Tuesday 1 May 2007
Nutritional Value of Seven Tropical Microalgae Species for Larvae of the Black-Lipped Pearl Oyster (Pinctada margaritifera)
In recent years, the culture and availability of tropical microalgae used to feed bivalves have made significant progress.
This study analyzes the nutritional value of seven small tropical microalgae species (< 9 µm), grouped into three categories:
two diatoms (Chaetoceros muelleri and Chaetoceros sp.), three golden-brown flagellates (Isochrysis sp., Pavlova salina and Pavlova sp.), one green flagellate (Micromonas pusilla), and one unidentified coccoid alga (CS-126).
Researchers determined their carbohydrate, lipid, and protein content, as well as their fatty acid composition, to assess their impact on larval growth.
Larval Feeding Experiment Each species of microalgae was fed individually to Pinctada margaritifera larvae at the D-veliger stage and then at the umbo-veliger stage.
Results showed that larvae fed with Pavlova sp. (CS-50) had the highest survival rate after ten days.
The greatest shell growth was observed in larvae fed with Pavlova sp. (CS-50) and Pav. salina. Microalgae could be grouped into three categories according to their effect on D-stage growth:
• Pav. salina and Pavlova sp.: growth clearly superior to other treatments.
• Isochrysis sp., C. muelleri, and M. pusilla: better growth than unfed control larvae.
• Chaetoceros sp. and CS-126: growth equivalent to unfed control larvae.
D-stage larval growth was strongly correlated with carbohydrate, lipid, and protein content, as well as with the proportion of polyunsaturated fatty acids, particularly DHA (r = 0.829; P = 0.021).
Second Phase of the Experiment During the second experiment, survival of umbo-stage larvae (including unfed controls) showed no significant difference between treatments after eight days of rearing (P < 0.05).
Larvae fed with Pavlova sp. and Pav. salina displayed the greatest growth increases, although the differences compared with those fed with TISO and C. muelleri were not statistically significant (P > 0.05).
Larvae fed with M. pusilla, Chaetoceros sp., and CS-126 had growth rates comparable to the control larvae (P < 0.05).
A First Comprehensive Analysis This study represents the first comprehensive analysis of the nutritional value of tropical microalgae for feeding P. margaritifera larvae.
The results will help develop more efficient larval rearing techniques and identify the microalgae best suited for each developmental stage of pearl oysters.
This study analyzes the nutritional value of seven small tropical microalgae species (< 9 µm), grouped into three categories:
two diatoms (Chaetoceros muelleri and Chaetoceros sp.), three golden-brown flagellates (Isochrysis sp., Pavlova salina and Pavlova sp.), one green flagellate (Micromonas pusilla), and one unidentified coccoid alga (CS-126).
Researchers determined their carbohydrate, lipid, and protein content, as well as their fatty acid composition, to assess their impact on larval growth.
Larval Feeding Experiment Each species of microalgae was fed individually to Pinctada margaritifera larvae at the D-veliger stage and then at the umbo-veliger stage.
Results showed that larvae fed with Pavlova sp. (CS-50) had the highest survival rate after ten days.
The greatest shell growth was observed in larvae fed with Pavlova sp. (CS-50) and Pav. salina. Microalgae could be grouped into three categories according to their effect on D-stage growth:
• Pav. salina and Pavlova sp.: growth clearly superior to other treatments.
• Isochrysis sp., C. muelleri, and M. pusilla: better growth than unfed control larvae.
• Chaetoceros sp. and CS-126: growth equivalent to unfed control larvae.
D-stage larval growth was strongly correlated with carbohydrate, lipid, and protein content, as well as with the proportion of polyunsaturated fatty acids, particularly DHA (r = 0.829; P = 0.021).
Second Phase of the Experiment During the second experiment, survival of umbo-stage larvae (including unfed controls) showed no significant difference between treatments after eight days of rearing (P < 0.05).
Larvae fed with Pavlova sp. and Pav. salina displayed the greatest growth increases, although the differences compared with those fed with TISO and C. muelleri were not statistically significant (P > 0.05).
Larvae fed with M. pusilla, Chaetoceros sp., and CS-126 had growth rates comparable to the control larvae (P < 0.05).
A First Comprehensive Analysis This study represents the first comprehensive analysis of the nutritional value of tropical microalgae for feeding P. margaritifera larvae.
The results will help develop more efficient larval rearing techniques and identify the microalgae best suited for each developmental stage of pearl oysters.