Molecular Screening on The Existence of Edwardsiella tarda in Hybrid Red Tilapia (Oreochromis sp.) from Inland Farm in Jeli, Kelantan

Edwardsiella tarda is an emerging fish pathogen that jeopardize the aquaculture industry worldwide by causing significance economic loss. Infection by E.tarda can be characterized by symptoms and clinical signs that varies depending on the aquaculture species. Lack of knowledge among farmers in Kelantan on edwardsiellosis induce risk on the public health of consumer. The present study aimed to screen for E.tarda infection in hybrid red tilapia from inland farm in Jeli through molecular screening hence determined the prevalence of E.tarda infection. Forty hybrid red tilapia weighed between 141.66 ± 4.02 g and 150.73 ± 3.71 g were randomly collected twice a month throughout two months of sampling period. Any abnormalities during necropsy of the fish sampled was recorded. The DNA was extracted from fish kidney and subjected to molecular screening through conventional polymerase chain reaction (PCR). Optimised PCR protocol was used for the rest of amplification reaction with annealing temperature at 52.8°C. The presence of E.tarda through PCR was confirmed through expected amplicon size of 415bp. From the result obtained, enlargement of kidney was observed during necropsy of sampled fish which indication to one of E.tarda infection clinical sign. On top of that, prevalence of E.tarda was the highest in Week 1 which contributed 40% prevalence while for Week 2 until Week 4, no prevalence was recorded. Even though there was low prevalence of E. tarda detected in the samples, it still may lead to outbreak of disease in the farm. Thus, development of prevention method against this pathogen deserved a serious attention and appropriate control need to be considered.