Summary of doctoral thesis: Isolation of bacillus subtilis and its application on the prevention of intestinal diseases in chicken

The objectives: At least one Bacillus subtilis strain was isolated in some provinces in the Mekong Delta, having probiotic properties such as: ability to produce digestive enzymes (amylase, protease, lipase); resistance to digestive juice (gastric juice and bile acid), ability to adhere to intestinal mucus and resistance to some pathogenic bacteria (S. enterica, E. coli).
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Summary of doctoral thesis: Isolation of bacillus subtilis and its application on the prevention of intestinal diseases in chicken MINISTRY OF EDUCATION AND TRAINING CAN THO UNIVERSITY SUMMARY OF DOCTORAL THESIS Specialization: Pathology and treatment of animals Code: 62 64 01 02 LE THI HAI YEN ISOLATION OF BACILLUS SUBTILIS AND ITS APPLICATION ON THE PREVENTION OF INTESTINAL DISEASES IN CHICKEN Can Tho, 2018 THE STUDY WAS COMPLETED AT CAN THO UNIVERSITY Scientific supervisor: Assoc. Prof. Doctor NGUYEN DUC HIEN The thesis was defended at the university examination committee At.………………………………………., Cantho University At……….. hour ….…, on date……..month…..…. year…… Reviewer 1: Reviewer 2: Reviewer 3: The dissertation is available in Libraries: 1. Central library of Can Tho University. 2. National library of Vietnam. LIST OF PUBLICATION RELATED TO THE THESIS 1. Le Thi Hai Yen and Nguyen Duc Hien, 2015. Bacillus subtilis isolated as a probiotic from soil and feces on chicken farms in Can Tho City. Veterinary Sciences and Techniques. ISSN 1859-4751. Vol. 6 (2015) 55- 62 2. Le Thi Hai Yen and Nguyen Duc Hien, 2015. Study on the probiotic properties of Bacillus spp. strains isolated from poultry farms at Cantho City. Proceedings of National Conference on Animal & Veterinary Science. ISBN 978-604-60-2019-6. Agriculture publishing house, page 485-491 3. Le Thi Hai Yen and Nguyen Duc Hien, 2016. Isolation and identification of Bacillus subtilis isolated from soil and feces on chicken farms in the Mekong delta, Vietnam. Proceedings of the 19th Federation of Asian Veterinary Associations Congress, Ho Chi Minh City, September 6-9th, 2016. Vietnam National University-Ho Chi Minh city Press, page 143- 147 4. Le Thi Hai Yen and Nguyen Duc Hien, 2016. Evaluation of the probiotic properties of Bacillus subtilis strains isolated from Mekong delta. ISSN 1859-2333. Can Tho University Journal of Science. Vol 2 (2016), 26-32 5. Le Thi Hai Yen and Nguyen Duc Hien, 2017. Assessment of gastric acid, bile salt tolerance and aggregation ability of Bacillus subtilis AG27 and VL28. Proceedings of National Conference on Animal & Veterinary Science. ISBN 978-604-60-2492-7. Agriculture publishing house, page 341-346 6. Le Thi Hai Yen and Nguyen Duc Hien, 2017. Isolation and characterization of probiotic Bacillus subtilis VL28 on chicken farms in Vietnam. Proceedings of 33rd World Veterinary Congress, Incheon – Korea, August 27-31, 2016. 7. Le,T.H.Y. and Nguyen,D.H., 2017. Bacillus subtilis strain VL28 16S ribosomal RNA gene, partial sequence. GenBank: KY346980.1 https://www.ncbi.nlm.nih.gov/nuccore/KY346980 Chapter I: INTRODUCTION 1.1. Necessity In recent years, the strong development of poultry breeding has brought great values to economo-social benefits. However, it also results in many concerns. One of the concerning issue is the overuse of antibiotics in the prevention from diseases and in the stimulating growth. In consequence, antibiotic resistant bacteria are increasing in nature and that affects significantly the use of antibiotics for infectious diseases in human beings. Therefore, the majority of developed countries did limit the use of antibiotics in breeding. In order to replace them in breeding, scientists put forward different solutions, one of them is using probiotic- useful microorganisms in gastro- intestinal activities and, broadly speaking, in improving health. Bacillus subtilis are universal bacteria that are present in nature, and they are almost not harmful to human being as well as to several kinds of animals but resistant strongly to several physical and chemical factors. As a result, they were selected and chosen as probiotics for human beings and breeding animals in industrial models. However, B. subtilis have the diversity in biological properties, so all of them could not be used as probiotic and just some strains of probiotic could be suitable and effective for certain animals. The thesis “Isolation of Bacillus subtilis and its applications on the prevention of intestinal diseases in chicken” was carried out in order to find out the alternatives that could replace antibiotics in breeding, to increase productivity and effectiveness in industrial chicken breeding and to reduce the risks of antibiotic resistant bacteria spreading in nature. 1.2. The objectives At least one Bacillus subtilis strain was isolated in some provinces in the Mekong Delta, having probiotic properties such as: ability to produce digestive enzymes (amylase, protease, lipase); resistance to digestive juice (gastric juice and bile acid), ability to adhere to intestinal mucus and resistance to some pathogenic bacteria (S. enterica, E. coli). - The effective dosages of that probiotic isolate were identified to prevent the intestinal diseases in chicken caused by E. coli and Salmonella. 1.3. Subjects and scope - Subjects: Bacillus subtilis strains - Scope: the strains of Bacillus subtilis were isolated form soil and chicken feces in 7 provinces belonging to the Mekong Delta namely: Can Tho, Hau Giang, An Giang, Vinh Long, Dong Thap, Soc Trang, Kien Giang. 1.4. Novel aspects - This is the first research did select the local B. subtilis strain that showed effectiveness in the prevention of intestinal diseases in chicken in Mekong Delta, especially the diseases were caused by S. enterica and E. coli. - This is the scientific research on the isolation and selection of probiotic bacteria systematically based on International Standards. - Twenty one B. subtilis isolates were correctly identified from fecal and soil samples ...