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Asian vaccine protects grouper juveniles against vibriosis

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					                 Aquaculture
               Health & Disease
                 Management
                         Issue 1 - June 2010




        Asian vaccine protects grouper
           juveniles against vibriosis




                                                                Published by




Disease control & management in the global aquaculture sector
                                       AquAculture HeAltH & DiseAse MAnAgeMent | Vibriosis                                                                                                        AquAculture HeAltH & DiseAse MAnAgeMent | Vibriosis



                                                                                                                                                       in 2004. Additionally, the situation where         fish were then held for 21 days with daily        from moribund sea bass and cultured at the
                                                                                                                                                       the only fish vaccines available were for          monitoring for mortality.                         Veterinary Medical Aquatic Animal Research
                                                                                                                                                       salmonids is now changing. New vaccines                                                              Centre of the Faculty of Veterinary Science
                                                                                                                                                       are being registered in Asia for Asian spe-        Monitoring water quality                          at Chulalongkorn University, Thailand.
                                                                                                                                                       cies, such as yellowtail in Japan, grass carp in       As with all 840 fish involved in the          Bacteria were identified using API® 20E
                                                                                                                                                       China and a recently launched commercial           study, these grouper
                                                                                                                                                       vaccine for use in Asian sea bass, tilapia and     had been purchased
                                                                                                                                                       other species in some south-east Asian             from a private farm
                                                                                                                                                       countries (Komar et al., 2005).                    in Thailand when they


 Asian vaccine protects grouper                                                                                                                            Various studies have been carried out
                                                                                                                                                       into the efficacy of various Vibrio vaccine
                                                                                                                                                       types on the survival of different grouper
                                                                                                                                                                                                          were approximately
                                                                                                                                                                                                          5.75g in weight and
                                                                                                                                                                                                          approximately 4.31 cm


 juveniles against vibriosis                                                                                                                           species. In the present study, juvenile
                                                                                                                                                       grouper were injected with a bivalent Vibrio
                                                                                                                                                       vaccine prepared (NovaQsol Holdings Inc.,
                                                                                                                                                                                                          in length. There were
                                                                                                                                                                                                          kept in plastic aquaria
                                                                                                                                                                                                          for an acclimatization
                                                                                                                                                       Philippines) from two virulent strains of          period of 14 days and
                                                                                                                                                                                                                                          Figure 1. Determination of LD50 and LD100 for V. chol-
                                                                                                                                                       V. harveyi and V. parahaemolyticus. These          the sacrifice of two
                                                                                                                                                                                                                                          erae in juvenile spotted grouper.
       This report from Thailand describes a trial in which an injectable vaccine successfully protected orange-                                       strains had been isolated from diseased,           fish to verify that they
                       spotted grouper from an experimental challenge with Vibrio pathogens                                                            moribund fish located in a farm near Phuket,       were free of Vibrio.
                                                                                                                                                       Thailand.                                          Throughout the study, half of the water in        (BioMerieux, Madrid, Spain) and the API
                                                                                                                                                           The vaccine’s safety was established           each tank was exchanged every alternate           profiles compared with the API database
 by John S Clark, Jirasak Tangtrongpiros and Nantarika Chansue                                                                                         by testing on a total of 240 juvenile              day. A commercial test kit (AQUA-VBC,             (Apilab Plus, version 3.3.3.; BioMerieux).




V
                                                                                                                                                       orange-spotted grouper which had been              Thailand) was used to monitor water qual-            To establish virulence, doses ranging
              accinating juvenile fish by        as grouper as well as the snapper and             Also, by their very nature, they act mainly         separated into four groups of 60 fish              ity parameters of pH, hardness, ammonia,          from 103 to 1010 CFU of bacteria per fish
              injection has given a high         pompano.                                          on bacterial pathogens; they have no direct         each. Sub-groups of 20 fish within each            nitrite and alkalinity. Salinity was measured     were injected intra-peritoneally into 540
              level of protection against                                                          effect on viruses and other pathogens.              group either were injected with 0.05 ml            each week with a refractometer.                   orange-spotted juveniles. Each dose had
              bacteria causing vibriosis, in     A most common disease                                 Vaccines, by contrast, can act against          or 0.10 ml of vaccine, or given a 0.10 ml              The experimental bacterial challenge          3 replicates with 20 fish in each replicate.
              a study involving cultured          Vibriosis is the most common disease             both bacteria and viruses and there is              saline injection as a positive control, or         for the vaccine assessment consisted of           Control groups were challenged with sterile
orange-spotted grouper in Thailand. The       affecting the culture of marine finfish in           even experimental evidence that they can            left uninjected. Immunised and control             Vibrio cholerae that had been isolated
bivalent Vibrio vaccine was administered      the Asian region and many epizootics have            be active against parasitic infections. But
intraperitoneally to each fish. Although      been attributed
this method of administration is difficult    in particular
                                                                    Table 1: Means of water quality parameters.
to apply in routine farm management,          to       Vibrio
                                                                    Parameters          Mean level and S.D.       Parameters     Mean level and S.D.
the evidence from the study strongly          cholerae.
suggests it should be a good prophylactic
measure against mortalities due to Vibrio
                                              Conventional
                                              treatments            Temperature              27.5±0.5°C           Alkalinity       60±19.27 ppm
                                                                                                                                                                                                  Reach a global digital
pathogens.

