Plasma lipid transport in the horse (Equus caballus).

The research studies the process of how fats are transported within the blood stream of horses (Equus caballus) by highlighting the role of lipoproteins, their types and functions.

Lipoproteins Presence and Composition

• The study identifies that horse plasma contains lipoproteins, which are molecules that transport fats in the bloodstream. These include very low density lipoproteins (VLDL), low density lipoproteins (LDL), and high density lipoproteins (HDL).
• High Density Lipoproteins (HDL) are the most prevalent, making up about 60% of the plasma lipoprotein mass. HDL lipoproteins consist of a single type of particles, while Low Density Lipoproteins (LDL) have a heterogenous composition, made up of three different types of subfractions.

Protein Structures in LDL and VLDL

• Two proteins are identified in the part of the lipoproteins known as apolipoprotein (apo) B-100, these are predominantly found in LDL and VLDL.
• An additional protein similar to apoB-48 was also found in VLDL.

Enzymes in Plasma

• The study also found that Lecithin:cholesterol acyl transferase, an enzyme that changes the lipids in lipoproteins to make them more soluble, is active in horse plasma.
• Hepatic lipase and lipoprotein lipase, which are responsible for breaking down fats, are present in post-heparin plasma, which is the plasma obtained after the administration of a drug called heparin that prevents blood clotting.

Cholesteryl Ester Transfer Protein Activity

• The researchers did not find significant activity of cholesteryl ester transfer protein, an important protein that facilitates the transport of cholesteryl esters and triglycerides between the lipoproteins.

These results aid in gaining a thorough understanding of equine fat metabolism and can have valuable implications in the nutritional management and treatment of equine diseases associated with fat metabolism.