Feeding regimes most conducive to growth do not necessarily maximize reproductive success.

Thinking of breeding fish and growing them out? This paper describes that feeding regimes most conducive to growth do not necessarily maximize reproductive success in the zebra danio. Feeding frequency for reproductive success is once every couple of days to to 3x/day, whereas to maximise growth rate, feeding them 5x/day is optimal.

 

Aquaculture
  Volume 369, Number 1-2 (November 2012)
     The effects of feeding frequency on growth and reproduction in zebrafish (Danio rerio)
   Authors: Christian Lawrence, Jason Best, Althea James, Kara Maloney
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   Source: Aquaculture, Volume 369, Number 1-2 (November 2012)
   Page Numbers: 103 – 108
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   Abstract: In the present study, we examined the effects of feeding regime on growth and reproductive performance in wild-type zebrafish (Danio rerio) maintained on a recirculating aquaculture system. Starting at 30days post-fertilization (dpf), we fed 8 replicate groups of age and strain matched fish a pelleted formulated diet (Gemma Micro 300, Skretting) either once every other day (EOD), one time (1×), three times (3×) or five times (5×) a day to achieve a total daily feed input of 5% of body weight per day compared against a “standard” control (C) of Artemia salinanauplii/metanauplii three times daily to apparent satiation. Fish in each treatment group were weighed and measured for fork length once every other week until 150dpf. We evaluated the effects of these feeding regimes on reproductive performance (breeding success, fecundity, and embryo viability) by setting up randomly sampled fish from each replicate groups in small group crosses (2 males, 3 females) once every other week starting at 76dpf until the experiment was terminated at 191dpf. Growth performance was significantly affected by feeding regime, especially in female fish, where fish in the 1×, 3×, and 5× groups were significantly (p<0.05, one way ANOVA) longer and heavier than fish in control and EOD groups at the end of experiment. Feeding regime had a less clear effect on reproductive performance. Mean fecundity and embryo viability varied little between groups, but the fish fed EOD, 1× and 3× showed significantly higher rates (p<0.05) of breeding success than the control and 5× groups. These results suggest that feeding regimes most conducive to growth do not necessarily maximize reproductive success in this species.
   Citation: Christian Lawrence, Jason Best, Althea James, Kara Maloney . The effects of feeding frequency on growth and reproduction in zebrafish (Danio rerio). Aquaculture, Volume 369, Numbers 1-2 (November 2012), pp. 103-108, <http://ejournals.ebsco.com/direct.asp?ArticleID=429B9A2DF011828948DD&gt;
   URL: http://ejournals.ebsco.com/direct.asp?ArticleID=429B9A2DF011828948DD

Cool change in Perth. What does it mean for fish health?

Those growing out barramundi in their Aquaponics setup will most likely experience issues with the cool weather, and the most common is saprolegniaisis. Make sure you run your UV and enrich their diet with vitamin C. Feed sparingly during the cool weather. If possible to heat their tanks, the better it is. Keep water temperature above at least 20-22 degrees Celsius.

Similar conditions can happen with cool water tolerant fishes such as koi and goldfish. So, keep an eye on them.

20121105-110058.jpg

Global recall for toxic Tasmanian mussels.

A toxic algae contaminates the filter-feeding shellfish. The toxin is not inactivated by cooking or freezing. My veterinary epidemiologist colleague suggests that maybe it’s an indication of rising sea temperatures allowing this algae to grow in locations where conditions were previously unsuitable.

Read more…
http://aquatichealth.net/node/63795

Fish-e Trivia for Monday-itis. Sex changing fish going both ways!

Following on from last week’s post about sex change in fishes, this week’s is about a fish that can change in both directions!

The blue-banded goby (Lythrypnus dalli) lives in a harem of one male with 4-6 females. The male is socially dominant and the females live as subordinates. However, if the male is removed, the highest ranking female assumes a poison of dominance. She begins to display male-typical social and sexual behaviours. Within a few weeks, her gonads, accessory sex glands, brain chemistry, endocrine profiles and growth rate become male. Interestingly, when a more dominant male is introduced into this mix, the newly transformed male will revert back to female.

All about fish’s white blood cells.

If you want to see pictures of fish white blood cells prior to reading the abstract, I’ve some on my Facebook “Fin” page – http://www.facebook.com/media/set/?set=a.392480934134195.85320.188036301245327&type=1&l=19d8c40a6b
The granulocytes of fishnext term

P.M. Hinea

a Fisheries Research Centre, Ministry of Agriculture and Fisheries, P.O. Box 297, Wellington, New Zealand

Received 16 June 1991; Accepted 20 September 1991. Available online 10 August 2007.

