Front Cover

Fish Diseases

Fish Diseases: Prevention and Control Strategies

Copyright

Dedication

Contents

List of Contributors

Preface

1. FISH

2. PATHOGENS

3. ENVIRONMENT

ACKNOWLEDGMENT

I - Fish

1 - Immunology: Improvement of Innate and Adaptive Immunity

1.1 INTRODUCTION

1.2 TELEOST IMMUNITY

1.2.1 Innate Immunity

1.2.2 Adaptive Immunity

1.2.2.1 Major Histocompatibility Complex

1.2.2.2 B-Cells and Antibodies

1.2.2.3 T-Cells

1.2.2.3.1 T-Helper Cells

1.2.2.3.2 Cytotoxic T-cells

1.2.2.3.3 Regulatory T-cells

1.2.3 Immune Tissues in Fish

1.3 EFFECTORS OF THE IMMUNE RESPONSE

1.4 IMPROVEMENT OF THE IMMUNE RESPONSE

1.4.1 Vaccines

1.4.2 Immunostimulants

1.4.3 Probiotics, Prebiotics, and Synbiotics

1.4.4 Nucleotide Diets

1.5 CONCLUDING REMARKS AND FUTURE PERSPECTIVES

REFERENCES

2 - Improvement of Disease Resistance by Genetic Methods

2.1 HOW TO ASSESS DISEASE RESISTANCE IN FISH?

2.1.1 Which Traits Can Be Used to Score Disease Resistance at the Individual Level?

2.1.2 Testing for Resistance: Natural Outbreaks Versus Controlled Challenge Testing

2.2 BASIC GENETIC PRINCIPLES

2.2.1 DNA, Chromosomes, and Inheritance

2.2.2 Genetic Variation

2.2.3 Heritability

2.2.4 Inbreeding

2.2.5 Correlation Between Traits

2.3 SELECTIVE BREEDING TO IMPROVE RESISTANCE

2.3.1 General Processes in Relation to Diseases

2.3.2 Heritability of Disease Resistance and Survival Traits

2.3.3 Response to Selection for Survival and Disease Resistance

2.3.4 Combining Resistance to Diseases and Production Traits in Breeding Objectives

2.3.4.1 Correlations With Production Traits

2.3.4.2 Correlations Among Resistance to Different Diseases

2.3.4.3 Correlation Between Survival in the Field and Survival After Experimental Disease Challenge

2.3.5 Resistance to Diseases in Selection Programs Worldwide

2.4 APPLICATION OF NEW BIOTECHNOLOGIES

2.4.1 Measuring Variation in the Nucleotide Sequence of DNA

2.4.2 Linkage Mapping and Genome-Wide Association

2.4.3 Gene Expression

2.4.4 Epigenetics

2.4.5 Marker-Assisted and Genomic Selection

2.5 ROLE OF SELECTIVE BREEDING IN AN OVERALL HEALTH IMPROVEMENT STRATEGY

2.5.1 Combining Different Health Management Strategies

2.5.1.1 Genetic Resistance and Vaccination

2.5.1.2 Stress Response, Cardiovascular Fitness and Disease Susceptibility

2.5.2 Selection for Sustainable Resistances: Integrating New Facets of Host Response

2.5.2.1 Targeting General or Specific Immune Responses?

2.5.2.2 Toward New Desirable Traits to Improve Resistance

2.6 CONCLUSION

REFERENCES

II - Pathogens

3 - Types of Pathogens in Fish, Waterborne Diseases

3.1 INTRODUCTION

3.2 HOST SPECIFICITY OF PATHOGENS

3.3 VIRAL PATHOGENS

3.3.1 Virally Induced Host Behavioral Changes

3.3.2 Viral Shedding

3.3.3 The Carrier Status

3.3.4 Vectors

3.3.5 Predator–Prey Relationships

3.3.6 Modes of Transmission of Bacterial Pathogens Between Fish

3.3.7 Bacteria

3.3.8 Bacterial Pathogens

