6 Safe and Nutritious Aquaculture Produce
187
Fish have proved fairly tolerant of changes in lipid and protein sources, in terms
of growth and survival, provided EFA and essential amino acid requirements are
met. However, there are potential detrimental effects, in the edible flesh, on biologically important fatty acid concentrations, due to replacement of FO with VO, and
also in micronutrient concentrations, when FO and FM are replaced. High dietary
VO inclusion can result in reductions of flesh DHA and EPA of ~65% in salmon
fed 100% VO or up to 50% in bass and bream fed 60% VO. However, flesh EPA
and DHA values can be restored to 70–100% of the values in fish fed FO, for the
whole grow out period, by the use of FO-containing finishing diets in the preharvest period (Bell et al. 2004a; Torstensen et al. 2005; Mourente et al. 2005;
Izquierdo et al. 2005).
Significant replacement of FO and FM also leads to changes in dietary supply,
bioavailability and requirement of micronutrients for the farmed fish. Greatest
focus has been on mineral bioavailability aspects related to the inherent antinutrient factors (ANF) in plant derived raw materials (Francis et al. 2001). Besides
the risks for suboptimal micronutrient nutrition for the fish, by lower gross nutrient
concentrations and bioavailability, this also implies subsequent alteration in product
composition and quality, since several vitamins and minerals in fish flesh are
tailored through diet (Baker 2001; Lie 2001). There has been less focus on these
secondary consequences of changes in feed ingredients, which especially includes
nutrients with antioxidant properties and those normally associated with the
benefits of seafood consumption, such as vitamins B 12 , D, E, carotenoids
( astaxanthin and canthaxanthin), iodine and selenium. Changes in product
composition will, like lipid retention, also depend on fish species (lean or fat), as
well as their feed intake and growth rate.
The importance of n-3 highly unsaturated fatty acids (HUFA), principally EPA
and DHA, in human nutrition was first recognised in the 1970s by Dyerberg and
Bang who suggested that the diet of Greenland Inuit populations resulted in
reduction, or absence, of disease conditions which were prevalent in developed
societies (Dyerberg et al. 1975; Bang et al. 1980). Over the last 50 years the
prevalence of diseases with an inflammatory pathology has increased dramatically
especially pathologies of the cardiovascular system (Kris-Etherton et al. 2002;
Wang et al. 2003). However, more recent research has implicated many more
disease conditions with an inflammatory pathology that may respond to n-3 HUFA
supplementation. These include asthma (Broughton et al. 1997), rheumatoid arthritis (Calder and Zurier 2001), Alzheimer’s disease (Morris et al. 2003), Crohn’s
disease (Belluzzi and Miglio 1998), lupus (Kelley et al. 1985), cancer (Hardman
2002), diabetes (Lombardo and Chicco 2006), psoriasis (Ziboh 1998), schizophrenia
(Peet et al. 2001), bipolar disorder (Noaghiul and Hibbeln 2003) and autism (Bell
et al. 2004b). In recent times, many countries in the developed world, as well as the
World Health Organisation and NATO, have produced recommendations on
combined EPA and DHA intake for improved human health which are generally in
the range of 0.3–0.5 g day
–1 . In 2004, ISSFAL (www.issfal.org.uk) updated their
recommendation for n-3 HUFA intake suggesting that consuming 500 mg of EPA +
DHA day
–1
, or 3.5 g week
−1 should provide for good cardiac health in adults.
187
Fish have proved fairly tolerant of changes in lipid and protein sources, in terms
of growth and survival, provided EFA and essential amino acid requirements are
met. However, there are potential detrimental effects, in the edible flesh, on biologically important fatty acid concentrations, due to replacement of FO with VO, and
also in micronutrient concentrations, when FO and FM are replaced. High dietary
VO inclusion can result in reductions of flesh DHA and EPA of ~65% in salmon
fed 100% VO or up to 50% in bass and bream fed 60% VO. However, flesh EPA
and DHA values can be restored to 70–100% of the values in fish fed FO, for the
whole grow out period, by the use of FO-containing finishing diets in the preharvest period (Bell et al. 2004a; Torstensen et al. 2005; Mourente et al. 2005;
Izquierdo et al. 2005).
Significant replacement of FO and FM also leads to changes in dietary supply,
bioavailability and requirement of micronutrients for the farmed fish. Greatest
focus has been on mineral bioavailability aspects related to the inherent antinutrient factors (ANF) in plant derived raw materials (Francis et al. 2001). Besides
the risks for suboptimal micronutrient nutrition for the fish, by lower gross nutrient
concentrations and bioavailability, this also implies subsequent alteration in product
composition and quality, since several vitamins and minerals in fish flesh are
tailored through diet (Baker 2001; Lie 2001). There has been less focus on these
secondary consequences of changes in feed ingredients, which especially includes
nutrients with antioxidant properties and those normally associated with the
benefits of seafood consumption, such as vitamins B 12 , D, E, carotenoids
( astaxanthin and canthaxanthin), iodine and selenium. Changes in product
composition will, like lipid retention, also depend on fish species (lean or fat), as
well as their feed intake and growth rate.
The importance of n-3 highly unsaturated fatty acids (HUFA), principally EPA
and DHA, in human nutrition was first recognised in the 1970s by Dyerberg and
Bang who suggested that the diet of Greenland Inuit populations resulted in
reduction, or absence, of disease conditions which were prevalent in developed
societies (Dyerberg et al. 1975; Bang et al. 1980). Over the last 50 years the
prevalence of diseases with an inflammatory pathology has increased dramatically
especially pathologies of the cardiovascular system (Kris-Etherton et al. 2002;
Wang et al. 2003). However, more recent research has implicated many more
disease conditions with an inflammatory pathology that may respond to n-3 HUFA
supplementation. These include asthma (Broughton et al. 1997), rheumatoid arthritis (Calder and Zurier 2001), Alzheimer’s disease (Morris et al. 2003), Crohn’s
disease (Belluzzi and Miglio 1998), lupus (Kelley et al. 1985), cancer (Hardman
2002), diabetes (Lombardo and Chicco 2006), psoriasis (Ziboh 1998), schizophrenia
(Peet et al. 2001), bipolar disorder (Noaghiul and Hibbeln 2003) and autism (Bell
et al. 2004b). In recent times, many countries in the developed world, as well as the
World Health Organisation and NATO, have produced recommendations on
combined EPA and DHA intake for improved human health which are generally in
the range of 0.3–0.5 g day
–1 . In 2004, ISSFAL (www.issfal.org.uk) updated their
recommendation for n-3 HUFA intake suggesting that consuming 500 mg of EPA +
DHA day
–1
, or 3.5 g week
−1 should provide for good cardiac health in adults.