Aquaculture Biotechnology

Introduction

Through deeper understanding of the plant and animal genetic principles and

through application of specific manipulations the green and white revolutions were

possible in India. A sustainable 'blue' revolution is also surely possible in the

similar manner.

Oceans are very vast ecosystems and are gifted with abundant resources for

research and development. Oceanic organisms constitute a major share of the

earth's biological resources. However the potential of this domain is largely

unexplored. A majority of marine microorganisms are yet to be identified and those

which are identified are not that studied, preventing their commercial exploitation.

As regards agriculture and animal husbandry, adoption of biotechnology in

fisheries also has proved useful in many aspects. A great potential for fruitful

research in biotechnology exists in aquaculture too. Development of popular

strains of cultivable species, improved varieties, mono-sex production for

enhanced productivity, cryo-preservation of gametes for off-season breeding and

effluent treatment for sustainable aquaculture, etc. are the thrust areas where

considerable work can be done. By employing biotechnological tools, remarkable

improvements can be made in the field of aquaculture management like health and

nutrition f fishes, development of new products, extraction of medicines and other

useful compounds.

Oceanic organisms posses unique structures, metabolic pathways, reproductive systems and

sensory and defence mechanisms. With their vast genetic and physiological diversity, marine

organisms are treasure houses of new classes of chemicals and processes including

pharmaceuticals, polymers, enzymes, vaccines and diagnostic and analytical reagents. Thus

aquatic organisms are not only valued as food but also as sources of commerce and

recreation.

Aquaculture involves farming of aquatic organisms (rather than hunting of fish form natural

water bodies for eating) including fishes, molluscs, crustaceans and plants. There seems to be

ample scope for the application of a variety of biotechnological techniques, starting from the

simple selective breeding, chromosome manipulation, transgenesis, mono-sex culture, fish

cell and tissue culture, nutrition and fish health, disease diagnosis, cryoprservation of fish

gametes and embryos for enhancing aquaculture production in India.

Transgenic Fish –

Genetically modified fish has promoters driving an over-production of "all fish" growth

hormone. This resulted in dramatic growth enhancement in several species,

includingsalmonids,[1] carps [2]  and tilapias.[3]

These fish have been created for use in the aquaculture industry to increase the speed

of development and potentially, reduce fishing pressure on wild stocks. None of these

GM fish have yet appeared on the market, mainly due to the concern expressed among

the public of the fish's potential negative effect on the ecosystem should they escape

from fish farms.[citation needed]

The GloFish is a patented brand of genetically modified (GM) fluorescent zebrafish with

bright red, green, and orange fluorescent color. Although not originally developed for the

ornamental fish trade, it is the first genetically modified animal to become publicly

available as a pet.

Attempts to produce transgenic fish started in 1985 and some encouraging results have been

obtained. The genes that have been introduced by microinjection in fish include the following:

(i) human or rat gene for growth hormone,

(ii) chicken gene for delta crystalline protein,

(iii) E. coli gene, for β-galactosidase,

(iv) E. coli gene for neomycin resistance,

(v) winter flounder gene for antifreeze protein (flounder = flat fish),

(vi) rainbow trout gene for growth hormone.

The technique of microinjection has been successfully used to generate transgenic fish in

many species such as common carp, catfish, goldfish, loach, medaka, salmon, Tilapia,

rainbow trout and zebrafish.

In other animals (e.g. mice, cows, pigs, sheep and rabbits), usually direct microinjection of

cloned DNA into male pronuclei of fertilized eggs has proved very successful, but in most fish

species studied so far, pronuclei can not be easily visualized (except in medaka), so that the

DNA needs to be injected into the cytoplasm.

Eggs and sperms from mature individuals are collected and placed into a separate dry

container. Fertilization is initiated by adding water and sperm to eggs, with gentle stirring to

facilitate the fertilization process.

Egg shells are hardened in water. About 106 to 108 molecules of linearized DNA in a volume

of 20 ml or less are microinjected into each egg (1-4 cells stage) within the first few hours

after fertilization. Following microinjection, eggs are incubated in appropriate hatching trays

and dead embryos arc removed daily.

Since in fish, fertilization is external, in vitro culturing of embryos and their subsequent transfer into foster mothers (required in mammalian systems) is not required. Further, the injection into the cytoplasm is not as harmful as that into the nucleus, so that the survival rate in fish is much higher (35% to 80%).

Human growth hormone gene transferred to transgenic fish allowed growth that was twice the size of their corresponding non- transgenic fish (goldfish, rainbow trout, salmon). Similarly antifreeze protein (AFP) gene was transferred in several cases and its expression as studied in transgenic salmon. It was shown that the level of AFP gene expression is still too low to provide protection against freeze.

GLOSFISH® FLUORESCENT FISH FAQ

GloFish® are brilliantly wonderful fish that add color and excitement to any aquarium, whether at home or the office, or in classrooms.

GloFish are similar to other zebrafish, except they have a much brighter disposition. GloFish are available for purchase in three stunningly beautiful colors: Starfire Red®, Electric Green®, and Sunburst Orange®.

Today's GloFish fluorescent fish are bred from the offspring of fluorescent zebrafish that were originally developed several years ago. Each new GloFish fluorescent fish inherits its unique color directly from its parents, maintains the color throughout its life, and passes the color along to its offspring.

Want to know more about GloFish? Click on a topic to learn more: • The Science of GloFish®• GloFish ® and the Environment • Caring for GloFish®• Displaying GloFish® • Where to Purchase GloFish®• GloFish ® Marketing and Media • GloFish ® Ethics • GloFish ® in California

The Science of GloFish®

Where do GloFish® fluorescent zebrafish come from?GloFish® fluorescent zebrafish were originally bred to help detect environmental pollutants. By adding a natural fluorescence gene to the fish, scientists hoped to one day quickly and easily determine when a waterway is contaminated. The first step in developing a pollution-detecting fish was to create fish that would be fluorescent all the time. Scientists soon realized the public's interest in sharing the benefits of this research, a process which lead to GloFish® fluorescent fish.

