Abstract
Hoxa1 mutation adversely affect fetal pig development, but whether all-trans retinoic acid (ATRA) administration to Hoxa1(+/-) pregnant sows can improve Hoxa1(-/-) fetal pig development defects has not been reported. A total of 24 healthy Hoxa1(+/-) sows were mated with a healthy Hoxa1(+/-) boar and randomly assigned to one control group and nine experiment groups. ATRA was orally administered to pregnant sows at the doses of 0, 4, 5, or 6 mg/kg maternal body weight on 12, 13, and 14 days post coitum (dpc), respectively, and a total of 146 live piglets were delivered including 37 Hoxa1(-/-) piglets and 109 non-Hoxa1(-/-) piglets. Results indicated that Hoxa1(-/-) piglets delivered by sows in control group had bilateral microtia, canal atresia and ear's internal defects, and had lower birth liveweight and external ear score than non-Hoxa1(-/-) neonatal piglets (P < 0.05). Maternal administration with ATRA can effectively correct the development defects of Hoxa1(-/-) fetal pigs, Hoxa1(-/-) neonatal piglets delivered by sows administered ATRA at a dose of 4 mg/kg body weight on 14 dpc had higher birth liveweight (P > 0.05) and higher scores of external ear (P < 0.05) compared to Hoxa1(-/-) neonatal piglets from the control group, but had no significantly difference in terms of birth liveweight and external ear integrity than non-Hoxa1(-/-) piglets from the control group (P > 0.05). The time of ATRA administration significantly affected Hoxa1(-/-) fetal development (P < 0.05). Administration of ATRA to Hoxa1(+/-) pregnant sows at 4 mg/kg body weight on 14 dpc can effectively improve the birth liveweight and ear defects of Hoxa1(-/-) piglets.