Effect of
additions of dietary triacylglycerol microspheres on growth, survival, and
settlement of mussel (Mytilus sp.) larvae
F. Pernet, R. Tremblay, C. Langdon, E. Bourget-2004
Marine Biology, 144(4):
693-703
Abstract:
This study reports the effect of additions of dietary
microspheres of triacylglycerol (TAG, extracted from the diatom
Chaetoceros muelleri) on larval development and settlement of Mytilus
sp. The first experiment showed that mussel larvae successfully ingested TAG
microspheres as soon as they acquired the ability to feed from exogenous
sources. In a second experiment, larvae were fed for 28 days on diets
consisting of 0, 1, 20, or 50% TAG microspheres (based on the cell
concentration of a full algal ration) added as partial replacements for a
ration of Isochrysis sp. (T-ISO). Lipid content and growth of larvae
fed on a diet composed of 20% TAG were higher than those of the control
groups, whereas survival was negatively affected. No growth or survival
effect was detected with larvae fed on a diet composed of 1% TAG, whereas
high mortality after 14 days was observed for larvae fed on a diet
composed of 50% TAG microspheres. In a third experiment, 22-day-old larvae
were fed on rations of Isochrysis sp. supplemented with 0, 1, 10, 20,
50, and 100% TAG for 2 days and allowed to settle for a 7-day period.
TAG content of the larvae increased with TAG added to the diet until a
saturation threshold was reached between a 20 and 50% supplementation level.
Similarly, free fatty acid (FFA) content increased with TAG level in the
diet and was linearly correlated with TAG content of larvae. Increased
levels of FFA in larvae were attributed to digestion of TAG supplements.
Settlement success and survival of larvae were not affected by diet;
however, regression analysis revealed that TAG level in pre-metamorphic
larvae explained 28% of survival variability among cultures.
(Québec Océan,
Université Laval, Pavillon Vachon, Cité Universitaire, Quebec, G1K 7P4,
Canada, e-mail: Fabrice.Pernet@nrc.ca)