How common is the use of fluorescent zebrafish in science?For over a decade, fluorescent zebrafish have been relied upon by scientists worldwide to better understand important questions in genetics, molecular biology, and vertebrate development. Fluorescent zebrafish have been particularly helpful in understanding cellular disease and development, as well as cancer and gene therapy.

Where does the fluorescent color come from?The fluorescent color in our fish is produced by a fluorescent protein gene, which creates the beautiful fluorescence that can be seen when looking at the fish. The fluorescent protein genes occur naturally, and are derived from marine organisms.

Do you have to add a fluorescence gene to every fish before it hatches?No. Today's GloFish® fluorescent fish are bred from the offspring of fluorescent zebrafish that were originally developed several years ago. Each new GloFish® fluorescent fish inherits its unique color directly from its parents, maintains the color throughout its life, and passes the color along to its offspring.

How exactly do GloFish® fluorescent zebrafish help in the fight against pollution?To achieve their goal of helping to fight water pollution, scientists are hoping to one day develop a ‘switch’ that will cause always-fluorescing zebrafish to selectively fluoresce in the presence of environmental toxins. A non-fluorescing fish will signal that the water is safe, while a fluorescing fish will signal trouble. To help further the research, a portion of the proceeds from sales of all GloFish® fluorescent fish goes directly to the lab where these fish were created. For more information on this project, please review the article entitled “Zebrafish as Pollution Indicators,” by the National University of Singapore.

What are the differences between fluorescent zebrafish and other zebrafish?Aside from their brilliant color, fluorescent zebrafish are the same as other zebrafish. This includes everything from general care and temperature preferences to growth rate and life expectancy.

Does the fluorescence harm the fish?No. The fish are as healthy as other zebrafish in every way. Scientists originally developed them several years ago by adding a natural fluorescence gene to the fish eggs before they hatched. Today's GloFish® fluorescent fish are bred from the offspring of these original fish.

Exactly how is the fluorescent protein gene added to the fish?Every line of GloFish® fluorescent fish (i.e., GloFish® Starfire Red® Zebra, GloFish® Electric Green® Zebra, and GloFish® Sunburst Orange® Zebra) starts with a single fish. The general process of developing fluorescent fish, as illustrated in this chart, begins by adding a fluorescence gene to the fish before it hatches from its egg. Once the gene integrates into the genome (i.e., genetic code) of the embryo, the developing fish will be able to pass the fluorescence gene along to its offspring upon maturity. Because of this, the gene only needs to be added to one embryo; from that point forward, all subsequent fluorescent fish are the result of traditional breeding.

Are you going to create more fluorescent fish?Scientists all around the world are working with fluorescent fish, whether it's to help protect the environment or come up with new disease-fighting drug therapies. As more fluorescent fish become available, they may be offered for sale to the public.

GloFish® and the Environment

Which federal agencies have reviewed these fish?We have submitted detailed information regarding our fish to the U.S. Food & Drug Administration, which has jurisdiction over biotech animals, as they consider the added gene to be an “animal drug”. Consistent with the findings of scientists worldwide, the FDA, working in coordination with the United States Department of Agriculture and United States Fish & Wildlife Service, found no evidence that our fluorescent zebrafish pose any more threat to the environment than wild-type zebrafish. If you would like to read the FDA statement regarding our fish, please click here.

Have any other governmental agencies reviewed GloFish® fluorescent fish?In addition to the Federal review described above, our fish have been reviewed by various state agencies, including the State of Florida Transgenic Aquatic Species Task Force and the California Department of Fish & Game. In accordance with the findings of the FDA, these reviews have concluded that our fluorescent zebrafish are as safe for the environment as wild-type zebrafish. To review their specific analyses, as well as those of independent third party experts, please see the GloFish ® Science section of our website.

What will happen if a GloFish® fluorescent zebrafish escapes into the waterways?Zebrafish are tropical fish and are unable to survive in non-tropical environments. They have been sold to aquarium owners worldwide for more than fifty years. Despite all these years of widespread distribution, zebrafish are only found in tropical environments, such as their native India. At the same time, please remember that GloFish® fluorescent fish are intended for use as aquarium fish only, and should never be intentionally released into the wild.

What if a GloFish® fluorescent zebrafish is eaten in the wild by another animal?For an animal in the wild, eating a fluorescent zebrafish is the same as eating any other zebrafish. Their fluorescence is derived from a gene that is already found in nature and is completely safe for the environment. Just as eating a blue fish would not turn a predator blue, eating a fluorescent fish will not make a predator fluoresce.

Can humans eat GloFish®?GloFish® fluorescent zebrafish, like all ornamental fish, are not intended for human consumption. Accordingly, GloFish should not be eaten.

Genetically modified organisms in aquaculture

Devin M. BartleyFAO Fisheries Department, Rome, Italy

ABSTRACT

Aquaculture is recognized as one of the fastest growing food production sectors; part of the reason for this growth is genetic innovations and improvements. However, one technology that has sparked controversy in the areas of human and environmental safety is that of genetically modified organisms (GMOs). The controversy is most intense in the plant agricultural sector where 52 million ha in 13 countries around the world are planted with GM crops; 60% of all processed foods in the US are genetically modified. At present, there are no GM fish available to the consumer, however attitudes in the fishery sector are being influenced by events in terrestrial agriculture. Approximately 70% of the crops that are genetically engineered are engineered to herbicide resistance and many other crops are engineered to produce pesticides. Genetic engineering in aquaculture does not involve the engineering of toxins or resistance to toxins, but primarily focuses on improved growth rate; other traits of interest are improved environmental tolerance, sterility, and the production of pharmaceuticals. Although there are similarities between the agriculture and aquaculture sectors, significant differences exist in the area of genetic engineering that necessitate careful and focused review of GMOs in aquaculture. Science-based risk assessment and the precautionary approach have been widely promoted as tools for the responsible use of GMOs. However, consumers are influenced more by popular media than by scientific arguments; the aquaculture industry will be influenced mostly by consumer demands. Development of advanced genetic technologies such as GMOs will need to address both the rational and irrational concerns of the general public.

