Nitrite toxicity in sturgeon.
What coincidence! I consulted with a client today about nitrite toxicity that occurred 2 weeks after he’d cleaned his filter a little too thoroughly using tap water!
Also, one of the co-authors, Dr Emily Donaldson is a colleague I met during Aquavet II last June!
| Journal of Fish Diseases | |||||||||||||||||
| Volume 35, Number 12 (December 2012) | |||||||||||||||||
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Effect of chloride on nitrite-induced methaemoglobinemia in Atlantic sturgeon, Acipenser oxyrinchus oxyrinchus(Mitchill) | ||||||||||||||||
| Authors: | M A Matsche, E Markin, E Donaldson, A Hengst, A Lazur | ||||||||||||||||
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| Source: | Journal of Fish Diseases, Volume 35, Number 12 (December 2012) | ||||||||||||||||
| Page Numbers: | 873 – 885 | ||||||||||||||||
| Available Full Text: |
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| Abstract: | We evaluated the effects of chloride concentration on the clinical pathology in juvenile Atlantic sturgeon, Acipenser oxyrinchus oxyrinchus(Mitchill),following semi-static exposures to 1 mg L-1nitrite for 96 h. In spring water naturally low in chloride (5 mg L-1), plasma nitrite concentrated to more than 40× environmental levels resulting in a severe methaemoglobinemia characterized by torpid behaviour, 30-fold increase in methaemoglobin fraction, anaemia, leucopenia and hyperkalaemia. Loss of intracellular water and potassium to extracellular space may have resulted in hyperkalaemia and haemodilution. Fish survived nitrite exposure, but 60% of torpid fish died following capture and tissue sampling. Fish acclimated to 10-fold higher chloride content (55 mg L-1) did not concentrate nitrite in the plasma above environmental levels or develop methaemoglobinemia, but did exhibit similar haematology and plasma chemistry changes. Plasma nitrite returned to preexposure levels by 14 days following nitrite exposures, but severity of clinical pathology changes persisted or increased, suggesting that Atlantic sturgeon have reduced capacity to recover from methaemoglobinemia. Fish that survive methaemoglobinemia may be susceptible to mortality from the cumulative effects of intoxication, handling and other stresses for two or more weeks following nitrite remediation. Chloride buffering in aquaculture systems reduces the toxic effects of nitrite accumulation. | ||||||||||||||||
| Citation: | M A Matsche, E Markin, E Donaldson, A Hengst, A Lazur . Effect of chloride on nitrite-induced methaemoglobinemia in Atlantic sturgeon, Acipenser oxyrinchus oxyrinchus(Mitchill). Journal of Fish Diseases, Volume 35, Number 12 (December 2012), pp. 873-885, <http://ejournals.ebsco.com/direct.asp?ArticleID=486DAA50900EBDFBB1BD> | ||||||||||||||||
| URL: | http://ejournals.ebsco.com/direct.asp?ArticleID=486DAA50900EBDFBB1BD | ||||||||||||||||
What products does The Fish Vet use?
Please find on my Facebook “Fin” page, some products that I find useful and have made available for purchase –
If the product you’re after is not already here, please send an email enquiry to: thefishvet@gmail.com
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) | |||||||||||||||||
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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> | ||||||||||||||||
| URL: | http://ejournals.ebsco.com/direct.asp?ArticleID=429B9A2DF011828948DD | ||||||||||||||||
Someone stole my logo! Calling it Dr Fish!
For a fish foot spa in Cambodia!
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.
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 fish
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 
fishes 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: fish 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