A method of enhancing the growth of an animal is provided. The method includes causing the animal to ingest or absorb an effective amount of a preparation obtainable by a process including, bringing a tyrosinate moiety into contact with an Fe(III)-containing substance, optionally wherein the tyrosinate moiety is tyrosine and it is brought into contact with the Fe(III)-containing substance in the presence of a base, or wherein the tyrosinate moiety is a tyrosine salt and it is brought into contact with an Fe(III)-containing substance. Methods for inhibiting, reducing, or preventing biofilm formation or buildup on a surface； the treatment of, inhibition of growth of, and inhibition of colonization by, bacteria, both in biological and non-biological environments； disinfecting surfaces, potentiating the effects of antibiotics and other anti-microbial agents, and increasing the sensitivity of bacteria and other microorganisms, to anti-microbial agents are also provided.
