关键词: 长爪沙鼠, 免疫功能, 体脂含量, 季节变化, 权衡

Abstract: Body fat mass is related to immune function in some small mammal species and can be affected by temperature, photoperiod, and population density. In order to understand their survival strategies, we measured seasonal changes in body mass, body fat mass, and organ masses in male and female wild Mongolian gerbils (Meriones unguiculatus) in summer (July and August)in 2004 and winter (January to March) in 2005,as well as the serum antibody contents of anti-keyhole limpet haemocyanin (KLH)after injections with KLH antigen in wild male gerbils. No sexual differences were found in organ mass but the carcass dry mass and body fat mass in male gerbils were higher than in females. Body mass, carcass dry mass, body fat mass, and brown adipose tissue mass for both sexes, as well as testes wet mass in males were significantly higher in winter than that in summer. Spleen mass showed a tendency to decrease in winter. Serum antibody levels of anti-KLH were significantly higher in KLH-challenged gerbils than controls in both summer and winter and also higher in winter compared with summer. Our results provide new evidence from wild Mongolian gerbils to support the hypothesis of “winter immunoenhancement hypothesis”. No trade-offs were detected between thermogenic and immunological organs and between reproductive and immunological organs.

Key words: Body fat mass, Immune function, Mongolian gerbil (Meriones unguiculatus), Seasonal change, Trade off