Molecular Fingerprints of the Human Fecal Microbiota From 9 to 18 Months Old and the Effect of Fish Oil Supplementation

Objectives: The aim of this study was to monitor changes in the fecal microbiota from 9 to 18 months and to investigate the effect of increasing dietary n-3 polyunsaturated fatty acids on the fecal microbiota. Patients and Methods: In a double-blind controlled trial with random allocation to daily supplementation with 5 mL of fish oil (FO) or sunflower oil (SO) from 9 to 18 months of age, stool samples were collected from 132 healthy Danish infants. Molecular fingerprints of the bacterial DNA were obtained by terminal restriction fragment length polymorphism (T-RFLP). Results: The T-RFLP profiles indicated that a few T-RFs became dominant with age (bp100 and 102, both presumed to be Bacteroidetes) concomitantly with an overall increase in the microbial diversity (P = 0.04). Breast-feeding influenced both the T-RFLP profiles at 9 months and the changes from 9 to 18 months, and breast-feeding cessation during the trial modified the response to the dietary oils. In the FO group, the increase in bp102 was significantly reduced among children weaned before compared with those weaned during the trial (P = 0.027), whereas the increase in bp100 was reduced in the preweaned children of the SO group relative to those weaned during the trial (P = 0.004). This was supported by intervention group differences in the changes in bp102 and bp100 among the earlier weaned children (P = 0.06 and P = 0.09, respectively). Conclusions: Cessation of breast-feeding played a dominant role relative to developmental changes in the fecal microbiota from 9 to 18 months. FO compared with SO supplementation affected changes in large bacterial groups, but only among children who had stopped breast-feeding before 9 months of age.