Blood and Tissue Chemical Studies in Fowl. ∗

Abstract

Normal blood and tissue levels of the usual organic constituents with especial reference to total cholesterol and cholesterol esters and other lipids, were determined as a basis for projected fat metabolism studies. Domestic fowl was the chosen experimental animal because of the known high normal cholesterol production, especially of certified 260 to 320 eggs per year R.O.P. sired hens. Laying hens, after the sixth month, have been found to have a subintimal atherosclerosis of the aorta and coronary arteries, quite similar microscopically to the human type, in half the specimens examined by Dauber. 1 As the age increases, the frequency of gross lesions has been noted to increase.

We have sacrificed 26 barred rocks fed on a standard growing mash (Purina) at ages from 11 weeks through 22 weeks and 26 hens of various standard breeds that had been on a standard laying mash, (Purina). Blood was collected from the severed neck vessels; part was oxalated and part was allowed to clot and the serum expressed. The aorta, heart, and in later studies, about 0.25 g of liver were removed. The gross adipose tissue was dissected off and approximately 0.25 g of cleaned aorta and lean heart muscle and liver were weighed accurately, minced carefully, extracted for 12 hours with 3 to 1 parts of alcohol and ether.

The blood serum was analyzed by Folin's microchemical methods for glucose; 2 non protein nitrogen; 3 and Leiboff and Kahn's method for urea nitrogen; 4 Bloor's original method for cholesterol 5 and Bloor and Knudson's digitonin method 6 for cholesterol esters; King's method 7 for total and inorganic phosphorus; and the C11SO₄ falling drop method 8 for calculating the total serum protein levels.