The occurrence and functions of granulocytes in previous termfishesnext term varies between and within groups. Primitive groups (agnathans, holocephalans, elasmobranchs) all have eosinophils with homogeneous round granules. Elasmobranchs also have eosinophils with granules containing an axial crystalline rod, which is the sole eosinophil type present in lungfish. Comparative study suggests that in elasmobranchs and lungfish, heterophils and different forms of eosinophil are all of the eosinophil lineage. Agnathans, holocephalans, dogfishes and lungfish possess fine granulocytes that may be related to neutrophils of teleosts and mammals. Holosteans and chondrosteans have eosinophils and neutrophils, and as in some elasmobranchs and lungfish, basophils are relatively common. Teleosts have neutrophils which are ultrastructurally, and possibly functionally, similar to mammalian neutrophils. More rarely they have cells with elongated granules similar to elasmobranch and reptilian heterophils. Teleost eosinophils have large round homogeneous granules, and cytochemical and functional studies indicate that in some groups, particularly cyprinids, these cells represent an undifferentiated eosinophil/basophil lineage. Roles in inflammation, enzyme cytochemistry, function and evolutionary trends are discussed.

Key words: previous termfishnext term granulocytes; eosinophils; basophils; neutrophils; heterophils; ultrastructure; enzyme cytochemistry

Full article can be viewed here:

Practice Good Biosecurity – Cleaning and Disinfection for every fish keeper and fish veterinarian.

In light of the killer koi herpesvirus sweeping the globe, and even though it is not yet here in Australia, every fish keeper should be practicing good biosecurity measures.Simple soap and detergent doesn’t always cover everything and this is why Dr Richmond Loh, The Fish Vet, uses Virkon to clean and disinfect all his equipment between site visits. This is all part of the behind the scenes service for his clients, even before he reaches your door step.
See how it works – http://youtu.be/7Mq-Och-Q80

International veterinary guidelines for the transport of live fish or fish eggs

International veterinary guidelines for the transport of live fishnext term or previous termfishnext term eggs

P. de Kinkelin Corresponding Author Contact Information, R.P. Hedrick

Laboratoire d’ichtyopathologie, Virologie et Immunologie Moleculaire, Institut National de la Recherche Agronomique, 78352 Jouy-en-Josas Cedex, France

Department of Medicine, School of Veterinary Medicine, University of California, Davis, California 95616 USA

Available online 22 September 2003.

Abstract

There are two existing codes of practice and one draft proposal with guidelines for the transport of live previous termfishnext term and previous termfishnext term eggs. They provide information for national policies and a level of international standardization. Their efficacy depends, first on implementation by the national official services which tends to restrict previous termfishnext term movements, and second, on acceptance of these guidelines by those involved in the production and utilization of previous termfishnext term. Thus, a critical balance between theory and reality must be achieved if the goals of such international codes are to be realized.

Keywords: previous termFishnext term; Pathogens; Control; Policies; Guidelines; Transfer

View full article here:

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Yours sincerely,

Dr Richmond Loh

BSc, BVMS, MPhil (Vet Path), MANZCVS (Aquatics), MANZCVS (Pathobiology), DipPM.
Veterinarian | Adjunct Senior Lecturer Murdoch University | WAVMA Communications Committee Member |
Secretary Aquatic Animal Health Chapter – Australian and New Zealand College of Veterinary Scientists (ANZCVS)
The Fish Vet, Perth, Western Australia, AUSTRALIA. Mobile Veterinary Service for fish and other aquatic creatures.
http://www.thefishvet.com.au
Ph: +61 (0)421 822 383

New York Aquarium, the havoc caused by Hurricane Sandy.

From Dr Rob Ossiboff via facebook:

Rob Oz Ossiboff 6:40am Nov 3
For those of you who are not aware, the New York Aquarium experienced tremendous damage from Hurricane Sandy. The grounds were inundated by the storm surge and backup from sewer drains. Aquarium staff have been working around the clock in a
n effort to save the inhabitants. Staff are working on restoring life support systems and have restored power to two exhibits. Water is still being pumped out of areas that house crucial operating systems. Many of the inhabitants weathered the initial floods, but the situation is still precarious. There is a desperate need to replace many of the operating systems for the tanks.

Images of the damage can be seen here: http://news.mongabay.com/2012/1102-ny-aquarium-photos-post-sandy.html [Dr Richmond Loh adds,”Very different from when I was last there in June, see pics here http://www.facebook.com/media/set/?set=a.378634905518798.82565.188036301245327&type=1&l=9440921838]
As you can see – the damage is severe and it will be months before the aquarium can reopen. But the top priority currently is the health of the animals.

I realize that there are many in need of help currently in the city and New Jersey, and there are many people desperately in need of supplies. But as I know many of my FB friends are animal lovers and animal health professionals, I wanted to reach out to you. If you are interested and able to contribute, please visit https://secure3.convio.net/wcs/site/Donation2?idb=1272578557&df_id=5341&5341.donation=form1

Donations are tax deductible. Please feel free to share.

Photos of flooded New York Aquarium released

news.mongabay.com
The Wildlife Conservation Society (WCS) today released pictures showing damage caused earlier this w…