Title : Nanovaccine recombinant testing based on hybrid chitosan-agnps nanoparticles in vivo on cantang grouper (Epinephalus sp.)
Abstract:
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. 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 research results indicate that the administration of the nanovaccine based on silver nanoparticles (C-AgNPs) from recombinant C.vulgaris had a significant effect on enhancing immune gene expression post-challenge in cantang grouper over 28 days, as observed from the fish's blood cellular response. In Treatment 4 (T4) (Cantang grouper + nanovaccine 33 µl + VNN virus), the best research outcomes were achieved with a survival rate (SR) of 88.9%, instantaneous growth (weight: 0.022; length: 0.014), relative growth (weight: 83.3%; length: 50%), and total growth (weight: 20%; length: 6%). Survival rate analysis results for cantang grouper that had been cultured for 28 days ranged from 16.7% to 94.4%. The highest survival rate was found in the nanovaccine administration treatment for healthy fish, specifically in Treatment 1 (T1) with 88.8%, while the highest survival rate in the nanovaccine administration followed by VNN virus infection was observed in Treatment 4 (T4) with 72.2%. The lowest survival rate was in Treatment K+ with 17.7%. The analysis results above indicate that the SR level of cantang grouper after receiving a nanovaccine based on marine microalga C.vulgaris was significantly higher in T1, T2, and T3 compared to Treatment K+. In T4, T5, and T6, which were given the nanovaccine and then challenged with VNN, the results were significantly different from Treatment K+. The analysis results of the Relative Percent Survival (RPS) for cantang grouper cultured for 28 days ranged from 56.3% to 87.5%. The highest RPS value was obtained in the treatment with a nanovaccine dosage of 33 µl, specifically in T1 (87.5%) and T4 (68.8%), followed by the treatment with a nanovaccine dosage of 66 µl, specifically in T2 (81.3%) and T5 (62.5%), and the treatment with a nanovaccine dosage of 112 µl, specifically in T3 (75%) and T6 (56.3%). The best leukocyte count was found in T4 (1.88x104 cells/mm3). The highest erythrocyte count was recorded in T4 (2.58x106 cells/mm3). The best Hb level was found in T4 (6.2 g/dL). The best differential leukocyte count was found in T4, specifically (lymphocytes: 92%; monocytes: 27%; basophils: 0.20%; neutrophils: 25%). 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.
