Fish oil source differentially affects rat immune cell alpha-tocopherol concentration

Area of Science:

• Nutrition Science
• Immunology
• Biochemistry

Background:

• Dietary vitamin E status is influenced by both the source of fish oil and the chemical form of vitamin E.
• Understanding these interactions is crucial for optimizing nutrient delivery and immune function.

Purpose of the Study:

• To investigate the specific effects of different fish oil sources on the vitamin E status of immune cells in rats.
• To determine how various fish oils impact alpha-tocopherol (alpha-T) levels in plasma, liver, and immune cells.

Main Methods:

• Rats were fed diets with lard, menhaden fish oil (MFO), sardine fish oil (SRD), or cod liver oil (CLO) as the primary lipid source.
• Diets were supplemented with alpha-tocopherol to ensure consistent vitamin E levels, except for a vitamin E-free control group.
• Alpha-tocopherol concentrations in plasma, liver, and immune cells (splenocytes, thymocytes) were analyzed using High-Performance Liquid Chromatography (HPLC) after 5 and 10 weeks.

Main Results:

• Cod liver oil (CLO) and sardine fish oil (SRD) significantly reduced plasma and liver alpha-T levels at 5 weeks compared to lard (LRD).
• Menhaden fish oil (MFO) did not significantly lower plasma or liver alpha-T compared to lard at either time point.
• Immune cells showed significantly higher alpha-T content when fed MFO or SRD compared to LRD, while CLO-fed rats had alpha-T levels similar to the vitamin E-deficient group.

Conclusions:

• The source of dietary fish oil profoundly affects vitamin E status in rat immune cells.
• Menhaden and sardine fish oils enhance immune cell alpha-tocopherol accumulation, whereas cod liver oil impairs it.
• These findings underscore the complex interplay between dietary (n-3) polyunsaturated fatty acids and vitamin E status.