Lipoprotein Lipase and Lipid Metabolism in Mammary Gland

Abstract

The lipid content of milk is the most variable of its major components. It ranges from zero in milk of rhinoceros and 2% in that of the horse to as much as 50% in milk of aquatic mammals (35). The lipid content of human and cow's milk is about 4%, rodent milk 12%, and milk of the polar bear 33% (Table 1). Fat provides about 70% of the calories in rat milk (1) and considerably more in milk of the polar bear and seal where fat content is extremely high and lactose content is low (Table 1). The major lipid component of milk of all species is triglyceride, accounting for >95% of the lipid (26). Milk fat droplets, which range from 1 to 7 μm in diameter (35), are composed of a core of trigly ceride with small amounts of digly cerides, free fatty acids and monoglycerides, and traces of cholesterol ester (15, 23, 36). © 1977, American Dairy Science Association. All rights reserved.