title: Temperature and photoperiod as environmental cues affect body mass and thermoregulation in Chinese bulbuls,Pycnonotus sinensis.
abstract: Seasonal changes in temperature and photoperiod are important environmental cues used by small birds to adjust their body mass (Mb) and thermogenesis. However, the relative importance of these cues with respect to seasonal adjustments inMband thermogenesis is difficult to distinguish. In particular, the effects of temperature and photoperiod on energy metabolism and thermoregulation are not well known in many passerines. To address this problem, we measured the effects of temperature and photoperiod onMb, energy intake, resting metabolic rate (RMR), organ mass and physiological and biochemical markers of metabolic activity in the Chinese bulbul (Pycnonotus sinensis). Groups of Chinese bulbuls were acclimated in a laboratory to the following conditions: (1) warm and long photoperiod, (2) warm and short photoperiod, (3) cold and long photoperiod, and (4) cold and short photoperiod, for 4 weeks. The results indicate that Chinese bulbuls exhibit adaptive physiological regulation when exposed to different temperatures and photoperiods.Mb, RMR, gross energy intake and digestible energy intake were higher in cold-acclimated than in warm-acclimated bulbuls, and in the short photoperiod than in the long photoperiod. The resultant flexibility in energy intake and RMR allows Chinese bulbuls exposed to different temperatures and photoperiods to adjust their energy balance and thermogenesis accordingly. Cold-acclimated birds had heightened state-4 respiration and cytochromecoxidase activity in their liver and muscle tissue compared with warm-acclimated birds indicating the cellular mechanisms underlying their adaptive thermogenesis. Temperature appears to be a primary cue for adjusting energy budget and thermogenic ability in Chinese bulbuls; photoperiod appears to intensify temperature-induced changes in energy metabolism and thermoregulation.
authors.affiliation: School of Life and Environmental Sciences, Wenzhou University, Wenzhou 325035, China.
authors.forename: Shi-Nan
authors.initials: SN
authors.lastname: Hu
authors.affiliation: School of Life and Environmental Sciences, Wenzhou University, Wenzhou 325035, China.
authors.forename: Ying-Yang
authors.initials: YY
authors.lastname: Zhu
authors.affiliation: School of Life and Environmental Sciences, Wenzhou University, Wenzhou 325035, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Lin
authors.affiliation: School of Life and Environmental Sciences, Wenzhou University, Wenzhou 325035, China.|Department of Biology, Zhejiang Provincial Key Lab for Subtropical Water Environment and Marine Biological Resources Protection, Wenzhou 325035, China.
authors.forename: Wei-Hong
authors.initials: WH
authors.lastname: Zheng
authors.affiliation: School of Life and Environmental Sciences, Wenzhou University, Wenzhou 325035, China ljs@wzu.edu.cn.|Department of Biology, Zhejiang Provincial Key Lab for Subtropical Water Environment and Marine Biological Resources Protection, Wenzhou 325035, China.
authors.forename: Jin-Song
authors.identifier: 0000-0002-1305-9955
authors.initials: JS
authors.lastname: Liu
mesh_terms: D000064:Acclimatization; D000818:Animals; D030161:Avian Proteins / Q000378:metabolism; D001481:Basal Metabolism; D001833:Body Temperature Regulation; D003576:Electron Transport Complex IV / Q000378:metabolism; D002149:Energy Intake; D008928:Mitochondria / Q000378:metabolism; D009929:Organ Size; D046109:Passeriformes / Q000502:physiology*; D017440:Photoperiod; D013696:Temperature
chemical_list: D030161:Avian Proteins; D003576:Electron Transport Complex IV
keywords: Acclimation; Cytochrome c oxidase; Mitochondria; Resting metabolic rate; State-4 respiration