INTRODUCTION

Aquaculture is recognized as one of the fastest growing food producing sectors globally. Part of the reason for this rapid growth is the application of genetic technologies. Although there is a range of genetic technologies including conventional animal breeding, chromosome-set manipulation, hybridization, genomics, marker assisted selection, and genetic engineering, it is genetic engineering, also known as the production of genetically modified organisms (GMOs) or transgenic organisms that has generated the most controversy.

It is the purpose of this paper to present a brief status of the field of genetic modification in aquatic species and identify some of the important issues that will bear on their commercialization.

Status of Genetic Modification in Aquatic Species

Genetically modified organisms (GMOs) are defined by the European Union as "Organisms (and micro-organisms) in which the genetic material (DNA) has been altered in a way that does not occur naturally by mating or natural recombination". The technology is often called "modern biotechnology" or "gene technology", sometimes also "recombinant DNA technology" or "genetic engineering". It allows selected individual genes to be transferred from one organism into another, also between non-related species". The term transgenics is used when the technology specifically involves gene transfer from one species to another.

FIGURE 1Diagrammatic view of a DNA construct for a "trans-gene". The gene product and

the environment act together to produce the transgenic fish.

Although the methodology is complex, the basic idea is that a new piece of DNA called a genetic "construct" is made that is composed of a promoter, or switch, the desired gene to be introduced into the GM fish, a reporter or marker segment that allows the geneticist to detect the presence of the new gene, and a terminator segment that switches the gene off (Figure 1, Beardmore and Porter, 2003). Real gene functioning is much more complex that in Figure 1. For instance, the gene product may affect other parts of the animal and produce unintended results, the switches may also activate or deactivate genes other that the desired trans-gene, also producing unintended impacts, and the location of where the construct goes into the animals DNA is also unknown and may be inconsistent.

At present there are no genetically modified (GM) aquatic species available to the aquaculture industry. However, in the crop sector the technology is well established and is currently the subject of substantial debate. In the US, where the technology is generally accepted, approximately 60% of all processed foods are genetically modified. These mostly include products from soya beans, corn and canola. Around the world, approximately 130 million acres (52 million ha) in 13 countries are planted with GM crops. Gene technology is one of the fastest growing technologies, at about 15% per year. In the US, 3.5 million acres (1.4 million ha) were planted with GM crops in 1996 rising to over 88 million acres (35 million ha) in 2001. The majority of the genetic modification, about 70% of the crops, involves herbicide resistance, thus allowing farmers to control weeds without killing important crops. The remainder of the GM crops includes primarily plants genetically modified to express pesticides, thus allowing farmers to use fewer pesticides.

There are approximately 30 aquatic species that are being genetically modified in laboratories and test facilities. Some of these are being studied for commercial application, whereas others form the basis of basic research on gene and cell functioning.

TABLE 1Experimental and developmental work on transgenic technology (GMOs) in aquatic species (after Bartley, 2000)

Desired trait Species Active genes

Better growth (faster, bigger, more efficient)

Atlantic salmon, coho salmon, chinook salmon, rainbow trout, cutthroat trout, Nile tilapia, tilapia hybrids, mud loach, channel catfish, common carp, Indian major carps, goldfish, abalone, Pacific oyster

Growth hormone, anti-freeze protein gene, insulin-like growth factor

Increased cold tolerance

Atlantic salmon, strawberries, potatoes Anti-freeze protein gene

Increased tolerance to low oxygen levels

Common carp, grass carp Growth hormone

Disease resistance

Salmon spp., striped bass, marine shrimp Lysosome gene, pleurocidin (flounder) gene

Sterility Oysters, medaka Interference RNA

Pigment synthesis

Marine bacteria Beta carotene gene

Production of human insulin

Tilapia Insulin producing gene

Production of calcitronin

Rabbit Salmon calcitronin producing gene

Table 1 lists some aquatic species being developed for genetic modification. There are two species of fish that are close to commercialization and awaiting government approval: 1) a transgenic Atlantic salmon in the United States and 2) a transgenic tilapia in Cuba. Both have been modified for improved growth.

ISSUES

The main issues involving GM fish are whether they present a danger to the environment or human health, and if they are ethical. Trade issues associated with GMOs are extremely complex and are not addressed here.

Environmental risk

The US National Research Council (USNRC) cited environmental issues as the greatest science-based concern for GM fish (USNRC, 2002). Their reasoning was that there are numerous uncertainties associated with how the genetic modification will affect the fish, how the GM fish will impact the environment and how the trans-gene may be passed to other populations in the environment. Further concern was raised because of the potential for GM aquatic species to escape from fish farming facilities and to spread easily and undetected through rivers and other water-bodies. The USNRC (2002) cited three main factors in environmental risk assessment: 1) the effect of the trans-gene on the GM animal - what change in the phenotype is expected and what are the potential unknown effects; 2) the specific animal, genetically modified - some animals have a tendency to become feral or invasive easily and have a history of causing environmental damage; and 3) the receiving environment - environments will be different as to their ability to withstand or recover from impacts of GM fish and environments will have different values to society.

Many of the environmental risks of GM fish are similar to those posed by non-GM fish. Any organism entering the environment can impact native biodiversity through predation/herbivory, competition, habitat modification and interbreeding with native species. Are these risks greater with GM fish? Due to a lack of adequate information from long-term and large-scale field studies, our ability to assess risks is not very good.

The ability of a GM animal to impact an environment will also depend on the specific environment. Ecosystems have different degrees of resistance to and resilience from adverse impacts. Resistant and resilient communities will be less impacted by GM fish than those unstable communities.

Many GM fish are modified to grow faster or have improved environmental tolerances (Table 1). If these fish escaped into nature, or if the gene or genes that confer these qualities on farmed fish were

passed to native species through interbreeding, ecosystems could be adversely impacted through the increased activity (predation, competition, range extension, etc.) of the GM fish. Existing ecological balances could be offset by the introduction of a highly competitive or highly predacious GM fish. However, some researchers feel that because GM fish are domesticated and designed for life in fish farms, they will not be very competitive in nature if they escape (Dunham, 1999). There is still considerable disagreement among scientists on the issue of fitness of GM fish in the wild. Thus, case-by-case examination, experimentation and risk assessment are required at present.

