Effects of Exogenous Ghrelin on Duodenal Growth and Development of African Ostrich Chicks

Background: The African ostrich is the largest herbivorous bird in the world, which has high economic value. However, the brooding period of African ostrich is long. During this period, the various organs of the body are not fully developed, the resistance is low and it is easy to get sick, thus affecting the growth and development. Therefore, it is of great significance to enhance the digestion and absorption capacity of ostrich chicks and improve its growth speed in shortening the incubation period of ostrich, improving the survival rate of ostrich and the economic benefits of ostrich breeding. Methods: Sixteen 40-day-old African ostrich chicks (male or female) were randomly divided into four groups and injected intravenously of Metatarsal vein with saline (control) or ghrelin (10, 50 and 100 mu g/kg) for 6 days. The morphology, gastrin and pepsin levels in the duodenum were measured using stereology, HE staining and radioimmunoassay. Result: The 10, 50 and 100 mu g/kg of ghrelin administered groups showed lower duodenal length and length index than the control group (P<0.05). Villus length increased in the 50 mu g/kg and 100 mu g/kg ghrelin administered groups (P<0.05). Crypt depth decreased in the 10 mu g/kg ghrelin administered group (P<0.05). The ratio of villus length to crypt depth in each group increased and the difference was significant in the 50 mu g/kg and 100 mu g/kg ghrelin administered groups (P<0.05). Pepsin content in the duodenum slightly increased in the 10 mu g/kg ghrelin administered group (P>0.05) and it significantly decreased in the 50 mu g/kg and 100 mu g/kg ghrelin administered groups (P<0.05). Gastrin content in the duodenum increased significantly (P<0.05) in the 10 mu g/kg ghrelin administered group and decreased in the 100 mu g/kg ghrelin administered group (P<0.05).