Comparative studies of the serum lipoproteins and lipids in some domestic, laboratory and wild animals.

1. The concentration of lipoproteins and lipids in the sera of several species of healthy adult laboratory animals (guinea-pig, rabbit and rat), domestic animals (cattle, sheep, goat, horse and swine) and wild animals (deer, wild boar, mink and fox) have been investigated under physiological conditions. Special attention was paid to the lipoproteins which are precipitated with heparin-MnCl2 and to the ratio of lipids in separated alpha and beta lipoproteins. 2. Most of the studied animals had significantly lower concentrations of total lipoproteins, beta lipoproteins and cholesterol than those in man (P < 0.001). Only some wild animals (mink and fox) had concentrations of total lipoproteins, beta lipoproteins, phospholipids and cholesterol which were significantly higher than man's (P < 0.001). 3. The ratio of lipids in the separated lipoprotein fractions also differed between the examined animals. Thus, in the sheep, rabbit, guinea-pig and wild boar most of the cholesterol (70-76%) was in beta lipoproteins. However, in the horse (60%), mink (60%), fox (65%), goat (70%) and cattle (73%) the high density lipoprotein fraction was the main carrier of cholesterol. 4. With the exception of the guinea-pig (42%) most of the serum phospholipids were found in the high density lipoprotein fraction.