Vaccination and quarantine

Oct 13, 2025 by leolavanderia.com.br 112 views

The Effect of Water Salinity on Viral Necrosis Viral Pathogenicity Levels on Tiger Grouper Seeds (Epinephelus Fuscoguttatus)

Introduction

Water salinity has a significant impact on the health and survival of fish, particularly in aquaculture settings. The tiger grouper (Epinephelus fuscoguttatus) is a popular species for aquaculture due to its high market demand and fast growth rate. However, the spread of viral nervous necrosis (VNN) has become a major concern in tiger grouper cultivation, leading to significant economic losses. This study aims to investigate the effect of water salinity on VNN pathogenicity levels in tiger grouper seeds.

Background

Viral nervous necrosis (VNN) is a highly contagious and deadly disease affecting fish worldwide. The virus causes severe damage to the nervous system, leading to symptoms such as lethargy, loss of appetite, and erratic swimming behavior. The disease has been reported in various fish species, including the tiger grouper, which is a popular species for aquaculture. The spread of VNN has been linked to various factors, including water quality, temperature, and salinity.

Methodology

This study was conducted from January to April 2011 at the molecular biology laboratory Center for Class I Polonia, Medan, and in the laboratory of anatomical pathology and Biochemical Investigation Laboratory at the Medan Regional Veterinary Testing Center. The experimental design used was Completely Randomized Design (CRD), with five salinity treatments: S20 (20 ppt), S25 (25 ppt), S30 (30 ppt), S35 (35 ppt), and S40 (40 ppt), and K30 control (30 ppt) that were not infected with VNN. Each treatment was carried out with three replications consisting of 10 fish in a 20-liter capacity aquarium. The fish were injected with an intramuscular virus with a concentration of 10-4/0.1ml (FID50). The data obtained was then analyzed using SPSS version 13.

Results

The results showed that the level of salinity had a significant effect on VNN pathogenicity (p <5%). The S30 treatment showed a high level of VNN pathogenicity, while the S25 treatment showed a low pathogenicity level. The hematological tests revealed a decrease in the number of erythrocytes and an increase in the number of leukocytes. The histopathological test showed the presence of vacuolization around glial cells and obstruction of blood vessels containing erythrocytes. The RT-PCR test confirmed that the S30 treatment had the highest pathogenicity level, while the S25 treatment had the lowest level.

Discussion

The results of this study indicate that 30 ppt salinity provides a more supportive environment for viruses to multiply, leading to an increase in VNN infection. Conversely, 25 ppt salinity showed a decrease in virus pathogenicity. This finding can be used as a basis for designing salinity management strategies in aquaculture ponds to prevent the spread of viral diseases.

Conclusion

This study provides an important insight into the optimal condition of salinity to maintain the health and survival of fish seeds. The results of this study can be used to develop effective management strategies for preventing the spread of VNN in tiger grouper cultivation. Further research is needed to examine other factors such as temperature, pH, and density of fish in relation to salinity and VNN infection.

Recommendations

Based on the findings of this study, the following recommendations are made:

Salinity management: Fish farmers should maintain a salinity level of 25 ppt to prevent the spread of VNN in tiger grouper cultivation.
Monitoring and testing: Regular monitoring and testing of water quality and fish health should be conducted to detect any signs of VNN infection.
Vaccination and quarantine: Vaccination and quarantine procedures should be implemented to prevent the spread of VNN in tiger grouper cultivation.
Further research: Further research is needed to examine other factors such as temperature, pH, and density of fish in relation to salinity and VNN infection.

Future Directions

This study provides a foundation for further research on the interaction between salinity and virus pathogenicity in tiger grouper cultivation. Future studies should investigate the effects of other environmental factors, such as temperature and pH, on VNN pathogenicity in tiger grouper seeds. Additionally, research on the development of effective management strategies for preventing the spread of VNN in tiger grouper cultivation is necessary.

