Growth Prior to Thermogenesis for a Quick Fledging of Adélie Penguin Chicks (Pygoscelis adeliae)

摘要: The evolutionary trade-off between tissue growth and mature function restricts the post natal development of polar birds. present study uses an original integrative approach as it includes gene expression, plus biochemical physiological analysis to investigate how Adelie penguin chicks achieve a rapid despite energetic constraints linked cold very short breeding season in Antarctica. In pectoralis muscle, main thermogenic birds, our data show that transition from ectothermy endothermy on Day 15 post- hatching is associated with substantial coordinated changes transcription key genes. While early activation genes controlling cell differentiation (avGHR, avIGF-1R, T3Rβ) rapidly down-regulated after hatching, global increase relative expression involved thermoregulation (avUCP, avANT, avLPL) transcriptional regulation (avPGC1α, avT3Rβ) underlie muscular acquisition oxidative metabolism. only become real endotherms at days age muscle phenotype ability shiver efficiently. persistent IGF-1 throughout probably acts local mediator adjust size its capacity anticipate new demands future Dives water. up-regulation T3Rβ mRNA levels suggests circulating T3 may play important role late maturation skeletal by reinforcing, least part, paracrine action IGF-1. From day 30, metabolic shift mixed substrate lipid metabolism, markedly increased avLPL, avANT avUCP, fatty acid-enhanced non-shivering thermogenesis mechanism. This molecular control this finely-tuned strategy which chick successfully heads for sea schedule.