8
Lipids and Essential Fatty Acids in
Aquatic Food Webs: What Can
Freshwater Ecologists Learn
from Mariculture?
Yngvar Olsen
8.1. Introduction
Only a few decades have passed since the major discovery that certain fatty acids,
or more precisely, the family of fatty acids denoted n-6 or ro6 polyunsaturated
fatty acid (PUFA), are essential for humans (Holman et aI., 1964; Hansen et aI.,
1963). These fatty acids are characterized by having their first double bond
between carbon number 6 and 7 from the methyl end. In the late 1970s, it was
shown that also the family of n-3 or co3 fatty acids, characterized by having the
first double bond between carbon number 3 and 4 from the methyl end, are
essential for normal growth and function of the human brain (Leaf, 1993; Bjerve,
1991; Neuringer et aI., 1988; Crawford et aI.,1981, 1976). The impact of dietary
co3 fatty acids on the incidences of vascular and coronary diseases was first
described by Danish scientists (Dyerberg et aI., 1977; 1975) who compared the
food habits and health of Greenland Inuits with people from Denmark (representative for the Western industrialized world). This classic work brought a major
change in thinking about how the current role of lipids in metabolism is viewed;
from being a metabolic fuel compound usually associated with obesity in the
Western world to an essential compound in a wide range of metabolic functions.
Since then, it has been thoroughly demonstrated that co3 fatty acids affect human
health by reducing blood lipid levels, by reducing the rate of atherosclerosis and
thrombus formation and by altering inflammatory and immune responses (see
review by Leaf, 1993).
The interest in cultivating marine fish species is old (Rollefsen, 1934), but the
early pioneers in this century usually failed in their attempts to make marine
larvae survive the early feeding stages. The Japanese were pioneers in using the
brackish water rotifer Brachionus plicatilis as live feed for cultured marine larvae
in the early 1960s (see review by Nagata and Hirata, 1986; Ito, 1960), but they did
not achieve major success until they realized that food quality was important,
especially in respect to essential fatty acids (EFA) (Fukusho, 1977, Kitajima and
Koda, 1976). Marine fish larvae tum out to have high dietary requirements for co3
fatty acids (Watanabe et aI., 1978). The Japanese and Danish findings were
161
Lipids and Essential Fatty Acids in
Aquatic Food Webs: What Can
Freshwater Ecologists Learn
from Mariculture?
Yngvar Olsen
8.1. Introduction
Only a few decades have passed since the major discovery that certain fatty acids,
or more precisely, the family of fatty acids denoted n-6 or ro6 polyunsaturated
fatty acid (PUFA), are essential for humans (Holman et aI., 1964; Hansen et aI.,
1963). These fatty acids are characterized by having their first double bond
between carbon number 6 and 7 from the methyl end. In the late 1970s, it was
shown that also the family of n-3 or co3 fatty acids, characterized by having the
first double bond between carbon number 3 and 4 from the methyl end, are
essential for normal growth and function of the human brain (Leaf, 1993; Bjerve,
1991; Neuringer et aI., 1988; Crawford et aI.,1981, 1976). The impact of dietary
co3 fatty acids on the incidences of vascular and coronary diseases was first
described by Danish scientists (Dyerberg et aI., 1977; 1975) who compared the
food habits and health of Greenland Inuits with people from Denmark (representative for the Western industrialized world). This classic work brought a major
change in thinking about how the current role of lipids in metabolism is viewed;
from being a metabolic fuel compound usually associated with obesity in the
Western world to an essential compound in a wide range of metabolic functions.
Since then, it has been thoroughly demonstrated that co3 fatty acids affect human
health by reducing blood lipid levels, by reducing the rate of atherosclerosis and
thrombus formation and by altering inflammatory and immune responses (see
review by Leaf, 1993).
The interest in cultivating marine fish species is old (Rollefsen, 1934), but the
early pioneers in this century usually failed in their attempts to make marine
larvae survive the early feeding stages. The Japanese were pioneers in using the
brackish water rotifer Brachionus plicatilis as live feed for cultured marine larvae
in the early 1960s (see review by Nagata and Hirata, 1986; Ito, 1960), but they did
not achieve major success until they realized that food quality was important,
especially in respect to essential fatty acids (EFA) (Fukusho, 1977, Kitajima and
Koda, 1976). Marine fish larvae tum out to have high dietary requirements for co3
fatty acids (Watanabe et aI., 1978). The Japanese and Danish findings were
161