Effect of lipid supplementation on digestion of nutrients in steers

Abstract

Lipids are commonly used in ruminant diets to increase the energy density of the ration and increasingly to manipulate the fatty acid (FA) composition of the final product (meat or milk). However, lipids may have negative effects on rumen function and in particular on the extent of carbohydrate digestion, which is accompanied by alterations in volatile fatty acid proportions, towards less acetate and more propionate. These alternations are more pronounced for lipids high in polyunsaturated fatty acids particularly linolenic acid (18:3n-3; found in linseed). However, there is some evidence to suggest that the opposite is true for longer chain C20 FAs, found in fish oil (Doreau and Chilliard, 1996). This experiment has examined the impact of lipid sources differing in their FA composition (saturated compared polyunsaturated FA) on digestion of nutrients in the rumen and small intestine.