1. The Veterinary HealthThe Veterinary Health
Management Of The LifeManagement Of The Life
Cycle Stages of TheCycle Stages of The
Japanese medaka (Japanese medaka ( OryziasOryzias
latipeslatipes))
Horace E. Walcott, DVM, MSPH, MScHorace E. Walcott, DVM, MSPH, MSc
Scientific Fellow Zoological Society ofScientific Fellow Zoological Society of
LondonLondon
Brooklyn TechBrooklyn Tech

2. The BlackThe Black
BoxBox
InIn
The LMMThe LMM

3. Carcinogen Concentration (ppt)
Log
Of
RISK ?
??????
??????

4. ObjectivesObjectives
• Develop a bioassay system for waterDevelop a bioassay system for water
borne carcinogensborne carcinogens
• Toxicological Pathology StudiesToxicological Pathology Studies
• Maintain a breeding colony of 20 tanks ofMaintain a breeding colony of 20 tanks of
medakamedaka

5. SCcFESCcFE

6. Chemicals?Chemicals?
• Methylene BlueMethylene Blue
• Sea SaltSea Salt
• MS222 (Tetracaine)MS222 (Tetracaine)

7. Concentrations/DosagesConcentrations/Dosages
• MB 1 ml Stock Solution:1LMB 1 ml Stock Solution:1L
of Waterof Water
• MS222 50 – 130 mg/L ofMS222 50 – 130 mg/L of
Water & 1 g/L of waterWater & 1 g/L of water

8. Collecting EggsCollecting Eggs

9. Specimens
µ
Macro Data

10. Life Cycle StagesLife Cycle Stages
• EggEgg
• EmbryoEmbryo
• LarvaLarva
• FryFry
• AdultAdult

11. Aquatic Medicine & BiologyAquatic Medicine & Biology
ProtocolProtocol
Egg & Embryo
Breeding
Adults
Larva & Frey
Juveniles

12. Water Quality ManagementWater Quality Management
Chemistry
Profile
Temperature
Microbial
Culture

13. ConditionsConditions
• pH = 6.8pH = 6.8 ±± 1.21.2
• Tank Temperature = 21.6Tank Temperature = 21.6 ±± 6.06.0 °°CC


14. ConclusionConclusion
A breeding colony of medakaA breeding colony of medaka
can be maintained undercan be maintained under
specific chemical freespecific chemical free
(carcinogen) conditions, in(carcinogen) conditions, in
which water chemistrywhich water chemistry
parameters, photo-periodparameters, photo-period
and nutrition contribute toand nutrition contribute to
optimal growth.optimal growth.

15. AcknowledgementsAcknowledgements
Dr. William R. HartleyDr. William R. Hartley
Dr. William A. Toscano, JrDr. William A. Toscano, Jr
Dr. Asaf AbdelghaniDr. Asaf Abdelghani
Dr. Mary B. AndersonDr. Mary B. Anderson
Ms. Jay BeeMs. Jay Bee
Dr. Chad RoyDr. Chad Roy
Dr. Chad NelsonDr. Chad Nelson

16. Best Aquatic Rat?Best Aquatic Rat?
Oryzias
latipes