The Journal of Nutrition Vol. 127 No. 7 July 1997, pp. 1388-1394
Copyright ©1997 by the American Society for Nutritional Sciences

Fish Oil Source Differentially Affects Rat Immune Cell -Tocopherol Concentration

Manuscript received 25 March 1996. Initial reviews completed 25 July 1996. Revision accepted 28 February 1997.

Graduate Nutritional Sciences Program and Department of Animal Sciences, University of Missouri, Columbia, MO 65211

We have previously reported that both the source of dietary fish oil and the chemical form of vitamin E supplied in the diet affect the vitamin E status of immune cells in rats. The purpose of this study was to investigate further the effect of fish oil source on immune cell vitamin E status using free -tocopherol (-T) at the AIN recommended level as the sole source of vitamin E. Sixty weanling female rats were fed semipurified, high fat (20 g/100 g) diets containing either tocopherol-stripped lard (LRD), menhaden fish oil (MFO), sardine fish oil (SRD) or cod liver oil (CLO) as the primary lipid source. Endogenous -T concentration was measured and equalized to 150 mg/kg oil by addition of free RRR--T to each lipid source, allowing for a final concentration of -T in the mixed diet of 30 mg/kg. An additional group of rats was fed LRD without supplemental vitamin E (LRD) as a negative control. After feeding experimental diets for 5 or 10 wk, tissues were collected for -T analysis by HPLC. After 5 wk, plasma and liver -T (µmol -T/g lipid) were significantly lower in SRD- and CLO-fed rats compared with LRD-fed rats. At 10 wk, only plasma -T in CLO-fed rats remained significantly depressed. Plasma and liver -T concentrations (µmol -T/g lipid) were not significantly lower in MFO-fed rats than LRD-fed rats at either time point. Compared with LRD, feeding MFO to rats for 5 or 10 wk resulted in significantly greater -T content of immune cells. In similar fashion, SRD-fed rats, compared with LRD-fed rats, also had significantly greater -T content in splenocytes at both time points and greater thymocyte -T at 10 wk. In all instances, the -T status of rats fed CLO was indistinguishable from that of rats fed the vitamin E-free diet (LRD). These data further demonstrate the complexity of the relationship between vitamin E status and dietary (n-3) polyunsaturated fatty acids (PUFA).

This article has been cited by other articles:

				R. Irons, P. Pinge-Filho, and K. L. Fritsche Dietary (n-3) Polyunsaturated Fatty Acids Do Not Affect the In Vivo Development and Function of Listeria-Specific CD4+ and CD8+ Effector and Memory/Effector T Cells in Mice J. Nutr., May 1, 2005; 135(5): 1151 - 1156. [Abstract] [Full Text] [PDF]

				S. Miret, A. T. McKie, M. P. Saiz, A. Bomford, and M. T. Mitjavila IRP1 Activity and Expression Are Increased in the Liver and the Spleen of Rats Fed Fish Oil-Rich Diets and Are Related to Oxidative Stress J. Nutr., April 1, 2003; 133(4): 999 - 1003. [Abstract] [Full Text] [PDF]

				R. Irons, M. J. Anderson, M. Zhang, and K. L. Fritsche Dietary Fish Oil Impairs Primary Host Resistance Against Listeria monocytogenes More than the Immunological Memory Response J. Nutr., April 1, 2003; 133(4): 1163 - 1169. [Abstract] [Full Text] [PDF]

				L. J. Pompos and K. L. Fritsche Antigen-Driven Murine CD4+ T Lymphocyte Proliferation and Interleukin-2 Production Are Diminished by Dietary (n-3) Polyunsaturated Fatty Acids J. Nutr., November 1, 2002; 132(11): 3293 - 3300. [Abstract] [Full Text] [PDF]