Document Type

Honors Thesis


Marine Sciences


Timothy Bowden

Committee Members

Ian Bricknell, Kristina Cammen, William Ellis, Melissa Ladenheim

Graduation Year

May 2023

Publication Date

Spring 2023


Aquaculture has taken over from capture fisheries as a primary global provider of seafood products. Seriola lalandi, or Yellowtail kingfish, has become a species of interest, as it is a fish notable for its marketability and culinary desirability. With the expansion of aquaculture and the increased amount of high-level operating facilities comes an increased risk of disease outbreaks. There are methods commonly used within these facilities for disease control, including incorporating nutritional feeds into the fishes’ diets, safe husbandry practices, and vaccinations. While these methods can be effective, they have caveats that must be considered. Adequate diets and improved husbandry techniques are only preventative measures of disease control, and vaccinations must be administered properly to ensure adequate efficiency. Timeliness of vaccination regimes during larval development is especially important, as to avoid tolerance and ineffectiveness of the vaccines, and to promote the survival of fish in their earlier, more vulnerable stages of development. Previous literature has investigated the early development of the immune system in the larval stages of many species through the expression of the RAG-1 and RAG-2 genes. These genes have been shown to be indicators of the physiological maturity of the immune system, playing an important role in the differentiation of B- and T-cells, both crucial for immune response. For this project, RNA was extracted from larval Yellowtail kingfish tissue samples ranging from 0 to 25 days post hatch (DPH). The RNA was then converted into cDNA through reverse transcription, and qPCR was conducted to quantify gene expression, using the ΔΔ𝐶𝑡 method, at the selected developmental time points. Between these two time points, there was no significant peak in the expression of the RAG-1 gene, however, there is a slight

increase starting at 21 DPH. This indicates that there is a possibility that RAG-1 expression may happen later in larval development (after 25 DPH), or, that there is no identifiable peak in its expression in development. More studies involving tracking the expression of genes associated with immune development in farmed species are incredibly important for the prevention of disease within aquaculture operations, assessing human health risk of consumption depending on pathogen exposure, and the continuity of aquaculture and food sourcing.

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