Inhibition of African swine fever virus in liquid and feed by medium-chain fatty acids and glycerol monolaurate

Abstract

Background The ongoing African swine fever virus (ASFv) epidemic has had a major impact on pig production globally and biosecurity efforts to curb ASFv infectivity and transmission are a high priority. It has been recently identified that feed and feed ingredients, along with drinking water, can serve as transmission vehicles and might facilitate transboundary spread of ASFv. Thus, it is important to test the antiviral activity of regulatory compatible, antiviral feed additives that might inhibit ASFv infectivity in feed. One promising group of feed additive candidates includes medium-chain fatty acids (MCFA) and monoglyceride derivatives, which are known to disrupt the lipid membrane surrounding certain enveloped viruses and bacteria. Results The antiviral activities of selected MCFA, namely caprylic, capric, and lauric acids, and a related monoglyceride, glycerol monolaurate (GML), to inhibit ASFv in liquid and feed conditions were investigated and suitable compounds and inclusion rates were identified that might be useful for mitigating ASFv in feed environments. Antiviral assays showed that all tested MCFA and GML inhibit ASFv. GML was more potent than MCFA because it worked at a lower concentration and inhibited ASFv due to direct virucidal activity along with one or more other antiviral mechanisms. Dose-dependent feed experiments further showed that sufficiently high GML doses can significantly reduce ASFv infectivity in feed in a linear manner in periods as short as 30 min, as determined by infectious viral titer measurements. Enzyme-linked immunosorbent assay (ELISA) experiments revealed that GML treatment also hinders antibody recognition of the membrane-associated ASFv p72 structural protein, which likely relates to protein conformational changes arising from viral membrane disruption. Conclusion Together, the findings in this study indicate that MCFA and GML inhibit ASFv in liquid conditions and that GML is also able to reduce ASFv infectivity in feed, which may help to curb disease transmission.

Glycerol Monolaurate Ameliorated Intestinal Barrier and Immunity in Broilers by Regulating Intestinal Inflammation, Antioxidant Balance, and Intestinal Microbiota

“…Medium-chain fatty acids (MCFA) have received widespread attention as feed additives, showing positive benefits and improving animal health, production, and feed digestibility ( 21 , 22 ). Current evidence supports that MCFA and monoglycerides are generally effective in supporting growth performance and intestinal health ( 23 ).…”

Flavonoid Library Screening Reveals Kaempferol as a Potential Antiviral Agent Against African Swine Fever Virus

“…However, these compounds have little chance to become commercially successful anti-ASFV drugs as most of them are expensive or unsafe. Therefore, we have focused our attention on the anti-ASFV activity of natural compounds because they are less toxic, cheaper, and can be used, for example, as feed additives in pig nutrition (Jackman et al, 2020). Previously, we have demonstrated the antiviral properties of several flavonoids against ASFV in vitro (Hakobyan et al, 2016(Hakobyan et al, , 2019Arabyan et al, 2018), thereby justifying our efforts to screen more flavonoids.…”

Lipid Nanoparticle Technology for Delivering Biologically Active Fatty Acids and Monoglycerides

“…Interestingly, however, such studies have only been conducted with free compounds and future efforts should be expanded to tracking the interactions of lipid nanoparticles with SLB platforms and membrane models. The need for such studies is further enhanced by emerging applications, e.g., antiviral mitigation in feed and drinking water [ 108 , 109 ], that would benefit from dilution-stable formulations of biologically active fatty acids, monoglycerides, and combinations thereof.…”