CategoryAnimal Science - Swine Nutrition
Date Full Report Received06/10/2014
Date Abstract Report Received06/10/2014
Funded ByIowa Pork Producers Association
While significant advances have been made through research efforts to enhance the health, productivity, and well-being of swine, the detrimental effects associated with disease outbreaks remains a significant challenge to the U.S. pork industry. Therefore, the goal of this research was to characterize over time the changes in blood metabolic and immunological parameters of pigs infected with porcine reproductive and reproductive syndrome (PRRS) virus using canonical discriminant analysis (CDA) model. A total of 76 gilts (16.1 ± 0.43 kg BW, 47-60 d old; EBX Pure; Choice Genetics, West Des Moines, IA) were selected and randomly assigned to one of four pens (19 pigs/pen) in a commercial finishing unit in central Iowa. Blood samples were collected before selection to verify that all gilts were PPRSV naïve. Body weights and blood samples were collected on each animal at 0, 7, 14, 28 and 56 days post-inoculation (dpi). Retrospectively, the 12 highest and 12 lowest growth rate gilts over a 56-day PRRS challenge study were selected for mutivariant blood analysis. Their serum was analyzed for 52 metabolites, 17 complete blood count (CBC), and inflammatory traits on dpi 0, 7, 14, 28 and 56. Our CDA analysis revealed no major differences in blood parameters between dpi 0 and 56. However, during early stages of PRRS infection (dpi 7 and 14), amino acid mobilization markers increased potentially for immune protein synthesis and energy requirements, whereas in later stages (dpi 28) we observed an increase in protein catabolism markers. Altogether, these results indicate dynamic changes in immune and energy requirements for pigs growing through a PRRS challenge. By understanding these changes or shifts in metabolism as a result of immune stress, long term, we hope to develop management strategies to optimize pig performance in the face of disease challenge.