Part C | 18.4
478 Part C Marine Genomics
18.4 Aquaculture
In order to continue to meet the worldwide demand for
seafood, it is estimated that fish production will have
to increase sevenfold by 2020 and that this will need
to be accomplished through aquaculture [18.13]. Although production levels of farmed shellfish and fish
are steadily increasing, the industry faces many challenges that must be met in order to be sustainable. Some
of the issues that the industry faces include improved
larviculture, prevention and treatment of disease, feed
quality and increased growth rates, nutritional quality
of the product, etc. Perhaps the greatest threat to the
future growth of aquaculture is the escalating rate of
climate change that will have a significant impact on
aquaculture in the same way that it will affect terrestrial
farming [18.17, 18].
18.4.1 Disease
Aquaculture of fish and shellfish is subject to the
same constant threat of infectious disease as farmed
terrestrial animals and plants [18.19–23]. For example, even though Scotland generates 97% of farmed
Atlantic salmon (Salmosalar) in the United Kingdom, it is estimated that a third of production is lost
due to disease [18.24]. Similarly, although 2:7 million
metric tons of the white leg shrimp Penaeus vannamei was produced in 2010, with a value of US$
11:3 billion [18.25], the cumulative loss in global
production since the emergence of white spot disease in the early 1990s is estimated at nearly US$
15 billion [18.26]. Although it is difficult to find definitive figures, it is estimated that the global loss of
aquacultured animals to disease amounts to approximately several billion US$ per annum [18.27]. Marine
organisms are subject to infection by viruses, bacteria, and parasites, many of which are uncharacterized and thus designated as emerging diseases [18.28].
Consequently, the means to either prevent or mitigate disease in aquacultured marine organisms is
currently quite limited. Antibiotics are no longer an
acceptable treatment against bacterial pathogens due
to the potential of resistance arising in target bacteria, as well as the fact that antibiotic residues in
seafood destined for human consumption are not acceptable [18.27]. Consequently, the development of
vaccines for treatment and disease prevention is receiving a great deal of attention [18.29, 30], while
probiotics are being investigated as an alternative to
antibiotics [18.21, 31].
Proteomics has been employed in a number of
studies investigating disease in aquacultured marine animals. It has become increasingly evident that stress
is intimately linked to the onset of disease in aquacultured organisms [18.17, 32–34]. Hypoxic conditions
in shrimp ponds has been shown to lead to stunted
growth rates and an increased susceptibility to infectious disease [18.35]. Consequently, the proteome of
the hepatopancreas of adult Chinese shrimp Fenneropenaeus chinensis was characterized to obtain a better
understanding of the hypoxia stress response in this
commercially important crustacean.
Two-dimensional electrophoresis identified 67 protein spots that were differentially expressed in response
to anoxic conditions [18.35]; 51 of these spots were
identified as 33 proteins by LC-ESI-MS/MS (LC: liquid
chromatography; ESI: electrospray ionization), including preamylase, arginine kinase, phosphopyruvate hydratase, citrate synthase, adenosine triphosphate (ATP)
synthase alpha subunit, chymotrypsin B1, chitinase,
ferritin, C-type lectin receptors, transketolase, formylglutathione hydrolase, formyltetrahydrofolate dehydrogenase, aldehyde dehydrogenase, glutathione peroxidase, cytosolic manganese superoxide dismutase, protein disulphide isomerase, ˇ-actin, oncoprotein 23 nm,
and crustacyanin-C1. Many of the proteins could be
classified into functional groups such as energy production, immunity, chaperones, and antioxidants, thus
providing insight into the type of metabolic processes
and stress response systems evoked in response to
hypoxia [18.35].
The effect of hypoxia on humoral immunity in
the Eurasian perch Perca fluviatilis, currently undergoing domestication for aquaculture, was investigated
by exposing captive fish from two generations (F1 and
F5) to either single or multiple 4 h hypoxic episodes
over a period of 46 days and examining the serum
proteome using 2D-DIGE [18.36]. C3 complement proteins were found to be up-regulated following a single exposure to hypoxia, while exposure to multiple
hypoxic events resulted in up-regulation of transferrin and differential expression (some up and others
down-regulated) of a number of C3 complement proteins. The study concluded that the serum proteome
responded to single and multiple hypoxic events in the
same way and that repeated exposure resulted in acclimation to the stress, suggesting that Perca fluviatilis
can adapt to hypoxic conditions that may arise during
aquaculture [18.36].
