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phospholipids (PLs), reduces the total lipids in the blood (Mastellone et al. 2000)
and enhances the activity of the brain (Chung et al. 1995). Phosphatidylethanolamine
and phosphatidylserine are also able to reduce lipid levels and improve the function
of the brain (McDaniel et al. 2003). The abundance of effective and potential seafood derived PLs like EPA and DHA has also been included in foods as a valuable
ingredient.
The administration of omega-3 PUFAs seems more effective if omega-3 PUFAs
were given as PL- rather TG-formulations (Wijendran et al. 2002). The beneficial
effects of dietary krill oil supplementation have also been examined in several clinical studies. Supplementation with krill oil has proven beneficial effects on the
human health, mainly by increasing the EPA and DHA levels in the plasma and the
cell membrane (Wang et al. 2011; Maki et al. 2009). In addition, obesity-related
metabolic disorders are ameliorated under the administration of PL-containing
omega-3 PUFAs (Shirouchi et al. 2007). Moreover, in several studies conducted on
animals, these agents were explored for their antioxidant (Hiratsuka et al. 2008),
anti-inflammatory (Ikemoto et al. 2001) and antineoplastic properties (Hosokawa
et al. 2001). Previous studies have reported a decrease in serum and liver TG following the addition of PL-containing omega-3 PUFAs derived from squid mantle muscle or from soybeans to the diet (Hosomi et al. 2010).
13.1.4 Protein, Peptide, and Non-protein Nitrogen Compounds
The human diet usually includes fish oil and whole fish. Dietary omega-3 PUFAs
reduce serum TG even if serum cholesterol is not reduced (Balk et al. 2006). The
main micronutrients found in fish are fish proteins. Around the globe, fish proteins
are essential elements in human nutrition and have been included as main ingredients in processed fish products such as fish sausages or the Japanese surimi (FAO
2010). The impressive levels of amino acids in seafood proteins can make up
between 10% and 25% of their content. Seafood proteins can be classified as sarcoplasmic, myofibrillar or stromal proteins. In terms of amino acid composition and
bioavailability, animal proteins are more acceptable versus vegetable proteins.
The potential impact of fish proteins on the lipid metabolism is another dimension of the role of fish proteins in health. In this context, researchers have shown
that the administration of fish proteins in laboratory animals influenced serum cholesterol levels (Wergedahl et al. 2009). The reduction in serum cholesterol was due
to the properties of fish protein to inhibit the absorption of cholesterol and bile
acids. Thereby, the catabolism of cholesterol in the liver increased (Hosomi et al.
2009). Additionally, other beneficial effects of these substances include the
enhancement of fibrinolysis (Murata et al. 2004), as well as their antihypertensive
(Boukortt et al. 2004) and anti-obesity properties (Oishi and Dohmoto 2009).
Furthermore, animal and human studies have concluded that dietary cod proteins
S. Hassan et al.
phospholipids (PLs), reduces the total lipids in the blood (Mastellone et al. 2000)
and enhances the activity of the brain (Chung et al. 1995). Phosphatidylethanolamine
and phosphatidylserine are also able to reduce lipid levels and improve the function
of the brain (McDaniel et al. 2003). The abundance of effective and potential seafood derived PLs like EPA and DHA has also been included in foods as a valuable
ingredient.
The administration of omega-3 PUFAs seems more effective if omega-3 PUFAs
were given as PL- rather TG-formulations (Wijendran et al. 2002). The beneficial
effects of dietary krill oil supplementation have also been examined in several clinical studies. Supplementation with krill oil has proven beneficial effects on the
human health, mainly by increasing the EPA and DHA levels in the plasma and the
cell membrane (Wang et al. 2011; Maki et al. 2009). In addition, obesity-related
metabolic disorders are ameliorated under the administration of PL-containing
omega-3 PUFAs (Shirouchi et al. 2007). Moreover, in several studies conducted on
animals, these agents were explored for their antioxidant (Hiratsuka et al. 2008),
anti-inflammatory (Ikemoto et al. 2001) and antineoplastic properties (Hosokawa
et al. 2001). Previous studies have reported a decrease in serum and liver TG following the addition of PL-containing omega-3 PUFAs derived from squid mantle muscle or from soybeans to the diet (Hosomi et al. 2010).
13.1.4 Protein, Peptide, and Non-protein Nitrogen Compounds
The human diet usually includes fish oil and whole fish. Dietary omega-3 PUFAs
reduce serum TG even if serum cholesterol is not reduced (Balk et al. 2006). The
main micronutrients found in fish are fish proteins. Around the globe, fish proteins
are essential elements in human nutrition and have been included as main ingredients in processed fish products such as fish sausages or the Japanese surimi (FAO
2010). The impressive levels of amino acids in seafood proteins can make up
between 10% and 25% of their content. Seafood proteins can be classified as sarcoplasmic, myofibrillar or stromal proteins. In terms of amino acid composition and
bioavailability, animal proteins are more acceptable versus vegetable proteins.
The potential impact of fish proteins on the lipid metabolism is another dimension of the role of fish proteins in health. In this context, researchers have shown
that the administration of fish proteins in laboratory animals influenced serum cholesterol levels (Wergedahl et al. 2009). The reduction in serum cholesterol was due
to the properties of fish protein to inhibit the absorption of cholesterol and bile
acids. Thereby, the catabolism of cholesterol in the liver increased (Hosomi et al.
2009). Additionally, other beneficial effects of these substances include the
enhancement of fibrinolysis (Murata et al. 2004), as well as their antihypertensive
(Boukortt et al. 2004) and anti-obesity properties (Oishi and Dohmoto 2009).
Furthermore, animal and human studies have concluded that dietary cod proteins
S. Hassan et al.