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Fish Diseases PRINCIPLES OF AQUACULTURE (AKU3201).

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Presentation on theme: "Fish Diseases PRINCIPLES OF AQUACULTURE (AKU3201)."— Presentation transcript:

1 Fish Diseases PRINCIPLES OF AQUACULTURE (AKU3201)

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4 HostEnvironment - Stocking density- Poor sanitation -Handling- Changes in pH, salinity -Transport temperature etc. -Chemotherapy -Nutrition -Behaviour Disease agent - Pathogen/ non-pathogen -Opportunistic pathogen Factors affecting fish health 3 Disease Host Disease agent Env

5 Physical barrier (skin, scales, exoskeleton, shell, mucous membranes) 1) Host susceptibility 4

6 Physical Signs Blistered areas Swollen bellies Popped-out eyes Bloody (hemorrhaged) areas on fins Discoloration or erosion of body parts Excessive mucus Growths on the body 5 Behavioral Signs Failure to feed properly Flashing (turning on their sides) Rubbing on the bottom Gathering around the water inflow Reduced vitality Gasping at the surface

7 Physiological defences - Immune system, detoxification by liver -Nutritional well-being Age (Young more susceptible) Spawners – stress due to their reproductive functions 6

8 Unusual behaviour -Scrap body to wall -Coming to surface, gulping for air - Erratic swim Loss appetite Physical changes Sick fish 7

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11 Exophthalmia (Pop-eye) Diseases 10

12 Extended belly 11

13 Haemorrhage 12

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18 Crucial role in disrupting the balance between host & pathogen Environmental stress => pathogen & host react = disease occur 2) Environment 17

19 Stress -Anoxia = absence of oxygen -Fright -Anaesthesia -Temperature changes -Injury -Pollution 18

20 High stocking density Restricted spaces – cages/tanks, raceway Large quantity of concentrated feeds/ fertilizer 19

21 2) Environment 20 Do not exceed carrying capacity – stocking density Always monitor water quality Maintain proper DO, pH, alkalinity, temperature Check accumulation of organic debris, nitrogenous waste (ammonia, nitrite), hydrogen sulfide Remove pond bottom sludge, dry & lime

22 21 Temperature changes – fluctuation day & night Poikilothermic Hatchery -Closed system -If temp. drops, used heater

23 Potential pathogens always present in aquatic environment 3) Disease agent 22

24 Parasites (cestodes, nematodes, trematodes & protozoans) Bacteria (vibriosis, edwardsiellosis, furunculosis) Viruses (IPN, lymphocystis) Fungi (saprolegniasis, branchimycosis) Disease agent 23

25 Common entry point 1) Wound in skin  Bacteria/viral infections => fungal infection 2)Gills  Pathogen enter body through delicate & thin epithelium  Protozoa establish themselves on them 3) Digestive tract  Bacteria penetrate intestinal lining  Protozoa 24

26 Most common cause of fish mortalities Especially in larvae & fingerling stages Multiply rapidly without intermediate host Attach themselves to the host – special organ such as suckers 1) Parasites 25

27 Penetrate host to multiply & invade vital organs Invade through ingestion, skin rupture, transgression of gill lamellae, penetration to the egg membrane 26

28 Protozoan: Ichthyopthirius multifiliis 27

29 Copepod : Argulus, Lernaea 28

30 Isopod (Sea lice) 29

31 Monogenean parasites 30 Dactylogyrus

32 31 Gyrodactylus

33 Nematode 32

34 Vibriosis - Vibrio harveyi 2) Bacterial disease 33

35 Vibrio anguillarum Vibrio alginolyticus 34

36 Quorum sensing 35

37 Monitor the environment & alter behaviour 2) Bacterial quorum sensing Quorum sensing (QS) 36

38 Signal molecules 2) Bacterial quorum sensing Diseases – controlled by QS AHL 37 (Found in 70 different G- bacterial species) BHL AHL

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40 Aeromonas -Aeromonas hydrophila -Aeromonas salmonicida 39

41 Furunculosis 40

42 Edwardsillosis -Edwardsiella tarda -Edwardsiella ictaluri 41

43 How to identify bacterial isolates 42

44 Cotton swab 43

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48 Biochemical test 47

49 Molecular techniques 48

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51 ELISA (Enzyme-linked immunosorbent assay) Serology 50 Antigen – Antibody Enzyme = Sensitive method

52 Infectious pancreatic necrosis (IPN) 3) Viral disease 51

53 Lymphocystis 52

54 White spot 53

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56 4) Fungal disease 55

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61 Case study- Malaysia 60

62 Mass mortality June- August 61

63 Import- export Exotic disease Stress during transport Fish weak & susceptible to disease How to overcome 1)Discourage/ ban import of live fish 2)Quarantine & sterilize the fish 3)Purchase from reliable source 4)Seed free from disease Spread of disease between country 62

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65 Spread of disease in pond/cages -Through water channel -Spread pond to pond -No barrier -Water current -Dead fish thrown into open waters -Other animals as carrier -Equipments 64

