Function and metabolism
• La nature des lipides alimentaires n’a pas d’effet sur la teneur en
lipides des nssus. Par contre, l'enrichissement de l'aliment en huile de
maïs entraîne une augmentation en AGPI (n-6) des triglycérides et des
phospholipides dans tous les tissus.
• Le transfert en eau de mer induit une diminution des lipides totaux
(principalement des triglycérides) dans les branchies et les intestins et
leur augmentation dans le muscle blanc et le foie. II n’affecte pas la composition des phospholipides du foie. Dans l’intestin et les branchies, le
taux de cardiolipides diminue tandis que le taux de PS augmente. Dans
le muscle blanc, le taux de PE diminue tandis que celui de PI augmente. Sauf dans l’intestin, les triglycérides des truites élevées en mer
sont moins riches en acides gras monoinsaturés et plus riches en acides
gras saturés (muscle blanc, foie) et en AGPI (n-6) (branchies, foie). Dans
l’intestin, le taux d’acides gras saturés diminue au profit de ceux des
AGPI (n-6) et (n-3). Aucune différente significative n’est observée sur
la composition en acides gras des phospholipides (à l’exception du foie).
Introduction
The transfer of fish from freshwater to sea water is often performed in
salmonids to increase the growth performances. Fish have to adapt
them to the salinity of the water. The transfer increases osmotic and
ionic concentrations of the tissues and it is suspected to affect lipid
metabolism, mainly membrane composition which regulates the
exchanges between the outer and the inner of cells. Despite numerous
studies have been devoted to lipid composition of fish according to
various parameters (species, diet) (Henclerson & Tocher, 1987), very
little is known on the effect of transfer in sea water.
In the present study, changes in lipids and fatty acids of several tissues
of trout were investigated to evaluate transfer in sea water in trout fed
diet with various dietary lipids (maize oil versus fish oil).
Material and methods
Animals
Eight-month-old female brown trout (Salmo trntta) were hatched and
reared in the Ifremer-Inra experimental hatchery (Drennec, France).
Trouts were clivided into two groups according to the dietary lipids
(maize oil or fish oil). Both groups were maintained for two months
in freshwater. Then half of eath group was transferred into sea water
and half maintained in fresh water. After two months, trouts were
slaughtered and light muscle, liver, gills and intestine were collected for
lipid analysis.
Methods
Lipids were extracted from tissues with dichloromethane-methanol
(2:1,v/v) according to the method of Folch et al. (1957). Total lipid
content was determined by weighing and was expressed in gramme
141
• La nature des lipides alimentaires n’a pas d’effet sur la teneur en
lipides des nssus. Par contre, l'enrichissement de l'aliment en huile de
maïs entraîne une augmentation en AGPI (n-6) des triglycérides et des
phospholipides dans tous les tissus.
• Le transfert en eau de mer induit une diminution des lipides totaux
(principalement des triglycérides) dans les branchies et les intestins et
leur augmentation dans le muscle blanc et le foie. II n’affecte pas la composition des phospholipides du foie. Dans l’intestin et les branchies, le
taux de cardiolipides diminue tandis que le taux de PS augmente. Dans
le muscle blanc, le taux de PE diminue tandis que celui de PI augmente. Sauf dans l’intestin, les triglycérides des truites élevées en mer
sont moins riches en acides gras monoinsaturés et plus riches en acides
gras saturés (muscle blanc, foie) et en AGPI (n-6) (branchies, foie). Dans
l’intestin, le taux d’acides gras saturés diminue au profit de ceux des
AGPI (n-6) et (n-3). Aucune différente significative n’est observée sur
la composition en acides gras des phospholipides (à l’exception du foie).
Introduction
The transfer of fish from freshwater to sea water is often performed in
salmonids to increase the growth performances. Fish have to adapt
them to the salinity of the water. The transfer increases osmotic and
ionic concentrations of the tissues and it is suspected to affect lipid
metabolism, mainly membrane composition which regulates the
exchanges between the outer and the inner of cells. Despite numerous
studies have been devoted to lipid composition of fish according to
various parameters (species, diet) (Henclerson & Tocher, 1987), very
little is known on the effect of transfer in sea water.
In the present study, changes in lipids and fatty acids of several tissues
of trout were investigated to evaluate transfer in sea water in trout fed
diet with various dietary lipids (maize oil versus fish oil).
Material and methods
Animals
Eight-month-old female brown trout (Salmo trntta) were hatched and
reared in the Ifremer-Inra experimental hatchery (Drennec, France).
Trouts were clivided into two groups according to the dietary lipids
(maize oil or fish oil). Both groups were maintained for two months
in freshwater. Then half of eath group was transferred into sea water
and half maintained in fresh water. After two months, trouts were
slaughtered and light muscle, liver, gills and intestine were collected for
lipid analysis.
Methods
Lipids were extracted from tissues with dichloromethane-methanol
(2:1,v/v) according to the method of Folch et al. (1957). Total lipid
content was determined by weighing and was expressed in gramme
141