The authors have nothing to disclose.

All procedures and behavioral testing were approved by MacEwan University&#8217;s Animal Research Ethics Board under protocol number 06-11-12, which is in compliance with the Canadian Council for Animal Care&#8217;s guidelines for the care and use of experimental animals.
1. Prepare Dosing Tanks, Solutions, and Administration Schedule
<ol>
	<li>Prepare an administration schedule such that the animals are dosed in the same environment and during the same time of day to avoid any confounds of ...

<ol>
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C., Mattioli, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Natural+preference+of+zebrafish+(Danio+rerio)+for+a+dark+environment.">Natural preference of zebrafish (Danio rerio) for a dark environment.</a> Braz J Med Biol Res. 32 (12), 1551-1553 (1999).</li><li>Maximino, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Behavioral+and+neurochemical+changes+in+the+zebrafish+leopard+strain.">Behavioral and neurochemical changes in the zebrafish leopard strain.</a> Genes Brain Behav. 12 (5), 576-582 (2013).</li><li>Levin, E. D., Bencan, Z., Cerutti, D. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anxiolytic+effects+of+nicotine+in+zebrafish.">Anxiolytic effects of nicotine in zebrafish.</a> Physiology &amp; Behavior. 90 (1), 54-58 (2007).</li><li>Gerlai, R., Chatterjee, D., Pereira, T., Sawashima, T., Krishnannair, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Acute+and+chronic+alcohol+dose:+population+differences+in+behavior+and+neurochemistry+of+zebrafish.">Acute and chronic alcohol dose: population differences in behavior and neurochemistry of zebrafish.</a> Genes, Brain and Behavior. 8 (6), 586-599 (2009).</li><li>Mathur, P., Berberoglu, M. A., Guo, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preference+for+ethanol+in+zebrafish+following+a+single+exposure.">Preference for ethanol in zebrafish following a single exposure.</a> Behavioural Brain Research. 217 (1), 128-133 (2011).</li><li>Renninger, S. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Investigating+the+genetics+of+visual+processing,+function+and+behaviour+in+zebrafish.">Investigating the genetics of visual processing, function and behaviour in zebrafish.</a> Neurogenetics. 12, 97-116 (2011).</li><li>Crawshaw, L. I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tolerance+and+withdrawal+in+goldfish+exposed+to+ethanol.">Tolerance and withdrawal in goldfish exposed to ethanol.</a> Physiology &amp; Behaviour. 87 (3), 460-468 (2006).</li><li>Hamilton, T. J., Holcombe, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tresguerres,+M.CO2-induced+ocean+acidification+increases+anxiety+in+rockfish+via+alteration+of+GABAA+receptor+functioning.">Tresguerres, M.CO2-induced ocean acidification increases anxiety in rockfish via alteration of GABAA receptor functioning.</a> Proceedings of the Royal Society B. , (2014).</li><li>Ramsay, J. M., Feist, G. W., Varga, Z. M., Westerfield, M., Kent, M. L., Schreck, C. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Whole-body+cortisol+response+of+zebrafish+to+acute+net+handling+stress.">Whole-body cortisol response of zebrafish to acute net handling stress.</a> Aquaculture. 297 (1-4), 157-164 (2009).</li><li>Hamilton, T. J., Paz-Yepes, J., Morrison, R. A., Palenik, B., Tresguerres, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Exposure+to+bloom-like+concentrations+of+two+marine+Synechococcus+cyanobacteria+(strains+CC9311+and+CC9902)+differentially+alters+fish+behaviour.">Exposure to bloom-like concentrations of two marine Synechococcus cyanobacteria (strains CC9311 and CC9902) differentially alters fish behaviour.</a> Conservation Physiology. 2 (1), (2014).</li></ol>

The authors acknowledge Joshua Gallup for use of his photography equipment used for Figure 1. This work was supported by a Natural Sciences and Engineering Research Council (NSERC) Canada Discovery grant (to T.J.H.).

Previous studies involving drug administration in zebrafish have simply relied on netting fish to transport them from their home tank into the drug solution12,16. Netting is not always consistent and often takes longer than expected due to the escape response of the zebrafish, which has significant individual variability. Traditional transfer methods, while useful, can be improved upon by decreasing the amount of total time the fish spend outside of water, as well as decreasing the amount of variability in tra...

