Effect of Excoecaria agallocha on non-specific immune responses and disease resistance of Oreochromis niloticus against Streptococcus agalactiae
The current study was designed to evaluate the effects of Excoecaria agallocha leaf extracts on immune mechanisms and resistance of tilapia, Oreochromis niloticus, after challenge with Streptococcus agalactiae. Fish were divided into 6 groups; groups 1–5 fed with E. agallocha leaf extracts at 10, 20...
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| Published in: | Research in veterinary science Vol. 112; pp. 192 - 200 |
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| Main Authors: | , , , , , , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
England
Elsevier Ltd
01-06-2017
Elsevier Limited |
| Subjects: | |
| Online Access: | Get full text |
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| Summary: | The current study was designed to evaluate the effects of Excoecaria agallocha leaf extracts on immune mechanisms and resistance of tilapia, Oreochromis niloticus, after challenge with Streptococcus agalactiae. Fish were divided into 6 groups; groups 1–5 fed with E. agallocha leaf extracts at 10, 20, 30, 40 and 50mgkg−1 level, respectively. Group 6 were fed without extract addition and acted as control. E. agallocha extracts were administered as feed supplement in fish diet for 28days and the hematological, immunological, and growth performance studies were conducted. Fish were infected with S. agalactiae at a dose of 15×105CFUmL−1 and the total white blood cell (WBC), phagocytosis and respiratory burst activities of leukocytes, serum bactericidal activity, lysozyme, total protein, albumin, and globulin levels were monitored and mortalities recorded for 15days post infection. Results revealed that feeding O. niloticus with 50mgkg−1 of E. agallocha enhanced WBC, phagocytic, respiratory burst, serum bactericidal and lysozyme activities on day 28 pre-challenge and on 3rd, 6th, 9th, 12th and 15th day post-challenge as compared to control. Total protein and albumin were not enhanced by E. agallocha diet. E. agallocha increased the survival of fish after challenge with S. agalactiae. The highest mortality rate (97%) was observed in control fish and the lowest mortality (27%) was observed with group fed with 50mgkg−1 extract. The results indicate that dietary intake of E. agallocha methanolic leaf extract in O. niloticus enhances the non-specific immunity and disease resistance against S. agalactiae pathogen.
•The effects of Excoecaria agallocha leaf extracts on immune mechanisms, haematological performance, growth performance studies and resistance of red hybrid tilapia (Oreochromis niloticus) before and after challenge with Streptoccus agalactiae are studied.•Fish were infected with S. agalactiae at doses of 15×105 CFU mL-1 and total white blood cell (WBC), phagocytosis, respiratory burst activity of blood leukocytes, serum bactericidal activity, serum lysozyme, total serum protein, albumin level, and globulin levels were monitored and mortalities recorded for 15 days post infection.•Results revealed that feeding red hybrid tilapia (O. niloticus) with 50 mg kg-1 of E. agallocha significantly enhanced white blood cell (WBC) count, phagocytic activity, respiratory burst activity, serum bactericidal activity, and lysozyme activity as compared to control. Total protein and albumin in serum were not enhanced by E. agallocha diet; however, globulin level in group fed with 50 mg kg-1 showed significant difference (P < 0.05) as compared to control. E. agallocha also increased the survival of fish, the highest mortality was observed in control fish at 97%, and the lowest mortality observed was with 50 mg kg-1 at 27%.•E. agallocha added to diets can be used in red hybrid tilapia (O. niloticus) as immunostimulants to enhance non-specific immunity, increase survival rate, and enhance resistance against S. agalactiae infections. |
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| Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
| ISSN: | 0034-5288 1532-2661 |
| DOI: | 10.1016/j.rvsc.2017.04.020 |