Effect on Components of the Intestinal Microflora and Plasma Neuropeptide Levels of Feeding Lactobacillus delbrueckii , Bifidobacterium lactis , and Inulin to Adult and Elderly Rats

Abstract

The aim of this study was to compare the effects of the mixture of Lactobacillus delbrueckii subsp. rhamnosus strain GG, Bifidobacterium lactis Bb12, and inulin on intestinal populations of lactobacilli, bifidobacteria, and enterobacteria in adult and elderly rats fed the same (in quality and quantity) diet. The portal plasma levels of two neuropeptides, neuropeptide Y (NPY) and peptide YY (PYY), were also evaluated to assess the physiological consequences of the synbiotic treatment for the gastrointestinal (GI) tracts of rats of different ages. Adult (n ‫؍‬ 24) and elderly (n ‫؍‬ 24) male rats were fed the AIN-93 M maintenance diet. After 2 weeks of adaptation, the diet of 12 rats of each age group was supplemented with 8% inulin and with strains GG and Bb12 to provide 2.2 ؋ 10 9 CFU of each strain g ؊1 of the diet. Blood and different regions of the GI tract were sampled from all rats after 21 days of the treatment. Treatment with the mixture of strain GG, strain BB12, and inulin induced significantly different changes in the numbers of lactobacilli, bifidobacteria, and enterobacteria of the stomach, small intestine, cecum, and colon microflora. Moreover, the GG, BB12, and inulin mixture increased the concentrations of NPY and PYY for adult rats. For the elderly animals, the PYY concentration was not changed, while the NPY concentration was decreased by treatment with the GG, BB12, and inulin mixture. The results of the present study indicate that the physiological status of the GI tract, and not just diet, has a major role in the regulation of important groups of the GI bacteria community, since even the outcome of the dietary modification with synbiotics depends on the ages of the animals.The composition of the gastrointestinal (GI) microflora changes with increasing age of the host (34). These changes involve a decrease in the number and diversity of bifidobacteria and bacteroides and an increase in the number of enterobacteria, clostridia, streptococci, and enterococci in elderly humans (17,20,51) and in older animals (5).The age-related changes in the GI bacterial community in elderly humans are likely related to changes in nutritional habits, since it is well recognized that diet/dietary components codetermine the spectrum of intestinal microflora (2,18,28,33,37). In particular, aging is associated with the decrease in daily fiber intake (27) related to the prolongation of mastication (42), the decline in olfactorial and gustatorial sensitivity (24), and a decrease in cognition (36). However, aging is also associated with alterations of GI physiology and function, such as gastric hypochlorhydria, alterations in intestinal motility, and decreased colonic transit time (23,31,44). Changes in GI tract physiology during the aging process may allow specific bacterial populations to take advantage of novel ecological niches, thereby altering the composition of the GI microbiota, in turn affecting intestinal homeostasis and function (22,28).Pro-and prebiotics and their combination (synbiotics) have been shown to...

The Effect of Dietary Prebiotics and Probiotics on Body Weight, Large Intestine Indices, and Fecal Bile Acid Profile in Wild Type and IL10−/− Mice

“…3B, 3C). Overall, our observation is consistent with the observations in some other long-term pre- and probiotic feeding studies where no dietary effects on food intake or body weight were found [39], [45]. Although epidemiological studies have linked higher fiber intake to lower body weight, it was likely a result of overall lower caloric density in a fiber-rich dietary pattern [46], [47].…”

Developmental Changes of Gut Microflora and Enzyme Activity in Rat Pups Exposed to Fat‐rich Diet

“…The small intestine as compared with large intestine has different metabolic function and its key physiological role is closely related with digestion and absorption of carbohydrates, proteins, and fats and short-chain fatty acids, respectively (36). Experimental studies in rats in which both luminal and tissue samples were used revealed a lowered number of total bacteria anaerobes, lactobacilli, enterobacteria, and bifidobacteria in proximal parts of small intestine (jejunum, ileum) and their substantially higher number in cecum and colon (37,38). At present time, however, the causal relationship between host metabolic efficiency and distinctive characteristic of microbial composition in upper part of intestinal tract is poorly understood.…”

Can Antibiotic Treatment in Preweaning Rats Alter Body Composition in Adulthood?

“…Interestingly, this increase occurred immediately after full weaning in the current study, namely at a period during which the ATB-treated group still had a distorted microbiota compared to the CTL group. Bacteria and/or bacterial metabolites can regulate the expression of several gut peptides that control satiety [29]. Therefore, we can hypothesize that ATB treatment, by affecting the global ecosystem, favoured the development of one/some specific species or metabolite(s), which could produce alterations in gut peptides, resulting in a rise in food intake.…”