66 1) Integrated health management 2) Health inspection & disease monitoring 3) Disease treatment 4) Sanitation 5) Immunization 6) Genetic resistance to disease 7) Farm disinfection Solution to fish disease 65

67 Guidelines for prevention, control & eradication Correction of disease-causing & disease spreading conditions Adoption & implementation of policies & regulations by the state – need cooperative effort 1) Integrated health management 66

68 Always monitor & record health status, water quality etc. – corrective measures can be taken One trained person & basic facilities to undertake regular health & environmental monitoring - if expensive then twice a year inspection 2) Health inspection & disease monitoring 67

69 Chemotherapy – temporary, effect on biofiter Antibiotic – resistant bacteria Vaccines – specific to certain fish 3) Disease treatment 68

70 Maintain good sanitation Good culture practices Monitor water supply –ozonation, UV, chlorination Egg disinfection 4) Sanitation 69

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72 Quarantine – particularly to prevent the introduction of communicable disease - Facilities located away from farm -Need to disinfect all facilities = chlorination 71

73 Mechanism of antibody production Antibody = specific immunoglobulin (modified protein) produced in response to & reacts specifically with an antigen (foreign substance that stimulate the formation of antibodies) Vaccines contains antigens that are generally attenuated or killed disease agents. When administered to a host, they stimulate the production of specific antibodies or non-specific resistance to that particular disease agent 5) Immunization 72

74 Vaccination -Immersion = small fish -Spray-shower = fish larger than 4g -Injection = intra-peritoneal -Retain immunity ~300 days 73

75 Disease resistant strains through genetic breeding Select strains with disease resistant High level of genetic diversity + hybrid vigour 6) Genetic resistance to disease 74

76 Disease outbreak = Farmer destroy stock & disinfect rearing facilities Easier fro small, well-controlled facilities e.g., hatcheries, tank, raceways. Earthern pond = difficult 7) Farm disinfection 75

77 During transportation -Minimize physical injury – use smooth net -Avoid sharp edge tank -Stop feeding 12-24h to reduce metabolism & excretion - Provide high oxygen level - Salt at 0.3-1% to minimize osmotic stress -Anesthesia if necessary -Put bag into Styrofoam box -Acclimatization- bag left floating for 30 minutes Special care during transportation 76

78 Quarantine new fish – check for pathogen Remove dead fish from system Dispose dead fish properly Good sanitation practices 77

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80 Ketapang leaves 79

81 Improve water quality o 80

82 Biosecurity= Steps taken to keep disease from a farm & to prevent the transmission of disease within an infected farm to neighboring farm. Consideration on initial facility layout design Breeder => hatchery => growout (need to ensure biosecurity measures) Need to have SOP Isolation, sanitation & control Closed system Open system? Biosecurity 81

83 1)Reduce the risk of disease introductions 2)Minimise the spread of diseases on-farm or to new areas 3)Promote fish health 4)Protect economic investment 5)Protect human health Biosecurity 82

84 1)Avoid the introduction of certain pathogens into an aquaculture facilities a)Purchase from a producing selling certified specific pathogen-free (SPF) stock b)SPF = special stock of animals that are kept in specific pathogen free facilities under rigorious monitoring system c) Problem: Only few spp. of SPF e.g. shrimp -Shrimp have primitive immune system -No workable vaccine Biosecurity 83

85 d) Tilapia & Pangasius no SPF but have vaccine e) Vaccinated Pathogen Free seed-stock (VPF) VPF = Fish vaccinated when they are healthy & before exposure to the nature f) Have own in house broodstock/spawning facilities g) Have a quarantine/ isolation facilities 84

86 2) Provide a pathogen- free water source -Mechanical filtration -Chemical treatment -UV filtration -Ozonation -Well- water -Biological treatment 85

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88 Drum-filter = filtration of suspend solids in closed system 87

89 Protein skimmer = remove dissolved organic matter in water 88

90 3) Disease monitoring -Always monitor for clinical signs of disease -Regular scheduled health evaluation -Sampled for diagnostic health techniques -Treat if warranted 89

91 4) Disinfection - Strict adherence to cleaning & disinfection techniques -Foot bath & hand wash -Container with disinfectant for nets etc. -Separate equipments (nets, feed bucket) -Disinfect vehicles -E.g disinfectant = Hypochlorite -Maintain good husbandry practices 90

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93 First chlorine, then thiosulphate to nuetralize chlorine 92

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95 Good aquaculture practices (GAP) -Improved production, food safety assurance & preservation of environments Hazard Analysis Critical Control Point (HACCP) Standard sanitation & operating procedures (SSOP) 94

96 Malaysian Aquaculture Farm Certification Scheme Sijil Pensijilan Ladang Akuakultur Malaysia (SPLAM) -Encourage Good Aquaculture Practice & emphasize implementation of HACCP - Aquaculture entrepreneurs need to fulfill requirements & criteria set by DOF -Make application, undergo a review audit & final approval - Valid for two years SPLAM 95

97 Official recognition to aquaculture entrepreneurs who have practiced GAP & environmental friendly concepts Objective SPLAM 96

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