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Aquatic Habitat: AQH
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Development of Aquatic Habitat (AQH)

 Introduction

JAXA has developed an aquatic animal experiment facility to perform many space experiments with various aquatic animals. We developed a next-generation aquatic animal experiment facility, Aquatic Habitat (AQH) for the International Space Station. The AQH is used for the experiments to clarify the genes and their protein network sensitive to space environment.


 Advantages of Aquatic Animals

  • Excellent animal model as vertebrate
  • Transparent eggs and larvae
  • High reproduction, short generation time
  • Various molecular tools are available for genomic analysis
  • High feasibility of medakamulti-generational experimentin space


 Model Animals for AQH Development

Small freshwater fish, Medaka and Zebrafish Amphibian, African clawed toad (Xenopus)
AQH will have the capabilities to accommodate three-generations of medaka and zebrafish. AQH will have the capabilities to maintain Xenopusfrom egg through metamorphosis.


 AQH Major Specifications

Experiment Duration Up to 90 days
Breeding Water Loop 1 loop/unit, 3-4 L total volume
Specimen Chamber 2 chambers/unit, inner dimensions15x7x7cm, 600 cc water and 100 cc air/1 chamber,air/water interface can be controlled by air sustainer
Environmental Control Water temperature: ±1 deg.C in the range of 20 to 30 deg.C, water flow rate :±0.1 L/min in the range of 0 to 0.5 L/min, O2 supply/CO2 removal: gas exchange by artificial lung
Water Quality Maintenance NH4/NO2 removal by bacteria filter, waste removal by physical filter and activated carbon, water exchange as backup
Day/night Cycle Light Intensity of max 1,000 Lux with selectable light/dark cycle time
Automatic Feeding Programmable feeding cassette is available
Specimen Sampling and Preservation Specimen sampling in various developmental stages, Specimen preservation with fixation, freezing, and/or refrigeration
Specimen Observation Low magnifications by AQH equipped CCD camera (850nm infrared observation available), high magnifications for embryo observation by external microscopic camera
Data Monitor Water temperature, water flow rate, waterpressure, DO, pH, lighting status, feeding status
Commanding Water temperature, water flow rate, lighting control, feeding control, CCD camera control


 Concept of AQH

Aquarium Unit AQH Core Unit


 AQH Bread Board Model

Outside

The BBM was assembled under the flight constraints of mass and dimensions. Tests to confirm the compatibility with model animals have been conducted successfully.

Automatic Feeding Test   Air Sustainer Test
Powdery food in the feeding tape is fed and opened one by one at the bottom of the chamber for adult medaka.
Air/water interface is maintained successfully with the air sustainer during micro gravity condition by parabolic flight test

 

Basic Tests with Small Freshwater FishBasic Tests with Small Freshwater Fish

Aquatic Habitat (AQH) breeding system prototype was manufacturedand basic tests for multi-generational breeding (fish spawning test and larvae breeding test) were performed with medakaand zebrafish. The prototype consists of one closed water circulation loop with two specimen chambers, two egg trappers, bacteria filter and artificial lung, which are functionally equivalent to the AQH.


 Breeding System Prototype

 

 Medaka Multi-generational Breeding Test

Test Conditions
Fish Number : 6 fish (3♀3♂) /chamber (spawning test)
10 larvae (<1day after hatching) /chamber(larvae growth test)
Total Water Volume : 4.4 L
Water Temperature : 26±1 deg. C
Water Flowrate : 0.3 L/min (spawning test)
0.1 L/min (larvae growth test)
Water Quality Control : NH4, NO2 removal by bacteria filter
Light Intensity : 1000 Lux , 14 hr light/10 hr dark
Feeding : 2 times/day (spawning test)
3 times/day (larvae growth test)

 

Test Results

  • Medaka mating and spawning behavior were performed successfully during two weeks test period.Fish spawning was observed every day.
  • Larvae grew up to adult fish with 100% survival rate and the first spawning was confirmed on 45th dayafter the hatching.(2-3 months in usual)
  • Water quality was maintained in good conditionduring spawning test and larvae growth test. NH4 and NO2 were maintained within 0.1mg-N/L.
Medakalarvae growth from hatching to the 1st spawning
Test Start
(<1day after hatching)
5th Day 15th Day
25th Day 35th Day 45th Day
(The 1st spawning was observed)

 

Water quality during medaka spawning and larvae growth tests

Test Days

 

 Zebrafish Multi-generational Breeding Test

Test Conditions
Fish Number : 4 fish (2♀2♂) /chamber (spawning test)
20 larvae (<1day after hatching) →6fish/chamber(larvae growth test)
Total Water Volume : 4.3 L
Water Temperature : 27±1 deg. C
Water Flowrate : 0.25 L/min (spawning test)
0.1 L/min (larvae growth test)
Water Quality Control : NH4, NO2 removal by biological filter
Light Intensity : 500 Lux , 14 hr light/10 hr dark
Feeding : 2 times/day (spawning test)
3 times/day (larvae growth test)

 

Test Results

  • Zebrafish mating and spawning behavior were performed successfully during two weeks test period. Fish spawning was observed almost every day.
  • Larvae grew up to adult fish with 100% survival rate and the first spawning was confirmed on 46th day after the hatching.(2-3 months in usual)
  • Water quality was maintained in good condition during spawning test and larvae growth test. NH4 and NO2 were maintained within 0.1mg-N/L.
Zebrafish larvae growth from hatching to the 1st spawning
Test Start
(<1day after hatching)
5th Day 15th Day
25th Day 35th Day 45th Day
(The 1st spawning was observed on 46th day)

 

Water quality during zebrafish spawning and larvae growth tests

Test Days

 

Last Updated : February 9, 2005

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