Expression Profile of the Digestive Enzymes of Manis javanica Reveals Its Adaptation to Diet Specialization

The expression of animal digestive enzymes reflects important dietary adaptations. The pangolin, also known as scaly anteater, is a specialized myrmecophage that consumes mainly ants and termites, but its digestive enzymes have not been fully investigated. Therefore, in this study, we used shotgun proteomic analysis to examine the protein components of the saliva and intestinal juice of a Sunda pangolin (Manis javanica) that died shortly after being rescued. The intestinal juice contained greater variety of digestive enzymes, including α-amylase, maltase-glucoamylase, α,α-trehalase, sucrase-isomaltase, pepsin A, trypsin, pancreatic endopeptidase E, carboxypeptidase A1, carboxypeptidase B, dipeptidyl-peptidase 4, and pancreatic triacylglycerol lipase. The digestive enzymes identified in the saliva were maltase-glucoamylase and trypsin, and chitinase which was also found in the intestinal juice. Compared with other animals, the Sunda pangolin has less intestinal protease diversity and lacks key digestive enzymes, such as chymotrypsin and pancreatic elastase. The expression profile of the digestive enzymes of the Sunda pangolin reveals animal's adaptation to a diet consisting mainly of ants and termites. Our results will facilitate the preparation of artificial food for rescued pangolins and for those in captivity for conservation breeding efforts.