Porcine Reproductive and Respiratory Syndrome Virus and Pig Feed Efficiency and Tissue Accretion

摘要

In pork production, the largest use of natural resources is through the production and consumption of feed. Health-challenged pigs can be a burden on production and pork quality. Therefore, improving feed efficiency and health of pigs is an importantgoal for sustainable and profitable pork production. The pig is under constant pathogenic challenge which can have adverse effects on intestinal and respiratory health and function, as well as on anabolic processes in peripheral tissues such as skeletalmuscle (Williams et al, 1997a, b; Escobar et al., 2004). Of the health challenges the pig industry faces, Porcine Reproductive and Respiratory Syndrome (PRRS) and now Porcine Epidemic Diarrhea (PED) viruses are arguably the two most economically costly viruses to U.S. and world pork production. Alone, PRRS virus infections are estimated to cost the U.S. pig industry more than USD $664 million annually (Holtkamp et al, 2013). In addition to mortality losses and costs of interventions, these viruses may reduce lean tissue accretion and feed efficiency in growing pigs from weaning to market. These reductions may be caused by the innate and adaptive responses to intense, prolonged or poorly contained immunological or stress stimuli. However, single infection alone often fails to induce overt disease; yet they are still recognized individually as important etiological agents in multi-factorial disease of pigs and can negatively impact pig performance. Although it is clearly known that PRRS virus impacts sow reproduction and attenuates average daily gain (ADG) of production pigs, its direct impact on feed efficiency, nutrient and energy digestibility, metabolism and whole body lean and fat accretion in grower / finisher pigs has been poorly characterized.