Limitations

This study has several limitations, including:

Small sample size: The sample size of this study was relatively small, which may limit the generalizability of the findings.
Limited environmental factors: This study only examined the effects of salinity on VNN pathogenicity, and did not consider other environmental factors such as temperature and pH.
Limited duration: This study was conducted over a relatively short period of time, which may not be representative of the long-term effects of salinity on VNN pathogenicity.

Conclusion

In conclusion, this study provides an important insight into the optimal condition of salinity to maintain the health and survival of fish seeds. The results of this study can be used to develop effective management strategies for preventing the spread of VNN in tiger grouper cultivation. Further research is needed to examine other factors such as temperature, pH, and density of fish in relation to salinity and VNN infection.
Frequently Asked Questions (FAQs) on the Effect of Water Salinity on Viral Necrosis Viral Pathogenicity Levels on Tiger Grouper Seeds (Epinephelus Fuscoguttatus)

Q: What is the main purpose of this study?

A: The main purpose of this study is to evaluate the impact of water salinity on the level of VNN pathogenity in infected tiger grouper fish.

Q: What is the experimental design used in this study?

A: The experimental design used in this study is Completely Randomized Design (CRD), with five salinity treatments: S20 (20 ppt), S25 (25 ppt), S30 (30 ppt), S35 (35 ppt), and S40 (40 ppt), and K30 control (30 ppt) that were not infected with VNN.

Q: What is the significance of the results obtained in this study?

A: The results obtained in this study indicate that the level of salinity has a significant effect on VNN pathogenicity (p <5%). The S30 treatment shows a high level of VNN pathogenicity, while the S25 treatment shows a low pathogenicity level.

Q: What are the implications of the findings of this study?

A: The findings of this study have significant implications for the management of tiger grouper cultivation. The results suggest that maintaining a salinity level of 25 ppt can help prevent the spread of VNN in tiger grouper cultivation.

Q: What are the limitations of this study?

A: The limitations of this study include a small sample size, limited environmental factors, and limited duration.

Q: What are the recommendations based on the findings of this study?

A: Based on the findings of this study, the following recommendations are made:

Salinity management: Fish farmers should maintain a salinity level of 25 ppt to prevent the spread of VNN in tiger grouper cultivation.
Monitoring and testing: Regular monitoring and testing of water quality and fish health should be conducted to detect any signs of VNN infection.
Vaccination and quarantine: Vaccination and quarantine procedures should be implemented to prevent the spread of VNN in tiger grouper cultivation.
Further research: Further research is needed to examine other factors such as temperature, pH, and density of fish in relation to salinity and VNN infection.

Q: What are the future directions for research based on the findings of this study?

A: The findings of this study provide a foundation for further research on the interaction between salinity and virus pathogenicity in tiger grouper cultivation. Future studies should investigate the effects of other environmental factors, such as temperature and pH, on VNN pathogenicity in tiger grouper seeds.

Q: What are the potential applications of the findings of this study?

A: The findings of this study have potential applications in the management of tiger grouper cultivation, including the development of effective management strategies for preventing the spread of VNN in tiger grouper cultivation.

Q: What are the potential benefits of the findings of this study?

A: The findings of this study have potential benefits for the aquaculture industry, including improved fish health and survival, reduced economic losses due to disease, and increased productivity.

Q: What are the potential risks associated with the findings of this study?

A: The findings of this study have potential risks associated with them, including the potential for the spread of VNN in tiger grouper cultivation if not managed properly.

Q: What are the potential implications for the environment of the findings of this study?

A: The findings of this study have potential implications for the environment, including the potential for changes in water quality and fish populations due to the spread of VNN in tiger grouper cultivation.

Q: What are the potential implications for human health of the findings of this study?

A: The findings of this study have potential implications for human health, including the potential for the spread of VNN to humans through the consumption of infected fish.

Q: What are the potential implications for the economy of the findings of this study?

A: The findings of this study have potential implications for the economy, including the potential for economic losses due to the spread of VNN in tiger grouper cultivation.

Q: What are the potential implications for the social and cultural aspects of the findings of this study?

A: The findings of this study have potential implications for the social and cultural aspects, including the potential for changes in the way fish are farmed and consumed.