Part C | 18.5
482 Part C Marine Genomics
mones regulate metabolism and somatic growth, which
in turn, require a sufficient nutrient supply. Thus the
aim of the study was to determine whether a feedback loop exists between nutritional status and pituitary hormone synthesis and secretion, since there is
very little information available regarding the effect
of dietary supplementation with AKG on the fish endocrine system. Ibarz et al. [18.51] found that AKG
supplementation resulted in up-regulation of proteins
such as fructose-bis-phosphate aldolase, glyceraldehyde-phosphate dehydrogenase and malate dehydrogenase that function in glucose metabolism. Proteins
responsible for protein folding, such as two heat shock
protein isoforms, cyclophylin and chaperonin, were
also up-regulated, as well as cofilin and Vat-protein,
which are involved in regeneration of neural function. On the other hand, an unusual apolipoproteinA-1 and the hormone somatolactin were down-regulated in fish fed the AKG-supplemented diet. These
observations led the authors to suggest that an endocrine/metabolic regulatory loop is, indeed, activated
by AKG supplementation [18.51].
Since the muscle tissue of the fish is the portion
that is consumed, it is important to safeguard the quality of farmed fish muscle tissue. Muscle quality is
based on its composition, which is a function of the
number and integrity of muscular fiber [18.52]. Since
muscle tissue is central to many aspects of fish aquaculture, such as physiology, growth, food safety, seafood
authentication and quality, traceability, and shelf-life,
Addis et al. [18.52] conducted a study of the muscle
proteome of Sparus aurata in which fish from four
offshore floating cages and two re-population lagoons,
located at remote sites from each other, were sampled
on a two-monthly basis over a period of 22 months
in order to investigate muscle proteome variability in
relation to fish size and environmental conditions. Although the expression pattern of the muscle proteome
was found to be relatively stable, the study revealed
significant variation in the abundance of parvalbumins,
troponins, and warm temperature acclimation-related
protein 65 isoforms (Wap65) in relation to fish length
and water temperature [18.52]. The authors also noted
that structural proteins were more abundant in longer
wild fish, while shorter farmed fish had an abundance
of proteins involved in glycolysis. However, the muscle proteome was found to be comparable in wild
and farmed fish of the same size, indicating that cage
farming does generate high-quality fish for commercial
production [18.52].
Similarly, since sea urchin gonads are a high-value
seafood product, farmed sea urchins must be provided
a quality diet to ensure gonad quality and quantity. Consequently, Sewell et al. [18.53] employed a proteomic
approach to define the proteome of mature ovaries
of the New Zealand sea urchin Evechinus chloroticus. The study successfully identified 138 proteins,
of which only 12 were linked to ovarian reproductive
function, and established a foundation for quantification of changes in expression of the ovary proteome
which could be correlated with gonad quality and diet
formulation [18.53].
18.5 Environment
As mentioned previously, the world’s oceans occupy
two-thirds of the earth’s surface and harbor a vast
diversity of microbes, plants, and animals. The marine environment plays an important role in regulating the earth’s climate and in turn, the ocean’s currents and temperatures are significantly influenced by
climate [18.18]. Climate change is not only a serious threat to terrestrial environments, but is also
impacting the marine environment and its inhabitants. Carbon dioxide emissions are directly responsible for ocean acidification and increased water
temperatures, which in turn, leads to oxygen limitation [18.17, 54]. In addition, the large proportion
of the human population living in close proximity to the coast has had a detrimental impact on
the marine environment due to over-exploitation of
biological resources and significant microbial and
chemical contamination of coastal and near-shore
regions [18.18, 55].
18.5.1 Climate Change
Ocean acidification (OA) affects marine organisms
by disrupting acid–base regulation, respiration, energy
turnover, and metabolism, as well as reducing growth
rates, reproductive success, calcification, and sensory
mechanisms [18.17]. Since climate change is responsible for increased temperatures and hypercapnia (elevated CO 2 levels), the negative effects on marine biota
are likely to be interactive and cumulative [18.56].
