Reference Intervals and Percentiles for Hematologic and Serum Biochemical Values in Captive Bred Rhesus (Macaca mulatta) and Cynomolgus Macaques (Macaca fascicularis)

Simple Summary We explored the effect of age, gender, weight-for-height indices, sedation protocol, and housing conditions on the hematologic and serum biochemical values of captive rhesus and cynomolgus macaques. Several blood parameters demonstrated significant and clinically relevant changes in relation to the investigated variables. The results will provide veterinarians and researchers with important reference intervals for evaluating experimental results and health control from rhesus and cynomolgus macaques. Several physiological characteristics and housing conditions are known to affect hematologic and serum biochemical values in macaques. However, the studies that have been conducted either report values calculated based on a small number of animals, were designed specifically to document the effect of a particular condition on the normal range of hematologic and serum biochemical values, or used parametric assumptions to calculate hematologic and serum biochemical reference intervals. We conducted a retrospective longitudinal cohort study to estimate reference intervals for hematologic and serum biochemical values in clinically healthy macaques based on observed percentiles without parametric assumptions. Data were obtained as part of the Biomedical Primate Research Centre (Rijswijk, The Netherlands) health monitoring program between 2018 and 2021. In total, 4009 blood samples from 1475 macaques were analyzed with a maximum of one repeat per year per animal. Data were established by species, gender, age, weight-for-height indices, pregnancy, sedation protocol, and housing conditions. Most of the parameters profoundly affected just some hematologic and serum biochemical values. A significant glucose difference was observed between the ketamine and ketamine-medetomidine sedation protocols. The results emphasize the importance of establishing uniform experimental groups with validated animal husbandry and housing conditions to improve the reproducibility of the experiments.

Automated summary

We investigated the effect of various factors on the hematologic and serum biochemical values of captive rhesus and cynomolgus macaques. The results provide important reference intervals for evaluating experimental results and health control in these macaques. Our study highlights the need for standardized experimental groups and validated animal husbandry to improve the reproducibility of experiments.