The zebrafish (Danio rerio) is a small teleost species originating in India that is a useful model organism for behavioral1 and medical research2,3. Zebrafish are also commonly used in the testing of various pharmacological substances in order to characterize their impact on behavior. Various dosages and schedules of drug administration have been used to investigate the behavior of the zebrafish after the administration of compounds such as stimulants4, anxiolytics5 and ethanol6-8.
Our lab has investigated the effects of differing schedules of ethanol administration on zebrafish anxiety and locomotion in the well-validated light/dark assay9,20, also commonly referred to as the scototaxic assay. A new method of ethanol administration was developed to increase efficiency for repetitive, daily administration over a long period of time (21 days)6. Previously used methods were practical, however, we sought to develop a method that reduced netting, with its associated time costs, and allowed simultaneous, precisely timed administration of the drug of interest to large numbers of fish. In traditional research using ethanol, zebrafish are netted and transferred from one tank to another containing the appropriate mixture of ethanol and water10-12. While this method is widely accepted, netting zebrafish may increase the variability in the time taken to introduce and remove the fish from the drug solution. Therefore, the exact exposure to the compound of interest may vary over the course of an experiment involving repeated dosing. A method that reduces sources of error stemming from variability in transport times is thus desirable. With our method we are able to move all fish simultaneously, resulting in identical dosing time in each fish. Following ethanol exposure (described here), zebrafish can be tested in any number of behavioral assays, including those that assess anxiety. Dosing groups of fish using the new method has practical uses beyond the ability to accurately replicate and standardize dosing between subjects and across groups of fish. The advent of new software that allows for the tracking of multiple fish at once may see researchers utilize our methods to ensure replicability and accuracy in their experiments. Considering the widespread use of zebrafish as a model organism for behavioral neuroscience, this method will increase efficiency and practicality in future pharmacological studies.
In the present paradigm, a repeated dosing schedule was employed that approximately mirrors human drinking schedules. Fish were randomly assigned to one of three groups: control, daily-moderate, or weekly-binge. The dosing schedule was 21 days in duration, chosen because it significantly exceeded exposure times in previous studies7. Control fish received zero alcohol, daily-moderate fish received 0.2% alcohol once per day, and weekly-binge fish received 1.4% alcohol once per week. The light/dark task was used to assess anxiety after 2 days of withdrawal. This is a relatively simple test to administer which uses a rectangular arena in which the walls on one side are white and on the other side are dark9. Adult zebrafish robustly prefer the dark side of the arena under control conditions6,9,13. Increased anxiety is operationally defined as significantly more time spent in the dark zone, and decreased anxiety can be assumed when the fish spends relatively more time spent in the light zone. With motion-tracking software, other informative variables can also be quantified, including average velocity, immobility, meandering, and zone transitions14.
The dosing method developed in our laboratory can apply to any research in which water-soluble compounds are administered to one or more zebrafish. Many other pharmacological agents which may benefit from this methodology are currently being tested in zebrafish. Commonly tested compounds include nicotine, chlordiazepoxide, buspirone, and scopolamine, which are dissolved in a similar manner to ethanol; by mixing the appropriate amount of the chemical into water. Therefore, the general scope of this procedure is much wider and not limited to ethanol. Furthermore, after dosing with drugs for multiple days, the light/dark task is only one of many behavioral tests that could be employed. After drug administration or during withdrawal, other popular assays that can be utilized include the novel tank diving test15 and tests of social behavior such as shoaling16. The following procedure will outline an efficient method of repeatedly transferring groups of fish or individual fish into solutions containing a pharmacological compound of interest. Additionally, the process of testing anxiety with the light/dark test in groups of fish who are in withdrawal after being exposed to long schedules of alcohol administration will be described.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Three Shelf benchtop housing system</td>
			<td>Aquatic Habitats</td>
			<td>N/A</td>
			<td><a href="http://aquatichabitats.com/research-systems/z-hab-system/">http://aquatichabitats.com/research-systems/z-hab-system/</a></td>
		</tr>
		<tr>
			<td>1.5L Spawning tank w/400 micron baffle</td>
			<td>Aquatic Habitats</td>
			<td>N/A</td>
			<td><a href="http://aquatichabitats.com/consumables/tanks-lids-and-baffles/info/nursery-tank-and-baffles/">http://aquatichabitats.com/consumables/tanks-lids-and-baffles/info/nursery-tank-and-baffles/</a></td>
		</tr>
		<tr>
			<td>Pure Grain Ethanol</td>
			<td>Luxco, INC</td>
			<td>N/A</td>
			<td><a href="http://www.fishersci.com/ecomm/servlet/fsproductdetail?storeId=10652&amp;aid=3759149&amp;store=Scientific">http://www.luxco.com/public/brands/brands.asp?brandid=21</a></td>
		</tr>
		<tr>
			<td>Ethovision XT Motion tracking software</td>
			<td>Noldus Information Technology</td>
			<td></td>
			<td><a href="http://www.noldus.com/animal-behavior-research/products/ethovision-xt">http://www.noldus.com/animal-behavior-research/products/ethovision-xt</a></td>
		</tr>
		<tr>
			<td>Pipette</td>
			<td>Eppendorf Canada</td>
			<td></td>
			<td><a href="http://www.eppendorf.ca/int/index.php?l=211&amp;pb=e396f9e705e754a3&amp;action=products&amp;contentid=1&amp;catalognode=9477.">http://www.eppendorf.ca/int/index.php?l=211&#38;pb=e396f9e705e754a3&#38;action=products&#38;contentid=1&#38;catalognode=9477.&#160;</a></td>
		</tr>
		<tr>
			<td>Light/Dark Arena</td>
			<td>Custom</td>
			<td></td>
			<td>Construct as per procedure description. 9.5cm wide, 9.5cm deep, 55cm long</td>
		</tr>
	</tbody>
</table>

