Development of probiotic formulations with immune enhancing activities for chickens

益生菌被定义为活的微生物，当给予足够的量时，通过改善肠道微生物平衡而对宿主的健康有益(FAO/WHO，2002)。几种共生细菌，包括一些乳杆菌，具有益生菌活性。尽管它们的作用模式还不完全清楚，但这些有益细菌在人类和农场动物中都是一个密集研究的领域。在家禽生产中，人们对益生菌的兴趣源于它们作为抗生素生长促进剂的替代品，以及控制肠道微生物在肠道定植的一种策略，这些微生物会导致人类的食源性疾病，如沙门氏菌和弯曲杆菌。特别是，沙门氏菌污染几十年来一直是对食品安全和人类健康的主要威胁。益生菌也可以影响免疫系统的发育。然而，目前已证实具有增强鸡免疫能力的益生菌产品数量非常有限。我们以前研究过乳酸菌的免疫调节活性，并开发了一种含有几种乳酸菌的配方，能够增强鸡的免疫反应和减少沙门氏菌的负担。拟议的研究旨在进一步评估这种益生菌制剂，并确定其安全性、给药途径、对生长、饲料效率、免疫系统发育和禽类的免疫反应性的影响。最后，我们打算在类似于商业家禽生产操作的环境中测试这种配方。

Probiotics are defined as live microorganisms, which when administered in adequate amounts confer a health benefit on the host through improvements to the intestinal microbial balance (FAO/WHO, 2002). Several species of commensal bacteria, including some Lactobacillus bacteria have probiotic activities. Although their mode of action is not completely understood, these beneficial bacteria are an area of intensive research in both humans and farm animals. In poultry production, interest in probiotics stems from their use as alternatives to antibiotic growth promoters and also as a strategy for control of intestinal colonization with enteric microbes that cause food-borne illness in humans, such as Salmonella and Campylobacter. In particular, Salmonella contamination has been a major on-going threat to food safety and human health for decades. Probiotic bacteria can also influence the development of the immune system. However, a very limited number of probiotic products are currently available with proven immune enhancing capabilities in chickens. We have previously investigated lactobacilli for their immunomodulatory activities and developed a formulation containing several lactobacilli with the ability to enhance immune responses and reduce Salmonella burden in chickens. The proposed studies are designed to further evaluate this probiotic formulation and to determine its safety, route of administration, effects on growth, feed efficiency, immune system development and immune responsiveness of birds. Finally, we intend to test this formulation in a setting similar to that found in commercial poultry production operations.