Variations in dietary fat and cholesterol intakes modify antioxidant status of SHR and WKY rats.
The effects of varying dietary fat saturation [butter (B), beef tallow (BT)] or polyunsaturation [(n-6) soybean oil (SBO), (n-3) menhaden oil (MO)] and cholesterol content (0.05 and 0.5 g/100 g) on systolic blood pressure (SBP), plasma lipids and tissue antioxidant status were investigated in 14-wk-old spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto (WKY) rats. Varying dietary fat composition for 9 wk had no influence on SBP in either SHR or WKY rats. Rats fed MO diets exhibited smaller (P < 0.05) body weight gains, lower (P < 0.05) feed efficiency ratios and lower (P < 0.05) plasma cholesterol concentrations than those fed the B, BT and SBO diets. Significant (P < 0.05) interactions for animal strain x cholesterol intake and animal strain x fat source were noted for serum cholesterol concentrations. SHR exhibited higher (P < 0.05) RBC and liver catalase (CAT), and heart and liver superoxide dismutase (SOD) activities similar to those of WKY rats. The lower (P <0.01) RBC, heart and liver glutathione peroxidase (GSH-Px) activities observed in SHR coincided with higher (P <0.01) glutathione reductase (GSSG-Red), compared with WKY rats. Dietary cholesterol intake had no effect on RBC, heart and liver total sulfhydryl concentration or GSH-Px activities, but increased (P <0. 001) liver GSSG-Red. Feeding MO resulted in lower (P <0.001) RBC and heart GSH-Px activities. In contrast, feeding B and BT resulted in lower GSH-Px in liver. The significant (P < 0.01) animal strain x fat source interaction obtained for liver GSH-Px activity indicated that SHR responded differently to polyunsaturated fatty acid feeding than their WKY counterparts. Diet-induced changes in tissue antioxidant status were tissue specific and did not affect the development of hypertension in SHR.
Department of Food Science, Faculty of Agriculture, University of British Columbia, Vancouver, BC, Canada.
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D000704:Analysis of Variance; D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D001794:Blood Pressure / Q000187:drug effects; D002374:Catalase / Q000378:metabolism; D002791:Cholesterol, Dietary / Q000008:administration & dosage / Q000494:pharmacology*; D004041:Dietary Fats / Q000008:administration & dosage / Q000494:pharmacology*; D004798:Enzymes; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage / Q000494:pharmacology; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated / Q000008:administration & dosage / Q000494:pharmacology; D008055:Lipids / Q000097:blood*; D008099:Liver / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D008297:Male; D009206:Myocardium / Q000201:enzymology / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D013045:Species Specificity; D013438:Sulfhydryl Compounds / Q000378:metabolism
D000975:Antioxidants; D002791:Cholesterol, Dietary; D004041:Dietary Fats; D004798:Enzymes; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated; D008055:Lipids; D013438:Sulfhydryl Compounds; D002374:Catalase