Neste trabalho, foram determinados os lipídios totais e a composição de ácidos graxos da cabeça in natura de três espécies de peixes do gênero Brycon, matrinxã (B. cephalus), piraputanga (B. microlepis) e piracanjuba (B. orbignyanus), criados em cativeiros (açudes e gaiolas) e, nativos coletados nos rios Cuiabá-Manso (piraputanga) e no rio Paraná (piracanjuba). Os teores de lipídios totais nas cabeças variaram de 14,26 a 22,00%. Com relação aos ácidos graxos, todas as espécies apresentaram como predominantes os ácidos oléico-C18:1ômega9 (40,21 a 44,41%), seguido dos ácidos palmítico-C16:0 (22,04 a 27,04%), esteárico-C18:0 (7,78 a 12,11%) e linoléico-18:2ômega6 (5,27 a 14,68%). O percentual dos ácidos alfa-linolênico (18:3ômega3), araquidônico (20:4ômega6), eicosapentaenóico (20:5ômega3) e docosahexaenóico (22:6ômega3) foram inferiores a 2,52%. A somatória dos ácidos graxos polinsaturados (AGPI) variou de 10,30 a 19,32%, e dos ácidos graxos saturados (AGS) de 32,42 a 39,41%. A espécie piraputanga nativa apresentou maior proporção de ácidos ômega3 (3,67%) e menor de ácidos ômega6 (6,02%).

This study was developed for evaluating the total lipid and fatty acid composition of in natura heads of Brazilian fishes. Brycon cephalus (matrinxã), B. microlepis (piraputanga) and B. orbignyanus (piracanjuba) were cultivated in fish farms (ponds and cages) and wild species were collected in Cuiabá-Manso river (B. microlepis) and in Paraná river (B. orbignyanus). The total lipid content of the head varied widely among the species (14.26 to 22.00%). In relation of fatty acid composition, all species presented the oleic acid, C18:1omega9, as the predominant acid (40.21 to 44.41%), followed by the palmitic acid-C16:0 (22.04 to 27.04%), stearic acid-C18:0 (7.78 to 12.11%) and linoleic acid-C18:2omega6 (5.27 to 14.68%). The levels of alpha-linolenic acid (C18:3omega3), arachidonic acid (C20:4omega6), eicosapentaenoic acid (C20:5omega3) and docosahexaenoic acid C22:6omega3 were lower than 2.52%. The sum of all polyunsaturated fatty acids (PUFA) varied from 10.30 to 19.32%, and the saturated fatty acids (SFA) from 32.42 to 39.41%. The wild specie B. microlepis (piraputanga) showed the highest amount of the omega-3 (3.67%) and the lowest amount of the omega-6 (6.02%) fatty acids.