In order to reduce the chance of escaped GM fish breeding in the wild, aquaculturists are examining techniques to make the fish sterile. This is easily accomplished in many aquatic species through adding an extra set of chromosomes (the creation of triploid organisms). Although this technique does not produce 100% sterile animals, and some males still exhibit secondary sexual characteristics, it greatly reduces the probability of fish breeding.

Health risk

Although most fishery regulatory agencies feel that environmental issues are of primary importance (USNRC, 2002), the human health concerns associated with GMOs in the human food chain[5] receive a great deal of attention worldwide. This is in part due to news about crops. Crops have been genetically modified to contain pesticides, herbicides and general antibiotics, and there are fears that these toxins could affect people; the uninformed consumer feels that genetically modified fish also may contain toxins. An additional difference between plants and animals is that animals, in general, do not produce natural toxins or anti-nutritional compounds as many plants do. Thus, there is less scope in animals for the trans-gene to activate inadvertently naturally occurring toxins.

Although the risks to human health are slight, they are present and should be considered. GM fish could express genes or gene products, i.e. proteins, that do not have a history of safe use in the human diet. Risk managers are calling for a case-by-case evaluation of GM fish that first identifies the potential differences between the GM product and the non-GM product and then to identify the nutritional and toxicological implications of the differences. In evaluating food safety of GM fish, the DNA construct used to change the fish should be considered, especially if the gene or promoter comes from viral source. In this case, horizontal gene transfer or recombination (DNA combining with other DNA) could occur and lead to the generation of new viruses. DNA fragments may not be completely digested by the human gut and may survive in the gastro-intestinal tract. These fragments could be absorbed by gut micro-flora and somatic cells in the gut.

There have been instances in crops where the foreign gene has caused allergic reactions; for example, a gene from a Brazil nut was placed in soybean and people who were allergic to Brazil nuts reacted to the soybean. In the fisheries sector, the most common gene construct involves a growth hormone gene (Table 1) and not the herbicides or pesticides used in plants. Many of the GMOs being tested for use in aquaculture only produce more of their own growth hormone.

Labelling of GM products is currently a debated issue. However, many of the nutritional, toxicological and allergenicity concerns would be alleviated by such labelling.

Thus, from the human health perspective the risks are present, but minor. One area of potential concern is the future development of disease resistance. A theoretical possibility is that, if a GMO is more disease-resistant, it may become a host for new pathogens, some of which may be transmissible or pathogenic to humans.

Ethics and Animal Welfare

Is it ethical to modify genetically animals? In order to answer this question we must define what we mean by "ethics" and establish an "ethical framework" with which to evaluate the issue. A system of ethics is related to, but different from a system of values which is very much dependent on specific cultures. Many ethical frameworks exist or can be established, here I use a framework used in part by the FAO Sub-Committee on Ethics in Food and Agriculture. Components of this framework state that ethics included:

Beneficence - towards people, animals and the environment. The use of GMOs that endanger people, harm or endanger animals, or have adverse environmental impacts could be judged unethical.

Justice and equity - The use of GMOs or the development of technology that allows such use should be governed by ethical notions of justice - and fair treatment. This has been an issue with regards to patenting of genetic resources that have been used by traditional people, without their consent and without compensating them for the use of the resource. There is a feeling that the US Food and Drug Administration will soon approve a transgenic salmon for sale in the USA. However, there is also a feeling that the FDA will not allow the salmon to be grown in the USA! This could be judged an unethical decision because it does not treat the US and foreign environments in an equitable manner.

Autonomy - the rights of individuals or groups for self-determination. This could also include the right to information to make informed choices. From the crop sector, control of GM seeds by multi-national businesses prevents farmers from saving seeds, forcing dependence on the multi-nationals and thereby reducing farmers' autonomy. Failure of labelling of gm foods also denies access to information that consumers need to exercise their autonomy in choosing GM or non-GM foods.

Ethical questions with regard to aquatic GMOs often focus on whether humans have the right to modify natural creations. Are we over-playing our autonomy? However, humans have been modifying plants, animals and the habitats they live in for millennia. The development of agriculture has been proposed as one of the most significant aspects of civilization in that it provided the time and resources that allowed humans to feed more people and left them free to develop fine arts and science. Genetic modification allows humankind to modify nature faster and to a greater extent than before.

LACK OF INFORMATION

From the above, it should be apparent that much of the controversy concerning the use of GMOs in fishery and aquaculture is due to a lack of information and scientific uncertainty. Major international agreements, such as the Convention on Biological Diversity (CBD, 1994) and the FAO Code of Conduct for Responsible Fisheries (FAO, 1995a), advocate a precautionary approach in such a situation.

The precautionary approach advocated by FAO and CBD states that where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation. The Government of Sweden and FAO convened a technical workshop to define elements of the precautionary approach as they apply to fisheries (FAO, 1995b). These elements state that:

reference points should be established to help determine desirable situations and undesirable impacts, e.g. limit reference points, such as lowest allowable population size of a fishery resource, and target reference points, such as optimum sustainable yield;

pre-agreed actions or contingency plans should be implemented in a timely manner when limit reference points are approached, or when adverse impacts are apparent. Thus monitoring of the fishery, aquaculture activities and the environment is necessary to know when reference points are reached;

priority should be given to maintaining the productive capacity of the resource where there is uncertainty as to the impact of development. This means that priority is given to conservation of stocks over harvesting the stocks when there is uncertainty. This can be extended to aquaculture where the productivity of aquatic resources in nature should be maintained when there is uncertainty as to the risk of GMOs adversely affecting them;

the impacts of a development plan should be reversible within the time frame of 2-3 decades. The eradication of naturalized populations of GM fish, i.e. the reversibility of the impact, is difficult or impossible, especially in marine areas or in extensive river systems;

the burden of proof should be placed according to the above requirements and standard of proof should commensurate with risks and benefits. The precautionary approach has often been taken to mean that the burden of proof rests with those proposing use or development of a resource, i.e. the aquaculture facility must prove that an introduced or newly

domesticated species will have an acceptable impact. This is the "guilty until proven otherwise" approach.

