linoleic-acid and cis-vaccenic-acid

Cis 9, trans 11 (c 9, t11)-18:2 and trans 10, cis 12 (t10, c12)-18:2 are the major conjugated linoleic acid (CLA) isomers in dietary supplements which reduce milk fat content in nursing women. The present study evaluated the effects of each CLA isomer or vaccenic acid on body composition and tissue fatty acids during lactation in mice. Dams were fed 30 g rapeseed oil (control)/kg diet or 20 g control plus 10 g 18:0, trans 11-18:1 (t11-18:1), c 9, t11-18:2, or t10, c12-18:2. Dietary t10, c12-18:2 reduced food intake by 18 % and carcass fat weight of the dams by 49 % compared with the other treatments. Milk fat percentage ranked by treatment was 18:0>t11-18:1=c 9, t11-18:2>t10, c12-18:2. The sum of saturated 12:0 to 16:0 in milk fat was lower when c 9, t11-18:2 was fed compared with the control, 18:0, or t11-18:1 treatments. Dietary t10, c12-18:2 caused further reductions in milk fat 12:0 to 16:0. The proportion of CLA isomers was 3-fold greater in milk fat than in the carcasses of the dams. The pups nursing from the dams fed t10, c12-18:2 had the lowest body weights and carcass fat, protein, and ash contents. Nursing from the dams fed c 9, t11-18:2 also resulted in lower carcass fat compared with the 18:0 or t11-18:1 treatments. The ratios of cis 9-16:1:16:0 or cis 9-18:1:18:0, proxies for Delta(9)-desaturase activity, were markedly lower in the carcasses of the dams and pups fed t10, c12-18:2. The ratio of 20:4n-6:18 : 2n-6, a proxy for Delta(6)- and Delta(5)-desaturase and elongase activity, in the liver of the dams and pups fed t10, c12-18:2 also was lower. Dietary t11-18:1 enhanced the content of c 9, t11-18:2 in milk fat and carcasses. As in previous studies, the reduction in food intake by t10, c12-18:2 could not entirely account for the marked decrease in carcass fat content and milk fat concentration. T10, c12-18:2 probably had a negative effect on Delta(9)-desaturase and mammary de novo fatty acid synthesis. Although these effects need to be confirmed in lactating women, the results suggest that the consumption of supplements containing t10, c12-18:2 should be avoided during the nursing period.

Topics: Animals; Animals, Suckling; Blood Glucose; Body Composition; Body Weight; Dietary Supplements; Eating; Fatty Acids; Female; Growth; Lactation; Linoleic Acid; Lipids; Liver; Mice; Mice, Inbred Strains; Milk; Oleic Acids

Weaned rats (21-day old, 44 +/- 2 g) were distributed into 3 groups. The first group was raised on a laboratory diet for 7 or 20 days (control group). The second was fed a diet containing 0.07% fat for 1, 2, 3, 7 or 66 days. The third one was fed the low-fat diet for 7 days and then switched to a laboratory chow diet for 1, 2, 5 or 9 days. Cardiolipin (CL) on the one hand and other mitochondrial phospholipids taken as a whole (PLm) on the other hand were prepared from liver mitochondria and their fatty acids analysed. Polyunsaturated fatty acids in PLm (18:2 (n-6), 20:4 (n-6), 22:6 (n-3) acids) decreased abruptly during the first 3 days of fat deficiency and then remained rather stable till day 7. CL behaved in a quite different way. 18:2 (n-6) acid, the major polyunsaturated fatty acid of CL, decreased continuously between day 1 and day 7 from 79% to 33%. A value of 19.6% was reached on day 66. When deficient rats were transferred to an equilibrated diet, the fatty acid profile of PLm was rapidly restored. Major effects were already achieved during the first 24 h and a fatty acid composition identical to that of control rats was reached within 2 days. A considerably longer period (about 9 days) was necessary for CL to reach a level analogous to that of control rats. The diminution of linoleic acid in CL was brought about by increases in the levels of monoenoic acids: palmitoleic (16:1 (n-7)), oleic (18:1 (n-9)) and cis-vaccenic (18:1 (n-7)) acids which accounted for 18.0%, 17.7% and 17.9% respectively on day 7. Increases in the (n-7) monoenes remained comparatively low in PLm, which showed a sharp rise in their oleic acid content (from 3.9% to 12.7% in 3 days). The proportion of cis-vaccenic acid relative to total octadecenoic acids was decreased from 75% to 50% in CL. A similar trend, but of smaller magnitude, was also noticed in PLm.(ABSTRACT TRUNCATED AT 400 WORDS)

