6 Safe and Nutritious Aquaculture Produce
199
cyclooxygenase-2 expression and that of other genes that are implicated in tumour
promotion (Hardman 2002). In a recent study, proliferation and gene expression in a
B-lymphocyte cell line were investigated when supplemented with EPA or DHA
(Verlengia et al. 2004). Cell proliferation was enhanced by both n-3 HUFA while
production of key immunomodulatory cytokines, including IL-10, TNF-α and INF-γ
was reduced. In addition, altered expression of specific genes including those involved
with cytokines, signal transduction, transcription, cell cycle, defence and repair,
apoptosis, cell adhesion, cytoskeleton and hormones was observed with EPA almost 3
times more active than DHA at the same concentration (Verlengia et al. 2004).
Although the health benefits of increased fish, and thereby n-3 HUFA, intake
have been regarded as beneficial for CHD for over 35 years, more recent focus has
turned to the role of essential HUFA in normal neural function and the prevention
and treatment of neuropsychiatric disorders (Young and Conquer 2005). It should
be no surprise that both ARA and DHA are vital for neural function as these two
HUFAs comprise around 30% of the dry weight of brain and retinal tissue (Sastry
1985). By contrast, EPA is not particularly enriched in neural tissues and its role is
more likely involved in an anti-inflammatory capacity, as an inhibitor of ARAderived eicosanoid production and activity as well as inhibiting phospholipase A 2
(PLA 2 ) activity (Finnen and Lovell 1991). Reduced blood concentrations of n-3
HUFA have been observed in numerous neurodevelopmental and neurodegenerative
disorders including Attention Deficit/Hyperactivity Disorder (ADHD) (Stevens
et al. 1995), Alzheimer’s disease and dementia (Coorigan et al. 1998), schizophrenia
(Richardson et al. 2003), bipolar, unipolar and post-natal depression (Peet et al.
1998; Frasure-Smith et al. 2004; Hibbeln 2002). More recently other neurological
disorders have also been implicated with abnormal blood n-3 HUFA levels,
although the evidence is less well founded at the present time. These include
dyslexia (Taylor et al. 2000), autism spectrum disorders (Bell et al. 2004b),
dyspraxia (Richardson 2004), obsessive compulsive disorder (Fox et al. 2004) and
aggression (Iribarren et al. 2004).
6.5 18:3n-3 and Human Health
While the data from section 6.3.3 above suggests that fish cultured using diets
containing a significant proportion of VO have reduced levels of n-3 HUFA in their
flesh lipids, they also contain significant levels of α-linolenic acid (18:3n-3; ALA)
as well as linoleic acid (18:2n-6; LA). However, while the results of clinical trials
with 18:3n-3 have been less clear than those with n-3 HUFA, there is still good
evidence that diets that provide increased tissue levels of 18:3n-3 may also be beneficial to human health (Sanderson et al. 2002). Benefits of increased 18:3n-3
intake for various cardiovascular disorders, as well as for both breast and prostate
cancer has been reported in the literature (Billman et al. 1999; Singh et al. 1997;
Ferreti and Flanagan 1996; Maillard et al. 2002; Newcomer et al. 2001). Therefore,
producing fish that provide moderate doses of EPA, DHA and 18:3n-3, but with low
199
cyclooxygenase-2 expression and that of other genes that are implicated in tumour
promotion (Hardman 2002). In a recent study, proliferation and gene expression in a
B-lymphocyte cell line were investigated when supplemented with EPA or DHA
(Verlengia et al. 2004). Cell proliferation was enhanced by both n-3 HUFA while
production of key immunomodulatory cytokines, including IL-10, TNF-α and INF-γ
was reduced. In addition, altered expression of specific genes including those involved
with cytokines, signal transduction, transcription, cell cycle, defence and repair,
apoptosis, cell adhesion, cytoskeleton and hormones was observed with EPA almost 3
times more active than DHA at the same concentration (Verlengia et al. 2004).
Although the health benefits of increased fish, and thereby n-3 HUFA, intake
have been regarded as beneficial for CHD for over 35 years, more recent focus has
turned to the role of essential HUFA in normal neural function and the prevention
and treatment of neuropsychiatric disorders (Young and Conquer 2005). It should
be no surprise that both ARA and DHA are vital for neural function as these two
HUFAs comprise around 30% of the dry weight of brain and retinal tissue (Sastry
1985). By contrast, EPA is not particularly enriched in neural tissues and its role is
more likely involved in an anti-inflammatory capacity, as an inhibitor of ARAderived eicosanoid production and activity as well as inhibiting phospholipase A 2
(PLA 2 ) activity (Finnen and Lovell 1991). Reduced blood concentrations of n-3
HUFA have been observed in numerous neurodevelopmental and neurodegenerative
disorders including Attention Deficit/Hyperactivity Disorder (ADHD) (Stevens
et al. 1995), Alzheimer’s disease and dementia (Coorigan et al. 1998), schizophrenia
(Richardson et al. 2003), bipolar, unipolar and post-natal depression (Peet et al.
1998; Frasure-Smith et al. 2004; Hibbeln 2002). More recently other neurological
disorders have also been implicated with abnormal blood n-3 HUFA levels,
although the evidence is less well founded at the present time. These include
dyslexia (Taylor et al. 2000), autism spectrum disorders (Bell et al. 2004b),
dyspraxia (Richardson 2004), obsessive compulsive disorder (Fox et al. 2004) and
aggression (Iribarren et al. 2004).
6.5 18:3n-3 and Human Health
While the data from section 6.3.3 above suggests that fish cultured using diets
containing a significant proportion of VO have reduced levels of n-3 HUFA in their
flesh lipids, they also contain significant levels of α-linolenic acid (18:3n-3; ALA)
as well as linoleic acid (18:2n-6; LA). However, while the results of clinical trials
with 18:3n-3 have been less clear than those with n-3 HUFA, there is still good
evidence that diets that provide increased tissue levels of 18:3n-3 may also be beneficial to human health (Sanderson et al. 2002). Benefits of increased 18:3n-3
intake for various cardiovascular disorders, as well as for both breast and prostate
cancer has been reported in the literature (Billman et al. 1999; Singh et al. 1997;
Ferreti and Flanagan 1996; Maillard et al. 2002; Newcomer et al. 2001). Therefore,
producing fish that provide moderate doses of EPA, DHA and 18:3n-3, but with low