478 Part C Marine Genomics
18.4 Aquaculture
In order to continue to meet the worldwide demand for
seafood, it is estimated that fish production will have
to increase sevenfold by 2020 and that this will need
to be accomplished through aquaculture [18.13]. Although production levels of farmed shellfish and fish
are steadily increasing, the industry faces many challenges that must be met in order to be sustainable. Some
of the issues that the industry faces include improved
larviculture, prevention and treatment of disease, feed
quality and increased growth rates, nutritional quality
of the product, etc. Perhaps the greatest threat to the
future growth of aquaculture is the escalating rate of
climate change that will have a significant impact on
aquaculture in the same way that it will affect terrestrial
farming [18.17, 18].
18.4.1 Disease
Aquaculture of fish and shellfish is subject to the
same constant threat of infectious disease as farmed
terrestrial animals and plants [18.19–23]. For example, even though Scotland generates 97% of farmed
Atlantic salmon (Salmosalar) in the United Kingdom, it is estimated that a third of production is lost
due to disease [18.24]. Similarly, although 2:7 million
metric tons of the white leg shrimp Penaeus vannamei was produced in 2010, with a value of US$
11:3 billion [18.25], the cumulative loss in global
production since the emergence of white spot disease in the early 1990s is estimated at nearly US$
15 billion [18.26]. Although it is difficult to find definitive figures, it is estimated that the global loss of
aquacultured animals to disease amounts to approximately several billion US$ per annum [18.27]. Marine
organisms are subject to infection by viruses, bacteria, and parasites, many of which are uncharacterized and thus designated as emerging diseases [18.28].
Consequently, the means to either prevent or mitigate disease in aquacultured marine organisms is
currently quite limited. Antibiotics are no longer an
acceptable treatment against bacterial pathogens due
to the potential of resistance arising in target bacteria, as well as the fact that antibiotic residues in
seafood destined for human consumption are not acceptable [18.27]. Consequently, the development of
vaccines for treatment and disease prevention is receiving a great deal of attention [18.29, 30], while
probiotics are being investigated as an alternative to
antibiotics [18.21, 31].
Proteomics has been employed in a number of
studies investigating disease in aquacultured marine animals. It has become increasingly evident that stress
is intimately linked to the onset of disease in aquacultured organisms [18.17, 32–34]. Hypoxic conditions
in shrimp ponds has been shown to lead to stunted
growth rates and an increased susceptibility to infectious disease [18.35]. Consequently, the proteome of
the hepatopancreas of adult Chinese shrimp Fenneropenaeus chinensis was characterized to obtain a better
understanding of the hypoxia stress response in this
commercially important crustacean.
Two-dimensional electrophoresis identified 67 protein spots that were differentially expressed in response
to anoxic conditions [18.35]; 51 of these spots were
identified as 33 proteins by LC-ESI-MS/MS (LC: liquid
chromatography; ESI: electrospray ionization), including preamylase, arginine kinase, phosphopyruvate hydratase, citrate synthase, adenosine triphosphate (ATP)
synthase alpha subunit, chymotrypsin B1, chitinase,
ferritin, C-type lectin receptors, transketolase, formylglutathione hydrolase, formyltetrahydrofolate dehydrogenase, aldehyde dehydrogenase, glutathione peroxidase, cytosolic manganese superoxide dismutase, protein disulphide isomerase, ˇ-actin, oncoprotein 23 nm,
and crustacyanin-C1. Many of the proteins could be
classified into functional groups such as energy production, immunity, chaperones, and antioxidants, thus
providing insight into the type of metabolic processes
and stress response systems evoked in response to
hypoxia [18.35].
The effect of hypoxia on humoral immunity in
the Eurasian perch Perca fluviatilis, currently undergoing domestication for aquaculture, was investigated
by exposing captive fish from two generations (F1 and
F5) to either single or multiple 4 h hypoxic episodes
over a period of 46 days and examining the serum
proteome using 2D-DIGE [18.36]. C3 complement proteins were found to be up-regulated following a single exposure to hypoxia, while exposure to multiple
hypoxic events resulted in up-regulation of transferrin and differential expression (some up and others
down-regulated) of a number of C3 complement proteins. The study concluded that the serum proteome
responded to single and multiple hypoxic events in the
same way and that repeated exposure resulted in acclimation to the stress, suggesting that Perca fluviatilis
can adapt to hypoxic conditions that may arise during
aquaculture [18.36].