Gene expression profiles during postnatal development of the liver and pancreas in giant pandas

Giant pandas are unique Carnivora with a strict bamboo diet. To investigate the molecular mechanism of giant panda nutrient metabolism from newborn to adult, the gene expression profiles of giant panda liver and pancreas tissues collected from three important feeding stages were investigated using RNA-seq. We found a total of 3,211 hepatic and 3,343 pancreatic differentially expressed genes (DEGs) from three comparisons between suckling and no feeding, adult and no feeding, and adult and suckling groups. Few differences in gene-expression profiles were exhibited between no feeding and suckling groups in both tissues. GO and KEGG analyses were performed to further understand the biological functions of the DEGs. In both the liver and pancreas, genes related mainly to cell cycle processes were highly up-regulated in newborn samples whereas genes related to metabolism and immunity were up-regulated in adult giant pandas. The high expression of metabolism-related genes in adult samples probably helps to fulfill the metabolic function requirements of the liver and pancreas. In contrast, several vital genes involved in cholesterol metabolism and protein digestion and absorption were over-expressed in newborn samples. This may indicate the importance of cholesterol metabolism and protein digestion and absorption processes in giant panda infancy.