ZnO/Chitosan Nanoconjugates from Chlorella vulgaris as Nanostimulants Against Viral Nervous Necrosis in Grouper
DOI:
https://doi.org/10.48048/tis.2026.12105Keywords:
Grouper, Viral Nervous Necrosis, Chlorella vulgaris, ZnO/Chitosan nanoconjugates, NanostimulantsAbstract
Grouper farming underpins Indonesia’s coastal livelihoods and supplies both domestic and export markets, yet disease-especially Viral Nervous Necrosis (VNN) in juveniles-remains a major constraint. Conventional tools (antibiotics, standard vaccines) have delivered limited protection, motivating alternative approaches. Leveraging nanotechnology, we evaluated a ZnO-chitosan nanoconjugate carrying a recombinant Chlorella vulgaris antigen for antiviral protection in cantang grouper (E. fuscoguttatus×E. lanceolatus). In a 56-day randomized block trial, 160 fish were allocated to 5 treatments (T1 - T5) and two controls. Endpoints included growth (length, weight, survival rate, SR; relative percent survival, RPS), hematology (erythrocytes, leukocytes, hematocrit, hemoglobin), gill histopathology, and flow cytometry of CD4⁺/CD8⁺ T-cell markers. The 33 µL regimen (T3) was consistently superior: length rose from 9.94 → 12.73 cm and weight from 13.57 → 18.00 g, with SR = 95% and RPS = 92%. Hematological profiles improved across all indices; gill lesions were minimal (mild edema, hyperplasia, lamellar fusion); and immunophenotyping showed moderated CD4⁺ activation alongside a marked increase in CD8⁺ expression, indicating effective cellular immunity. While T1 and T4 performed well and T2/T5 yielded moderate responses, T3 delivered the most balanced protection and significantly lowered viral load. These results highlight the promise of recombinant Chlorella antigens formulated in ZnO-chitosan nanoconjugates to strengthen grouper health and bolster aquaculture sustainability.
HIGHLIGHTS
- Recombinant Chlorella vulgaris combined with ZnO/Chitosan nanoconjugates significantly enhanced grouper fish growth, immune response, and survival against Viral Nervous Necrosis (VNN).
- Optimal nanovaccine dose (33 µL) resulted in the highest Survival Rate (95%) and Relative Percent Survival (92%) compared to control groups.
- Nanostimulants improved hematological parameters (RBC, WBC, Hb, Hct), indicating better overall fish health and immune function.
- Histopathology showed reduced tissue damage in the gills (mild edema, hyperplasia, and lamella fusion), suggesting the nanovaccine mitigates viral-induced damage.
- Flow cytometry analysis revealed controlled T-cell activation, indicating a well-balanced immune response and avoiding excessive immune stimulation.
GRAPHICAL ABSTRACT
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