The Distribution And Developmental Changes Of Orexin In The Small Intestine Of African Ostrich

Orexin are exclusively expressed by neurons in the lateral hypothalamic area, which includes Orexin-A and Orexin-B. Orexin plays a variety of physiological functions in the animal body, involved in the regulation of food intake and drinking water, energy homeostasis, sleep-wake cycle, reproductive, nervous and endocrine. Orexin mainly distributed in the hypothalamus, stomach, intestines, pancreas, testes, and other organs. However, many researches have found that the structural characteristics, distribution and physiological functions of Orexin in different animals vary considerably, especially the relationship between Orexin and gastrointestinal activity. The function of gastrointestinal tract has a direct impact on the growth and development of the ostrich. The research about the relationship between Orexin of African ostrich can not only increase morphological data of Orexin about wild animals, but also provide scientific guidance for the study of the growth and production performance of ostrich, and provide theoretical basis for the physiological functions of Orexin in African ostrich. The localization of Orexin in African ostrich has not yet been reported. To explore these issues, the present study use paraffin sections, AB-PAS staining and immunohistochemistry technologies to investigate the distribution and development regularity of Orexin in the small intestine of African ostrich.The main research contents and research results, including the following two aspects:1. The morphology and distribution of goblet cells in the small intestine of African ostrich90d healthy African ostriches were used in the present research for experimental animals to investigate the morphological structure and distribution of goblet cells by using paraffin sections, AB-PAS staining method. The result showed that in the duodenum, jejunum and ileum, four different goblet cells can be discovered. Type Ⅰ was pure red, AB negative and PAS positive containing neutral mucoitin. Type Ⅱ was pure blue, AB positive and PAS negative containing acidic mucoitin. Type Ⅲ was purple reddish, PAS positive more than AB. Type Ⅳ was purple blue, AB positive more than PAS.Four types of goblet cells all can be found in the crypts and villus of the small intestine, and AB-positive goblet cells are more than PAS-positive cells. This result shows that goblet cells of the small intestine mainly are Ⅱ and Ⅳ type, and their acid mucoprotein can resist the invasion of foreign substance and infection. In the duodenum and jejunum, immature goblet cells are in the majority, while it is contrary in the ileum. On the one hand, it was attributed to the differences between various sections of the small intestine, such as the secretory function strength of the digestive gland; on the other hand, mucus cells may be at different developmental stages.2. The distribution of endocrine cells in the small intestine of African ostrichIn the present study,90d healthy African ostrich were used to study the distribution and structure of endocrine cells in the small intestine of African ostrich by using paraffin sections and silver staining method. The results showed that endocrine cells scattered in the intestinal villus and intestinal glands. The cytoplasmic was brown and nucleus was colorless or pale yellow. Endocrine cells can be divided into two types:closed-type cells and open-type cells. Opened-type cells are triangular or elongated shapes. They contact with the lumen through their apical cytoplasmic process. Closed-type endocrine cells are not in contact with the intestinal lumen. The secretory granules was able to enter the lamina propria and blood circulation. And it is suggested that endocrine cells both have endocrine function and exocrine function.3. The distribution and development change of Orexin in the small intestine of African ostrichIn the present study,1d,45d,90d and adult African ostrich were used as experimental animals. The distribution, morphological characteristic and the developmental changes of Orexin in the small intestinal tract of African ostrich were investigated by using immunohistochemistry(SABC). And the results showed:(1) The distribution of Orexin in the small intestine of African ostrichIn the duodenum, Orexin-A and Orexin-B were mainly scattered in the epithelial of villus and crypts and fewer in the lamina propria. In the jejunum and ileum, Orexin-A and Orexin-B were mainly located in the lamina propria, and few located in the intestine gland and the villus.The OX1R mainly located in the lamina propria of the mucosa of the small intestine, and cells were mostly oval. The distribution of Orexin in the small intestine of African ostrich had similarities and some differences, which indicated that there were conservative and diversity among different animals. According to the distribution of the three positive cells,we can speculate that Orexin-A and Orexin-B must be transported into the lamina propria and then binded with the receptor to play a physiological function.(2) The developmental changes of Orexin in the small intestine of African ostrichThe development changes of Orexin-A, Orexin-B and0X1R were similar. With the change of age, the number of orexin firstly increased and then decreased, and peaked on45d, which showed Orexin played a key role in the intestine development of ostrich. The number of Orexin-B was less than Orexin-A, which showed that Orexin-A was more effective than Orexin-B. Ostriches on45d were in the stage of rapid development, and they needed more Orexin to participate in the regulation of growth and development. According to these changes, we can suggest that Orexin and its receptors play regulatory roles in the development of the small intestine and the digestive function of African ostrich.