Anti-coccidial activity of human milk.

Sporozoites of Eimeria tenella, an important pathogen of poultry, were killed in vitro in a time- and concentration-dependent manner by exposure to diluted concentrations of normal human milk. Sodium cholate (bile salt stimulator) potentiated the anti-coccidial activity. The anti-coccidial activity was not found in the milk of lower mammals (cow, sheep, goat, dog). The component in human milk showing the activity was initially hypothesized to be a bile salt-stimulated lipase. However, testing of purified lipase (with or without sodium cholate) indicated no anti-coccidial activity. Consequently, we theorize that the active component may be a free fatty acid.