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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Food Safety and Enteric Pathogens Research » Research » Publications at this Location » Publication #124583
Title: THE EFFECT OF DIETARY SOY GENISTEIN ON PIG GROWTH AND VIRAL REPLICATION DURING A VIRAL CHALLENGE

Author
item GREINER, L - IOWA STATE UNIVERSITY
item STAHLY, T - IOWA STATE UNIVERSITY
item Stabel, Thomas

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/31/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary: Continuous exposure or low level infection with disease causing bacteria or virus can cause a reduction in body growth, desire to eat, and ability to properly digest food. It has been shown that factors that minimize the presence of virus in pigs result in improved pig growth. We chose to measure the effects of dietary genistein, a primary compound found in soybeans, on pig growth and virus persistence during viral infection. To mimic a naturally occurring viral infection, we experimentally infected pigs with porcine reproductive and respiratory syndrome (PRRS) virus, an economically important and widespread viral disease in the pork industry. As dietary genistein concentration increased, serum concentrations of PRRS virus decreased and interferon responded independent of days post-inoculation (PI). The AGP concentrations increased with the magnitude of the response to dietary genistein maximized at 12 to 16 d PI. Daily pig gains from d 0 to 24 PI were improved as dietary genistein increased. Daily feed intakes also were increased as genistein concentration increased. These data indicate that soy genistein at dietary concentrations of 200 to 400 ppm is an orally active immune modulator that enhances systemic serum virus elimination and body growth in virally infected pigs. Application of scientifically proven practices will have immediate economic benefits to the pork producer and eventually the American consumer since new control measures for disease will allow a continued supply of inexpensive, wholesome pork and pork products.

Technical Abstract: Pigs were randomly allotted to one of four dietary soy genistein concentrations (0, 200, 400, and 800 ppm) to quantify the effect of soy genistein on pig growth and virus replication during a viral challenge. Genistein was provided as the soy glycoside, genistin. Pigs were oronasally inoculated with porcine reproductive and respiratory syndrome (PRRS) virus and blood was collected every 4 d from d 0 to 24 postinoculation (PI) and analyzed for serum PRRS virus, interferon activity, and alpha1-acylglycoprotein (AGP) concentrations. Serum virus and interferon peaked at 10**5 virus/ml and 57% protection, respectively, at 4 d PI and then declined steadily. Serum AGP concentration peaked at 12 d PI. Each log increase in serum virus was associated with a reduction of daily gain. As dietary genistein concentration increased, serum concentrations of PRRS virus decreased linearly and interferon responded quadratically independent of days PI. The AGP concentrations increased quadratically with the magnitude of the response to dietary genistein maximized at 12 to 16 d PI. Daily pig gains from d 0 to 24 PI were improved as dietary genistein increased, but the magnitude of the response to dietary genistein concentration lessened as the serum virus concentrations were minimized. Daily feed intakes also were increased quadratically as genistein concentration increased. These data indicate that soy genistein at dietary concentrations of 200 to 400 ppm is an orally active immune modulator that enhances systemic serum virus elimination and body growth in virally challenged pigs.