Scientific Opinion on the use of cobalt compounds as additives in animal nutrition
In the light of genotoxicity of cobalt(II) compounds and their presumed carcinogenicity after inhalatory exposure, the use of cobalt compounds as additives in animal nutrition has been assessed, considering (i) the necessity of its use for all animal species, (ii) its implications for consumer safety and (iii) on the safety of persons handling cobalt compounds. Since the only known role of cobalt in animals is that of the central atom of vitamin B12, only animals with the capacity of synthesizing vitamin B12 in the intestinal tract like ruminants, horses and coprophagous rabbits can utilise cobalt. Consequently, there is no necessity for cobalt supplementation of feed for other animals. No data are available in the open literature on the potential carcinogenicity of cobalt following the exposure via the oral route either in humans or in experimental animals. The exposure of consumers to total dietary cobalt has been considered. There was no indication that the thresholds for non-carcinogenic events (i.e. cardio-myopathy, polycythaemia, goiter, developmental) would be exceeded at present. Users are exposed to cobalt compounds. In the re-evaluation of cobalt compounds their dusting potential deserves therefore particular attention. As a first step, the FEEDAP Panel recommends minimizing exposure of users. The FEEDAP Panel recommends modifying the authorisation of cobalt compounds in feedstuffs by (i) restricting the use of cobalt compounds as additives to feed for ruminants (except milk replacer), horses and rabbits, (ii) limiting cobalt supplementation in feed for ruminants (except milk replacer), horses and rabbits to a maximum of 0.3 mg Co/kg complete feed, and (iii) reducing the authorised maximum cobalt content from all sources from 2 to 1 mg/kg complete feed for all species except fish. Any negative consequences of these measures on animal health and the efficiency of animal production are not expected.