Topics: Animals; Cardiolipins; Dietary Fats; Fatty Acids; Fatty Acids, Essential; Fatty Acids, Monounsaturated; Fatty Acids, Unsaturated; Linoleic Acid; Linoleic Acids; Male; Mitochondria, Liver; Oleic Acid; Oleic Acids; Palmitic Acids; Phospholipids; Rats; Rats, Inbred Strains

Exogenously supplied long-chain fatty acids have been shown to markedly alleviate the inhibition of phototrophic growth of cultures of Rhodopseudomonas sphaeroides caused by the antibiotic cerulenin. Monounsaturated and polyunsaturated C18 fatty acids were most effective in relieving growth inhibition mediated by cerulenin. Medium supplementation with saturated fatty acids (C14 to C18) failed to influence the inhibitory effect of cerulenin. The addition of mixtures of unsaturated and saturated fatty acids to the growth medium did not enhance the growth of cerulenin-inhibited cultures above that obtained with individual unsaturated fatty acids as supplements. Resolution and fatty acid analysis of the extractable lipids of R. sphaeroides revealed that exogenously supplied fatty acids were directly incorporated into cellular phospholipids. Cells treated with cerulenin displayed an enrichment in their percentage of total saturated fatty acids irrespective of the presence of exogenous fatty acids. Cerulenin produced comparable inhibitions of the rates of both fatty acid and phospholipid synthesis and was further found to preferentially inhibit unsaturated fatty acid synthesis.

Topics: Cerulenin; Fatty Acids; Fatty Acids, Unsaturated; Linoleic Acid; Linoleic Acids; Linolenic Acids; Membrane Lipids; Oleic Acid; Oleic Acids; Phospholipids; Rhodobacter sphaeroides

The fatty acid composition of the dimorphic bacterium Caulobacter crescentus was found to consist primarily of 16- and 18-carbon fatty acids, both saturated and monounsaturated, in agreement with the findings of Chow and Schmidt (J. Gen. Microbiol. 83:359-373, 1974). In addition, two minor but as yet unidentified fatty acids were detected. Chromatographic mobilities suggested that these fatty acids may be a cyclopropane and a branched-chain fatty acid. In addition, we demonstrated that the fatty acid composition of wild-type C. crescentus can be altered by growing the cells in medium supplemented with any one of a variety of unsaturated fatty acids. Linoleic acid, a diunsaturated fatty acid which is not synthesized by C. crescentus, was incorporated into phospholipids without apparent modification. In addition, we found that C. crescentus, like Escherichia coli, synthesizes vaccenic acid (18:1 delta 11,cis) rather than oleic acid (18:1 delta 9,cis). This result allowed us to deduce that the mechanism of fatty acid desaturation in C. crescentus is anaerobic, as it is in E. coli. Finally, we examined the fatty acid biosynthesis and composition of two unsaturated fatty acid auxotrophs of C. crescentus. Neither of these mutants resembled the E. coli unsaturated fatty acid auxotrophs, which have defined enzymatic lesions in fatty acid biosynthesis. Rather, the mutants appeared to have defects relating to the complex coordination of membrane biogenesis and cell cycle events in C. crescentus.

Topics: Bacteria; Culture Media; Fatty Acids; Fatty Acids, Unsaturated; Linoleic Acid; Linoleic Acids; Mutation; Oleic Acid; Oleic Acids; Phospholipids