Changes in myoglobin content and proximate compositions of the dorsal ordinary muscles of full-cycle cultured Pacific bluefin tuna Thunnus orientalis (Temminck et Schlegel) with body size

Abstract

We investigated the changes in myoglobin (Mb) content and proximate compositions of the cephalad parts of the dorsal ordinary muscles (Ce-DOM) of full-cycle cultured (FC) Pacific bluefin tuna [body length: 42.6-115.4 cm, body weight (BW): 1.7-38.4 kg, killed from July 2004 to October 2005]. The Mb content of Ce-DOM increased (P<0.01) until a BW of 7.0 kg was reached. However, the Mb content of Ce-DOM had a wide variety above a BW of 7.0 kg. On the other hand, the moisture, protein and ash contents of Ce-DOM of FC tuna decreased (P<0.05 and 0.01) with an increase in BW. However, the lipid content of Ce-DOM increased gradually above about a BW of 20.0 kg. Furthermore, the Mb content in protein of the Ce-DOM of FC tuna increased with an increase in BW. These results indicated that the increase in Mb content of Ce-DOM of FC tuna was not related to changes in proximate composition between a BW of 1.7 and 38.4 kg.