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| Author(s): |
Gustavo Moraes Ramos Valladão
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Jaboticabal. 2018-03-09. |
| Institution: | Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal |
| Defense date: | 2018-02-26 |
| Advisor: | Fabiana Pilarski |
| Abstract | |
Essential oils (EOs) of plants are compounds studied as food additive in animal production a few years ago. They have already been described by several authors, as growth promoter, immunostimulant and antimicrobial. However, the effects of its addition on the diet of aquatic organisms are still poorly understood. In the present study, different supplementation strategies with different EOs were tested. In the first study, the EOs of Mentha piperita and Melaleuca alternifolia were supplied for a long period (2 months) in the diet of Nile tilapia Oreochromis niloticus, and aspects of health (hematological, biochemical and immunological parameters) and intestine (morphology and morphometry) were evaluated. In a second moment, M. piperita, M. alternifolia, Citrus aurantium, Cymbopogon nardus, Ocimum basilicum and Thymus vulgaris were tested in vitro against the intestinal isolates (Aeromonas hydrophila, Staphylococcus aureus and Edwardsiella tarda) from Nile tilapia to select the one with the greatest capacity to modulate the microbiota of fish. Thymus vulgaris EO was the one that presented the highest activity against the bacteria tested. In a final study, the Thymus vulgaris EO was provided for 15 days in the diet of Nile tilapia where its effects on the health, intestine and on the population of bacteria of the genus Bacillus were evaluated. In the first experiment, it was shown that M. piperita and M. alternifolia were able to immunostimulate components of fish humoral response (activating the complement system) and M. alternifolia was still able to alter intestinal morphology (increasing their villi). The T. vulgaris EO presented higher antibacterial activity when compared to five other EOs, and when added to the diet it was able to immunostimulate components of the cellular response of fish (increasing the number of leukocytes and lymphocytes). In addition, despite its strong antibacterial activity, it was not able to alter the population of beneficial bacteria of the genus Bacillus present in the intestine. In both in vivo experiments, diets supplemented with EO showed no toxic effects on fish under the conditions tested. In conclusion, supplementation with EOs was safe, showed an immunostimulating effect on different components of the immune response, may in some cases alter the intestinal morphology and appear to have little impact on the fish microbiota. (AU) | |
| FAPESP's process: | 14/14039-9 - Phytotherapics in diets for fish: molecular characterization of the microbiota, morphology and study of molecules associated with gut health |
| Grantee: | Gustavo Moraes Ramos Valladão |
| Support Opportunities: | Scholarships in Brazil - Doctorate |