Fatty acid analysis of experimental diets, muscle and liver

Analysis of fatty acids in diets, muscle and liver were performed as previously described in [17]. Feed as well as muscle and liver were grinded into fine powder. Chloroform-methanol in the ratio of 2:1 (V/V) was used to extract total lipids according to the [18] method. 0.4 M KOH-methanol was used to prepare fatty acid methyl esters by transesterification. Individual fatty acids were detected by gas chromatograph (GC-7890A) with methyl heneicosanoate (C21:0) as an internal standard. Peak times of each sample were compared to that of the manufacturer to identify individual fatty acids. The percentages of the individual fatty acids were determined using peak areas. All measurements were performed in triplicates and the fatty acids content expressed as % total FA.