Mice were fed one of four semi-purified diets, varying only in the type of fat (15%, w/w) (corn oil vs fish oil) and fiber (6%, w/w) (cellulose vs pectin) for 4 weeks. Mice were subsequently killed and colonic mucosa isolated by scraping. Three mouse colons were pooled per sample, and the fatty acyl composition of cardiolipin molecular species was quantified by mass spectrometry. Data are presented as total cardiolipin mass per mg protein (mean ± SE, n=5). Means not sharing a common letter are significantly different (P < 0.05).