Date of Award
Doctor of Philosophy (PhD)
Test diets containing ground beef extended with 0, 10, 20 and 30% ISP were fed to Single Comb White Leghorn chicks and 28 days to determine the effect of isolated soy protein (ISP) on the availability of copper naturally present in meat. Copper content of the test diets decreased with increasing levels of ISP, ranging from 6.89 (+OR-) 0.17 ppm to 2.09 (+OR-) 0.12 ppm. Mean feed consumption per diet also decreased with increasing ISP levels as did the amount of copper consumed per bird. Although the mg copper consumed per bird decreased from diet I to diet IV, the mean liver copper values decreased from 1.48 ppm for the first diet to 0.61 ppm for diet III but increased to 1.03 ppm for diet IV. The calculated availability of natural copper in the diets increased from a low of 21.86% for diet I to 74.19% for diet IV. This high availability of copper from diet IV was probably due to an increased absorption of copper and larger liver weights in these animals. It appeared that the ISP had little or no negative effect on the availability of copper in the diets. Mean copper values of uncooked ISP extended meats by the in-vitro method decreased with increasing levels of ISP. Copper content of the in-vitro diets decreased also as did the percent copper transferred across the dialysis membrane. A slight binding of copper by ISP may occur. Cooking the meat mixture reduced the amount of copper crossing the semipermeable membrane. Electrophoresis of water and salt soluble proteins from chick duodenum showed high molecular weight proteins, none of which contained measurable amounts of copper. High molecular weight proteins also resulted from the electrophoresis of water and salt soluble proteins from chick ileum. Mineral analysis of the protein bands showed copper to be associated with two high molecular weight water soluble proteins and one high molecular weight salt soluble protein.
Smith, James L., "Effect of Isolated Soy Protein on the Bioavailability of Copper in Ground Beef." (1983). LSU Historical Dissertations and Theses. 3939.