Table 2.
Studies reporting the efficacy of various feed additives in mitigating the risk of porcine viruses in feed.
| Pathogen | Mitigant Composition | Inclusion Rate | Testing Method | Outcome or Effects | Reference |
|---|---|---|---|---|---|
| ASFV | Aqueous formaldehyde and propionic acid, MCFA (C6:C8:C10) | 0.03–1.0% | Cell culture; tested in complete feed and ingredients at mean 12.3 °C temperature in a 30-day transoceanic shipment model | Dose-dependent inactivation; reduced infectivity in feed ingredients; decreased viral DNA quantity in feed a | [94] |
| ASFV | MCFA (C8:C10:C12); GML | 0.25–2.0% | Cell culture; complete feed stored for 30 min or 1 day at room temperature | Decreased virus titers in cell culture by MCFA and GML; dose-dependent antiviral activity by GML; reduced infectivity in complete feed by GML at ≥1.0%; no effect on viral DNA | [95] |
| PRRSV, SVA, PEDV | Aqueous formaldehyde, organic acids, acidifiers, HMTBa, SCFA, MCFA, LCFA, GML, and essential oils | 0.1–3.0% | Ingestion of complete feed via natural consumption for 15 days | Decreased clinical signs and virus detection in biological samples; increased weight gain b | [96] |
| PEDV | Lactic acid | 0.75–1.5% | Stored in complete feed at 20 °C for 1 day | Reduced infectivity in feed | [97] |
| PEDV | Aqueous formaldehyde and propionic acid | 0.33% | Stored in complete feed and ingredients under winter conditions (mean temperature between −9 °C and −18 °C) for 30 days | Reduced infectivity in feed and ingredients; decreased viral RNA quantity in feed | [98] |
| PEDV | Aqueous formaldehyde and propionic acid; MCFA (C6:C8:C10) | 0.36–11.1% | Tested in rice hulls flushed through feed manufacturing equipment after complete feed | Decreased viral RNA quantity in rice hull flush a | [99] |
| PEDV | Benzoic acid and essential oils | 0.02–0.5% | Stored in complete feed for 42 days | Decreased viral RNA quantity in feed on combination treatment with both additives; no effect on virus infectivity in feed | [100] |
| PEDV | Aqueous formaldehyde and propionic acid; MCFA (C6:C8:C10) | 0.33–2.0% | Tested in complete feed and ingredients at a mean 6.1 °C temperature in a 37-day transoceanic shipment model | Reduced infectivity in feed ingredients; decreased viral RNA quantity in feed a | [41] |
| PEDV | Aqueous formaldehyde and propionic acid | 0.32% | Ingestion of complete feed via natural consumption for 14 days | Prevented transmission to pigs through contaminated feed; decreased viral RNA quantity in feed | [101] |
| PEDV | Organic acids, acidifiers, sucrose, and sodium chloride | 0.2–0.4% | Stored in complete feed at 25 °C for 21 days | Increased rate of virus decay in complete feed c | [89] |
| PEDV | Aqueous formaldehyde and propionic acid; MCFA (C6:C8:C10) | 0.125–1.0% | Stored in complete feed at room temperature for 1 day | Reduced infectivity in feed; dose-dependent decreased viral RNA quantity in feed | [102] |
| PEDV | MCFA (C6:C8:C10) | 0.25–1.5% | Stored in complete feed at a mean 25.8 °C temperature for 40 days pre-inoculation; stored at room temperature for 3 days post-inoculation | Dose-dependent decreased viral RNA quantity in feed | [103] |
| PDCoV | Organic acids, acidifiers, sucrose, and sodium chloride | Low: 0.2–3.0% High: 0.4–6.0% |
Stored in complete feed at 25 °C for 35 days | No effect at lower concentrations; increased rate of virus decay in complete feed at higher concentrations d | [104] |
Key: ASFV, African swine fever virus; PEDV, porcine epidemic diarrhea virus; PRRSV, porcine reproductive and respiratory syndrome virus; SVA, Seneca virus A; SCFA, short-chain fatty acids; MCFA, medium-chain fatty acids; LCFA, long-chain fatty acids; GML, glycerol monolaurate; HMTBa, methionine hydroxyl analogue. a Decreased nucleic acid quantity only associated with aqueous formaldehyde or high MCFA (11.1%) treatment; b improved outcome not seen with Vigilex (oils, fermentation products, whey products, plant protein) treatment; c increased rate of PEDV decay not seen after sodium chloride or Ultracid P (orthophosphoric, citric, fumaric, malic acids) treatment; d increased rate of PDCoV decay not seen after treatment with high concentrations of sucrose or formic acid.