Potential antiviral properties of alpha-monolaurin

Nutritionists are increasingly including MCFAs in their feed formulations. MCFAs are smaller than long-chain fatty acids and therefore can permeate cell membranes more easily and don’t require special enzymes to utilise them. They are easily digested because they naturally put less strain on digestive systems, which makes them a good energy source in animal nutrition.

Inhibitory effects on the pathogenic pressure in the gut

An additional feature of MCFAs is that they have inhibitory effects on the pathogenic pressure in the gut. Yet as far back as 1972, Jon J Kabara, a professor emeritus of Michigan State University in East Lansing, USA, discovered that monoglycerides are more active against pathogens than their free fatty acids. Additional research on medium-chain 1-monoglycerides (especially monolaurin, a monoester formed from lauric acid) revealed that these molecules possess antibacterial and anti-viral properties. Medium-chain 1-monoglycerides primarily inhibit gram-positive pathogenic bacteria. In addition, alpha-monolaurin seems to be able to deactivate fat-enveloped viruses by breaking down their outer cell wall.

As a result of the unique mode of action, medium-chain 1-monoglycerides are active in the entire gastrointestinal tract and blood stream. A special feature is the fact that pathogens do not develop resistance against 1-monoglycerides and they are therefore a promising tool to add to the effort to reduce the use of antibiotics in the poultry industry.

Alpha-monolaurin

Based on the above-mentioned features of medium-chain 1-monoglycerides, a feed additive has been developed by FRAmelco to effectively inhibit the pathogenic pressure exerted by pathogenic gram-positive bacteria (e.g. Streptococcus sp.) and fat-enveloped viruses (e.g. Marek, Newcastle disease (ND), infectious bronchitis (IB), avian influenza (AI)). The main ingredient of this additive is alpha-monolaurin, which is a fat-like, heat-stable molecule (up to 160°C) produced by the esterification of lauric acid and glycerol. Due to the chemical characteristics of alpha-monolaurin, the molecule is pH independent and will not dissociate in the intestinal tract (pH around 6-6.5). The product is non-corrosive and has no negative effect on smell and taste.

Based on literature, it was expected that the active ingredients of the additive would be partially transported to the systemic circulation via the intestinal lymphatic transport system. Research findings support the assumed systemic mode of action. Alpha-monolaurin is not being transported via the hepatic portal vein to the liver, but rather enters the blood stream via the lymphatic system and bloodstream without losing its characteristics. Hence, alpha-monolaurin is able to use its antibacterial and antiviral properties to good effect before it is broken down by the liver.

Antibacterial properties

During their lives, animals are often subjected to stress factors that result from stocking density, climate conditions, the type of housing or changes in feed formulation or ingredients.
This makes them highly susceptible to infectious diseases and (metabolic) disorders caused by gram-positive pathogenic bacteria, such as Streptococci or Staphylococci, and viral infections, such as IB or ND. These infections may lead to decreased reproduction and growth performance, high mortality rates and lower profitability.

To prevent losses, antibiotics and vaccination programmes are used that, due to economic and/or practical disadvantages, do not target all bacteria and viruses. By feeding poultry the additive, whose main ingredient is alpha-monolaurin, health and production performance can be stimulated.

Trials conducted at broiler farms known to have problems with the Runting Stunting Syndrome showed that supplementation using additive FRA® C12 dry at a high dose level (5kg/tonne of feed) during the starter period and 3 kg/tonne in the grower feed improved the final weight and FCR. (see Table 1)

Dr Moh Chee Jin, working for Pahang Pharmacy Ltd in Malaysia, used the additive dry at broiler farms suffering from very virulent Newcastle Disease. The result was that mortality dropped from 10% to 8% and the birds looked healthier than before. At layer farms, Dr Moh experienced that alpha-monolaurin suppressed clinical signs and mortality caused by Marek’s Disease, as well as secondary infections such as Necrotic Enteritis. In addition, the performance figures went back to normal.

Controlling AI

Positive results were also obtained in Taiwan, where many poultry farms suffered from an outbreak of high pathogenic avian influenza earlier this year. Although waterfowl commonly do not suffer from AI, this time the problems were huge. Breeder farms especially suffered from the disease. Because vaccination programmes are not allowed to be implemented in Taiwan, Taiwanese producers had to go for alternatives. An afflicted goose farmer culled his first flock, but the disease reoccurred, which prompted him to include FRA® C12 dry at a low level (1-2 kg/ton of feed) in the diet from day 1 for 70 days. At the end of the trial, there was no sign of AI left in the flock.

Results from trials conducted with layers, in which a high dose of the additive (3kg/tonne of feed) was given for a short period (0-35 days), were less pronounced, though the infection rate was reduced slightly. It can therefore be assumed that continuous feeding of the additive would be better than feeding it for a short period. A case study at a broiler breeder farm supports this. After an outbreak of AI, the new flock received 2kg FRA® C12 dry/ton of feed until it reached peak production, at which time the amount was reduced to 1.5 kg of the additive dry/tonne. The result was a peak production of 82%, which was higher than the peak before the AI outbreak. These results indicate that FRA® C12 dry is potent enough to have antiviral properties and therefore benefits the health and performance of the animals.