Blood transport and tissue metabolism of lipids in the preruminant calf given a milk diet containing coconut oil or beef tallow

Abstract

This article describes blood transportation and tissue metabolism of lipids in the preruminant calf given a milk diet containing coconut oil (rich in medium chain fatty acids) or beef tallow (rich in long chain saturated and unsaturated fatty acids). In blood plasma, coconut oil led to hyperlipidemia by increasing concentrations of cholesterol and phospholipids. C12:0 and C14:0 of coconut oil are specifically transported by triglyceride (38%) and cholesterol (44%) -rich lipoproteins. Uptake of coconut oil fatty acids by the liver led to hepatic steatosis due to a marked deposition of triglycerides (×18). This may be the result of a higher process of elongation of products generated by the oxidation of medium chain fatty acids (C12:0), a lower capacity of oxidation associated with a higher capacity of esterification of long chain fatty acids (C18:1 n-9) into triglycerides, and of a low and non-inducible capacity of triglyceride secretion. Muscle fatty acid oxidation and lipogenic potentiality of adipose tissues were not modified by dietary fatty acids. On the contrary, C12:0 and C14:0 provided by the coconut oil diet were accumulated in muscle and adipose tissues to the detriment of C18:1 n-9, increasing the degree of saturation of fatty acids in stored lipids. In conclusion, distribution of coconut oil as the sole source of lipids in the milk diet of the preruminant calf is not recommended since it induced an hepatic steatosis, it did not improved zootechnical performances, and it decreased the dietetic quality of meat for consumers by favouring deposition of atherogenic saturated fatty acids.