Aquaculture Research
Volume 43, Number 5 (April 2012)
	Feed intake, growth and metabolism of Nile tilapia (Oreochromis niloticus) in relation to dissolved oxygen concentration
	Authors:	An Tran-Duy 1, Anne A van Dam 2, Johan W Schrama 1
	Author Affiliations:	1: Department of Animal Sciences, Aquaculture and Fisheries Group, Wageningen University, Wageningen, The Netherlands 2: Department of Environmental Resources, UNESCO-IHE Institute for Water Education, Delft, The Netherlands
	Source:	Aquaculture Research, Volume 43, Number 5 (April 2012)
	Page Numbers:	730 – 744
	Available Full Text:	Full Text: Subscription Required to view full text Format: PDF Size: unknown Location: Publisher’s Site Authentication: EBSCOhost EJS
	Abstract:	The objectives of the present study were to determine, for Nile tilapia of different body weights and fed to satiation, (1) the incipient dissolved oxygen (DO) concentration at which feed intake starts to level off and (2) the effect of DO on nitrogen and energy balances. Two successive experiments were conducted with two weight classes of male Nile tilapia (>200 g, Experiment 1, and <100 g, Experiment 2). Twelve aquaria were assigned to four DO levels in each experiment. Fish were fed to apparent satiation for 16 and 20 days in Experiments 1 and 2 respectively. The DO-feed intake curve of fish<100 g appeared to level off at a DO of 3 mg L-1, while that of fish>200 g continued to increase as DO increased from 2.6 to 6.0 mg L-1. The latter curve suggests that the incipient DO for fish>200 g is about 5.5 mg L-1. Fish tended to reduce the energy requirement for maintenance as DO declined. A DO reduction caused an increase in the apparent digestibility coefficient (ADC), but further declines in DO to levels below a critical level decreased ADC. The DO did not have a considerable effect on the metabolizable energy: digestible energy ratio of the diet.
	Citation:	An Tran-Duy, Anne A van Dam, Johan W Schrama . Feed intake, growth and metabolism of Nile tilapia (Oreochromis niloticus) in relation to dissolved oxygen concentration. Aquaculture Research, Volume 43, Number 5 (April 2012), pp. 730-744, <http://ejournals.ebsco.com/direct.asp?ArticleID=412EB83B501BE3B259FF&gt;
	URL:	http://ejournals.ebsco.com/direct.asp?ArticleID=412EB83B501BE3B259FF

Ever filled your pond or aquarium up with a hose before? Ever forget to turn it off? Forgetting to turn the water off for long periods can lead to massive fish losses due to chlorine toxicity. This happened to a client of mine a few months back.

How can we avoid this? My suggestion is to use the hose with an in-line timer set at 10min intervals. Timers come in all designs, but a simple one can be easily purchased from your local hardware store for around $10. This will save your fish, save water and save flooding your floor.

Depending on how much you need to refill, you can set the timer for 15, 30 or 45 min…

When fish suffer from respiratory disease, they will often be sitting at the surface, gasping for air. Their activity will be reduced and appetite will decline. What causes this?

This paper describes all the reasons for it.

Disorders of the Respiratory System in Pet and
Ornamental Fish
Roberts HE & SA Smith (2011). In: SE Orosz & CA
Johnson (eds), Veterinary Clinics of North America:
Exotic Animal Practice, 14(2): 179-206.
Abstract
The respiratory organ of fish is the gill. In addition to
respiration, the gills also perform functions of acid-base
regulation, osmoregulation, and excretion of nitrogenous
compounds. Because of their intimate association

with the environment, the gills are often the primary
target organ of pollutants, poor water quality, infectious
disease agents, and noninfectious problems, making
examination of the gills essential to the complete examination
of sick individual fish and fish populations.
The degree of response of the gill tissue depends on
type, severity, and degree of injury and functional
changes will precede morphologic changes. Antemortem
tests and water quality testing can, and should, be
performed on clinically affected fish whenever possible.

Books received

Fish Vetting Essentials Loh Richmond Dr.Landos Matt Dr. 215 pages, paperback, AUD 99. Richmond Loh Publishing. 2012. ISBN 978 0 9871571 0 2

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364 | Veterinary Record | April 7, 2012

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http://veterinaryrecord.bmj.com/content/170/14/364.3.full

To be reviewed.