Evaluation of breast milk and breast milk substitutes on growing rats

Experiments were performed to find out whether it is possible to formulate a mixture of individual proteins from cow's milk which is more similar to human milk than presently available commercial breast milk substitutes. This was made possible by large-scale fractionation of bovine whey proteins and by mixing the latter with casein to obtain a protein mixture similar to that of breast milk. Our results indicate that the use of a rat growth assay for this purpose may be misleading and that the results of such evaluations should be interpreted with extreme caution.