13-Month Follow Up of Acclimation of Cynomolgus Macaques (Macaca fascicularis) on Haematology, Serum Biochemistry, and Body Weight Changes.

BACKGROUND: Acclimation involves physiological adjustments to environmental factors such as geographic origin and housing conditions. Proper acclimation is essential for animal welfare and ensuring the reliability of experimental data. However, the long-term acclimation of cynomolgus macaques has not been systematically examined. Therefore, we compared serum chemistry values between cynomolgus macaques from Vietnam and housed in Laos. The Vietnamese-imported macaques were then monitored while housed indoors at the Korean Institute of Toxicology (KIT), Korea for 13 months. METHODS: Serum biochemical values were compared between male and female Vietnam-imported and Laotian-housed cynomolgus macaques (n = 68 each). Additionally, the haematology, serum biochemistry, and body weight of male and female Vietnam-imported macaques (n = 70 each) were followed up for 405 days while they were housed in KIT. RESULTS: Significant differences in alkaline phosphatase and creatine kinase levels were observed between the two populations. Over the 13-month follow-up in Vietnamese-imported macaques, gradually and continuously increasing body weights were observed, with a temporary decline during the first 12 days following relocation to the indoor facility in male macaques. CONCLUSION: Environmental factors of exporting countries may influence the physiological baseline of cynomolgus macaques, and long-term adaptation is needed when they are translocated from outdoor housing to an indoor closed system.