Effects of maternal and post‐natal infection with porcine reproductive and respiratory syndrome virus on muscle growth and development in piglets (731.10)

Abstract

Prenatal muscle development is altered by maternal nutrition, the effect of maternal infection during pregnancy on offspring muscle growth and development is less clear. We assessed muscle development in piglets born of dams infected with porcine reproductive and respiratory syndrome virus (PRRSV) during pregnancy and in postnatally infected PRRSV pigs. In study 1, pregnant gilts were inoculated with PRRSV or sterile culture medium (control) at d76 of gestation. Data collected from offspring at d0 and d28 of age included body and muscle weights and gene expression of longissumus dorsi muscle. In study 2, similar measurements were collected from pigs inoculated with PRRSV at d35 and sacrificed at d49 of age. Longissumus dorsi weight was reduced (P<0.01) at d28 in piglets from PRRSV inoculated gilts compared with control, but body or other muscle weights were unaffected at d0 and d28 of age. Furthermore, IGF1, IL‐6, and Pax7 expression tended to be reduced (P<0.10) at d28 in piglets from PRRSV inoculated gilts compared with controls, while myostatin and UCP3 expression did not differ. In addition, TNF‐α expression was increased (P<0.05) at d28 in piglets from PPRSV inoculated gilts compared with controls. Postnatal infection reduced (P<0.01) body and muscle weights in PRRSV inoculated‐piglets compared with controls. However, postnatal infection did not alter expression of myostatin, IGF1, Pax7, IL‐6, or TNF‐α.