The effect of crushed mature oyster ova as a supplementary diet on the growth and survival of planktonic larvae of the ark shell Scapharca globosa ursus
2007
Ohashi, S.(Nagasaki-ken. Inst. of Fisheries (Japan)) | Iwanaga, S. | Osako, K. | Yoshikoshi, K.
A feeding experiment was conducted to investigate the effect of adding crushed mature ova prepared from the Pacific oyster Crassostrea gigas, to the diet for Scapharca globosa ursus larvae as a supplement to microalgae. Crushed oyster ova were high in both crude protein content and taurine concentration. Analysis of fatty acid composition showed that crushed oyster ova had lower EPA concentration than Chaetoceros calcitrans but was 6 times higher in DHA concentration than Pavlova lutheri. When crushed oyster ova was added into the diet, growth and survival rate of larvae in the experimental group were significantly higher than those in the control that were fed only with algae. During the umbo stage, the control group showed high mortality and a stagnant larval growth. In addition, significant differences in the lipid droplet contents in the gastric and digestive diverticular epithelia were observed between larvae of the two groups on 7 and 11 days post-hatch. These results suggest that giving crushed mature ova prepared from Pacific oyster as a supplementary diet to S. g. ursus larvae prevented delayed growth that may occur following the consumption of egg yolk reserves, and effectively maintained their normal growth.
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