Fatty acid profiles and lipid peroxidation of microsomes and mitochondria from liver, heart and brain of Cairina moschata

Studies were done to analyze the fatty acid composition and sensitivity to lipid peroxidation (LP) of mitochondria and microsomes from duck liver, heart and brain. The fatty acid composition of mitochondria and microsomes was tissue-dependent. In particular, arachidonic acid comprised 17.39 +/- 2.32, 11.75 +/- 3.25 and 9.70 +/- 0.40% of the total fatty acids in heart, liver and brain mitochondria respectively but only 13.39 +/- 1.31, 8.22 +/- 2.43 and 6.44 +/- 0.22% of the total fatty acids in heart, liver and brain microsomes, respectively. Docosahexahenoic acid comprised 17.02 +/- 0.78, 4.47 +/- 1.02 and 0.89 +/- 0.07% of the total fatty acids in brain, liver and heart mitochondria respectively but only 7.76 +/- 0.53, 3.27 +/- 0.73 and 1.97 +/- 0.38% of the total fatty acids in brain, liver and heart microsomes. Incubation of organelles with ascorbate-Fe2+ at 37 degreesC caused a stimulation of LP as indicated by the increase in light emission: chemiluminescence (CL) and the decrease of arachidonic acid to: 5.17 +/- 1.34, 8.86 +/- 0.71 and 5.86 +/- 0.68% of the total fatty acids in heart, liver and brain mitochondria, respectively, and to 4.10 +/- 0.61 in liver microsomes. After LP docosahexahenoic acid decrease to 7.29 +/- 1.47, 1.36 +/- 0.18 and 0.30 +/- 0.11% of the total fatty acids in brain, liver and heart mitochondria. Statistically significant differences in the percent of both peroxidable fatty acids (arachidonic and docosahexaenoic acid) were not observed in heart and brain microsomes and this was coincident with absence of stimulation of LP. The results indicate a close relationship between tissue sensitivity to LP in vitro and long chain polyunsaturated fatty acid concentration. Nevertheless, any oxidative stress in vitro caused by ascorbate-Fe2+ at 37 degreesC seems to avoid degradation of arachidonic and docosahexaenoic acids in duck liver and brain microsomes. It is possible that because of the important physiological functions of arachidonic and docosahexaenoic acids in these tissues, they are protected to maintain membrane content during oxidative stress. (C) 2002 Elsevier Science Ltd. All rights reserved.