Department of Microbiology, Stellenbosch University, Private Bag X1, Matieland, Stellenbosch, 7602, South Africa.
Probiotics Antimicrob Proteins. 2021 Feb;13(1):1-11. doi: 10.1007/s12602-020-09640-z.
Pathogens develop resistance to antibiotics at a rate much faster than the discovery of new antimicrobial compounds. Reports of multidrug-resistant bacteria isolated from broilers, and the possibility that these strains may spread diseases amongst humans, prompted many European countries to ban the inclusion of antibiotics in feed. Probiotics added to broiler feed controlled a number of bacterial infections. A combination of Enterococcus faecium, Pediococcus acidilactici, Bacillus animalis, Lactobacillus salivarius and Lactobacillus reuteri decreased the colonisation of Campylobacter jejuni and Salmonella Enteritidis in the gastro-intestinal tract (GIT) of broilers, whereas Bacillus subtilis improved feed conversion, intestinal morphology, stimulated the immune system and inhibited the colonisation of Campylobacter jejuni, Escherichia coli and Salmonella Minnesota. Lactobacillus salivarius and Pediococcus parvulus improved weight gain, bone characteristics, intestinal morphology and immune response, and decreased the colonisation of S. Enteritidis. Lactobacillus crispatus, L. salivarius, Lactobacillus gallinarum, Lactobacillus johnsonii, Enterococcus faecalis and Bacillus amyloliquefaciens decreased the Salmonella count and led to an increase in lysozyme and T lymphocytes. Probiotics may also improve feed digestion through production of phytases, lipases, amylases and proteases or stimulate the GIT to secrete digestive enzymes. Some strains increase the nutritional value of feed by production of vitamins, exopolysaccharides and antioxidants. Bacteriocins, if produced, regulate pathogen numbers in the GIT and keep pro-inflammatory and anti-inflammatory reactions in balance.
病原体对抗生素的耐药性发展速度远远快于新抗菌化合物的发现。从肉鸡中分离出的多药耐药菌的报告，以及这些菌株可能在人类中传播疾病的可能性，促使许多欧洲国家禁止在饲料中添加抗生素。益生菌添加到肉鸡饲料中控制了许多细菌感染。肠球菌、嗜酸乳杆菌、动物双歧杆菌、唾液乳杆菌和鼠李糖乳杆菌的组合降低了空肠弯曲菌和肠炎沙门氏菌在肉鸡胃肠道中的定植，而枯草芽孢杆菌改善了饲料转化率、肠道形态、刺激了免疫系统，并抑制了空肠弯曲菌、大肠杆菌和明尼苏达沙门氏菌的定植。唾液乳杆菌和戊糖片球菌提高了增重、骨骼特性、肠道形态和免疫反应，并降低了肠炎沙门氏菌的定植。嗜酸乳杆菌、唾液乳杆菌、鸡源乳杆菌、约氏乳杆菌、粪肠球菌和解淀粉芽孢杆菌降低了沙门氏菌数量，并导致溶菌酶和 T 淋巴细胞增加。益生菌还可以通过产生植酸酶、脂肪酶、淀粉酶和蛋白酶来改善饲料消化，或刺激胃肠道分泌消化酶。一些菌株通过产生维生素、胞外多糖和抗氧化剂来提高饲料的营养价值。如果产生细菌素，它们可以调节胃肠道中的病原体数量，保持促炎和抗炎反应的平衡。
