A two-stage continuous culture system to study the effect of supplemental alpha-lactalbumin and glycomacropeptide on mixed cultures of human gut bacteria challenged with enteropathogenic Escherichia coli and Salmonella serotype Typhimurium

Abstract

Aims: Certain milk factors may promote the growth of a gastrointestinal microflora predominated by bifidobacteria and may aid in overcoming enteric infections. This may explain why breast-fed infants experience fewer intestinal infections than their formula-fed counterparts. The effect of formula supplementation with two such factors was investigated in this study. Methods and Results: Infant faecal specimens were used to ferment formulae supplemented with glycomacropeptide (GMP) and a-lactalbumin (a-la) in a two-stage compound continuous culture model. At steady state, all fermenter vessels were inoculated with 5 ml of 0AE1 M M phosphate-buffered saline (pH 7AE2) containing 10 8 CFU mlof either enteropathogenic Escherichia coli 2348/69 (O127:H6) or Salmonella serotype Typhimurium (DSMZ 5569). Bacteriology was determined by independent fluorescence in situ hybridization. Vessels that contained breast milk (BM), as well as a-la and GMP supplemented formula had stable total counts of bifidobacteria while lactobacilli increased significantly only in vessels with breast milk. Bacteroides, clostridia and E. coli decreased significantly in all three groups prior to pathogen addition. Escherichia coli counts decreased in vessels containing BM and a-la while Salmonella decreased significantly in all vessels containing BM, a-la and GMP. Acetate was the predominant acid. Significance and Impact of the Study: Supplementation of infant formulae with appropriate milk proteins may be useful in mimicking the beneficial bacteriological effects of breast milk.

Exopolysaccharides Produced by Intestinal Bifidobacterium Strains Act as Fermentable Substrates for Human Intestinal Bacteria

“…Molar proportions of the different SCFA measured in our fecal cultures were within the same order of that reported by others. Thus, most authors indicated that acetic acid is produced at higher levels than propionic and butyric acids (1,4,9,25,46). Incubation of the intestinal microbiota in the presence of our EPS or inulin promoted a shift in the SCFA profile of fecal cultures, causing a decrease through the incubation of molar proportions of acetic acid, an increase in propionic acid levels, decreases or moderate increases in butyric acid levels, and a reduction in the acetic acid-to-propionic acid ratio through time.…”

Health effects and technological features of caseinomacropeptide

“…Supplementation of milk with 2% CMP, either of bovine, ovine or caprine origin, increased the counts of B. lactis by 1.5 log cycles after 24 h incubation at 37 1C when compared with unsupplemented milk (Janer, Pela´ez, & Requena, 1994). The ability of CMP to nourish healthy gut microflora points at its potential as a prebiotic in functional foods, or as a supplement in infant formulae to simulate the beneficial bacteriological effects of breast milk (Bruck, Graverholt, & Gibson, 2003a;Bruck et al, 2003b). Dietary intake of CMP as a source of NANA was found to increase the sialic acid content of the saliva in piglets, which influences its viscosity and protective properties (Wang et al, 2004).…”

Caseins as source of bioactive peptides

“…caseinomacropeptide, may help to promote growth of a host-friendly colonic microflora, mainly bifidobacteria or lactobacilli, and may help to overcome some enteric infections (Bruck, Graverholt, & Gibson, 2003;.…”