Basis for regulation of selenium supplements in animal diets.

The research paper delves into the regulatory history and scientific basis of selenium supplementation in animal diets, highlighting its progression from a disregarded or even feared element to a crucial component in animal nutrition.

History and Importance of Selenium

• The article begins by pointing out that even though Selenium was discovered 174 years ago, it remained largely ignored by biologists until 1957.
• Primarily, Selenium was seen as a toxic substance that caused harm to grazing animals like horses and ruminants in the northern Great Plains.
• However, when its status as an essential nutrient was established, scientists began to intensively study Selenium, publishing numerous papers on its metabolic functions and the effects of Selenium deficiency.

Challenges in Selenium Supplementation

• Due to large areas of Selenium deficiency in the United States, significant efforts were made to secure FDA approval for Selenium supplementation in animal diets.
• These endeavors were, at first, obstructed by worries that Selenium might be carcinogenic or cancer causing.
• Once those concerns were mitigated, researchers worked to ascertain the safe, effective levels of Selenium supplementation, ensuring it posed no risk to animals, humans consuming animal products, or the environment.

Regulatory Approval and Gaps

• The FDA first authorized Selenium supplements in 1974 for use in the diet of pigs and growing chickens.
• In 1987, the approved levels of supplemental Selenium for animals including chickens, turkeys, ducks, pigs, sheep, and cattle were established at 0.3 ppm.
• However, the research paper highlights a regulatory gap as FDA regulations do not mention horses or zoo animals. As a result, attempts to supplement their diets with Selenium might be viewed as a violation of FDA guidelines.

Environmental Concerns

• The paper concludes by indicating that the association of Selenium with bird mortality and deformities at the Kesterson Reservoir in California has led to pressure on the FDA to reverse the 1987 amendments to the feed additive regulation.