野生ニホンザルが採食する植物の脂肪酸組成

Abstract

Animals cannot synthesize polyunsaturated fatty acids (PUFAs), but PUFAs are an important source material for eicosanoids, and thus must be consumed as essential fatty acids. Furthermore, blood cholesterol levels are dependent on the types of fatty acids consumed. However, the composition of fatty acids in food consumed by wild Japanese macaques has not yet been reported. In this study, the fatty acid composition of 58 species/parts of plants were analyzed by capillary gas chromatography. A total of 11 types of fatty acid were found. A UPGMA (Unweighted Pair Group Method with Arithmetic mean) dendrogram by PCA (Principal Component Analysis)was drawn from all 8 principal component scores. Leaves, petals, and fruits and seeds diverged into three groups. The fruit of Hazenoki (Rhus succedanea) diverged from other samples due to its extremely high palmitic acid content. Fruits and seeds in Group 1 contained high C18 monoenoic acid levels, but low α -linolenic acid (C18:3, n-3) levels. Group 1 was divided into two sub-groups based on the composition of linoleic acid (C18:2, n-6). All leaves and petals included in Group2 had higher α -linolenic acid (C18:3, n-3) and lower C18 monoenoic acid than fruits and seeds in the same group. From these results, it appears that Japanese macaques consume more α -linolenic acid (C18:3, n-3) and that the ratio of (n-6)/(n-3) decreases in seasons when they take more leaves. Furthermore, blood cholesterol levels might have been kept low, as myristic acid (C14:0) was scarce, and a high linoleic acid (C18:2, n-6) content is included in the fruits and seeds of Group 1.