Objectives: Certain milk factors may help to promote the growth of a host-friendly colonic microflora (e.g. bifidobacteria, lactobacilli) and explain why breast-fed infants experience fewer and milder intestinal infections than those who are formula-fed. The effects of supplementation of formula with two such milk factors was investigated in this study.
Materials and methods: Infant rhesus macaques were breast-fed, fed control formula, or formula supplemented with glycomacropeptide (GMP) or alpha-lactalbumin (alpha-LA) from birth to 5 months of age. Blood was drawn monthly and rectal swabs were collected weekly. At 4.5 months of age, 10(8) colony-forming units of enteropathogenic E.coli O127, strain 2349/68 (EPEC) was given orally and the response to infection assessed. The bacteriology of rectal swabs pre- and post-infection was determined by culture independent fluorescence in situ hybridization.
Results: Post-challenge, breast-fed infants and infants fed alpha-LA-supplemented formula had no diarrhea, whilst those infants fed GMP-supplemented formula had intermittent diarrhea. In infants fed control formula the diarrhea was acute.
Conclusions: Supplementation of infant formula with appropriate milk proteins may be useful for improving the infant's ability to resist acute infection caused by E.coli.