<p style="text-align: justify;">
<span style="text-align: justify;">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.</span></p>