Changes in the proximate composition of bluefin tuna (Thunnus thynnus) reared in the cages located on the Gulf of Antalya (Turkey's Western Mediterranean coast) during the fattening period

Abstract

The aim of this study was to investigate the changes in the proximate composition of bluefin tuna (Thunnus thynnus) muscle reared in cages during the fattening period. Samples were taken from tunas at monthly intervals between July and October. Moisture, crude protein, crude fat and crude ash were analysed. The fat and ash contents increased, and the moisture content decreased during the fattening period. There were no significant differences in the protein content during this period. The mean protein concentration was 21% over this period. The highest levels of dry matter (40%), fat (15%) and ash (1.21%) were found in October. Baitfish (Sardina pilchardus, Sardinella aurita and Alosa fallax nilotica) were also analysed. There were no differences in the moisture, protein and fat contents between baitfish, but a lower ash content was found in sardine than in the others. The mean moisture, protein, fat and ash contents of baitfish were found to be 68.28%; 19.2%; 8.5%; and 1.4% respectively.