Feed has been shown to be a vector for viral transmission. Four experiments were conducted to: 1) determine if medium chain fatty acids (MCFA) are effective mitigants when applied to feed both pre- and post-porcine epidemic diarrhea virus (PEDV) inoculation measured by quantitative reverse transcription polymerase chain reaction (qRT-PCR), 2) evaluate varying levels and combinations of MCFA measured by qRT-PCR, and 3) evaluate selected treatments in bioassay to determine infectivity. In exp. 1, treatments were arranged in a 2 × 2 + 1 factorial with main effects of treatment (0.3% commercial formaldehyde [CF] product, Sal CURB [Kemin Industries, Inc.; Des Moines, IA], or 1% MCFA blend (Blend) of 1:1:1 C6:C8:C10 [PMI, Arden Hills, MN]) and timing of application (pre- or post-inoculation with PEDV) plus a positive control (PC; feed inoculated with PEDV and no treatment). All combinations of treatment and timing decreased detectable PEDV compared with the PC (P < 0.05). Pre-inoculation treatment elicited decreased magnitude of PEDV detection (cycle threshold value) compared with post-inoculation (P = 0.009). Magnitude of PEDV detection was decreased for CF compared with Blend (P < 0.0001). In exp. 2, pre-inoculation treatments consisted of: 1) PC, 2) 0.3% CF, 3 to 5) 0.125% to 0.33% C6:0, 6 to 8) 0.125% to 0.33% C8:0, 9 to 11) 0.125% to 0.33% C10:0, and 12 to 15) 0.125% to 0.66% C5:0. Treating feed with 0.33% C8:0 resulted in decreased (P < 0.05) PEDV detection compared with all other treatments. Increasing concentration of each individual MCFA decreased PEDV detectability (P < 0.042). In exp. 3, pre-inoculation treatments consisted of: 1) PC, 2) 0.3% CF, 3 to 7) 0.25% to 1% Blend, 8 to 10) 0.125% to 0.33% C6:0 + C8:0, 11 to 13) 0.125% to 0.33% C6:0 + C10:0, and 14 to 16) 0.125% to 0.33% C8:0 + C10:0. Treating feed with CF, 0.5% Blend, 0.75% Blend, 1% Blend, all levels of C6:0+C8:0, 0.25% C6:0 + 0.25% C10:0, 0.33% C6:0 + 0.33% C10:0, 0.25% C8:0 + 0.25% C10:0, or 0.33% C8:0 + 0.33% C10:0 elicited decreased detection of PEDV compared with PC (P < 0.05). Increasing concentration of each MCFA combination decreased PEDV detectability (linear, P < 0.012). In exp. 4, feed was treated pre-inoculation with: 1) no treatment (PC), 2) 0.3% CF, 3) 0.5% Blend, or 4) 0.3% C8:0 and analyzed via qRT-PCR and bioassay. Adding 0.5% Blend or 0.3% C8:0 resulted in decreased PEDV compared with PC and only PC resulted in a positive bioassay. Therefore, MCFA can decrease detection of PEDV in feed. Further, inclusion of lower levels of MCFA than previously evaluated are effective against PEDV.

中文翻译：

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中链脂肪酸作为猪饲料中猪流行性腹泻病毒的缓解或预防策略。

饲料已被证明是病毒传播的载体。进行了四个实验，以：1）确定中链脂肪酸（MCFA）是否适用于通过定量逆转录聚合酶链反应（qRT-PCR）测量的猪前和后流行性腹泻病毒（PEDV）接种饲料），2）评估通过qRT-PCR测量的MCFA的不同水平和组合，以及3）评估生物测定中选择的治疗方法以确定感染性。在实验中 1，将治疗安排在2×2 +1阶乘中，具有主要治疗效果（0.3％商业甲醛[ CF]产品Sal Sal CURB [Kemin Industries，Inc .; 得梅因州，IA]或1％1：1 C6：C8：C10 [PMI，明尼阿达州阿登希尔斯市]的1％MCFA混合物（混合）和施用时间（接种PEDV前后）阳性对照（PC；饲料中接种了PEDV，未进行处理）。与PC相比，所有治疗和时机组合均降低了可检测到的PEDV（P <0.05）。与接种后相比，接种前治疗引起的PEDV检测幅度（循环阈值）降低（P = 0.009）。与Blend相比，CF的PEDV检测幅度降低了（P<0.0001）。在实验中 2，接种前治疗包括：1）PC，2）0.3％CF，3至5）0.125％至0.33％C6：0，6至8）0.125％至0.33％C8：0，9至11）0.125 ％至0.33％C10：0，以及12至15）0.125％至0.66％C5：0。与所有其他处理相比，用0.33％C8：0处理饲料导致PEDV检出率降低（P <0.05）。每个MCFA浓度的增加会降低PEDV的可检测性（P<0.042）。在实验中 3，接种前处理包括：1）PC，2）0.3％CF，3至7）0.25％至1％Blend，8至10）0.125％至0.33％C6：0 + C8：0，11至13 ）0.125％至0.33％C6：0 + C10：0，以及14至16）0.125％至0.33％C8：0 + C10：0。用CF，0.5％共混物，0.75％共混物，1％共混物，所有水平的C6：0 + C8：0、0.25％C6：0 + 0.25％C10：0、0.33％C6：0 + 0.33％C10处理饲料：与PC相比，0、0.25％C8：0 + 0.25％C10：0或0.33％C8：0 + 0.33％C10：0导致PEDV的检出率降低（P <0.05）。每种MCFA组合浓度的增加会降低PEDV的可检测性（线性，P<0.012）。在实验中 如图4所示，将饲料接种前进行处理：1）不进行处理（PC），2）0.3％CF，3）0.5％Blend或4）0.3％C8：0，并通过qRT-PCR和生物分析进行分析。与PC相比，添加0.5％Blend或0.3％C8：0导致PEDV降低，仅PC导致阳性生物测定。因此，MCFA可以减少饲料中PEDV的检测。此外，包含比先前评估的更低水平的MCFA对PEDV有效。