Composition of Chemical Components in Bone of Striped Dolphin,Stenella coeruleoalba: Distribution Characteristics of Major Inorganic and Organic Components in Various Bones, and Their Age-related Changes

Abstract

The distribution of major inorganic and organic components (Ca, PO4, Na, Mg, Sr, K, lipid and protein) and their age-related changes were investigated in various bones of striped dolphin, Stenella coeruleoalba. Significant differences were observed between the component concentrations of the compact and cancellous bones: the former was high in concentrations of Ca, P04, Na, Mg and Sr, while the latter was high in moisture, lipid, protein and K concentrations, and particularly high in lipid contents of the skull and caudal vertebrae. No significant difference was found in the composition of Ca, PO4, Na, Mg and Sr in various bones of both the immature and the mature dolphins. The skull of the fetus, and the tympano-periotic bones in particular, showed a higher accumulation of Ca and a lower accumulation of Na, Mg and Sr compared with that of the vertebrae and ribs. Significant differences of the component concentrations in the bones were observed between the fetus and the adult: the concentration of moisture and K was high in the former, while other components were high in the latter, and their concentrations varied widely during the fetal and caff periods during rapid bone growth. However, the concentrations of lipid, protein and Sr showed specific age-related changes. In particular, the concentration of Sr increased markedly during the fetal and pup periods, then decreased with age until 8 yr and thereafter increased with age. Based on these results, the part(s) of the bone most suitable for research and investigation are also discussed, the 10th dorsal vertebra emerging as the most representative bone of the total skelton for measuring the concentration of inorganic and organic components.