Influence of Various Chelating Agents on the

Influence of Various Chelating Agents on the Availability of Zinc

PRAN VOHRA and F.H. KRATZER

Department of Poultry Husbandry, University of California,

Davis, California

ABSTRACT chelates with stability constants for zinc ranging from 5.3 to 18.8 were tested for growth-promoting activity with turkey poults in a zinc-deficient diet containing isolated soybean protein. The chelates were fed at a level of 0.684 mmole/kg diet for about 20 days. EDDADP, HEDTA and EDTA were most active in improving growth under these conditions. NTA and EDDA were moderately effective in promoting growth while DHEG, IDA, HIEDA, EDDHA, EBONTA, TETA, DTPA and CDTA had only slight or no effect on the growth of poults. A stability constant for zinc between 13 and 17 was most satisfactory.

The improvement of the availability of zinc by the addition of the disodium salt of ethylenediaminetetraacetic acid (EDTA) from diets that contained isolated soybean protein has been established for turkey poults by Kratzer et al. (1) and for chickens by Davis et al. (2) and Scott and Zeigler (3). Kratzer and Starcher (4) reported that 100 mg/kg of disodium salt of EDTA gave growth in the turkey poults equivalent to approximately 8 mg/kg of zinc when added to a zinc-deficient, purified diet containing isolated soybean protein.

A number of synthetic chelating agents, besides EDTA, are know to improve the availability of zinc for plants, as reviewed by Wallace. Since similar information was lacking for poultry, the present study was undertaken to compare a large number of chelating agents to EDTA in improving the availability of zinc for turkey poults.

Received for publication September 23, 1963.
Supported in part by grant number A-5334 from the National Institutes of Health, U.S. Public Health Services
Wallace, A. 1962 a decade of synthetic chelating agents in inorganic plant nutrition (Arthur Wallace, 2278 Parnell Avenue, Los Angeles 64).