect to achieve an antibacterial cocktail effect that will make it more difficult for the bacteria to develop resistance.

- The cocktail effect is the synergy of effects that means we can use lower concentrations of individual plant species and thus avoid that the taste becomes too strong. Humans and pigs are not, in fact, terribly keen on high concentrations of, for example, wild garlic and horseradish, explains Martin Jensen.

The selected mixtures will be tested in the laboratory in a pig stomach-gut model that mimics the environment in the gut in order to examine the ability of the mixtures to inhibit the pathogenic intestinal bacteria. The aim is not necessarily to kill the bacteria, but to achieve a healthy balance in the gut flora. If the results are positive, Aarhus University will attempt to get funding for a larger follow-on project that also includes feeding experiments with live pigs.

Further information

The MAFFRA project is part of the Organic RDD 2.2 programme, which is coordinated by ICROFS (International Centre for Research in Organic Food systems). It is funded by the Green Development and Demonstration Programme under the Ministry of Environment and Food.

Senior Researcher Martin Jensen
Department of Food Science
Mail: martin.jensen@food.au.dk 
Telephone: +45 8715 8331
Mobile: +45 4059 4286