Metabolic Research Centre, Illawarra Health and Medical Research Institute, School of Health Sciences, University of Wollongong, Wollongong, NSW 2522, Australia.
J Exp Biol. 2013 Feb 1;216(Pt 3):347-51. doi: 10.1242/jeb.065383.
Lactation is a process associated with mammals, yet a number of birds feed their newly hatched young on secretions analogous to the milk of mammals. These secretions are produced from various sections (crop organ, oesophageal lining and proventriculus) of the upper digestive tract and possess similar levels of fat and protein, as well as added carotenoids, antibodies and, in the case of pigeons and doves, epidermal growth factor. Parental care in avian species has been proposed to originate from dinosaurs. This study examines the possibility that some dinosaurs used secretory feeding to increase the rate of growth of their young, estimated to be similar to that of present day birds and mammals. Dinosaur 'lactation' could also have facilitated immune responses as well as extending parental protection as a result of feeding newly hatched young in nest environments. While the arguments for dinosaur lactation are somewhat generic, a case study for lactation in herbivorous site-nesting dinosaurs is presented. It is proposes that secretory feeding could have been used to bridge the gap between hatching and establishment of the normal diet in some dinosaurs.
泌乳是与哺乳动物相关的过程，但许多鸟类会用类似哺乳动物乳汁的分泌物来喂养刚孵化的幼鸟。这些分泌物是由上消化道的不同部位（嗉囊器官、食管衬里和前胃）产生的，具有相似的脂肪和蛋白质含量，以及添加的类胡萝卜素、抗体，而且在鸽子和鸠鸽中还添加了表皮生长因子。鸟类的亲代养育被认为起源于恐龙。本研究探讨了某些恐龙是否曾利用分泌性喂养来提高幼仔的生长速度，据估计，这与现代鸟类和哺乳动物的生长速度相似。恐龙的“泌乳”还可能促进了免疫反应，并由于在巢环境中喂养刚孵化的幼仔而延长了亲代的保护。虽然恐龙泌乳的论据有些一般性，但提出了一个关于草食性定点筑巢恐龙泌乳的案例研究。提出分泌性喂养可能被用来弥合一些恐龙从孵化到建立正常饮食之间的差距。