3.3.9 Methods of Bacterial Transmission

3.3.9.1 Behavioral Changes

3.3.9.2 Shedding

3.3.9.3 Adhesion

3.3.9.4 Host-Seeking

3.3.9.5 Carriers

3.3.9.6 Vertical Transmission

3.3.9.7 Vectors

3.3.9.8 Predator–Prey Relationships

3.4 TRANSMISSION OF FUNGAL DISEASE: THE WATER MOLDS

3.4.1 External “Fungal” Pathogens

3.4.2 Egg, Fry, and Larvae Infections

3.4.3 Shedding

3.4.4 Biofilms and Secondary Infection of Open Wounds

3.4.5 Internal Infections and Behavioral Changes

3.5 PARASITE TRANSMISSION

3.5.1 Parasite-Induced Host Behavior Changes

3.5.2 Shedding

3.5.3 Predatory–Prey Relationships

3.5.4 Host-Seeking Behavior

3.5.5 Vectors

3.5.6 Sexually Transmitted Parasites

3.5.7 Hormonal Manipulation

3.6 CONCLUSION

REFERENCES

4 - Prophylactic and Prevention Methods Against Diseases in Aquaculture

4.1 INTRODUCTION

4.2 GENERAL DISEASE PREVENTION AND CONTROL METHODS

4.2.1 Quality Seeds

4.2.2 Culture Hygiene

4.2.3 Water Quality Parameters

4.2.4 Nutrition

4.2.4.1 Vitamins

4.2.4.2 Minerals

4.2.4.3 Proteins

4.2.4.4 Lipids and Sterols

4.2.4.5 Carbohydrates

4.2.5 Chemicals Used to Control Diseases

4.2.5.1 Disinfectants

4.2.5.2 Antiparasitic

4.2.5.3 Antibiotics

4.3 BIOLOGICS

4.3.1 Vaccines

4.3.1.1 Types

4.3.1.2 Vaccination Methods

4.3.1.3 Current Status and Future Perspectives

4.3.2 Immunostimulants

4.3.2.1 Sources

4.3.2.1.1 Plant-derived Immunostimulants

4.3.2.1.2 Microbial-derived Immunostimulants

4.3.2.1.3 Algal-Derived Immunostimulants

4.3.2.1.4 Synthetic Immunostimulants

4.3.2.1.5 Animals and Other Sources

4.3.2.2 Mechanism of Action of Immunostimulants

4.3.2.3 Future Prospects

4.3.3 Probiotics

4.4 CONCLUSIONS

ACKNOWLEDGMENT

REFERENCES

5 - Integrated Pathogen Management Strategies in Fish Farming

5.1 THE CONCEPT: WHAT ARE INTEGRATED PATHOGEN MANAGEMENT STRATEGIES AND WHY DOES AQUACULTURE NEED THEM?

5.2 DIAGNOSTIC TOOLS, THE KEY FOR IDENTIFICATION AND MONITORING OF PATHOGENS

5.3 MODELING DISEASE TRANSMISSION AND RISK ASSESSMENT

5.3.1 Risk Factors

5.3.2 Disease Modeling

5.4 PREVENTION STRATEGIES IN FISH FARMING

5.4.1 Management of Environmental Risks

5.4.1.1 Management of Water

5.4.1.2 Management of Farming Conditions

5.4.1.2.1 Site Location and Timing of Site Use

5.4.1.2.2 Removal/Reduction of Biofouling

5.4.1.2.3 Minimizing Contact With Wild Fauna

5.4.1.2.4 Reducing Contact With the Pathogen

5.4.2 Management of Host Risks

5.4.2.1 Management of Farming Conditions

5.4.2.2 Exploitation of the Immune System

5.5 TREATMENT STRATEGIES IN FISH FARMING

5.5.1 Chemical Control

5.5.1.1 Antibiotics

5.5.1.2 Parasiticides

5.5.1.3 Other Chemicals

5.5.2 Biological Control

5.5.2.1 Cleaner Fish

5.5.2.2 Microorganisms

5.5.2.3 Filter-Feeding Organisms

5.5.3 Physical Control

5.6 CONCLUSIONS AND FUTURE PERSPECTIVES

ABBREVIATIONS

ACKNOWLEDGMENT

REFERENCES

III - Environment

6 - General Relationship Between Water Quality and Aquaculture Performance in Ponds