CONCLUSION

GM technology could have much to offer the aquaculture industry, but it must be developed ethically with regard for the environment and human health. It is difficult to determine when GM fish will be commercialized and available to the consumer. Although scientists have established hazards to the environment and human health posed by aquatic GMOs, the likelihood and severity of these hazards is still unknown. GMOs offer the aquaculture industry additional opportunities to produce food and economic benefits. Improved growth-rate could mean less inputs and less waste from aquaculture; increased environmental tolerance could allow farming in marginal areas and provide additional employment opportunity; improved efficiency may allow fish farmers to move farms away from fragile coastal areas to areas less environmentally sensitive.

However, at present in some areas there is strong consumer resistance to the use of GMOs. GM plants and plant products are accepted in the USA and other areas, but not in Europe. Some question the need for GMOs and recommend traditional methods to achieve the same results. According to the United Nations, over the last decades food production has outpaced human population growth, yet approximately 800 million people are food insecure.

Part of the reason for consumer resistance is that there is a perception that GM technology benefits only the multi-national agriculture businesses and not the consumer. This seems to be the case with the plant sector as cost savings in GM food production were not passed on to the consumer. The crop biotech sector has strongly resisted labelling of GM products, causing further distrust of the technology by consumers. In general consumers do not know how their food is produced. In order for GM foods from aquaculture to be accepted, the industry must show how this technology benefits the consumer - is it cheaper, is it more nutritious, is it more environmentally friendly, is it more ethical? In the absence of clear and accurate messages on the benefits, consumers will base their opinion of GM fish on popular media and special interests groups. It will be necessary to produce science-based assessments of the risks and benefits of GM technology to consumers, policy makers and society in general.

REFERENCES

Bartley, D.M. 2000. Genetically modified organisms in fisheries. In: The State of the World Fisheries and Aquaculture. Rome, FAO. pp. 71-77.

Beardmore, J.A. & Porter, J.S. 2003. Genetically modified organisms and aquaculture. FAO Fisheries Circular. No. 989. Rome, FAO. 38p.

Dunham, R.A. 1999. Utilization of transgenic fish in developing countries: potential benefits and risks. J. World Aquaculture Soc. 30:1-11.

CBD. 1994. Convention on Biological Diversity. Text and Annexes. Interim Secretariat for the Convention on Biological Diversity, Chatelaine, Switzerland. 34p.

FAO. 1995a. Code of conduct for responsible fisheries. Food and Agriculture Organization of the United Nations, Rome, Italy. 41p.

FAO. 1995b. Precautionary Approach to Fisheries. Part 1: Guidelines on the precautionary approach to capture fisheries and species introductions. FAO Fisheries Technical Paper 350/1. Food and Agriculture Organization of the United Nations, Rome, Italy.

USNRC. 2002. Animal Biotechnology: science based concerns. US National Research Council. National Academy Press. Washington, DC. USA.(http://www.nap.edu/books/0309084393/html)

Transgenic Zebrafish:Sentinels for Water Security

Barbara Wimpee, Stacy Kaltenbachand Michael J. Carvan

Photomicrograph of injectinga zebrafish embryo

Making of a transgenic fish. Pollution responsive reporter genes are microinjected into one-celled fish embryos shortly after fertilization. The functional gene is incorporated into the

genome of a small portion of the injected fish, and the degree to which it mimics native gene expression is

determined.

 

  Project Summary:Municipal drinking water systems are potential targets for terrorists and are vulnerable to both intentional and accidental contamination.  Intentional contamination could result from direct introduction of a toxic chemical into a drinking water system, or intentional destruction of a structure, that causes chemical contamination of the system.

The distribution systems for drinking water are the most vulnerable and deliver their product directly to numerous homes and workplaces. This transgenic sentinel can monitor these vulnerable systems by detecting biologically significant doses of innumerable different chemicals.

In our laboratory we have assayed 18 potential environmental chemical contaminants, including biological warfare agents such as parathion and paraoxon (chemical relatives of sarin). We will generate lines of transgenic zebrafish biomonitors by introducing an easily assayable reporter gene under the control of pollution responsive DNA elements.  The final product of this project will be a sentinel for biological monitoring of environmental pollution capable of recognizing

Representation of our transgenic fish sentinel for biological monitoring. Transgenic zebrafish with pollution responsive

DNA elements are placed in a body of water. The contaminants bioconcentrate 1,000- to 100,000-fold in the tissues of the fish, activating the response elements (RE)

that induce the production of luciferase. This assay does not require killing the fish and allows for repeated analysis of the

same site with the same fish.

toxic chemicals within a complex environmental mixture, using an easily assayable reporter gene in live fish.

fficient transposition of the Tol2 transposable element from a single copy donor in zebrafishAkihiro Urasaki, Kazuhide Asakawa, and Koichi KawakamiProc. Natl. Acad. Sci. USA (2008) doi: 10.1073/pnas.0810380105

We described the in vivo Tol2 transposition system in zebrafish. First, we constructed transgenic zebrafish carrying single copy integrations of Tol2 on the genome and injected transposase mRNA into one-cell stage embryos. The Tol2 insertions were mobilized efficiently in the germ lineage. We then mobilized a Tol2 insertion in the nup214 gene, which caused a recessive lethal mutant phenotype, and successfully created revertants. Second, we constructed transgenic fish carrying the transposase cDNA downstream of the hsp70 promoter. Double transgenic fish containing the transposase gene and a single copy Tol2 insertion were heat-shocked in a hot bath. Transposition was induced efficiently in the male germ cells. We found that the majority (83%) of the new integration sites were mapped on chromosomes other than the donor chromosome. Thus, our in vivo transposition system is useful to create genome-wide insertions and facilitates functional genomics and transposon biology in vertebrate.

Fuji70;HG6D double transgenic fish (A, B) were heat-shocked and mated (C). Fish with new enhancer trap patterns (D, E) and new insertions (F) were created.

