Dietary supplementation of termitarium soil ameliorated the gut microbiota in captive Chinese pangolins

Abstract Background: Chinese pangolin (Manis pentadactyla), one of the most endangered species in the world, has suffered a sharp decline due to heavy hunting and illegal trade. The artificial diet has difficulty satisfying the nutritional needs of captive pangolins, and it has become one of the main factors limiting the development of ex-situ conservation of pangolins. Gastrointestinal diseases are one of the most common diseases affecting the survival of captive Chinese pangolins and arecaused by an imbalance in gut microbiota. In the wild, the pangolin is a highly specialized species with a diet dominated by ants and termites and an intake ofsome termitarium soil. However, the effects of supplementation with termitarium soil on the gut microbiota of captive Chinese pangolins are poorly understood. Results: Using 16S rRNA sequencing technology, the gut microbiota of the control group (CZ), the sterilized termitarium soil group (MZ), and the unsterilized termitarium soil group (BZ) were compared. These results showed that there was no significant difference in alpha diversity, while the results of unweighted UniFrac PCoA showed obvious separation among the three groups. At the phylum level, Firmicutes, Proteobacteria, and Bacteroidetes were the main bacterial phyla. The relative abundance of Bacteroidetes was decreased in the BZ group compared to the CZ group. Clostridium_sensu_stricto_1, Streptococcus, Cellulosilyticum, and Escherichia_Shigella were the main bacterial genera at the genus level. Unsterilized termitarium soilincreased the relative abundances of Cellulosilyticum, Bacillus, and Clostridium_sensu_stricto_13 and decreased the relative abundances of Bacteroides, Clostridiales_unclassified, Ruminococcus]_gnavus_group, and Veillonella. The Lefse results showed that Cellulosilyticum, Clostridium_sensu_stricto_13, and Bacillus were enriched in the BZ group. The concentrations of acetic acid, propionic acid, and butyric acid were decreased in the BZ and MZ groups. Conclusions: These results indicated that dietary supplementation with termitarium soil did not alterthe richness of the gut microbiota, but reduced proinflammatory-related bacteria and increased intestinal absorption-related bacteria, which improves the efficiency of SCFA absorption. Collectively, this study provides a potential method for ameliorating the intestinal homeostasis of captive Chinese pangolins.