Vibriosis is one of the common diseases caused by gram-negative bacteria from the genus Vibrio. To treat vibriosis, vaccination has been proven to be the most effective treatment as it can avoid the risk of drugs or antibiotics resistance. Microalgae are commonly used as feed for aquatic organisms and Nannochloropsis sp. is one of the highly utilized species for fish feed. This study focused on the use of microalga, Nannochloropsis sp. as a vaccine carrier. Transgenic Nannochloropsis sp. harbouring an outer membrane protein kinase (OmpK) gene fragment of the Vibrio species namely V1, V2, CV1, CV2, CPV1 and CPV2 were utilized in this study. The stability of OmpK gene in transgenic Nannochloropsis sp. over a number of generations was evaluated. DNA and RNA from the Nannochloropsis sp. transgenic lines were extracted and subjected to PCR amplification of OmpK gene fragment. The OmpK gene fragment was successfully amplified and expressed up to the fifth generation (F5). For V1, V2, CV1 and CV2, the gene was present and expressed in fourth generation (F4) and F5 respectively but CPV1 and CPV2 the OmpK genes were present up to F4. From the results obtained, Nannochloropsis sp. is shown to be suitable as a vaccine carrier and can be utilized as a vaccine carrier to ameliorate vibriosis.