幼龄羔羊高致病高致死现象普遍存在，严重制约着我国养羊业的发展。新生羔羊出生后尽快采食初乳并获得充足被动免疫可提高幼龄羔羊存活率，其主要原因是：新生羔羊出生后肠道处于‘打开’状态，通过采食初乳进入消化道内腔的大分子免疫球蛋白可直接渗透过肠道上皮组织进入血液，这种‘打开’状态持续24-36 h后进入‘闭合’，通过肠道直接吸收免疫球蛋白的能力也随之消失。然而，对于肠道闭合控制和调控因素却鲜有研究。本项目拟以浏阳黑山羊为试验动物，围绕新生羔羊采食初乳后免疫球蛋白变化、控制新生羔羊肠道闭合的分子基础、以及新生羔羊被动免疫调控因素三个方面进行研究，以揭示新生羔羊采食初乳后被动免疫建立规律，探明控制这一被动免疫的分子生物学机制，并探索影响新生羔羊被动免疫的调控因子。项目的实施将丰富对山羊免疫球蛋白吸收代谢与新生羔羊关系的认知，为制定合适的幼龄羔羊饲养管理措施，进而改善其生长发育和健康状况提供科学依据。

Neonatal morbidity and mortality in goats remain high in China, which badly influences the development of goats industry. Obtaining adequate passive transfer by feeding high quality and high quantity colostrum after birth can improve neonatal survival in goats. Increased knowledge on the biology of neonatal goats suggests that the immunoglobulin (IgG) in the colostrum can be absorbed directly through the epithelium of gut since it is considered to be ‘open’ after birth. However, after 24-36 h of life, the gut becomes less permeable to IgG which is termed ‘gut closure’, thereby the capacity of transferring IgG from colostrum to blood disappears. The mechanisms controlling and regulating gut closure are rarely studied. Using Liuyang Black Goats as experimental animals, this project will conduct studies focusing on IgG kinetics in neonatal goats after colostrum feeding, molecular basis which controls the development of passive immunity, and the mechanisms regulating passive immunity. The aims of this project are to uncover the pattern of establishing passive immunity in goats, and to explore the molecular mechanisms which control and regulate passive immunity. The implement of this project will increase our knowledge regarding the IgG absorption and metabolism after feeding colostrum and its relationship with neonatal goats. This will provide farmers appropriate feeding strategies to improve neonatal growth and health in goats.