Source: www.nig.ac.jp/hot/2008/kawakami0812.html

Risks Involved With Transgenic FishScienceDaily (Sep. 1, 2009) — Fast growing transgenic fish can revolutionise commercial fish farming and relieve the pressure on overexploited fish stocks. But what happens in the natural environment if transgenic fish escape? Researchers at the University of Gothenburg have studied transgenic fish on behalf of the EU and are urging caution:

See Also:

Plants & Animals

Fish Marine Biology

Earth & Climate

Natural Disasters Sustainability

Science & Society

Resource Shortage World Development

Reference

Transgenic plants Fish migration Genetically modified organism Trout

"Until further notice transgenic fish should be bred in closed systems on land," says Fredrik Sundström at the Department of Zoology, University of Gothenburg, Sweden.By furnishing fish with genes from other organisms, so-called transgenes, researchers have succeeded in producing fish that grow considerably faster or are more resistant to diseases. Fish can also be modified to cope better with cold, which facilitates breeding in colder conditions. There are major benefits for commercial fish farming as transgenic fish are expected to deliver higher production and better yields. However, transgenic fish can also entail risks and undesirable effects on the natural environment.More resistant to toxinsFor example, transgenic fish can be more resistant to environmental toxins, which could entail the accumulation of toxins that ultimately end up in consumers. There are also misgivings that the higher level of growth hormone in the fish can affect people. Researchers at the University of Gothenburg have therefore been commissioned by the EU to study the environmental effects of GMO (genetically modified organisms) within fish farming. The results of the studies show that the genetically modified fish should be treated with great care.Simulated escapes

Sundström, PhD at the Department of Zoology, has studied transgenic salmon and rainbow trout to ascertain what ecological risks they might constitute for the natural environment. The study, which simulated escapes in a laboratory environment, shows that transgenic fish have a considerably greater effect on the natural environment than hatchery-reared non-transgenic fish when they escape. For example, genetically modified fish survive better when there is a shortage of food, and benefit more than non-transgenic fish from increasing water temperatures."It is probably due to the fact that genetically modified fish have a greater ability to compete and are better at converting food," says Sundström.Natural breeds are under threatIf transgenic fish become established in natural stocks they would be able to outcompete the natural breeds. However, conducting studies in a laboratory environment that imitates nature is complicated, which makes it difficult to predict how escaped transgenic fish affect the natural environment. Sundström's conclusion is that international consensus is required before commercial farming can be permitted, and that a precautionary principle must be applied."One option is to farm the transgenic fish on land, which would make escape impossible. At least fertile fish should be kept in a closed system," says Sundström.As of yet no country has permitted commercial farming of transgenic fish, but several applications for such operations are under consideration by authorities in both the USA and the EU

Source: http://www.sciencedaily.com/releases/2009/08/090827073250.htm

Home > Policy Issues > Transgenic Fish > Introduction

INTRODUCTION

As the field of genetic engineering advances, we are beginning to see increased commercial application of this technology. Aquatic animals are being engineered to increase aquaculture production, for medical and industrial research, and for ornamental reasons. While some of these alterations may provide some benefits, the potential effects on human health and the environmental risks that transgenic fish pose to native ecosystems remain unstudied and unknown.

Some of the same genes inserted to provide benefit for transgenic fish may also contribute to higher risk for other species, including humans. Genes inserted to promote disease resistance may allow transgenic fish to absorb higher levels of toxic substances, including heavy metals.(1) In turn, consumers of these fish may be ingesting higher amounts of substances such as mercury and selenium. Transgenic fish that have genes from species such as peanuts or shellfish that are common causes of allergic reactions in humans may prompt allergic reactions in an unsuspecting consumer.

Transgenic species may behave much like invasive species when interacting with the natural environment. They may compete with native species for resources and pose a threat to the genetic diversity of native populations, especially when genetic modifications – such as a rapid growth rate – offer advantages over slower-developing native species. Despite industry assurances that transgenic fish would be unable to naturally reproduce or significantly threaten the environment, some scientists are far more doubtful.(2)

Photo courtesy of Davidson College

Currently, there are no federal laws regulating the production, sale, importation and consumption of transgenic fish. The issues surrounding transgenic fish are coming to the forefront as aquaculture companies petition the Food and Drug Administration for approval to sell transgenic fish to the public.

The sample bill included in this package addresses these concerns by banning the importation, transportation, possession, spawning, incubation, cultivation, or release of aquatic transgenic animals except under a permit.

This web site offers the tools necessary for you to protect your state’s waterways and coasts from transgenic fish, including a legislative summary, talking points, press clips, a fact pack, links, and other background information.

We may have other useful materials on this subject, which are not posted on our web site. Please feel free to contact us at info@serconline.org or call our office in Madison, Wisconsin, at (608) 252-9800.

Also see SERC’s package on Genetically Engineered Food.

If you’ve used this site and found it helpful or, if you have suggestions about how it could be made more helpful, please let us know. Feel free to use the sample bill text included here in your state. If you do, please notify us.

Sources:(1) Hallerman, Eric M. “Genetically Modified Fish and Shellfish: Food for Thought.” Virginia Issues and Answers 8.1 (Winter 2002). Virginia Tech Publications & Outreach Communications. 9 February 2005 <http://www.via.vt.edu/winter02/article2.pdf>.(2) Williams, Rose Marie. “Health Risks and Environmental Issues: ‘Frankenfish’ Await FDA Approval.” Townsend Letter for Doctors and Patients. May 2003. 9 February 2005 <http://www.townsendletter.com/May2003/environissues0503.htm>.

This package was last updated on February 11, 2005.

Sorce: http://www.serconline.org/transFish/index.html

The tiny zebra fish that lives in aquariums, a popular laboratory animal, was genetically modified to produce a fluorescent red pigment, and is being promoted for sale as a household aquarium pet, the "glofish". The glofish caused a stir in the United States because regulation of such transgenic pets is murky and none of the major regulatory agencies: FDA, USDA or EPA has been willing to take the lead in regulating the glofish (even though USDA does deal with pet animals). The glofish is set to go on sale January 5, 2004 without regulatory approval.