6.1 INTRODUCTION

6.2 WATER QUALITY–AQUATIC ANIMAL HEALTH INTERACTIONS

6.2.1 Stress

6.2.2 Toxicity

6.2.3 Optimum Ranges

6.2.4 Avoiding Diseases

6.3 MANAGEMENT AND WATER QUALITY

6.4 WATER QUALITY–RELATED STRESSORS

6.4.1 Temperature and Salinity

6.4.2 pH

6.4.3 Dissolved Oxygen

6.4.4 Carbon Dioxide

6.4.5 Ammonia

6.4.6 Hydrogen Sulfide

6.4.7 Gas Supersaturation

6.4.8 Toxic Algae

6.4.9 Ionic Imbalance

6.5 WATER-QUALITY MANAGEMENT

6.5.1 Alkalinity and pH

6.5.2 Dissolved Oxygen

6.5.3 Nitrogenous Metabolites

6.5.4 Hydrogen Sulfide

6.5.5 Toxic Algae

6.5.6 Gas Supersaturation

6.5.7 Ionic Imbalance

6.6 Conclusion

REFERENCES

7 - Water Quality–Disease Relationship on Commercial Fish Farms

7.1 WATER TEMPERATURE

7.1.1 Etiology

7.1.2 Mechanism of Action

7.1.3 Clinical Symptoms

7.1.4 Pathological–Morphologic Symptoms

7.1.5 Diagnosis

7.1.6 Prevention

7.2 WATER PH

7.2.1 Etiology

7.2.2 Mechanism of Action and Toxicity

7.2.3 The Impact of Water pH on the Toxicity of Some Substances

7.2.4 Clinical Symptoms

7.2.5 Pathological–Morphologic Symptoms

7.2.6 Diagnosis

7.2.7 Therapy

7.2.8 Prevention

7.3 OXYGEN

7.3.1 Etiology and Mechanism of Action

7.3.2 The Impact of Dissolved Oxygen Level on the Toxicity of Selected Substances

7.3.3 Clinical Symptoms

7.3.4 Pathological–Morphologic Symptoms

7.3.5 Diagnosis

7.3.6 Therapy

7.3.7 Prevention

7.4 AMMONIA

7.4.1 Etiology

7.4.2 Mechanism of Action

7.4.3 Toxicity

7.4.4 Clinical Symptoms

7.4.5 Pathological–Morphologic Symptoms

7.4.6 Diagnosis

7.4.7 Therapy

7.4.8 Prevention

7.5 NITRITE

7.5.1 Etiology

7.5.2 Mechanism of Action

7.5.3 Toxicity

7.5.4 Clinical Symptoms

7.5.5 Pathological–Morphologic Symptoms

7.5.6 Diagnosis

7.5.7 Therapy

7.5.8 Prevention

7.6 CHLORINE

7.6.1 Etiology

7.6.2 Mechanism of Action

7.6.3 Toxicity

7.6.4 Clinical Symptoms

7.6.5 Pathological–Morphologic Symptoms

7.6.6 Diagnosis

7.6.7 Therapy

7.6.8 Prevention

ACKNOWLEDGMENTS

REFERENCES

8 - Stress and Disease in Fish

8.1 STRESS AND DISEASE

8.1.1 What Is Stress? The Impact of Stress on Aquaculture

8.1.2 Physiological Effects and Relationship to Disease

8.1.2.1 Stress: A Three-Stage Model

8.1.2.2 Allostasis

8.1.2.3 Stress and the Immune System

8.1.2.4 Stress and Metabolism

8.1.2.5 Stress and Ion Homeostasis

8.1.3 Endocrine Control and Mediators

8.1.3.1 Cortisol and Glucocorticoids

8.1.3.2 Other Factors of the HPI Axis

8.1.3.3 The Adrenergic System

8.1.3.4 The Somatotropin Family

8.1.4 Gene Network and Regulation Linking the Immune System to Disease Resistance

