Abstract
Four genetically identical cloned dogs were produced from a single donor using the somatic cell nuclear transfer technique. They stayed in the same facility during youth period, and were later assigned to different locations according to their roles as working dogs. In this study, we report observations from four genetically identical cloned working dogs exposed to different environments, including an airport and a police station, for two years. Hair and fecal samples were collected to assess potential environmental influences on mineral content and intestinal microbiota composition. The concentrations of toxic minerals, such as Pb and Ni, were significantly higher in the hair mineral analysis of the dog exposed to the airport compared to those of the three police station-working dogs. Fecal microbiota analysis showed that the intestinal microbiota of the airport-exposed dog was simplified, with an increased proportion of Actinobacteria and a decreased proportion of Lachnospiraceae and Fusobacteria. Our observations suggest that environmental conditions may influence the accumulation of harmful substances in the body and affect intestinal microbiota community. This finding also highlights the potential of non-invasive methods for evaluating workplace-related environmental influences on working dogs. These results suggest that different environments may contribute to physiological differences even among genetically identical individuals. Future studies should investigate the mechanisms underlying these variations and assess their long-term implications for canine health monitoring with larger sample sizes.