   The        orange-spotted         grouper
                                              regionally use
                                              antibiotics.
                                              Unfortunately,
                                                                    pH
                                                                    Salinity
                                                                                              7.66±0.23
                                                                                                 34ppt
                                                                                                                  Ammonia
                                                                                                                  Nitrite
                                                                                                                                   0.88±0.77 ppm
                                                                                                                                   1.56±1.55 ppm                                                  audience of industry
Epinephelus coioides has formed part of
a diversification of culture in Thailand over
                                              these are often
                                              applied incor-
                                                                    Hardness                 >1000 ppm            23.15±18.61bc        77.59
                                                                                                                                                                                                     professionals
recent years (de Silva and Phillips, 2007)    rectly. Therefore they fail to control the           it is also important to remember another
that illustrates the expanding diversity of   disease and they can lead to the spread of           difference in the fact that antibiotics cure
                                                             bacterial resistance.                 whereas vaccines prevent. So while the                                               •        You can advertise within this space for £1139
                                                                 Many other problems are           application of an antibiotic is a curative                                                    or see the back page of this document for other prices & sizes
                                                             associated with the use of            measure or therapy against an existing                                               •        The advert size can be changed to suit your existing artwork
                                                             antibiotics. For example, the         infection, a vaccine is applied preventively
                                                             efficiency of oral delivery is        to prepare the immune system before a                                                •        Advertising space within this feature is limited and sold on a first
                                                             questionable because sick fish        specific challenge.What is more, the protec-                                                  come first served basis, so hurry to ensure you get the space you
                                                             often do not eat. Antibiotics         tion secured by vaccinating normally lasts                                                    require
                                                             that are water soluble may            longer than that from applying antibiotics.                                          •        Deadline for advertising is 18/06/10
                                                             leach from feed. The efficacy                                                                                                                                                                              Display advertising:
                                                                                                                                                                                        Contact the sales team today to book your space:
                                                             of using some antibiotics such        Vaccination reduces
                                                                                                                                                                                        Tel: +44 1242 267706
                                                             as oxytetracycline is highly          antibiotic useage                                                                                                                                                            Ad size     price
                                                                                                                                                                                        Caroline Wearn - Email: carolinew@perendale.co.uk
                                                             reduced where they form                   Data from Norway show that vaccina-                                                                                                                                    Full page    £2036
                                                                                                                                                                                        Sabby Major - Email: sabbym@perendale.co.uk
                          Septicaemia of hepatic tissue      complexes with calcium and            tion of fish has greatly reduced the use of
                                                             magnesium ions in seawater            antibiotics in Norwegian salmon produc-
                                                                                                                                                                                                                                                                              Mini page    £1504
                                                             or hard water. Technically, of        tion. Over a period of two decades while                                                                                                                                   Half page    £1139
marine fish species being farmed in Asian     course, it should always be remembered               salmonid production increased by a factor                                                                                                                                 Third page    £772
aquaculture. Across the region, however,      that antibiotics cannot work unless they             of 20 times, the weight of antibiotics used
vibriosis has caused catastrophic eco-        are delivered to the correct target organ            each year dropped from a high of over                                                                                                                                  Quarter page     £625
nomic losses in higher value species such     or tissue at the appropriate concentration.          50 tonnes in 1984 to less than 2 tonnes                                                                                                                                  Eighth page     £457


                                          Vibriosis | AquAculture Health & Disease Management                                                                                                        AquAculture Health & Disease Management | Vibriosis
                                        AquAculture HeAltH & DiseAse MAnAgeMent | Vibriosis



