[Zbrafish] Zebrafish Age / Size Variations;

[Philippe Herbomel]

Sorry, please replace my previous message (in which the reference of  
the book wasn't quite accurate)
by this one.
Philippe Herbomel


Dear Oliver,

Body length appears indeed to be the adequate, simple parameter for  
estimating postembryonic developmental stage.
Our reference in this matter is Tom Schilling's excellent chapter on  
"The morphology of larval and adult zebrafish" (pp. 59-94 In  
"Zebrafish: A Practical Approach." 2002, eds. C. Nusslein-Volhard and  
R. Dahm, Oxford Univ. Press), in which Table 2 provides a typical  
correspondence between "age" and body length" up to 90 days.
In their study of the development and maturation of the immune system  
in zebrafish, Lam et al. ( Dev. Compar. Immunol. 28 : 9-28, 2004)  
also described this maturation relative not only to age but also to  
body length (see Discussion), which is obviously more significant and  
helpful. You will see that they give the same correspondence between  
age and body length as Tom Schilling at 2 weeks but not at 4 weeks.
Interestingly, an older paper comparing the role of thyroid hormone  
in zebrafish (vs. axolotl) metamorphosis, i.e. their gradual  
transformation form larvae into juveniles, also used body length to  
express the developmental stages (Brown D., PNAS 94 : 13011-16, 1997).

This is obviously an important issue, and certainly all zebrafish  
studies dealing with stages past the first week of development should  
refer to body length in addition to or instead of nominal age.
Also, the community should agree about how to measure that length. In  
Figure 1 and Table 2 of his chapter refered above, Tom Schilling  
provided two different measurements : 'Full length' i.e. up to the  
tip of the caudal fin, and 'standard length', ie up to the base of  
the caudal fin.

I wasn't at the last Madison meeting but since there was a workshop  
there about "working with post-embryonic stages", maybe this staging  
issue was raised ? I would be interested to learn about this from  
participants to this workshop.

Best wishes,

Philippe

–––––––––––––––––––––––––––––––––––––––––
Philippe Herbomel
Unite Macrophages et Developpement de l'Immunite
Departement de Biologie du Developpement
Institut Pasteur
25 rue du Dr Roux, 75724 Paris cedex 15, France

tel. : 33 1 44 38 95 29   mobile: 33 6 73 35 74 20
fax : 33 1 45 68 89 21
http://www.pasteur.fr/recherche/RAR/RAR2006/Mdi-en.html
––––––––––––––––––––––––––––––––––––––
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Le 7 août 08 à 21:02, Oliver Braubach a écrit :

> Dear All.
>
> I have been working on aspects of postembryonic development in the  
> zebrafish brain, and have been trying to determine a standard  
> method for 'aging' zebrafish. As many of you may be aware, the  
> development of individual fish varies greatly during the first  
> month of development, which ultimately leads to very noticeable  
> differences in the size of individual fish and their organs.
>
> Thus, age does not accurately characterize developmental stages of  
> fish, and I have been trying to determine if there's another  
> standard method to do so. Has anyone tried to correlate body length  
> to fish age? Are there any citations for expected / optimal size of  
> fish are a certain age?
>
> Any input regarding this problem would be greatly appreciated.
> Best,
>
> Oliver Braubach
> Department of Physiology and Biophysics
> Dalhousie University
> Halifax, NS B3H 1X5 Canada
> Tel: 902.494.6471
> Fax: 902.494.1685
>
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