71 - The Use of Medium Chain Fatty Acids to Reduce Porcine Reproductive Respiratory Syndrome Virus Replication in MARC-145 Cells

Porcine reproductive respiratory syndrome virus (PPRSV) costs the U.S. Swine Industry an estimated $664 million annually. The objective of this study was to evaluate the effect of medium chain fatty acids (MCFA) on PRRSV replication in M-145 cells. Two experiments were conducted to 1) evaluate the use of individual MCFAs (C6, C8, C10), and 2) evaluate MCFA combinations (C8/C10, C10/C12, C8/C10/C12) on viral replication of PRRSV. Experiment one used individual MCFAs at 7 concentrations from 1-1000µg/ml compared to a control. Experiment two used MCFA combinations at 6 different concentrations from 50-500µg/ml compared to a control. North American Type II P-129 PRRSV and European Type I Lelystad PRRSV strains were used. Viral replication was determined using FITC labeled IgG anti-PRRSV monoclonal antibody and TCID₅₀ was calculated for each treatment concentration using 5 wells per treatment at each virus concentration with plates run in triplicate. Data were analyzed using Proc Mixed procedures of SAS. In experiment 1, C6 had no effect on replication of PRRSV in M145 cells. C8 induced a 3.02 and 2.02 log reduction in TCID₅₀ for type I and type II virus strains, respectively (P < 0.01) at 1000µg/ml. C10 induced a 2.85 and 3.23 log reduction in TCID₅₀ for type I and type II virus strains, respectively (P < 0.01) at 300µg/ml. In experiment 2, C8/C10 induced a 1.9 and 2.2 log reduction in TCID₅₀ for type I and type II virus strains, respectively (P < 0.01) at 200µg/ml. C10/C12 resulted in a 3.37 and 2.14 log reduction in TCID₅₀ at 200µg/ml for type I and type II virus strains, respectively (P < 0.01). C8/C10/C12 resulted in a 1.34 and 1.56 log reduction in TCID₅₀ at 200µg/ml for type I and type II virus strains (P < 0.01), respectively.