Marine Life Park
Benefits versus risks of eating fish.
From: “Dr. David Scarfe”
Date: 9 October 2012 17:53:53 AWST
Subject: AquaVetMed: FAO/WHO Report – Risks and Benefits of Fish Consumption
October 9, 2012
Food and Agriculture Organization of the United States/World Health Organization – Expert Consultation on the Risks and Benefits of Fish Consumption Report
Rome, Italy – Based on a request and recommendation from the FAO/WHO Food Standards Programme, Codex Alimentarius Commission, and the Codex Committee on Food Additives and Contaminants, a Joint FAO/WHO Expert Consultation on the Risks and Benefits of Fish Consumption (primarily focused on health risks associated with methylmercury and dioxins and dioxin-like PCBs in fish), was convened in January 2010 in Rome to provide scientific advice on how to consider the risks and benefits of fish consumption. The Consultation recommended a series of steps, such as the need to emphasize the neurodevelopment benefits to offspring from fish consumption by women of childbearing age, and the neurodevelopment risks to offspring of such women not consuming fish.
Conclusions
· Consumption of fish provides energy, protein and a range of essential nutrients.
· Eating fish is part of the cultural traditions of many peoples. In some populations, fish is a major source of food and essential nutrients.
· Among the general adult population, consumption of fish, particularly fatty fish, lowers the risk of coronary heart disease mortality. There is an absence of probable or convincing evidence of coronary heart disease risks of methylmercury. Potential cancer risks of dioxins are well below established coronary heart disease benefits.
· Among women of childbearing age, pregnant women and nursing mothers, considering benefits of docosahexaenoic acid (DHA) versus risks of methylmercury, fish consumption lowers the risk of suboptimal neurodevelopment in their offspring compared with not eating fish in most circumstances evaluated.
· At levels of maternal dioxin exposure (from fish and other dietary sources) that do not exceed the provisional tolerable monthly intake (PTMI), neurodevelopmental risk is negligible. At levels of maternal dioxin exposure (from fish and other dietary sources) that exceed the PTMI, neurodevelopmental risk may no longer be negligible.
· Among infants, young children and adolescents, evidence is insufficient to derive a quantitative framework of health risks and benefits. However, healthy dietary patterns that include fish consumption and are established early in life influence dietary habits and health during adult life.
Recommendations
To minimize risks in target populations, the Expert Consultation recommends that Member States should:
· Acknowledge fish as an important food source of energy, protein and a range of essential nutrients and fish consumption as part of the cultural traditions of many peoples;
· Emphasize the benefits of fish consumption on reducing coronary heart disease mortality (and the risks of mortality from coronary heart disease associated with not eating fish) for the general adult population;
· Emphasize the net neurodevelopmental benefits to offspring of fish consumption by women of childbearing age, particularly pregnant women and nursing mothers, and the neurodevelopmental risks of not consuming fish to offspring of such women;
· Develop, maintain and improve existing databases on specific nutrients and contaminants, particularly methylmercury and dioxins, in fish consumed in their region;
· Develop and evaluate risk management and communication strategies that both minimize risks and maximize benefits from eating fish.
The further information on the Consultation and the full report can be downloaded from http://tinyurl.com/99ouxol.
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Exposure to air is stressful to oysters.
Air exposure and mechanical agitation are commonly used methods for decreasing shell biofouling in the shellfish industry. However, these techniques cause significant stress to the bivalves. Could these anthropomorphic measures have contributed to the major decline of the Australian pearl oyster industry (see tech notes on Oyster Oedema Disease)? Some food for thought.
