Studies on development of mucosal immune system in piglets for establishment of animal production system with reduced use of antimicrobials

在畜牧业生产中，幼畜的疾病控制是保证生产效率的关键。断奶期是最易感染的时期。因此，许多抗菌剂已作为饲料添加剂、生长促进剂应用于断奶动物。然而，由于社会压力要求食品不受任何化学品污染，因此需要建立不使用任何抗菌剂或最少使用抗菌剂的动物生产系统。在这种情况下，很明显，要提高幼动物对传染病的抵抗力。为此，有必要加速幼动物粘膜免疫系统的发育。在本研究中，我们发现：（1）断奶前后肠道伊加浓度降低，（2）在这一特定时期感染的风险增加，（3）晚断奶（35日龄）诱导粘膜免疫系统的发育，（4）益生菌乳酸杆菌的刺激对晚断奶动物更有帮助。

In the animal agriculture, the disease control of infant animals is crucial for the efficient production. Weaning period is the most vulnerable period to the infection. Therefore, many antimicrobials have been applied as feed additive, growth promoters, to the weaning animals. However, it is required to establish animal production systems without any anitimicrobials or with minimum use of antimicrobials from the social pressure that demands non-contaminated food with any chemicals. In this context, it is obvious to increase the resistance of infant animals against the infectious diseases. To this end, it is necessary to accelerate the developemnt of the mucosal immune system of the infant animals. In this study, we have shown (1) decrease in luminal IgA concentration around weaning, (2) Increase in the risk of infection in this particular period, (3) late weaning(35d old) induced development of mucosal immune system, (4) Stimulation by probiotic lactobaciilus was more helpful in late weaning animals.