Role of thermal physiology and bioenergetics on adaptation in tree shrew (Tupaia belangeri): the experiment test

Abstract

Ambient conditions, as temperature and photoperiod, play a key role in animals' physiology and behaviors. To test the hypothesis that the maximum thermal physiological and bioenergetics tolerances are induced by extreme environments in Tupaia belangeri. We integrated the acclimatized and acclimated data in several physiological, hormonal, and biochemical markers of thermogenic capacity and bioenergetics in T. belangeri. Results showed that T. belangeri increased body mass, thermogenesis capacity, protein contents and cytochrome c oxidase (COX) activity of liver and brown adipose tissue in winter-like environments, which indicated that temperature was the primary signal for T. belangeri to regulate several physiological capacities. The associated photoperiod signal also elevated the physiological capacities. The regulations of critical physiological traits play a primary role in meeting the survival challenges of winter-like condition in T. belangeri. Together, to cope with cold, leptin may play a potential role in thermogenesis and body mass regulation, as this hormonal signal is associated with other hormones. The strategies of thermal physiology and bioenergetics differs between typical Palearctic species and the local species. However, the maximum thermal physiology and bioenergetic tolerance maybe is an important strategy to cope with winter-like condition of T. belangeri.Phenotypic plasticity is the ability of individuals to change phenotype with fluctuations in climate conditions, and responses mainly include aspects of morphology, physiology, behavior, and phenology 1 . The energy metabolism of small mammals may be the most suitable field for studying phenotypic plasticity changes 2 . The variation in physiological traits in individuals is an important response to the environment 1,3,4 . Climate conditions, including temperature and photoperiod, play a key role in seasonal variation in body mass, food intake, body fat mass, and other traits 5-9 for many species inhabiting in temperature zone, especially mammals. However, different species show different responses to climate conditions, such as Phodopus sungorus . Small mammals' response to seasonal variations such as cold or short photoperiods, by regulating physiological strategies, such as body mass and thermogenic capacity (e.g., nonshivering thermogenesis, NST) [6][7][8][12][13][14][15][16][17][18][19][20][21][22][23] . The brown adipose tissue (BAT) is a specialized organ that is involved in NST [24][25][26] , and in increased energy expenditure involves the hypothalamic-pituitary-thyroid axis and sympathetic nervous system 27 . The NST capacity entirely depends on uncoupling protein 1(UCP1) in BAT, a 32-kD carrier protein located in the inner membrane of mitochondria, that separates oxidative phosphorylation from adenosine triphosphate synthesis, with energy dissipated as heat 27

Seasonal variations of adipose tissue in Tupaia belangeri (Mammalia: Scandentia: Tupaiidae)

“…The cage environment was maintained on a 12L:12D cycle (lights on at 08:00), 25 ± 1°C, and 65-92% relative humidity. The shrews were fed a food mixture containing 25.0% crude protein, 6.3% crude fat, 4.6% crude fiber, 7.4% ash, and 0.96 kJ/g gross energy, as well as apples, pears and other fruits twice weekly (Zhang et al 2017).…”

“…The data derived from the Mx3000P quantitative software were expressed as relative amounts. Gene expression was calculated by the 2 −ΔΔCt method (Zhang et al 2017).…”

“…In order to adapt to changeable climate conditions, small mammals have evolved strategies in physiology, behavior and morphology for survival (Jackson et al 2001;Zhu et al 2017b). Many animals face food resource scarcity and lower temperature in winter; they usually increase thermogenic capacity to improve their ability to resist environmental stress (Zhang et al 2017).…”

“…It inhabits tropical rain forests, secondary forests and mountain forests, and feeds on insects and sweet fruits (Zhu et al 2017a). It is widely used in medicine and biology because of its close relationship with primates, fast reproduction and low feeding cost (Zhang et al 2017). In a previous study (Hou et al 2017), we explored the changes of adipose tissue of T. belangeri during seasonal variations at individual, tissue and molecular levels, and laid a foundation for establishing an energy homeostasis maintenance mechanism and survival adaptation model of T. belangeri.…”

Analysis of volatile chemical substances in urine of the kinship and non-kinship Tupaia belangeri (Mammalia: Scandentia: Tupaiidae)

“…T. belangeri often perch in coniferous and broad-leaved forests, where they mainly eat fruit, insects and other animal food (Kawamichi, 1982). Now it is being used as a promising animal model in biomedical research, physiological and morphological characteristics were reported (Zhang et al, 2017;Gao et al, 2016;Zhang et al, 2014;Gao et al, 2014), but chemical communication in urine on kin recognition had never been known. Volatile chemical substances in urine of the kinship and non-kinship Tupaia belangeri were measured in the present study, we hypothesized that volatile chemicals in urine may related to its kin recognition in T. belangeri.…”