8.1.4.1 Innate Immunity

8.1.4.2 Acquired Immunity

8.1.4.3 Stress and Immune-Associated Disease

8.1.5 Stress Management

8.1.6 Conclusions

ACKNOWLEDGMENT

REFERENCES

9 - Planning a Fish-Health Program

9.1 INTRODUCTION

9.1.1 Formulating a Fish-Health Management Plan at the Farm/Facility Level

9.2 FISH DISEASE-PREVENTION PLAN DURING THE FACILITY SITE SELECTION, DESIGN, AND CONSTRUCTION

9.2.1 Choosing an Optimal Site for an Aquaculture Facility Can Minimize Disease Outbreaks

9.2.2 Water Quality

9.2.3 Temperature

9.2.4 Facility Design

9.3 FISH DISEASE-PREVENTION PLAN PRIOR TO OPERATION

9.3.1 Training of Personnel

9.3.2 Fish Eggs

9.3.3 Food Source and Storage

9.3.4 Quarantine

9.3.5 Medicine Cabinet

9.4 FISH-HEALTH MAINTENANCE PLAN DURING OPERATION

9.4.1 Prophylactic Measures to Minimize Pathogen Introduction Through Gametes

9.4.2 Food, Nutrition, Immunostimulants, and Probiotics

9.4.3 Maintain an Optimum Environment

9.4.4 Disease-Prevention by Segregation and Logistical Planning

9.4.5 Fish Handling

9.4.6 Monitoring Fish for Disease Signs

9.4.7 Sedation and Anesthesia in Fish

9.5 PROPER SPECIMEN COLLECTION FOR DIAGNOSTIC PURPOSES

9.5.1 Purpose of Investigation

9.5.2 Samples Needed

9.5.3 Sample Integrity

9.5.4 Available Resources

9.5.5 Consultation

9.5.6 Case History

9.6 FISH TRANSPORTATION

9.6.1 Shipping Live Specimens

9.6.2 Shipping Fresh Fish Specimens on Ice

9.6.3 Frozen Specimens

9.7 VACCINATION

9.8 BIOSECURITY

9.8.1 Minimizing Pathogen Introductions

9.8.2 Hygienic Practices to Minimize Pathogen Loads and Interrupt Their Transmission

9.9 CONTROL MEASURES UPON ERUPTION OF A DISEASE OUTBREAK

9.10 FORMULATING A FISH-HEALTH MANAGEMENT PLAN AT THE REGIONAL/NATIONAL AND INTERNATIONAL LEVELS

9.10.1 National, Regional, and International Efforts to Control Pathogen Transfer

9.10.2 Components of a Fish-Health Plan at the National and International Levels

9.10.3 Disease Surveillance

9.10.4 Certification

9.10.5 Zoning

9.10.6 Risk Assessment

9.10.7 Quarantine

9.11 CONCLUSION

REFERENCES

10 - Aquatic Animal Health and the Environmental Impacts

10.1 INTRODUCTION

10.2 NATURAL RESOURCE USE

10.2.1 Land

10.2.2 Water

10.2.3 Energy

10.2.4 Embodied Natural Resources

10.3 DISEASE TRANSFER

10.4 CHEMICAL USE

10.4.1 Fertilizers

10.4.2 Antibiotics

10.4.3 Insecticides

10.4.4 Herbicides

10.4.5 Other Chemicals

10.5 CONCLUSION

REFERENCES

Index

A

B

C

D

E

F

G

H

I

K

L

M

N

O

P

Q

R

S

T

V

W

Y

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