Salinity and preservation conditions of lipofuscin extracts in blue swimming crab, portunus pelagicus

Abstract

Background and Objective: Fundamental information on how environmental conditions affect lipofuscin (LF) levels could be useful to those furthering the development of an effective management plan to control certain populations in certain geographical areas. Thus, the effects of salinity upon LF levels were examined using 7 salinities in the range 10-40% (increasing in steps of 5%). Materials and Methods: The impacts of freezing preservation were also examined for 60 crab samples with carapace widths of 7-8 cm randomly allocated for either immediate or post-freezing (-80EC) analysis. Results: The result showed that 25% salinity was optimum for LF accumulation in both males and females crabs. The mean value of LF production was higher for males compared to females. Higher and lower salinity of 10 and 40% were the most stressed conditions for LF accumulation. The LF index (LI) of P. pelagicus decreased in salinities below and above the typical range. Conclusion: For both sexes, the frozen samples exhibited notably higher LI values than the fresh samples (p<0.05). These results will be applicable in numerous respects, for example in the selection of farm locations and for optimising productivity by controlling salinity levels.