Morphological Changes Of Small Intestinal Villi Of Seven Birds,including Bam Swallow,Ostrich And Common Pheasant

The small intestine is the main place for vertebrates to absorb nutrients.Mammals and birds have evolved complex intestinal tracts with villi structure to improve absorption efficiency and meet the requirements of maintaining high body temperature and high metabolic rate.lt is generally believed that the morphology of small intestinal villi of birds and mammals are similar and finger-shaped.Recent studies by our research group have found that the morphology and structure of small intestinal villi of birds may be different from that of mammals.In order to explore the morphological structure and development process of the small intestinal villi of birds,the morphological changes of the small intestinal mucosal surface in the development process of seven species of birds including Bam swallow(Hirundo rustica),Common pheasant(Phasianus colchicus),Black-winged stilt(Himantopus himantopus),African ostrich(Strut hi o camelus),chicken(Gallus gallus domesticus),goose(Anmer cygnoides domestica)and pigeon(Columba livia domestica)were observed by entity microscope and scanning electron microscope.The results showed that the small intestinal villi of seven species of birds showed a W-shaped villi plate state at least at a certain individual development stage during the development process.The morphology of small intestinal villi changed in segments during the whole individual development period,in which the morphology of small intestinal mucosa of four birds including chicken,Common pheasant,goose and Barn swallow experienced a change process:ridge shape?continuous W-plate shape?finger shapes?W-plate shape.During the development of pigeon,the surface morphology of small intestinal mucosa experienced a change:ridge shape?continuous W-plate shape?finger shape?discontinuous short W-piate shape?finger shape.During the development of Black-winged stilt,the surface morphology of duodenal mucosa experienced a change:ridge shape?continuous W-plate shape?discontinuous W-plate,while jejunum experienced a change:ridge shape?continuous W-plate shape?discontinuous W-plate shape?continuous W-plate shape.During the development of African ostrich,the surface morphology of small intestinal mucosa experienced a change:ridge shape?continuous W-plate shape?discontinuous S-net shape.Through studying and comparing the similarities and differences of the morphological changes of the inner surface of the slall intestine during the development of seven species of birds,this paper analyzes the morphology and function of this W-shaped villus plate different from lammals,and explores how birds can utilize the smaller intestinal tract than mammals to obtain more efficient nutrient absorption rate.The effects of feeding habits,flight ability and other factors on the morphological changes of small intestinal villi and the differences of adult intestinal villi during the development of 7 birds were also discussed.Based on paleontological data,analyzes the regularity and functional significance of this segmented change,it is suggested that the regular changes in the surface of small intestinal mucosa during bird ontogeny may be an orderly re-oeeurrence of phylogeny,and it can reflect the re-occurrence of food habit evolution,providing theoretical basis for the study of morphology and function of small intestinal mucosa and food habit evolution of birds.