a novel method of drug administration to multiple zebrafish (danio rerio) and the quantification of withdrawal

Anxiety testing in zebrafish is often studied in combination with the application of pharmacological substances. In these studies, fish are routinely netted and transported between home aquaria and dosing tanks. In order to enhance the ease of compound administration, a novel method for transferring fish between tanks for drug administration was developed. Inserts that are designed for spawning were used to transfer groups of fish into the drug solution, allowing accurate dosing of all fish in the group. This increases the precision and efficiency of dosing, which becomes very important in long schedules of repeated drug administration. We implemented this procedure for use in a study examining the behavior of zebrafish in the light/dark test after administering ethanol with differing 21 day schedules. In fish exposed to daily-moderate amounts of alcohol there was a significant difference in location preference after 2 days of withdrawal when compared to the control group. However, a significant difference in location preference in a group exposed to weekly-binge administration was not observed. 
This protocol can be generalized for use with all types of compounds that are water-soluble and may be used in any situation when the behavior of fish during or after long schedules of drug administration is being examined. The light/dark test is also a valuable method of assessing withdrawal-induced changes in anxiety.

To maintain accuracy and control in pharmacological studies with zebrafish it is important to time the duration of ethanol administration consistently and accurately as described above. Our procedure can increase the ease and throughput of the dosing procedure. The administration of ethanol on either a weekly-binge or daily-moderate schedule resulted in altered anxiety levels, measured with the light/dark test, compared to controls. When tested two days after the last dosing, zebrafish in the control group (who received ...

Watch this Scientific Journal Video about A Novel Method of Drug Administration to Multiple Zebrafish Danio rerio and the Quantification of Withdrawal at JoVE.com

A Novel Method of Drug Administration to Multiple Zebrafish Danio rerio and the Quantification of Withdrawal

A novel method for reducing variability when exposing fish to drugs is explained. Fish exposed to various patterns of ethanol exposure were found to have altered anxiety levels during withdrawal in a light/dark scototaxic assay.

A Novel Method of Drug Administration to Multiple Zebrafish (Danio rerio) and the Quantification of Withdrawal

Anxiety testing in zebrafish is often studied in combination with the application of pharmacological substances. In these studies, fish are routinely ...

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12.0K ビュー.  MacEwan University. A novel method for reducing variability when exposing fish to drugs is explained. Fish exposed to various patterns of ethanol exposure were found to have altered anxiety levels during withdrawal in a light/dark scototaxic assay.