C2: BASIC AND APPROPRIATE BIOLOGY O F ZEBRAFISH – STEVEN VAN CRUCHTEN
LEARNING OUTCOMES
❖ You can identify key anatomical features, organs and structures of zebrafish according to life stages
❖ You can describe different breeding strategies
❖ You can recognize that there are different strains in zebrafish, and that these can have different
characteristics which can affect both welfare and science.
❖ You can recognize that alterations to the genome can affect the phenotype in zebrafish in unexpected and
subtle ways, and the importance of monitoring such animals very carefully.
MORPHOLOGY OF THE ADULT ZEBRAFISH
DIFFERENCES BETWEEN FEMALES AND MALES
❖ Not easy to distinguish sexes when they are swimming with lots of them in the tank
❖ For breeding you always use one female and one male !
Females
❖ Females have a round belly when eggs will be presented
❖ Female fish have a silver like anal fin
Males
❖ Males have a more straight line at the bottom of their body = slender body
❖ Normally the males have a brighter color than females
❖ Males have a yellow anal fin
ORGANS
Some structures are also present in other fish or mammals, but some are
specific for zebrafish
❖ Swim bladder has a posterior and anterior chamber
o Toxicity in fish → the swim bladder will not inflate anymore
o anterior chamber is connected to the inner ear
❖ Kidney is different from mammals! (kidney looks like a translucent
pink structure)
o the mesonephros in zebrafish is the definitive kidney (which is not the case in mammals, we have
the metanephros as our adult kidney)
o fish have stopped earlier in the evolution so they use the mesonephros as their adult kidney → it is a
very long kidney that takes a long part of the abdomen
❖ GI tract → simple conformation compared to what mammals have → they do have a pancreas, a spleen,…
❖ The heart is way more simple than ours, they have a one circuit system (we have a double circulation)
❖ Fish have 7 arches (we only have one left that makes up our ear opening) → LOOK UP
o Arches and gills are important for the exchange of gas
❖ They have a thymus which plays an important role in the IS → can be used for studies in this field
❖ Urogenital pore → females use this spot to lay their eggs
❖ Melanocytes are highly present in zebrafish ~ they are bright colored fish
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LEARNING OUTCOMES
❖ You can identify key anatomical features, organs and structures of zebrafish according to life stages
❖ You can describe different breeding strategies
❖ You can recognize that there are different strains in zebrafish, and that these can have different
characteristics which can affect both welfare and science.
❖ You can recognize that alterations to the genome can affect the phenotype in zebrafish in unexpected and
subtle ways, and the importance of monitoring such animals very carefully.
MORPHOLOGY OF THE ADULT ZEBRAFISH
DIFFERENCES BETWEEN FEMALES AND MALES
❖ Not easy to distinguish sexes when they are swimming with lots of them in the tank
❖ For breeding you always use one female and one male !
Females
❖ Females have a round belly when eggs will be presented
❖ Female fish have a silver like anal fin
Males
❖ Males have a more straight line at the bottom of their body = slender body
❖ Normally the males have a brighter color than females
❖ Males have a yellow anal fin
ORGANS
Some structures are also present in other fish or mammals, but some are
specific for zebrafish
❖ Swim bladder has a posterior and anterior chamber
o Toxicity in fish → the swim bladder will not inflate anymore
o anterior chamber is connected to the inner ear
❖ Kidney is different from mammals! (kidney looks like a translucent
pink structure)
o the mesonephros in zebrafish is the definitive kidney (which is not the case in mammals, we have
the metanephros as our adult kidney)
o fish have stopped earlier in the evolution so they use the mesonephros as their adult kidney → it is a
very long kidney that takes a long part of the abdomen
❖ GI tract → simple conformation compared to what mammals have → they do have a pancreas, a spleen,…
❖ The heart is way more simple than ours, they have a one circuit system (we have a double circulation)
❖ Fish have 7 arches (we only have one left that makes up our ear opening) → LOOK UP
o Arches and gills are important for the exchange of gas
❖ They have a thymus which plays an important role in the IS → can be used for studies in this field
❖ Urogenital pore → females use this spot to lay their eggs
❖ Melanocytes are highly present in zebrafish ~ they are bright colored fish
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