Immune response of Litopenaeus vannamei juveniles immersed in Gracilariopsis heteroclada hot-water extract

The emergence of diseases such as Acute Hepatopancreatic Necrosis Disease and White Spot Syndrome has compelled researchers in shrimp aquaculture to develop more innovative methods in improving shrimp health management for the prevention of diseases. One of these methods involves the use of immunostimulants, which enhance the innate immunity of shrimp. Polysaccharides extracted from red seaweeds such as Gracilariopsis heteroclada, locally known as “Gulaman”, present a great source of immunostimulants. Thus, this study aimed to evaluate Gracilariopsis heteroclada as an immunostimulant for Litopenaeus vannamei, or Pacific white shrimp. Hot-water extracts of Gracilariopsis heteroclada were administered through immersion. Results showed no significant changes in total haemocyte count, ambiguous fluctuations in phenoloxidase activity, and a late temporary increase in respiratory burst activity. Overall, these indicate a lack of significant immunostimulation in Litopenaeus vannamei juveniles when immersed in Gracilariopsis heteroclada hot-water extract