Ms Sherilyn Abarra

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 candidate - Biological Sciences

Member of the Fish Health and Nutrition Research Group

Project Title: Effects of Host-derived Probiotics on the Growth Performance and Health of Tilapia and Carp
Director 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 utilisation and intestinal health 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 are screened in vitro for pathogen antagonism activity, haemolytic activity, and extracellular enzyme activity. The potential probiotic candidates are tested for antagonism against important fish pathogens such as Aeromonas hydrophila, Streptococcus iniae, Vibrio anguillarum, Vibrio parahaemolyticus, and Yersinia ruckeri. The potential candidate isolates are also subjected to qualitative screening for phytase, xylanase, and tannase activity.
Potential probiotic candidates from the in vitro assays are incorporated in the fish diets and used for in vivo studies. In vivo trials are conducted to assess the effects of the probiotic diets on fish growth performance and carcass composition. Fish intestinal samples are processed for histological examination, microbiological analysis, and gene expression analysis to assess wider impacts of the probiotic diets on gut health status.