| Aquaculture | |||||||||||||||||
| Volume 363, Number 8 (September 2012) | |||||||||||||||||
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Changes in the transcriptional expression of oxidative stress response genes in Akoya pearl oysters (Pinctada fucata) exposed to air and mechanical agitation | ||||||||||||||||
| Authors: | Rhiannon P. Kuchel, Sham Nair, David A. Raftos | ||||||||||||||||
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| Source: | Aquaculture, Volume 363, Number 8 (September 2012) | ||||||||||||||||
| Page Numbers: | 33 – 38 | ||||||||||||||||
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| Abstract: | The Akoya pearl oyster is an economically important species farmed throughout Japan and China, and on a small scale in Australia. Recent proliferation of Akoya viral disease (AVD) has dramatically reduced both wild and farmed populations in Asia. It is thought that AVD is exacerbated by anthropogenic pressures associated with over-crowding and stress caused by fluctuations in the environment, as well as by husbandry and handling. To test the effects of these stressors, the differential expression of genes encoding three antioxidant enzymes (peroxiredoxin, PRx; glutathione-S-transferase, GST; glutathione peroxidase, GPx) and the generic stress biomarker heat shock protein 70 (HSP-70) was investigated using quantitative real-time PCR on mRNA extracted from gill tissues of Pinctada fucatathat had been exposed to either mechanical agitation (MA, a combination of air exposure and shaking) or air alone for 1h and 6h. We observed a significant decline (up to 50%; p<0.05) in the expression of both GST and PRx 60min after oysters were exposed to air and MA. GPx transcription declined significantly 60min after exposure to MA. Hierarchical cluster analysis and multidimensional scaling (MDS) demonstrated that, even though no significant differences were identified in the expression of these genes 6h after exposure to stress, there was still a clear differentiation between controls and the two stress treatments. After 6h, the MDS analysis showed that antioxidant enzyme expression was intermediate between the 60min time point and the non-stressed controls. The MDS plot also demonstrated that there was no clear distinction between exposure to air and MA, suggesting that air exposure (which was a component of both treatments) is the main causative agent of transcriptional stress responses. HSP-70 expression also declined when oysters were exposed to both stressors, but these decreases were not statistically significant. Overall, the data suggest that the antioxidant systems of oysters are affected by exposure to air. This contributes to a growing understanding of short-term stress responses in bivalve molluscs and their potential effects on cellular homeostasis. | ||||||||||||||||
| Citation: | Rhiannon P. Kuchel, Sham Nair, David A. Raftos . Changes in the transcriptional expression of oxidative stress response genes in Akoya pearl oysters (Pinctada fucata) exposed to air and mechanical agitation. Aquaculture, Volume 363, Number 8 (September 2012), pp. 33-38, <http://ejournals.ebsco.com/direct.asp?ArticleID=4BA7B78B31C5AA067019> | ||||||||||||||||
| URL: | http://ejournals.ebsco.com/direct.asp?ArticleID=4BA7B78B31C5AA067019 | ||||||||||||||||
Interesting comments on “How do salmon achieve that growth spurt once at sea?”
I received some interesting anecdotal comments on my previous blog (www.thefishvet.com) via LinkedIn and would like to share with you.
“A lot of mumbo jumbo for those uninitiated in science speak, but the summary [of the scientific article] is that there are hormonal changes help them to very efficiently convert everything they eat into growth during the spring/summer period. (link to the original post)”
Kabir Chowdhury Very interesting! Although we suspected the prioritization of the resources consumed in fishes, this article clearly describes the physiological changes inside the animal responsible for the variations in resource allocations. Could similar changes happen in any other migratory species? Or in any other species in response to the seasonal environmental modulations? Any reference?
Richmond Loh This same thing could happen in other species too. Rainbow trout show a similar growth pattern, but not to the same extent as Atlantic salmon.
Dominique Bureau Anecdotal evidence but we have seen the same significant increase in growth when moving Atlantic salmon, held in fresh water for their entire life cycle and that went through smoltification ( incomplete), from small tanks to much larger tanks. It was not compensatory growth. I always though that vision played a role.
- Richmond Loh
Are you saying that the salmon have their growth spurt even if left in freshwater?
- Dominique Bureau
I have to be cautious since we did not systematically and specifically study this issue. However, we did observed very significant improvement in the growth rate (expressed as TGC) in two or three experiments with a wild Atlantic salmon strain (LaHave River) held in freshwater when we moved the fish to larger tanks.
Eureka moment in crown of thorns starfish fight | News.com.au
More on the war against the crown of thorns.
http://mobile.news.com.au/travel/news/eureka-moment-in-starfish-fight/story-e6frfq80-1226490688221
Scientists inject ‘Bovril-like’ hope into reef starfish fight – ABC News (Australian Broadcasting Corporation)
Fish-e Trivia for Monday-itis.
What do you call a pregnant goldfish?
You don’t call it anything because goldfish do not get pregnant! They are egg scatterers and fertilisation occurs outside of the body. Fish that are very full of eggs can be called “gravid”.
How do salmon achieve that growth spurt once at sea?
A lot of mumbo jumbo for those uninitiated in science speak, but the summary is that there are hormonal changes help them to very efficiently convert everything they eat into growth during the spring/summer period.
