Biotechnology
How to provide essential nutriments
to bivalves in hatchery
J. Moal
(1) , C. Séguineau
(1) , J.-F. Samain
(1) , P. Soudant
(1) , M. Cansell
(2) ,
J.-R. Le Coz
(1) , H. Migaud (1) , M. Val Sanles
(1) , B. Ponce
(1) , C. Langdon
(3)
(1) Ifremer Brest, Drv/ra, laboratoire de physiologie des invertébrés,
BP 70, 29280 Plouzané, France -jmoal@ifremer.fr
(2) Université de Bordeaux 1, ISTAB, laboratoire de lipochimie alimentaire,
1 av. des Facultés, 33405 Talence Cedex, France
(3) Hatfield Manne Science Center, 2030 S. Marine Science Drive, Newport, OR 97365, USA
Essential molecules as vitamins, polyunsaturated fatty acids, sterols
are required at each step of development of molluscs in hatchery.
Nowadays, the food offered in bivalve hatchery-nursery is a mixture of
microalgae. Each algal strain exhibits characteristic profiles in these
nutriments. But, depending on the algal culture conditions, the biochemical composition varies. Then, according to the place and the way
they are produced these algal diets do not always satisfy the nutritional
requirements of molluscs and needs for supplementation of essential
nutriments are requested. Development of artificial diet is a promising
way to complement deficient algal regime.
A large variability is observed in biochemical composition between
eggs from different spawnings and from different females. It depends on
the food regime of broodstock. In this poster, we have tested different
ways to correct the egg and the larvae composition either by changing
the food regime of adults and larvae or by direct modification of egg
composition by lipofection technique.
If today, no successfull artificial food has been developed, it is primarily
due to the small size of particules ingested by bivalves (5-15 pm).
We have tested three types of artificial particules that satisfied this
criterion:
- emulsions (INVE Aquaculture: ICES 30/0.6/C). They are greatly enriched
in HUFAs and are good vectors for lipid supplementation;
- liposomes offer a double enrichment possibility: lipids from their
membrane and an aqueous internal volume. Their preparation by
extrusion, using marine lipids, produce different sizes of particules
that are compatible with the ingestion. Moreover, the similarity of
their membrane lipid composition with that of mollusc membranes is
a promising way to study the lipofection process;
- spray beads are good candidates for food supplementation of aqueous
and lipophyle molecules. They were prepared according to the method of
Buchal and Langdon (in press) with 60% tripalmitine, 40% menhaden
oil and 12.95% riboflavine.
Experiments were conducted to determine first if these different particules were ingested and digested by the japanese oyster C. gigas at
different developmental stages. Empty liposomes were radiolabelled on
the membrane and mixed to an oocyte preparation to study the lipofection possibilities. Results are presented and discussecl.
227
How to provide essential nutriments
to bivalves in hatchery
J. Moal
(1) , C. Séguineau
(1) , J.-F. Samain
(1) , P. Soudant
(1) , M. Cansell
(2) ,
J.-R. Le Coz
(1) , H. Migaud (1) , M. Val Sanles
(1) , B. Ponce
(1) , C. Langdon
(3)
(1) Ifremer Brest, Drv/ra, laboratoire de physiologie des invertébrés,
BP 70, 29280 Plouzané, France -jmoal@ifremer.fr
(2) Université de Bordeaux 1, ISTAB, laboratoire de lipochimie alimentaire,
1 av. des Facultés, 33405 Talence Cedex, France
(3) Hatfield Manne Science Center, 2030 S. Marine Science Drive, Newport, OR 97365, USA
Essential molecules as vitamins, polyunsaturated fatty acids, sterols
are required at each step of development of molluscs in hatchery.
Nowadays, the food offered in bivalve hatchery-nursery is a mixture of
microalgae. Each algal strain exhibits characteristic profiles in these
nutriments. But, depending on the algal culture conditions, the biochemical composition varies. Then, according to the place and the way
they are produced these algal diets do not always satisfy the nutritional
requirements of molluscs and needs for supplementation of essential
nutriments are requested. Development of artificial diet is a promising
way to complement deficient algal regime.
A large variability is observed in biochemical composition between
eggs from different spawnings and from different females. It depends on
the food regime of broodstock. In this poster, we have tested different
ways to correct the egg and the larvae composition either by changing
the food regime of adults and larvae or by direct modification of egg
composition by lipofection technique.
If today, no successfull artificial food has been developed, it is primarily
due to the small size of particules ingested by bivalves (5-15 pm).
We have tested three types of artificial particules that satisfied this
criterion:
- emulsions (INVE Aquaculture: ICES 30/0.6/C). They are greatly enriched
in HUFAs and are good vectors for lipid supplementation;
- liposomes offer a double enrichment possibility: lipids from their
membrane and an aqueous internal volume. Their preparation by
extrusion, using marine lipids, produce different sizes of particules
that are compatible with the ingestion. Moreover, the similarity of
their membrane lipid composition with that of mollusc membranes is
a promising way to study the lipofection process;
- spray beads are good candidates for food supplementation of aqueous
and lipophyle molecules. They were prepared according to the method of
Buchal and Langdon (in press) with 60% tripalmitine, 40% menhaden
oil and 12.95% riboflavine.
Experiments were conducted to determine first if these different particules were ingested and digested by the japanese oyster C. gigas at
different developmental stages. Empty liposomes were radiolabelled on
the membrane and mixed to an oocyte preparation to study the lipofection possibilities. Results are presented and discussecl.
227