Effect of seasonal changes on the innate immunity of wild Pseudois nayaur: potential reason for its endangerment

Abstract

It has been widely concerned that seasonal climate change may impose stress on mammal's immune system, but this has never been connected to wildlife endangerment reasons. This study focuses on pseudois nayaur, a rare Chinese sheep facing a severe situation of disappearing. Wild pseudois nayaurs in Sichuan, China were observed in this research by an integrated method including habitat environment, foraging rules, and breeding activities investigation in ecology filed, accompanied with immunity research by PB (peripheral blood), including erythrocyte, neutrophils, NK(natural kill) cells, and macrophages immunity by means of erythrocyte rosette, phagocytosis, LDH (lactate dehydrogenase) release and ANAE (acid α-naphthyl acetate esterase) method, respectively. The results show that pseudois nayaurs's innate and red blood cell immune functions were in degradation in autumn and winter, which were speculated to be the results of energy reallocation between reproduction and the immune system. In addition, the environment pressure found in Zhu Balong, Sichuan, China including food reduction, human disturbance, low temperature, and severe drought still existed, which may prevent the pseudois nayaur from normally immunity enhancement before winter. In conclusion, the innate immunosuppression found in this study especially at their breeding season in autumn and winter may be the ignored cause of wild pseudois nayaur endangerment and should be considered in their protection strategy.