| Aquaculture | |||||||||||||||||
| Volume 363, Number 8 (September 2012) | |||||||||||||||||
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Growth, osmoregulation and endocrine changes in wild Atlantic salmon smolts and post-smolts during marine migration | ||||||||||||||||
| Authors: | Sigurd O. Stefansson, Monika Haugland, Björn Thrandur Björnsson, Stephen D. McCormick, Marianne Holm, Lars O.E. Ebbesson, Jens Chr. Holst, Tom O. Nilsen | ||||||||||||||||
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| Source: | Aquaculture, Volume 363, Number 8 (September 2012) | ||||||||||||||||
| Page Numbers: | 127 – 136 | ||||||||||||||||
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| Abstract: | We have examined physiological parameters associated with seawater adaptability, growth and energetics, as well as major endocrine regulators of these processes in wild migrating Atlantic salmon smolts and post-smolts from the river through the fjord, coastal areas and the open ocean. Muscle RNA/DNA ratio suggests that growth rate increases soon after entry into seawater and continues to increase after the post-smolts reach the offshore banks and the feeding grounds in the Norwegian Sea. Post-smolts prioritize rapid growth and protein deposition in spring and summer, and their energy intake during this period is so high that deposition of energy is possible in addition to muscle growth. An increase in thyroxine (T4) and triiodothyronine (T3) levels was observed, suggesting a major activation of hepatic conversion of T4to T3in post-smolts in seawater, probably related to the high metabolic activity and rapid growth and development of the post-smolts. Decreased plasma growth hormone (GH) levels were observed from the river through the fjord, with levels around 2ngml-1in rapidly growing post-smolts, concurrent with an increase in circulating insulin-like growth factor I (IGF-I). An increase in pituitary GH expression levels and hepatic GH receptor (GH-R) and local IGF-I mRNA levels suggest a physiological basis for the changes in circulating GH and IGF-I levels. Receptor expression in brain and pituitary suggests that both hormones are actively involved in the growth and differentiation of these tissues during the critical early marine phase. Gill Na+,K+-ATPase (NKA) activity increased to post-smolt levels above 20µmol ADP mgprot.÷1h÷1, probably representing long-term NKA activity levels of Atlantic salmon in seawater. Concurrent with the changes in NKA activity the expression of the NKA a1b isoform remained high in post-smolts, while the expression of the NKA a1a decreased from smolts to post-smolts. Both cystic fibrosis transmembrane conductance regulator (CFTR) I and II showed a reduction in mRNA levels from smolts to post-smolts, and remained stable at low expression levels in seawater. | ||||||||||||||||
| Citation: | Sigurd O. Stefansson, Monika Haugland, Björn Thrandur Björnsson, Stephen D. McCormick, Marianne Holm, Lars O.E. Ebbesson, Jens Chr. Holst, Tom O. Nilsen . Growth, osmoregulation and endocrine changes in wild Atlantic salmon smolts and post-smolts during marine migration. Aquaculture, Volume 363, Number 8 (September 2012), pp. 127-136, <http://ejournals.ebsco.com/direct.asp?ArticleID=4BB787BD8A151B2092BC> | ||||||||||||||||
| URL: | http://ejournals.ebsco.com/direct.asp?ArticleID=4BB787BD8A151B2092BC | ||||||||||||||||
Lighting colour, moulting and growth in prawns – their relationship.
Anyone who has cultured or kept crustacea will know that the animals seem to “grow” much larger after immediately after moulting and nothing much seems to happen in between. This clever experiment demonstrates how different coloured lights can play a role in growth rates and moulting frequency. Such experimentation will become more practical if/when shrimp culture migrates to the predicted “super-intensive” systems.
| Aquaculture | |||||||||||||||||
| Volume 363, Number 8 (September 2012) | |||||||||||||||||
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Effect of periodic light color change on the molting frequency and growth of Litopenaeus vannamei | ||||||||||||||||
| Authors: | Biao Guo, Yingchun Mu, Fang Wang, Shuanglin Dong | ||||||||||||||||
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| Source: | Aquaculture, Volume 363, Number 8 (September 2012) | ||||||||||||||||
| Page Numbers: | 67 – 71 | ||||||||||||||||
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| Abstract: | Six color treatments Yellow light (Y), Green light (G), Blue light (B), Blue light to Yellow light (BY), Blue light to Green light (BG), Green to Yellow light (GY) were tested to determine if light color change can promote the growth of Litopenaeus vannamai. After a 45-day experiment, shrimp in BG treatment showed the best weight gain (WG) and the specific growth rate (SGRd), which might have been caused by high food conversion efficiency (FCEd), lowest energy allocation for respiration and highest energy allocation for growth. The molting frequency in GY treatment was the highest, but the growth was not the best. These results suggest that the periodic fluctuation from blue region of the spectrum to green region of the spectrum could promote the growth of L. vannameiand this periodic light color fluctuation may be used as a pattern of regulation of light color in the commercial shrimp culture. | ||||||||||||||||
| Citation: | Biao Guo, Yingchun Mu, Fang Wang, Shuanglin Dong . Effect of periodic light color change on the molting frequency and growth of Litopenaeus vannamei. Aquaculture, Volume 363, Number 8 (September 2012), pp. 67-71, <http://ejournals.ebsco.com/direct.asp?ArticleID=4CD28768DFA6A9DD42E9> | ||||||||||||||||
| URL: | http://ejournals.ebsco.com/direct.asp?ArticleID=4CD28768DFA6A9DD42E9 | ||||||||||||||||
Rushing out work this Friday afternoon?
Sent in by my friend, Yancey, via Facebook.
