ISSUE FOCUS FEED & ADDITIVE MAGAZINE March 2026 37 measures against viral pathogens in the feed must be implemented – and they must follow local regulations that increasingly prohibit the use of chemical mitigants that can put operators at risk from feed mills to barns. MEDIUM CHAIN FATTY ACIDS (MCFAs) – A NATURAL SOLUTION AGAINST VIRUSASSOCIATED RISKS Medium Chain Fatty Acids (MCFAs) are molecules available naturally – for instance, in coconut oil. These molecules are used today in food, nutraceutical, and pharmaceutical industries for their proven action against various types of pathogenic microorganisms. Because MCFAs damage the phospholipid bilayers of potential pathogens, we recently developed a blend of free MCFAs (FeedLock; Royal Agrifirm Group, The Netherlands) that is specifically optimized in vitro against enveloped viruses (Tran et al. 2021). Furthermore, we investigated the impact of this blend using the “ice-block challenge” model described by Dee et al., 2021, a model that mimics the natural contamination of animals with multiple viruses. In brief, the experimental set-up involved preparing 1-lb ice blocks (–80 °C) inoculated with several viruses: PRRSv, PEDv, and SVAv (Seneca virus, the only non-enveloped virus included in the study) at a concentration of 10⁵ TCID₅₀/mL × 100 mL each. These blocks were placed in feed bins at the start of the study and again after 6 days, allowing the progressive release of viruses into the feed as it was consumed by the animals. A total of 12 pens, each housing 7 to 8 weaned pigs, were used. Half of the pens received the contaminated diet alone (Control), while the other half was fed the same diet supplemented with FeedLock MCFA (Royal Agrifirm Group, NL). Clinical scores were recorded: dyspnea, weight loss, and rough hair coat for PRRSv; diarrhea for PEDv; and lameness for SVAv; along with post-mortem sampling of relevant biological compartments (e.g., serum for PRRSv, rectal swabs for PEDv, and tonsils for SVAv). In addition, in order to assess the link between feed contamination and oral exposure, viral RNA was detected using dedicated PCR procedures in feeders and in chewing ropes available to the pigs in the different pens. Supplementing the contaminated feed with FeedLock was associated with the absence of morbidity Picture 1. Example of possible contamination via birds of raw materials that are dried in open air after harvesting. Birds can be seen as fomites transmitting virus via feed/beak from dead corpses in the wild to raw materials in the field.
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