FDA announced: "Because tropical aquarium fish are not used for food purposes, they pose no threat to the food supply. There is no evidence that these genetically engineered zebra danio fish pose any more threat to the environment than their unmodified counterparts which have long been widely sold in the United States. In the absence of a clear risk to the public health, the FDA finds no reason to regulate these particular fish."

The FDA position that transgenic glofish are substantially equivalent to unmodified fish is hypothetical and no effort has been made to test the transgenic fish in contained, but wild-like environments. Fish pigmentation with "poster" colors is an aphrodisiac to wild fish and may even provide protection from predators in certain light conditions, or the pigment fluorescence may signal toxic defence as in the stinging sea anemone from which the glofish transgene was prepared and in that way discourage predators.

FDA was presumptuous in washing its hands of the regulation of the transgenic zebra fish, which is likely to become a major pest of warm water areas.

Other transgenic fish to follow in droves

The release of glofish may signal relaxation of the regulation of transgenic fish now being promoted for commercial release. To ensure that transgenic fish do not overpower or seriously pollute the gene pool, both promoters and regulators stress the safety of "sterile" transgenic fish released to bodies of water. Previously, "sterile" fish are produced using synthetic triploid strains of fish produced from treatment of eggspressure or temperature shock and with sex hormones. As ISIS reported, the sterile triploids were "leaky" and tend to produce a few fertile progeny, which can establish transgenic populations.

In spite of these problems, the transgenic fish are being promoted as the first marketable transgenic animals for human consumption. More effort seems to have been spent on promoting the existing defective transgenic fish than on improving them so that they can be safely released for commercial production. Muir and Howard defined conditions under which transgenic fish can cause rapid extinction to wild fish stock, thus posing extreme risk; but this has been ignored in the rush to commercialization.

Development of transgenic fish has focused on a few species including salmon, trout, carp, tilapia and a few others. Salmon and trout are cash crops while the others primarily provide sources of protein. The salmon nearest to commercial release is the Atlantic salmon engineered with a pacific salmon growth hormone driven by the arctic antifreeze promoter gene. The rapid growth of that transgenic salmon is achieved, not so much by the transgenic growth hormone as by the antifreeze gene promoter that functions in the

cool water desirable for salmon flavor. The commercial release of transgenic salmon, even in somewhat contained fish farms, is likely to lead to problems similar to those experienced in the Atlantic salmon farms of the northwest Pacific. A number of studies indicate that salmon produced in sea pens escape and breed with native species, introducing new disease and spreading pollution from the culture pens. These problems will probably be amplified in the fast growing transgenic stocks.

Tilapia fish, native to Africa, are cultured world wide as "poor man’s food", second only to carp as warm water food fish, and exceeding the production of Atlantic salmon (whose market value is twice that of tilapia). Tilapia has been extensively genetically modified and promoted as a transgenic fish exclusive for isolated or contained production. Transgenic tilapia, modified with pig growth-hormone, were three times larger than their non transgenic siblings. Tilapia genetically modified with human insulin grew faster than non-transgenic siblings, and could also serve as a source of islet cells for transplantation to human subjects. Trout growth hormone was used to produce transgenic carp with improved dressing properties. Such transgenic carp are recommended for production in earthen ponds.

Giant mud loach was produced by linking the mud loach growth hormone with its actin promoter. These giant fish are not, technically speaking, "transgenic", as they contain no foreign genes even though the inserted construct is artificial, and pose a paradox for regulators.

Silk moth genes were introduced into Medaka fish to create resistance to bacterial pathogens. Some commercially desirable fish and crustaceans have been difficult to genetically engineer because embryonic tissue is difficult to manipulate. But it has been found that the parental gonads of such animals could be modified using replication defective pantropic retroviral vectors. Pantropic vectors can transform an array of species they are modified forms of the Moloney mouse leukemia virus used extensively in gene therapy. Such vectors have proven useful in modification of a range of edible marine animals including mollusks. Animals produced using modified mammalian leukemia viruses will require extensive testing and long-term evaluation prior to release for human consumption. This is particularly important in view of the leukemia cases found among the handful of successes in human gene therapy, which were done with a retroviral vector (see "Gene therapy risks exposed", Science in Society   19 ).

Contained cultures of transgenic fish

The current generation of transgenic fish has not passed the test of complete sterility if released or escaped to the environment. Fish production in inland earthen ponds may prove acceptable for contained transgenic fish culture. But such facilities should be provided with fail-safe destruction of the pond animals in the event of flooding and adequate protection from theft. Pond commercial culture is effective for carp and tilapia, but more difficult with salmon and trout. Currently, pond culture is suitable for carp and tilapia because the fish are vegetarians, carnivorous salmon and trout depend on a diet of fish and fishmeal but the worldwide stock of feed fish has diminished and suitable vegetable meat substitutes must be found. Atlantic salmon (as typical cold water carnivores) cannot thrive on a diet of rapeseed oils but the fish can achieve maturity if finished with fish oils at least 20 weeks near the end of their maturity cycle. GM oil rape

seed with enhanced production of long chain fatty acids are proposed to serve as feed for pond cultured fish. And glyphosate-tolerant GM canola meal has been pronounced substantially equivalent to non-GM canola as feed for rainbow trout.

