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 one or more Fe III complex compounds, including but not limited to Fe III complexes comprising ligands bound to the iron centre selected from amino acids or α-hydroxy acids, o-hydroxy benzoic acids or pyridine-2-carboxylic acids, such as ferric quinate, ferric tyrosine, ferric DOPA and ferric phenylalanine. Compounds which are structural and/or functional variants, derivatives and/or analogs of the foregoing compounds, as further described herein are also disclosed. 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.