Scientific Opinion on the safety and efficacy of copper compounds (E4) as feed additives for all animal species:
cupric sulphate pentahydrate based on a dossier submitted by Manica S.p.A.

Copper sulphate pentahydrate is safe for all animal species up to the maximum total copper content authorised in feed. No concerns for consumer safety are expected from the use of the feed additive. The maximum residue limits (MRLs) for copper in foods of animal origin established by European Union pesticides legislation are not consistent with legal practices in animal nutrition. As copper is an essential micronutrient, the FEEDAP Panel is not in favour of establishing MRLs for animal products, unless there is a clear consumer safety issue; if MRLs are to be maintained, the Panel has proposed amended values. The additive is an eye irritant and may induce allergic dermatitis in sensitive persons which might be exacerbated by the contamination with nickel. Users may be exposed to hazardous copper concentrations by inhalation. Potential risks to soil organisms have been identified after the application of piglet manure; there might be a potential concern related to sediment contamination. Drawing final conclusions would need further model validation and refinement to the assessment of copper-based additives in livestock. The use of copper compounds in aquaculture is not expected to pose a risk. The limited database available on the influence of copper to the development of antibiotic resistance in gut and soil bacteria indicates that high copper concentrations in the microbial environment increase the number of copper-resistant bacteria, and copper resistance seems to be correlated with more frequent resistance to several antibiotics in certain bacterial species. A potential copper threshold concentration could not be derived. The total pool of macrolide resistance in animals probably originates from antibiotic treatment and not from the use of high dietary copper. The extent to which copper-resistant bacteria contribute to the overall antibiotic resistance can not be quantified at present. Copper sulphate pentahydrate is efficacious in meeting animal requirements.