Antimicrobial compounds and compositions, and uses thereof

A method of treating microbial infection/colonization in an animal in an amount effective to enhance growth and weight gain, the method comprising administering to the infected or at risk animal a pharmaceutical or veterinary product, a medical device or a dietary product comprising one or more compounds having the structure:

• wherein X, X1, and X2 are NH2, and
• R, R1, and R2 are independently selected from the group consisting of H, CH3, CH2SH, CH2CO2H, CH2CH2CO2H, CH2C6H5, CH(CH3)CH2CH3, CH2CH(CH3)2, CH2CH2SCH3, CH2CH2CH2, CH2OH, CH(OH)CH3, CH(CH3)2, or CH2C6H4OH,
• wherein R′, R1′, and R2′ are H;
• wherein the compound has the formula
• and the compound is formed of iron complexed with alpha-amino acids, wherein the alpha-amino acid is selected from the group consisting of alanine, aspartic acid, cysteine, methionine, glutamic acid, glycine, isoleucine, leucine, phenylalanine, proline, serine, threonine, tyrosine, and valine, wherein the alpha-amino acid is L-form, D-form or a mixture of D, L-forms, wherein the compound is the only ferric amino acid complex in the pharmaceutical, veterinary, or dietary product or medical device.