Nramp1 gene expression in different tissues of Meishan piglets from newborn to weaning

Natural resistance-associated macrophage protein gene 1 (Nramp1) plays an important role in the innate immune response of swine, and is believed to influence disease resistance. In this study, a real-time quantitative polymerase chain reaction technique was used to investigate Nramp1 expression in 12 different tissues in newborn and 7-, 14-, 21-, 28-, and 35-day-old Meishan piglets. Results indicated that Nramp1 was expressed to varying degrees in all sample tissues, although expression differed among growth stages. For example, Nramp1 was highly expressed in the spleen, but minimally expressed in heart, liver, and muscle tissues among the various piglet age classes. Overall, Nramp1 expression increased with age, reaching significant levels in 21- and 28-day-old animals. Nramp1 was expressed in all 12 tissues tested; however, expression in spleen, lung, kidney, and thymus tissues was highest among newborns, which is consistent with this gene's role in innate immunity improvement. Before and after weaning, Nramp1 was highly expressed in digestive (stomach) and intestinal (duodenum, jejunum, and ileum) tissues, further indicating a genetic role in both immune regulation to compensate for weaning stress and enhanced development of intestinal immunity.