1974 年 40 巻 5 号 p. 471-478
The amino acid compositions of cultured phytoplanktons, suspensoids, zooplanktons and sand eel, Ammodytes personatus, collected at the Hiuchi Nada in the central part of the Seto Inland Sea, were analyzed to determine the nutritional relationships between the primary producers and the consumers. The nutritional values of proteins were compared using the essential amino acid indexes (EAA index) proposed by OSER with slight modification. Besides these, hard clam, Meretrix meretrix lusoria, and yellow tail, Seriola quinqueradiata, were chosen as standard animals.
EAA indexes of phytoplanktons and suspensoids for zooplankton and hard clam were about 85 on average, while the respective indexes for yellow tail decreased to about 70. These results indicate that phytoplanktons and suspensoids are relatively excellent as protein sources for lower consumers but not for higher ones. It may be reasonable to say that the nutritional values of marine proteins improve step by step on ingestion by animals situated in the higher ranks of the marine food chain.