Aquaculture can help feed the world without diminishing ocean resources, but premature releases of transgenic fish stocks will do more harm than good. Bad decisions have plagued aquaculture, resulting in pollution and extensive damage to native stocks. International agencies such as the World Bank, the International Development Bank and the Food and Agriculture Organization of the United Nations have created harm by ill- advised projects that led to damage to native resources and pollution. Scientists Julio E. Pérez and Mauro Nirchio of Venezuala along with Juan A. Gomez of Panama commented in Nature: "However, if the aquaculture industry is going to reduce the pressure on wild fish stocks and provide food for the world’s growing population, substantial changes must be made by governments, the private sector and international funding agencies. They must protect coastal ecosystems; promote research and development of native species; and encourage farming of low-trophic-level fish — those low on the food chain. International technical funding agencies can exert great influence in changing practices". Without such constructive thinking, the aquaculture industry poses a threat, not only to ocean fisheries but also to itself.

http://www.i-sis.org.uk/TFC.php

Transgenic Salmon Close to FDA Approval [science!]May 21, 2009, 9:00 am   0 Comments (closed)

Genetically-engineered Atlantic salmon from a company called Aqua Bounty

Technologies are on the brink of getting U.S. FDA approval. The fish of the

future have finally arrived! Canada's Globe and Mail reports:

Tweaked with genetic material from chinook salmon and an eel-like creature

called an ocean pout, it reaches market size twice as fast as normal

Atlantic salmon, the company says. Aqua Bounty has spent more than a

decade chasing U.S. regulatory approval, which Food and Drug

Administration officials have reportedly said is coming 'soon.'

The AquAdvantage® Salmon, infertile by design (out of concern they might

interbreed with other species), would be the first genetically-engineered

animals to be made available as food. The company, unsurprisingly, is

expecting a bit of backlash but stand behind their "product." CEO Ronal

Stotish says he has "tasted and enjoyed the modified fish."

www.eatmedaily.com/.../

RECOMBINANT CONSTRUCTS AND TRANSGENIC FLUORESCENT ORNAMENTAL FISH THEREFROM - diagram, schematic, and image 06

http://www.faqs.org/patents/img/20100037331_06.png

Genetically Engineered Salmon?While not on anyone's dinner table just yet, genetically engineered salmon are just a pen stroke away. GE salmon are being developed by a U.S. company called Aqua Bounty Farms and are preferred for their ability to grow two to four times faster than other farmed salmon:

"The goal of producing faster growing Atlantic Salmon for the commercial food market is well on its way at Aqua Bounty Farms, a research facility located in Fortune, Prince Edward Island, Canada. This experimental hatchery has been injecting growth hormone genes into fertilized salmonid eggs to produce fast growing salmon, trout and Arctic char."Research at Aqua Bounty Farms, Aqua Bounty Farms webpage.

Transgenesis

           Transgenesis or transgenics may be defined as the introduction of exogenous gene /

DNA into host genome resulting in its stable maintenance, transmission and expression. The

technology offers an excellent opportunity for modifying or improving the genetic traits of

commercially important fishers, mollusks and crustaceans for aquaculture. The idea of

producting transgenic animals became popular when Palmitter et al. (1982) first produced

transgenic mouse by introducing metallothionein human growth hormone fusion gene (mT-

hGH) into mouse egg, resulting in dramatic increase in growth. This triggered a series of

attemptson gene transfer in economically important animals including fish.

            The first transgenic fish was produced Zhu et al. (1985) in China, who claimed the

transient expression n putative transgenics, although they gave no molecular evidence for the

integration of the transgene. The technique has now seen successfully applied to a number of

fish species. Dramatic growth enhancement has been shown using this technique especially in

salmonids (Devlin et al., 1994). Some studies have revealed enhancement of growth in adult

salmon to an average of 3 Ð 5 times the size of non Ð transgenic controls, with some

individuals, especially during the first few months of growth, reaching as much as 10 Ð 30

times the size of the controls (Devlin et al., 1994; Hew et al., 1995).The introduction of

transgenic technique has simultaneously put more emphasis on the need for production of

sterile progeny in order to minimize the risk of transgenic stocks mixing in the wild

populations. The technical development has expanded the possibilities for producing either

sterile fish or those whose reproductive activity can be specifically turned on or off using

inducible promoters. This would clearly be of considerable value allowing both optimal

growth and controlled reproduction of the transgenic stocks while ensuring that any escaped

fish would be unable to breed. An increased resistance of fish to cold temperatures has been

another subject of research in fish transgenics for the past several years (Fletcher et al., 2001).

Coldwater temperatures pose a considerable stressor to many fish and few are able to survive

water temperatures much below 0-1oC. this is often a major problem in aquaculture in cold

climates. Interestingly, some marine teleosts have high levels (10 Ð 25 mg/ml) of serum

antifreeze proteins (AFP) or glycoproteins (AFGP) which effectively reduce the freezing

temperature by preventing ice-crystal growth. The isolation, characterization and regulation

of these antifreeze proteins particularly of the inter flounder Pleuronectas americanus has

been the subject of research for a considerable period in Canada. Consequently, the gene

encoding the liver AFP from winter flounder was successfully introduced into the genome of

Atlantic salmon where it became integrated into the germ line and then passed onto the off Ð

spring F3 where it was expressed specifically in the liver (Hew et al., 1995).The introduction

of AFPs to gold fish also increased their cold tolerance, to temperatures at which all the

control fish died (12 h at 0o C; Wang et al., 1995). Similarly, injection or oral administration

of AFP to juvenile milkfish or tilapia led to an increase in resistance to a 26 to 13o  C. drop in

temperature (Wu et al., 1998). The development of stocks harbouring this gene would be a

major benefit in commercial aquaculture in counties where winter temperatures often border

the physiological limits of these species.

         The most promising tool for the future of transgenic fish production is  undoubtedly in

the development of the embryonic stem cell (ESC) technology. There cells are

undifferentiated and remain totipotent so they can be manipulated in vitro and subsequently

reintroduce into early embryos where they can contribute to the germ line of the host. This

would facilitate the genes to be stably introduced or deleted (Melamed et al., 2002).Although

significant progress has been made in several laboratories around the world, there are

numerous problems to be resolved before the successful commercialization of the transgenic

brood stock for aquaculture. To realize the full potential of the transgenic fish technology in

aquaculture, several important scientific break Ð through are required. There include (i) more

efficient technologies for mass gene transfer (ii) targeted gene transfer technologies such as

embryonic stem cell gene transfer (iii) suitable promoters to direct the expression of

transgenes at optimal levels during the desired developmental stages (iv) identified genes of

desireable traits for aquaculture and other applications (v) informations on the physiological,

nutritional, immunological and environmental factors that maximize the performance of the

transgenics of the transgenics and (vi) safety and environmental impacts of transgenic fish.