Annual Evolution of Fatty Acid Profile from Muscle Lipids of the Common Carp (Cyprinus carpio) in Madagascar Inland Waters

Annual evolution of muscle lipids fatty acid (FA) from common carp (Cyprinus carpio) has been determined in 2001 through monthly samplings in the reserve pond of Sisaony (SIS series) and Itasy Lake (ITA series) of the Madagascar highlands. Total lipids from muscle were extracted and quantified according to the Bligh and Dyer method. FA identification was performed by GC-MS of FA methyl esters and FA pyrrolidides and led to the identification of 41 FA; routine analyses of FA were made by capillary GC. Principal component analysis (PCA) was performed on the data set to compare FA profiles. Lipid content is low, ranging from 0.91 to 1.73% of wet muscle, with a low stage during the hot season (January−April) and a higher stage during the cold season (July−October). Three FA dominated the FA composition: oleic acid (17.0−21.5%), palmitic acid (13.1−16.1%), and linoleic acid (9.6−13.2%). Polyunsaturated fatty acids (PUFA) were present in appreciable amounts: arachidonic acid (AA; 2.9−5.9%), docosahexaenoic acid (DHA; 2.9−6.7%), eicosapentaenoic acid (EPA; 1.9−3.4%), and docosapentaenoic acid (DPA; 1.9−4.3%). Two opposite evolution schemes appear within two groups of FA; on the one hand PUFA (both n−3 and n−6 series) show a maximum in August−October and a minimum in January−April, and, on the other hand, oleic, palmitic, and linoleic acids show the opposite maxima and minima. PCA results give confirmation of these evolution schemes, the two groups of FA giving opposite high factor loadings on axis 1. The SIS and ITA series are differentiated by axis 2 by mean of minor FA, mostly odd- and branched-chain. Results indicate that common carp, the second most abundant freshwater fish in Madagascar highlands waters, may be an interesting source of dietary PUFA. Keywords: Carp; fatty acid; evolution; lipids; Madagascar