Effects of diets containing sunflower oil and fish oil on lipid metabolism and fatty acid flow to the duodenum of beef steers

M Lee,N Scollan,A Moloney,J Tweed

doi:10.22358/jafs/73760/2004

Abstract

Duodenal fistulated steers were offered grass silage at 14 g/kg liveweight and one of three concentrates at a ratio of 60:40 (forage:concentrate on a dry matter basis): FISH0, FISH1 or FISH2 designed to be iso-lipid and to provide the same amount of sunflower oil but increasing amounts of fish oil: 0, 1 and 4%, respectively. Fatty acid intakes and duodenal flows were examined to determine the effects of fish oil on polyunsaturated fatty acid (PUFA) metabolism. Fish oil significantly increased the flow of long chain PUFA, conjugated linoleic acid and trans vaccenic acid to the duodenum and decreased the flow of stearic acid. Biohydrogenation of linoleic and linolenic acids was not affected by fish oil inclusion.

Highlights

Clinical research has shown that the intake of polyunsaturated fatty acids (PUFA) and in particular long chain PUFA such as C20:5n-3 and C22:6n-3 found in fish oil are beneficial to human health (Tapiero et al, 2002)
There were no significant differences in nutrient and total fatty acid intake and duodenal flow
All three diets in the present study resulted in net synthesis of fatty acids across the rumen as previously reported by Scollan et al (2001b) when feeding a fish oil supplement, and this maybe due to endogenous lipid or microbial synthesis

Summary

Introduction

Clinical research has shown that the intake of polyunsaturated fatty acids (PUFA) and in particular long chain PUFA such as C20:5n-3 and C22:6n-3 found in fish oil are beneficial to human health (Tapiero et al, 2002). Previous studies have shown that fish oil inclusion in the diet of ruminants has increased the concentration of long chain PUFA in milk (Shingfield et al, 2003) and muscle (Scollan et al, 2001a). This study was designed to report the effect of graded levels of fish oil on the flow of long chain PUFA and biohydrogenation intermediates such as TVA and CLA, when steers were offered a flat rate of linoleic acid, supplied from sunflower oil. It was hoped this would create a greater understanding of the effect of fish oil in the biohydrogenation of C18 PUFA

Methods

Results

Conclusion