One of the biggest challenges in grouper farming is the attack from various parasites or intracellular viruses, such as Viral Nervous Necrosis (VNN). This virus targets grouper during the larval and juvenile stages and can cause mortality rates of up to 100%. The aim of this research is to study the impact of administering a nanovaccine with recombinant protein from Chlorella vulgaris based on hybrid Chitosan-AgNPs nanoparticles in enhancing the growth, survival rates, Relative Percent Survival, and immune response of cantang grouper infected with VNN through the blood cellular response. The treatments are divided into 8 groups: K+ (Fish infected with VNN), K- (Healthy fish), T1 (Cantang Grouper + nanovaccine 33 µl), T2 (Cantang Grouper + nanovaccine 66 µl), T3 (Cantang Grouper + nanovaccine 112 µl), T4 (Cantang Grouper + nanovaccine 33 µl + VNN), T5 (Cantang Grouper + nanovaccine 66 µl + VNN), and T6 (Cantang Grouper + nanovaccine 112 µl + VNN). Parameters observed in this study include growth, instantaneous growth, relative growth, and total growth over 28 days. Observations of survival rate, Relative Percent Survival, and blood immune response, including measurements of erythrocyte and leukocyte counts, hemoglobin levels, and leukocyte differentials (lymphocytes, monocytes, basophils, and neutrophils).
The study shows that administering the recombinant nanovaccine, based on silver nanoparticles (C-AgNPs ) derived from C.vulgaris , significantly boosts immune gene expression in cantang grouper post-challenge. Treatment 4 (Cantang grouper + nanovaccine 33 µl + VNN virus) yields the best outcomes: a survival rate (SR) of 88.9%, enhanced growth rates, and notable blood cellular responses. Survival rates for 28-day cultured cantang grouper range from 16.7% to 94.4%, with the highest in Treatment 1 (T1) and Treatment 4 (T4). Relative Percent Survival (RPS) ranges from 56.3% to 87.5%, with T1 and T4 showing the highest values.
Notably, T4 exhibits the best leukocyte and erythrocyte counts, as well as hemoglobin levels. In conclusion, the administration of the recombinant nanovaccine from Chlorella vulgaris based on silver nanoparticles (C-AgNPs ) in vivo shows a preventive response to Viral Nervous Necrosis virus infection. The optimal nanovaccine dosage is 33 µl, representing an effective vaccine immunogenicity level in enhancing the immune system of cantang grouper. This is evidenced by the growth response, survival rates, Relative Percent Survival, and blood cellular response of cantang grouper.