Detection of vibrio harveyi using iavh primer in shrimp fry infected under different immersion time

Abstract

Methods for the early detection of the pathogenic luminous Vibrio bacteria would be beneficial through enabling timely (early) implementation of preventative measures to reduce shrimp mortality due to vibriosis. This study aimed to measure the sensitivity of the IAVh haemolysin primer in detecting pathogenic Vibrio harveyi in tiger shrimp (Penaeus monodon) fry. This research was conducted in the Fish Health and Environment Laboratory at the Research Institute for Coastal Aquaculture (BPPBAP) in Maros, South Sulawesi, Indonesia. In this study, tiger shrimp fry were infected with the pathogenic V. harveyi bacteria through an immersion method at concentrations of 105, 106, and 107CFU/mL. Samples were collected after immersion times of 6 hours, 12 hours, and 24 hours. The presence of the haemolysin gene was detected through the PCR (Polymerase Chain Reaction) technique using the IAVh primer set. Electrophoresis results detected the presence of pathogenic V. harveyi bacteria after 6 hours of exposure, although the DNA bands produced were still thin. After 12 hours exposure, the DNA bands of pathogenic V. harveyi bacteria were clearly visible. However, after 24 hours exposure, the presence of the haemolysin gene of pathogenic V. harveyi bacteria was no longer detected. Similar results were obtained for all bacterial concentrations tested. It is thought that the 24 hour results are due to a decline in the population of V. harveyi bacteria living within the shrimp body and shrimp culture media. These findings indicate that it is important to implement rapid detection methods early on in cases of bacterial infection in shrimp (0 - 12 hours), since it was difficult to detect the presence of pathogenic bacteria in the shrimp body tissues more than 12 hours post infection.