Liver miRNA profiles of newborn male Erhualian and Large White piglets using LC Sciences Pig miRNA Array

Erhualian (EHL) is one of the seven strains included in a Chinese indigenous pig breed called Taihu. EHL is famous for its early sexual maturity, large litter size, high adiposity, mild temper, good maternity and high tolerance to roughage and stress. To further investigate the role of miRNAs in different breed-specific metabolic characters, a comparison of miRNA expression profiles in liver of newborn Erhualian (EHL) and Large White (LW) piglets was carried out. Six LC sciences microarrays containing 236 miRNA procine probes based on miRBase Release 16.0 and 100 custom miRNA probes based on the solex deep sequencing results (li et al.,2010) were used. When compaired with LW piglets, 5 down-regulated and 8 up-regulated miRNAs were detected (fold change >1.2 and p value < 0.1) in the liver of EHL among the 236 miRbase probes. When considering the 100 custom miRNA probes, 2 down-regulated and 5 up-regulated miRNAs were observed. These results were further described in the unpublished paper Coordinated miRNA/mRNA expression profiles for understanding breed-specific metabolic characters of liver between Erhualian and Large White pigs. Six newborn male piglets were sampled from three litters (2 from each litter) of purebred EHL and LW sows and sacrificed. Liver samples were immersed in liquid nitrogen immediately after collection and then stored at -70 °C. Total RNA was isolated using the Trizol reagent (Invitrogen, Carlsbad, CA, USA), according to the manufacturer’s instructions. Total RNAs of the two littermate piglets were pooled for the microarray analysis. The pooled samples were named as EHL1-3 and LW1-3, representing 3 mixed liver RNA samples each from EHL and LW piglets, respectively. Microarray experiment was performed by a service provider (LC sciences).