Study On The Distribution Rule And Biosynthetic Mechanism Of Melanin In Taihe Silky Fowls And Ningdu Yellow Chicken

Taihe silky fowls and Ningdu yellow chicken belong to the famous indigenous genetic resources in jiangxi province, have a distinctive appearance, especially the difference in complexion and viscera.This study through variety of histochemical staining to research distribution rule of melanin, the distribution characteristics of melanocytes and identify the main cells that involved melanin synthesis in Taihe silky fowls and Ningdu yellow chicken, in order to illuminate the difference of complexion and serosa in two local breeds, the cytological basis for the biosynthesis and the theoretical foundation for deposition mechanism of melanin.In this study, HE staining was applied for the study on the melanin deposition in different organs of Taihe silky fowls and Ningdu yellow chicken.The Lillie and DOPA staining were applied for the study on the location of melanocyte in different parts of skin, to determine the distribution characteristics and identify the mature state of melanocytes.Improved toluidine blue staining and Grimelin’s silver nitrate reaction method identified the main cell types participated in melanin synthesis. The presence of melanosome types in melanocytes and the mature state of melanocytes were identificated by transmission electron microscope.The results indicated that the mast cells located mainly in capillary network of dermis. Melanin deposition quantity in tested tissues and organs have different degrees of variation,Melanin in Taihe silky fowls and Ningdu yellow chicken was deposited difference in various tissues and organs. Melanin in Taihe silky fowls was deposited in all organs and in Ningdu yellow chicken was only deposited in hair follicle and eyes, not seen in other organs.Mature melanocytes located mainly in stratum basale of epidermis,hair bulb in Taihe silky fowls and hair bulb, outer root sheath in Ningdu yellow chicken.Amelanotic melanocytes located mainly in stratum basale of epidermis in Ningdu yellow chicken and outer root sheath in Taihe silky fowls.Argentaffin cells in gastrointestinal tract of Taihe silky fowls and Ningdu yellow chicken have varied shapes and protuberance, located mainly in epithelial of enteraden, mucosa epithelium and lamina propria. The trend of distribution density of the argentaffin cells was cecum>rectum >ileum>jejunum>duodenum>glandular stomach, and the distribution density in the Taihe silky fowls is significantly higher than the Ningdu yellow chicken.Using electron microscopy, melanosomes in mel-anocvte in Taihe silky fowls was divided into four stages I, II, III andIV, most in the mature stage IV, which indicated the mel-anocvte were in naturty state and has the ability to secrete melanin. Most melanosomes in mel-anocvte in Ningdu yellow chickens were in the stageⅡ,Ⅲ, and few in stage IV, so the mel-anocvte could be regarded as amelanotic melanocytes and had disability to secrete melanin.These results indicate that melanin biosynthesis was influenced by the mature state of mel-anocvte and hair follicle melanocytes.Skin mast cells and argentaffin cells in gastrointestinal tract can secrete some biological activity materials such as 5-HT, after catalyzed by tyrosine kinase can be involved in melanin biosynthesis. The formation causes of black skin in Taihe silky fowls associated with the mature state of epidermal melanocytes, and white feather associated with the mature state of outer root sheath melanocytes.