The Global Goals
In 2015, UN member states agreed to 17 global Sustainable Development Goals (SDGs) to end poverty, protect the planet and ensure prosperity for all. Sherilyn's work contributes towards the following SDG(s):
About Sherilyn
PhD student - Biological Sciences Project Title: Effects of Host-derived Probiotics on the Growth Performance and Health of Tilapia and CarpDirector of Studies: Dr Daniel Merrifield
2nd Supervisor: Dr Mark Rawling
My PhD project investigates on the effects of potential host-derived probiotics on growth, feed utilization, intestinal health, and digestive enzymes of tilapia and carp. Probiotics derived from the host have gained attention for its suitability and capacity to establish effective colonisation of the host gut. Autochthonous probiotic candidate isolates from mirror carp and Nile tilapia will be screened in vitrofor pathogen antagonism activity, pathogen-mucosal colonisation studies, and extracellular enzyme activity. The potential probiotic candidates will be tested for antagonism against important fish pathogens such as Aeromonas hydrophila, Streptococcus iniae, Vibrio anguillarum, Vibrio parahaemolyticus, Yersinia ruckeri, and Pseudomonas anguilliseptica. Promising candidate isolates will be selected for use in pathogen-mucosal colonisation studies on a range of aquacultured freshwater fish species. This assay will be conducted to investigate the potential of the probiotic candidate isolates to inhibit the proliferation of the fish pathogen in the rearing medium and on the mucosal surfaces of the fish. To perform this, the fish will be euthanized and exposure assays will be conducted using whole fish bodies immediately post-mortem. This is a pilot approach to reduce the negative impacts on welfare by challenging live fish. The potential candidate isolates will also be subjected to qualitative screening for phytase, xylanase, tannase, and chitinase production.
Potential probiotic candidates from the in vitro assays will be incorporated in the fish diets to be used for in vivo studies. In vivo trials will be conducted to assess the effects of the probiotic diets on fish growth performance and carcass composition. Fish intestinal samples will be processed for histological examination, microbiological analysis, and gene expression analysis to assess wider impacts of the probiotic diets on gut health status.
Teaching
Teaching Faculty - De La Salle University Integrated School(2017-2022) Subjects Taught:- General Biology (Botany and Zoology) -Lecture and Laboratory
- Practical Research
- Earth and Life Science