                                                                                                    were significantly lower than for all infected                                                       production, development and sustainable           fry, quarantine measures, optimized feeding
                                                                                                    groups. Although not significantly different         Authors                                         expansion of marine fish aquaculture in           and good husbandry techniques. Monitoring
                                                                                                    from the 0.10 ml vaccinated fish for per-            Dr John S Clark obtained his Ph.D.             the Asian region. Most Asian aquaculture          diseases by surveillance and reporting is
                                                                                                    centage mortality, the 0.05 ml vaccine group         in micro-encapsulation at Heriot-Watt           is operated on a small scale. Added to the        essential, as is good sanitation and an
                                                                                                    registered a lower RPS of 45.76%.                    University in Edinburgh, Scotland in 1983.      other factors mentioned and the diversity         emphasis on being responsible in the use
                                                                                                                                                         He currently works on formulation of            of organisms in tropical waters, this contrib-    of chemicals and antibiotics when diseases
                                                                                                    Higher survival and                                  anti-parasitics, vaccines, nutritional/         utes to a truly challenging disease situation     occur.
                                                                                                    lower mortality                                      health products for a variety of clients.       in which pathogens have various opportuni-            There will certainly be a role for vac-
                                                                                                          Clearly, therefore, injecting 0.10 ml of       Email: aquavax2003@yahoo.co.uk                  ties for entry points. Only now are moves         cination as the overall emphasis changes
                                                                                                     the bivalent vaccine gave a higher rela-            Dr Nantarika Chansue is the                    being made to correct the failure to collect,     to preventing diseases rather than treating
                                                                                                     tive survival and the lowest mortality rate         Associate Professor and Director                report and analyse epidemiological data in        or curing them. Vaccination on its own is
                                                                                                     of any group in the test. The test also             of the Veterinary Medicine Aquatic              the event of a disease outbreak.                  not sufficient on its own to guarantee high
                                                                                                     demonstrated that the European model of             Animal Research Centre (VMAARC) at                   On a more positive note, more attention      survival and profitability (see box), but it is
                                                                                                     using vaccination as a primary prophylactic         Chulalongkorn University in Bangkok.            has been given in past few years to the iden-     one of the tools to employ in good health
                                                                                                     tool could be applied successfully in Asia to       She specializes in disease identifica-          tification of aetiological agents involved in     management strategies.
                                                                                                     reduce losses in spotted grouper juveniles          tion and control methods for shrimp,            fish disease epidemics. The following studies
                                                                         Acute peritonitis           from a Vibrio infection.                            marine and freshwater fish, turtles and         give a solid indication of the diversity of
                                                                                                          This points to a new direction in Asian        aquatic mammals. Aquatic immunoto-              major pathogens affecting the fish farming
                                                                                                     grouper culture for health management. So           xicology has been her major research            industry in Asia (Bondad-Reantaso et al.,           Acknowledgements
   0.9 % (v/v) saline. The aim was to find     lated by the Reed and Muench procedure as             far, the development of effective strategies in     interest for some 20 years.                     2005; Komar et al., 2005; Labrie et al., 2005;      The authors would like to convey their
pathogen doses that would kill 50% and         the basis for deciding the optimal challenge          Asia for disease prevention and control has         Professor Jirasak Tangtrongpiros               Leong et al., 2005, 2006 and Tan et al., 2003).     thanks to all the staff of VMAARC in
100% of injected fish within three days, so    dose to be used during testing of vaccine             been hampered by a lack of data on the wide         is the head of the Veterinary Medicine          Meanwhile, significant progress has been            Chulalongkorn University, Bangkok
that the mean lethal dose could be calcu-      efficacy.                                             variety of disease-causing agents present and       Aquatic Animal Research Centre                  made in the field of vaccine research and           Thailand, and to the supporting staff of
                                                    Figure 1 illustrates the clear dose              the immune systems of Asian fish species.           (VMAARC)         at    Chulalongkorn            development (Grisez and Tan, 2005).                 the Research Institute at Rayong, Rayong
                                               response curve found from the virulence               Technical support in such matters as disease        University in Bangkok, Thailand. He                  But as Asian aquaculture continues to          Province, Thailand, and finally to Drs. Gee,
  Measures to sustain a                        assays. The LD100 dose (killing 100% of               diagnosis is often lacking at farm level.           specialises in aquatic animal disease           grow, inevitably its problems with disease          Na, Lin and Jim for their endless patience.
  successful aquaculture                       fish within three days) for this particular                There is also a stark contrast between         and his primary interest is in methods          will worsen unless key steps are taken. New         References are available on request.
  (Tan et al., 2006)                           isolate of Vibrio cholerae was 1x1010 CFU/            the Asian situation and modern salmonid             for disease prevention and control.             disease control concepts must be imple-
                                               ml, with the LD50 established as 1x108                aquaculture in countries such as Norway.                                                            mented. This includes the use of healthy
  Recommended                                  CFU/ml.                                               Intensified salmon production has brought
  1.  Use healthy (not necessarily                  At 21 days after immunization, the vacci-        a separation between the hatchery sites
      cheap) fry                               nated and control fish were challenged with           producing fry and those for grow-out,
  2. Quarantine incoming animals               the LD100 as a 0.10 ml injection adminis-             together with optimized feed strategies and
  3. Use formulated pelleted feed              tered intraperitoneally while the positive            virtually disease-free fingerlings. However,
  4. Grade fish periodically                   controls received 0.10 ml of sterile saline.          the segregation in year classes that is
  5. Monitor water quality                     Monitored for three days post-challenge,              obligatory for salmon in Europe does not

