[Fat and fatty acid content in freshwater and saltwater fish in 4 provinces].

Objective: To explore the differences in fat and fatty acids content between freshwater and saltwater fish.

Methods: The fat and fatty acids content in 83 fish meat samples from four regions(Hainan, Jiangsu, Fujian, and Guangxi) were detected by national standard method. Mann-Whitney U tests and t-tests were used to compare the differences in fat and major fatty acid content between freshwater and saltwater fish.

Results: The fat content in fish meat ranged from 0.1 to 26.0 g/100 g, containing various fatty acids such as palmitic acid, oleic acid, and linoleic acid. There was no significant difference in fat content between freshwater and saltwater fish(P>0.05). The percentage content of saturated fatty acids(SFA) and monounsaturated fatty acids(MUFA) showed a statistically significant difference(P<0.05), but there was no significant difference in absolute content(P>0.05). The content of linoleic acid, alpha-linolenic acid, eicosapentaenoic acid(EPA), docosahexaenoic acid(DHA), n-3 and n-6 polyunsaturated fatty acids(PUFA) showed statistically significant differences between the two types of fish(P<0.05).

Conclusion: There are certain differences in the fatty acid composition between freshwater and saltwater fish. Saltwater fish have a higher percentage content of SFA, while freshwater fish have a higher percentage of MUFA, but there is no difference in the absolute content of SFA and MUFA. The PUFA composition also varies. The composition of PUFA also shows certain differences between the two types of fish. In freshwater fish, the contents of linoleic acid and alpha-linolenic acid) are relatively high, whereas in saltwater fish, the contents of EPA and DHA are higher. In freshwater fish, the PUFA primarily exists in the n-6 form, while in saltwater fish, the PUFA is mainly in the n-3 form.