Determination of the efficacy of herbal extracts on immune response and disease resistance in striped catfish (Pangasius hypophthalmus) against aeromonas hydrophila infection | |
| Author | Duc Nguyen Thanh |
| Call Number | AIT Thesis no.AQ-15-02 |
| Subject(s) | Catfishes Aquaculture Fishes--Feeding and feeds Catfishes--Feeding and feeds |
| Note | A thesis submitted in partial fulfillment of the re quirements for the Degree of Master of Science in Aquaculture and Aquatic Resources Management, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. AQ-15-02 |
| Abstract | Aeromonas hydrophila is one of the most serious pathogenic bacteria in striped catfish, Pangasius hypophthalmus , causing major losses to the aquaculture industry in Vietnam . The use of antibiotics to treat fish disea ses has been increasing recently, and that has led to enhanced antibiotic resistance as well as the presence of residual antibiotic residues in fish and fish products. The objective of the present study was to evaluate potential herbal extracts for their a ntibacterial activities, hematology, and immune response of striped catfish juveniles challenged with A. hydrophila . Ethanol, methanol and distilled water were tested as solvents to prepare extracts from two herbs with known antibacterial properties, viz. , stone breaker, Phyllanthus niruri (leaves and fruits) and false daisy, Eclipta alba (leaves). Extracts from the two plants were initially tested for their antimicrobial activities and minimum inhibitory concentration (MIC) against A. hydrophila , which re vealed that the extract of P. niruri prepared in ethanol had the strongest antimicrobial activity (11.3 mm inhibition zone) and the best MIC ( 1.25 mg/ml) against A. hydrophila , while none of the extracts from E. alba was found to be effective . The ethanol extract was then incorporated into test diets containing levels of 0% (control), 0.5%, 1%, and 1.5% and fed to striped catfish juveniles (20 – 25 g/fish) challenged with A. hydrophila in an experiment that lasted six weeks to test the effect of the extract on hematology parameters of fish such as white blood cells (WBC), red blood cells (RBC), hematocrit (Hct), hemoglobin (Hb), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC); immune response para meters such as phagocytic activity and respiratory burst activity; and relative percentage survival of the fish tested. Feeding striped catfish with the test diets with ethanol extract of P. niruri resulted in significant (P < 0.05) increase in WBC, RBC, Hct, and Hb after four weeks of rearing while there was no significant (P > 0.05) increase in MCV, MCH and MCHC over the entire rearing period of six weeks, compared to the control. Phagocytic activity significantly (P < 0.05) increased after four weeks a nd six weeks of feeding, while respiratory burst activity did not differ significantly (P > 0.05) when compared to the control. The highest survival of striped catfish obtained was 62 % at 1% level of extract in feed, compared to 51% in the control. From t he results obtained in the present study it is concluded that the ethanol extract of P. niruri has potential to control A. hydrophila disease in striped catfish, and further validation of the immume parameters with extensive trials on several other commerc ially important fish species are recommended to establish its wider applications. |
| Year | 2015 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. AQ-15-02 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Aquaculture and Aquatic Resources Management (AQ) |
| Chairperson(s) | Salin, Krisha R. |
| Examination Committee(s) | Anal, Anil Kumar;Yakupitiyage, Amararatne |
| Scholarship Donor(s) | Deutscher Akademischer Austausch Dienst (DAAD), Germany;AIT Fellowship |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 2015 |