Dietary Essential Fatty Acid Deficiency Differentially Affects Tissues of Rats

Abstract

Quantitative variations of polyunsaturated fatty acids (PUFA) were studied in various tissues: red blood cells (RBC), hepatic microsomes, kidney, skeletal muscle and heart of young rats fed either a control diet (n = 7) or an essential fatty acid (EFA)-deficient diet (n = 7). After 4 wk, the EFA-[deficient rats had significantly lower proportions of (n-6) and (n-3) fatty acids in RBC, hepatic microsomes and kidney than the control group. Paradoxically, normal proportions of arachidonic acid [20:4(n-6)] and 5,8,11,14,17-eicosapentaenoic acid [20:5(n-3)] were retained in heart and skeletal muscle despite generally lower proportions of the precursors, 18:2(n-6) and 18:3(n-3). Moreover, absolute levels of 20:4(n-6) and 20:5(n-3) in skeletal muscle of the EFA deficient group were significantly higher than in controls and 22:5(n-3) and 22:6(n-3) levels were comparable. This suggests that fatty acid proportions alone, without any consideration of long-chain polyunsaturated fatty acid quantities, may not reflect the (n-6) and (n-3) PUFA status of individual tissues. This study indicates that diet-[induced changes in the PUFA composition of RBC, which are often used in clinical investigations, do not fully reflect the changes in the fatty acid composition of organs, and that individual tissues respond differently to EFA deficiency. The conservation of proportional and absolute levels of 20:5(n-3) and 20:4(n-6), and the decrease in the more unsaturated homologues in the heart, suggest that this organ may avidly retain 20:5(n-3) and 20:4(n-6) in order to maintain eicosanoid production.

Comparative fatty acid profiles of wild and farmed tropical freshwater fish rohu (Labeo rohita)

“…Arachidonate is conserved during periods in which there is a deficiency of essential fatty acids in the heart, renal cortex, and liver, when the formation of prostaglandins is also blocked (Lefkowith et al 1985). The conservation of arachidonate and the depletion of other PUFAs in these tissues is required for maintaining eicosanoid production (Moussa et al 1996). The major n-3 PUFA in both the cultured and wild rohu was DHA (C22:6 n-3), with significantly higher levels being found in the muscle, liver, eye, and brain of wild rohu; these results are in agreement with those previously reported by Grigorakis et al (2002) and Serot et al (1998).…”

Essential fatty acids and the brain: possible health implications

“…For example, epidemiological evidence suggests that diets rich in DHA might protect against cardiovascular disease, by working at two levels: lowering plasma lipids and aecting eicosanoid biosynthesis [1,92]. Fish oils, as shown in Table 2, provide a rich source of PUFAs, especially EPA and DHA, which as discussed previously, have been found to increase membrane compositions of these respective PUFAs in various peripheral tissues [8,19,74,88,89,95,100]. Enrichment of the diet with EPA is followed by a concomitant enhancement in the activity of 5-lypoxygenase enzyme, because this FA is a preferred substrate for 5-lypoxygenase as compared with AA [97].…”

Effects of the type of dietary fat on acetylcholine-evoked amylase secretion and calcium mobilization in isolated rat pancreatic acinar cells

“…Erythrocyte and liver membranes have been shown to have a marked adaptive capacity as demonstrated in the rat, rabbit and swine [1,7,10,11]. For other tissues such as the brain, skeletal muscle and heart, a great variability has been reported in their sensitivity to dietary changes [1,7,8,12,13], which probably reflects the influence of the antecedent diet [11], age, percentage and type of dietary fat and duration of the feeding period.…”