Fig. 2

Diversity of intestinal microbiota composition across regions in captive cynomolgus macaques of differing ages. Alpha diversity is assessed using three metrics: A Chao1 index B Inverse Simpson’s index C Shannon’s index. D Tables summarizing statistically significant differences in alpha diversity between intestinal regions (* = p < 0.05). E NMDS plot based on Bray–Curtis dissimilarity, showing the clustering of samples by intestinal region and age group. Age groups are defined as 4–7 years (Young), 8–12 years (Adult) and 13–20 years (Aged). D Duodenum, J Jejunum, I Ileum, C Caecum, PC Proximal Colon, DC Distal Colon