Animals, sample collection, and transportation

Fresh feces from 20 cynomolgus macaques (M. fascicularis) aged 13–16 years were sampled. The animals were housed at room temperature with a 12-hour light/dark cycle at the JinJieKang Biotechnology Company, Yunnan, China, following guidelines approved by the Association for Assessment and Accreditation of Laboratory Animal Care. The experimental protocol was approved by the Animal Care and Use Committee at the JinJieKang Biotechnology Company. The animals had ad libitum access to water. The animals were divided into two groups of 10 animals. Ten males were fed a low-fat/high-fiber diet (8% of energy from fat, 131 g fiber/kg), and nine males and one female were fed a high-fat/low-fiber diet (39% of energy from fat, 20 g fiber/kg) for three months. After three months, the animals were weighed and blood was collected for blood glucose measurements at Kunming Jinyu Medical Laboratory Co., Ltd. Fresh feces were collected, immediately frozen, and kept on dry ice during transportation to BGI Shenzhen for further processing.