482 Part C Marine Genomics
mones regulate metabolism and somatic growth, which
in turn, require a sufficient nutrient supply. Thus the
aim of the study was to determine whether a feedback loop exists between nutritional status and pituitary hormone synthesis and secretion, since there is
very little information available regarding the effect
of dietary supplementation with AKG on the fish endocrine system. Ibarz et al. [18.51] found that AKG
supplementation resulted in up-regulation of proteins
such as fructose-bis-phosphate aldolase, glyceraldehyde-phosphate dehydrogenase and malate dehydrogenase that function in glucose metabolism. Proteins
responsible for protein folding, such as two heat shock
protein isoforms, cyclophylin and chaperonin, were
also up-regulated, as well as cofilin and Vat-protein,
which are involved in regeneration of neural function. On the other hand, an unusual apolipoproteinA-1 and the hormone somatolactin were down-regulated in fish fed the AKG-supplemented diet. These
observations led the authors to suggest that an endocrine/metabolic regulatory loop is, indeed, activated
by AKG supplementation [18.51].
Since the muscle tissue of the fish is the portion
that is consumed, it is important to safeguard the quality of farmed fish muscle tissue. Muscle quality is
based on its composition, which is a function of the
number and integrity of muscular fiber [18.52]. Since
muscle tissue is central to many aspects of fish aquaculture, such as physiology, growth, food safety, seafood
authentication and quality, traceability, and shelf-life,
Addis et al. [18.52] conducted a study of the muscle
proteome of Sparus aurata in which fish from four
offshore floating cages and two re-population lagoons,
located at remote sites from each other, were sampled
on a two-monthly basis over a period of 22 months
in order to investigate muscle proteome variability in
relation to fish size and environmental conditions. Although the expression pattern of the muscle proteome
was found to be relatively stable, the study revealed
significant variation in the abundance of parvalbumins,
troponins, and warm temperature acclimation-related
protein 65 isoforms (Wap65) in relation to fish length
and water temperature [18.52]. The authors also noted
that structural proteins were more abundant in longer
wild fish, while shorter farmed fish had an abundance
of proteins involved in glycolysis. However, the muscle proteome was found to be comparable in wild
and farmed fish of the same size, indicating that cage
farming does generate high-quality fish for commercial
production [18.52].
Similarly, since sea urchin gonads are a high-value
seafood product, farmed sea urchins must be provided
a quality diet to ensure gonad quality and quantity. Consequently, Sewell et al. [18.53] employed a proteomic
approach to define the proteome of mature ovaries
of the New Zealand sea urchin Evechinus chloroticus. The study successfully identified 138 proteins,
of which only 12 were linked to ovarian reproductive
function, and established a foundation for quantification of changes in expression of the ovary proteome
which could be correlated with gonad quality and diet
formulation [18.53].
18.5 Environment
As mentioned previously, the world’s oceans occupy
two-thirds of the earth’s surface and harbor a vast
diversity of microbes, plants, and animals. The marine environment plays an important role in regulating the earth’s climate and in turn, the ocean’s currents and temperatures are significantly influenced by
climate [18.18]. Climate change is not only a serious threat to terrestrial environments, but is also
impacting the marine environment and its inhabitants. Carbon dioxide emissions are directly responsible for ocean acidification and increased water
temperatures, which in turn, leads to oxygen limitation [18.17, 54]. In addition, the large proportion
of the human population living in close proximity to the coast has had a detrimental impact on
the marine environment due to over-exploitation of
biological resources and significant microbial and
chemical contamination of coastal and near-shore
regions [18.18, 55].
18.5.1 Climate Change
Ocean acidification (OA) affects marine organisms
by disrupting acid–base regulation, respiration, energy
turnover, and metabolism, as well as reducing growth
rates, reproductive success, calcification, and sensory
mechanisms [18.17]. Since climate change is responsible for increased temperatures and hypercapnia (elevated CO 2 levels), the negative effects on marine biota
are likely to be interactive and cumulative [18.56].