Study On The Development Of Skin And Hair Follicle In The Down Of Jilin White Goose

The down line of Jilin White goose is selected as experimental material to study the developmental regulation of its skin and follicle during embryonic (E) and postnatal (P) stage.To provide dependable theories for skin and hair follicles biology of animals and reseaching the artificial adjusts to control the development.The conclusion is:The skin comprises epidermis, dermis and epithelial connective tissue. There is only simple squamous epithelium in epidermis at E12 and epidermis has established completely at E14. Then the thickness of epidermis is about 10μm without change from embryonic to postnatal stage. The thickness of dermis becomes stable after E26, and becomes maximal at P48, which is about 1299±159μm.The follicle is divided into primary follicle (feather follicle) and secondary follicle ( down follicle) . The primordium of primary follicle initiates at E13～14. The density of primary follicle becomes maximal at E18, which is about 11.2 ±0.6/cm~2. During postnatal stage, primary follicle does not continue to occur any longer, so the density decreases as the body weight increases. The deepness of primary follicle becomes maximal at P48, according to the change of dermis, which is about 1001 ± 130μm, which explains the deepness of primary follicle changes with thickness of dermis. The breadth of hair bulb in primary follicle increases gradually from embryonic stage to P88 and becomes maximal at P88, which is about 1202±411μm. After that it decreases and it is supposed that the decrease of average breadth of hair bulb relates to the atrophy of follicle. The primordium of secondary follicle initiates at E17～18. The breadth of hair bulb in secondary follicle becomes maximal at P38, which is about 190±18μm. The density and deepness of secondary follicle become maximal at P48, which is about 19.1±2.6/ cm~2 and 600±37μm respectively. The time when the thickness of dermis becomes maximal is when the secondary follicle develops most rapidly, which explains the thickness of dermis influences the development of secondary follicle greatly. The ratio of primary follicle and secondary follicle (S/P) increases gradually from embryonic stage to P128 and during E38～E88, it changes most, the S/P is about 6.79 ±0.48. The growth rate of the number of secondary follicle is more than that of primary follicle. The number of primary follicle is already stable during embryonic stage, but that of secondary follicle continue to occur.The thickness of epidermis and dermis and the breadth , deepness and S/P of hair bulb in...