Young Scholar Presentation: A Review of Medium Chain Fatty Acids and Their Recent Role in Feed Safety

Medium chain fatty acids (MCFA), have been researched extensively to reduce the likelihood of animal feed being contaminated by biological pathogens, including bacteria and viruses. Medium chain fatty acids have shown to be bactericidal and bacteriostatic by incorporating themselves into the lipid membrane of bacteria, which alters the cell membrane permeability leading to cell death. However, the effectiveness can be dependent upon the MCFA chain length and species of bacteria. Most research completed prior to 2013 focused on the antimicrobial properties of MCFA. However, with the emergence of Porcine Epidemic Diarrhea Virus (PEDV), MCFA began to gain more attention for their potential uses in feed safety and swine nutrition as a potential antiviral additive. Medium chain fatty acids have shown repeated success against PEDV in vivo and in vitro. Notably, 2% MCFA [1:1:1 blend of caproic, caprylic, and capric] was equally successful at mitigating PEDV as commercially-available formaldehyde products in complete swine feed (P>0.05). However, the effectiveness varies within feed matrix, as MCFA was not as effective as formaldehyde at mitigation in spray dried animal plasma and meat and bone meal (P<0.05). A lower concentration of the MCFA blend (1%), as well as the individual addition of 0.66% caproic, 0.66% caprylic, or 0.66% capric acids also enhanced the RNA degradation of PEDV in complete swine feed (P<0.05). Other research has evaluated the same 2% MCFA blend in a transboundary based study, replicating the time and environmental condition that feed ingredients undertake during a trip from China to the United States. Again, the MCFA treated ingredients were deemed to be negative throughout the simulated transboundary trip (P<0.05). Medium chain fatty acids have also been evaluated as a surface decontaminate and as a potential feed mill flush step. However, the overall effectiveness was not as substantial as the results observed in the feed ingredient studies. Currently, it is not known what the exact mode of action of the MCFA is against PEDV, but it is hypothesize that the MCFA are interacting with the lipid bilayer envelope of the virus and altering the envelope in a way in which it cannot bind with the host receptors. This mode of action would be similar to that of the bacteria as both outer membranes consist of a lipid bilayer. Future research is now focused on the use of MCFA against other enveloped and non-enveloped swine viruses as well as an antibiotic alternative in swine production.