Bovine lactoferrin and its functions in animals - A review

Lactoferrin (Lf) was discovered in 1939 as “red protein from milk whey”. Bovine lactoferrin (bLf) gene is located on Bos taurus autosome, long arm of chromosome no.22 (BTA 22q24) in cattle. Its size varies from 23-35kbp among different species. The lactoferrin gene consists of 17 exons and 16 introns ranging from 82bp (exon-1) to 225bp (exon-17). The presence of multiple regulatory elements within lactoferrin promoter contributes differential gene expression and variable content of lactoferrin in milk. The concentration of lactoferrin in normal bovine milk is about 0.02-0.2 mg/ml. The primary function of Lf lies in its role in iron metabolism including iron transport, storage and chelation. Lf exhibits strong antimicrobial activity against a broad spectrum of bacteria (gram-positive & negative), fungi, yeasts, viruses and parasites. Lf exerts bacteriostatic and bactericidal activity. Its main contribution to antiviral defence consists in its binding to the cell membrane glycosaminoglycan, thus lactoferrin prevents viruses from entering cells and infection is stopped at an early age. More than 140 SNPs in this gene have been identiûed. Such a high variability in Lactoferrin gene implies that it may be used as candidate gene for screening animals also a marker of milk yield.