The effect of short-term exposure to water extract of phycobiliproteins on adult Pacific oysters (Magallana gigas)

In the context of the rapid development of Russian aquaculture for bivalve mollusks in the 21st century, it has become crucial to develop technologies that aim to minimize stress levels and enhance the resistance of oysters against diseases and parasitic infections in hatcheries. This research investigated the effect of an aqueous extract of phycobiliproteins (CBP), derived from the blue-green alga Spirulina platensis, at concentrations ranging from 2 to 200 μg/mL on adult Pacific oysters (Magallana gigas) for 24-48 hours. Using flow cytometry, we assessed the cellular composition of oyster hemolymph, apoptosis induction in hemocytes, and their metabolic activity. Furthermore, oyster mortality and respiratory activity have been evaluated throughout the experiment. The findings revealed that the highest extract concentration (200 μg/ml) decreased hemocyte metabolic activity and reduced the relative proportion of granulocytes within the oyster hemolymph. At the same time, there was no significant difference in the proportion of apoptotic hemocytes between the experimental and control groups. The survival rate of mollusks in the experiment was 100%, indicating that the extract may be relatively safe for these organisms. These findings suggest that the extract could be used as a basis for the development of functional feeds based on spirulina derivatives, which could increase resistance and reduce stress in oysters during cultivation in aquaculture nurseries.