Lecture: Zebrafish in science
We use zebrafish (Danio rerio) because it has everything other animal models also have:
- Powerful genetic tools like the Drosophila (fruit fly)
- Relevance as a vertebrate model like the mouse (mus musculus)
- Powerful embryological techniques like the Xenopus (frog)
Fish are the second most used laboratory animals in Belgium after the rodents! Fish are
mostly used in fundamental research, toxicology & safety and other purposes.
When we look at disease types we often use fish in cardiovascular diseases but also
embryology related diseases.
Fish in general
If we look at the phylogenetic tree, we see that there are also fish with lungs that are
closely related to the tetrapods. Fish can be classified in different classes:
- Jawless fish
- Vertebral column
- Jaw fish
- Lungs or lung derivatives
- Reptiles and amphibians
The offspring of fish can also be divided in fish that lay eggs or fish that don’t lay eggs:
- Ovuliparous
o External fecundation of the eggs à female lays eggs and male will fertilize
the eggs externally
o In most fish (incl. zebrafish) and frogs
- Oviparous
o Internal fecundation, female lays zygotic eggs à fertilization internally
o In birds
- Ovoviviparous
o Internal fecundation, breeding within (fe)males à fertilization internally
o No interaction between zygote and parent
o In sharks, guppy, reptiles, snails
- Viviparous
o Internal fecundation à fertilization internally
o Interaction between zygote and female, nutrient
o In mammals and some sharks (hemotrophic and histotrophic)
Lets first take a look at the jawless fish (Agnatha).
Agnatha à They don’t have a jaw (important feature in evolution)
- Myxini
- Cephalaspidomorphi
Long shape body
Most extinct
In science they are used to study very early evolution of vertebrates.
Saif Haify Laboratory Animal Science – Summary 6-November-2015
, Lamprey is already higher in evolution since they have cartilage compared with the
Hagfish.
Bony fish
- Most numerous fish
- Largest variety à they can everywhere
- They have a endoskeleton
- They have a swim bladder and/or lungs
- There are 3 classes:
o Ray finned fish
o Lobe finned fish
o Lung fish
Ray finned fish
- They have rays in their fins
- Most known species and the largest class
- They live in sweet and salt water
- Variety of habitats
- They have an obvious skeleton
- Most of them are oviparous (egg laying)
Their anatomy is comparable to that of the mammals. They have the several organs we
see in mammals; liver, heart, kidney, some kind of stomach, intestine (simplified), spinal
cord, and brain.
Mudskipper = amphibian fish à around 10 cm long; puts oxygen in the cheeks
Saif Haify Laboratory Animal Science – Summary 6-November-2015
We use zebrafish (Danio rerio) because it has everything other animal models also have:
- Powerful genetic tools like the Drosophila (fruit fly)
- Relevance as a vertebrate model like the mouse (mus musculus)
- Powerful embryological techniques like the Xenopus (frog)
Fish are the second most used laboratory animals in Belgium after the rodents! Fish are
mostly used in fundamental research, toxicology & safety and other purposes.
When we look at disease types we often use fish in cardiovascular diseases but also
embryology related diseases.
Fish in general
If we look at the phylogenetic tree, we see that there are also fish with lungs that are
closely related to the tetrapods. Fish can be classified in different classes:
- Jawless fish
- Vertebral column
- Jaw fish
- Lungs or lung derivatives
- Reptiles and amphibians
The offspring of fish can also be divided in fish that lay eggs or fish that don’t lay eggs:
- Ovuliparous
o External fecundation of the eggs à female lays eggs and male will fertilize
the eggs externally
o In most fish (incl. zebrafish) and frogs
- Oviparous
o Internal fecundation, female lays zygotic eggs à fertilization internally
o In birds
- Ovoviviparous
o Internal fecundation, breeding within (fe)males à fertilization internally
o No interaction between zygote and parent
o In sharks, guppy, reptiles, snails
- Viviparous
o Internal fecundation à fertilization internally
o Interaction between zygote and female, nutrient
o In mammals and some sharks (hemotrophic and histotrophic)
Lets first take a look at the jawless fish (Agnatha).
Agnatha à They don’t have a jaw (important feature in evolution)
- Myxini
- Cephalaspidomorphi
Long shape body
Most extinct
In science they are used to study very early evolution of vertebrates.
Saif Haify Laboratory Animal Science – Summary 6-November-2015
, Lamprey is already higher in evolution since they have cartilage compared with the
Hagfish.
Bony fish
- Most numerous fish
- Largest variety à they can everywhere
- They have a endoskeleton
- They have a swim bladder and/or lungs
- There are 3 classes:
o Ray finned fish
o Lobe finned fish
o Lung fish
Ray finned fish
- They have rays in their fins
- Most known species and the largest class
- They live in sweet and salt water
- Variety of habitats
- They have an obvious skeleton
- Most of them are oviparous (egg laying)
Their anatomy is comparable to that of the mammals. They have the several organs we
see in mammals; liver, heart, kidney, some kind of stomach, intestine (simplified), spinal
cord, and brain.
Mudskipper = amphibian fish à around 10 cm long; puts oxygen in the cheeks
Saif Haify Laboratory Animal Science – Summary 6-November-2015
