February 21, 2013

FEEDAP shares opinion on safety, efficacy of iodine compounds as feed additives

The Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was requested by the European Commission to deliver a scientific opinion on safety and efficacy of calcium iodate anhydrous and potassium iodide as feed additives for all animal species.

The only known role of iodine in the metabolism is its incorporation into the thyroid hormones, thyroxine and triiodothyronine as well as the precursor iodothyrosines. Both hormones have multiple functions as regulators of cell activity (energy metabolism) and growth and as transmitters of nervous stimuli and play an important role in brain development.

The use of calcium iodate anhydrous and potassium iodide as sources of iodine is considered safe for all animal species/categories when used up to the currently authorised maximum content of total iodine in complete feed, with the exception of horses, cats and dogs, for which maximum tolerated levels are three, six and four milligrams (mg) I/kilogramme (kg) complete feed, respectively.

Exposure of consumers was calculated in two scenarios applying the currently authorised maximum iodine contents in feed and reduced contents. The iodine content of food of animal origin, if produced taking account of the currently authorised maximum content of iodine in feed, would represent a substantial risk to high consumers. The risk would originate primarily from the consumption of milk and to a minor extent from consumption of eggs.

If the authorised maximum iodine in feed for dairy cows and laying hens were reduced to two and three mg I/kg feed, respectively, the exposure of adult consumers would be below the Underwriters Laboratories (UL). However, iodine intake in high-consuming toddlers would remain above the UL (1.6-fold). In the absence of data, the additives are considered as irritant to the eyes, skin and respiratory tract, and as dermal sensitizers. Exposure by inhalation should be avoided. The use of the additives in animal nutrition is not expected to pose a risk to the environment.

Calcium iodate and potassium iodide are efficacious sources of iodine to meet animal requirements. The FEEDAP Panel recommends that some of the currently authorised maximum iodine contents in complete feed be modified as follows: dairy cows and minor dairy ruminants, two mg I/kg; and laying hens, three mg I/kg.