                                                                                                                                                                                                        Reach a global digital
  6. Record diseases and feeding               there was a 100% mortality rate for the fish          yet exist in Asia.
  7. Observe withdrawal period of              in the positive control group. All dead fish in            Asian farms also commonly produce
      drugs                                    the challenge experiment were confirmed               different species of fish at the same site,
  8. Remove dead fish at least once a
      day
                                               by re-culture and re-identification using API
                                               20E as positive for Vibrio cholerae infection.
                                                                                                     they make widespread use of trash fish as
                                                                                                     feed and their fry are often wild-caught or                                                        audience of industry
                                                                                                                                                                                                           professionals
  9. Clean and disinfect equipment                  Results of the efficacy test in Table 1          derived from wild-caught brood stock. With
  10. Vaccination if available                 confirmed that giving 0.10 ml of the vaccine          farm licensing and zoning policies virtually
                                               provided the highest rate of protection               non-existent in most Asian countries, the
                                               against Vibrio cholerae.This vaccination gave         spread of diseases is promoted by having
  NOT recommended                              relative percentage survival (RPS) values of          too many fish and too many farms in a                                                      •      You can advertise within this space for £1139
  1.     Place your farm too close to          up to 77.59% compared with the relevant               concentrated area.                                                                                or see the back page of this document for other prices & sizes
         others                                controls. Its percentage mortality rates                   It explains why the salmon farms of
  2.     Have several species in one farm                                                                              Norway or Chile consider a                                               •      The advert size can be changed to suit your existing artwork
  3.     Use fingerlings from unknown                                                                                  survival rate of lower than                                              •      Advertising space within this feature is limited and sold on a first
                                                 Table 2: Percentage mortality of juvenile orange-spotted grouper,
         sources                                 non-vaccinated and vaccinated by two intraperitoneally injected       95% as a sign of a disease                                                      come first served basis, so hurry to ensure you get the space you
  4.     Overstock (to overcome low              doses of a Vibrio vaccine and relative percentage survival (RPS)      outbreak, whereas a survival    Display advertising:
                                                                                                                                                                                                       require
         survival)                               after challenge with Vibrio cholerae.                                 rate of 50% at fish farms in
  5.     Use trash fish                                                                                                Asia is often considered to              Ad size         price           •      Deadline for advertising is 18/06/10
                                                 Group                                   Mortality*         RPS
  6.     Overfeed                                                                                                      be acceptable.                                                           Contact the sales team today to book your space:
                                                                                                                                                               Full page       £2036
  7.     Use drugs without diagnosis                                                                                                                                                            Tel: +44 1242 267706
  8.     Leave or throw dead fish in the        NC        Control, no infection        2.63±3.72c        97.44
                                                                                                                     The biggest                              Mini page        £1504
                                                                                                                                                                                                Caroline Wearn - Email: carolinew@perendale.co.uk
         water                                  PC        Control, normal saline IP    100.00±0.00a      0.00        constraint to                            Half page        £1139            Sabby Major - Email: sabbym@perendale.co.uk
  9.     Restock fish without cleaning the      T1        0.05 ml. vaccine IP          54.04±31.73b      45.76       procution                               Third page        £772
         cages                                                                                                          Disease undoubtedly
                                                T2        0.10 ml. vaccine IP          23.15±18.61bc     77.59
  10.   Ignore diseases until heavy mor-                                                                             represents one of the big-          Quarter page          £625
                                                Data was subjected to two way analysis of variance using an SPSS
         tality occurs                          program. Significant differences were determined at P<0.05.          gest constraints to the                Eighth page         £457
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                         Disease control & management in the global aquaculture sector

				
DOCUMENT INFO
Description: Vaccinating juvenile fish by injection has given a high level of protection against bacteria causing vibriosis, in a study involving cultured orange-spotted grouper in Thailand. The bivalent Vibrio vaccine was administered intraperitoneally to each fish. Although this method of administration is difficult to apply in routine farm management, the evidence from the study strongly suggests it should be a good prophylactic measure against mortalities due to Vibrio pathogens.