Requirements, Feed Supplementation and Toxicity Assessment of Essential Trace Metals such as Selenium, Copper, Zinc and Vanadium

Abstract

To obtain better reproductive efficiency in cows, plasma Se concentration is suggested to be more than 70 ppb. To. attain such a high plasma Se concentration the dietary Se concentration must be increased to 0.3 ppm by Se supplementation. In order to supplement Se it is necessary to amend the present law that designates all Se-containing substances as toxic and prohibits the Se usage for feed supplementation. The governmental guidance for Cu and Zn supplementation to swine rations are questionable from a nutritional standpoint because the recommended upper Cu supplementation level is too low to be effective for the improvement of body weight gain and feed efficiency in growing and fattening pigs, and the recommended upper Zn level in composts is also too low, which makes the Zn supplementation to swine rations almost as difficult. However, the Zn requirement for pigs is relatively high and Zn is essentially nontoxic. V also faces the dichotomy of being either an essential nutrient or a radical-producing element accumulated in the kidneys.