Low temperature induced discoloration of juvenile red sea bream, Pagrus major

Effects of low temperature on the color of red sea bream (Pagrus major) were investigated. In colorimetric evaluation using L*a*b* system the fish reared under low-temperature (10 deg C) for two months lost their L * value compared to control (bred under 22 deg C) while no change was observed in a* and b * value. No significant difference was found in blood test (GOT, GPT, ALP, gamma-GTP, total bilirubin, direct bilirubin, indirect bilirubin and bile acid). We also examined the properties of the "yellowed" juvenile red seabream which sometimes occur in winter season in Fisheries Laboratory of Kinki University. The b* value was significantly lower than that of control while no significant difference could be found in L* value. The blood test showed no clear difference in direct and indirect bilirubin conc as well as in other measurements. We also examined the concentration of yellow melanin (pheomelanin), however, no significant gap could be found in nomal and yellowed red seabream, indicating that the cause of yellowness is not bilirubin and pheomelanin accumulation.