Intestinal flora during the first months of life: new perspectives

Studies of the Immunomodulatory Activity of Polysaccharides from the Stem of Cynomorium songaricum Based on Intestinal Microbial Analysis

Polysaccharides are the main effective components of Cynomorium songaricum's stem that perform biological activities and have positive impacts on immune enhancement. In this study, the polysaccharide CSP-III of Cynomorium songaricum's stem was isolated using a DEAE-52 cellulose column through Sephadex G-100 gel column chromatography. Upon analysis, the monosaccharide composition of CSP-III included Mannose (Man), Glucuronic acid (GlcA), Galacturonic acid (GalA), Rhamnose (Rha), Glucose (Glc), Galactose (Gal), and Arabinose (Ara), at a molar ratio of 0.01:0.11:0.03:0.57:0.02:0.32:1. The molecular weight of CSP-III was 4018234 Da. Meanwhile, the capacity of CSP-III, at various concentrations, to stimulate the proliferation of mouse spleen lymphocytes in vitro was compared, and the influence of CSP-III on cell proliferation was examined using RAW264.7 mouse mononuclear macrophages as a model. The influence of CSP-III on the expression of important phosphorylating proteins in the MAPK signaling pathway was initially analyzed by Western blotting. In RAW264.7 cells, CSP-III promoted the phosphorylation of JNK proteins, which thus activated the MAPK signaling cascade and exerted immunomodulatory effects. Moreover, according to in vivo studies using cyclophosphamide (CTX)-induced immunosuppression mouse models, CSP-III improved the CTX-induced histopathological damage, promoted T and B lymphocyte proliferation, upregulated CD4+ and CD8+ T-lymphocyte counts in the spleen, increased the serum levels of IgG and IgM, and activated three essential proteins of the MAPK signaling pathway. As revealed by analysis of intestinal flora, CSP-III improved the immune function by maintaining the homeostasis of the bacterial flora by boosting the relative abundances of some beneficial bacterial groups, such as Bacteroidetes, Desmodium, and Actinomyces, and reducing the relative abundance of Aspergillus phylum. Through in vitro and in vivo experiments, our present study demonstrates that polysaccharides from the stem of Cynomorium songaricum possess strong immunoregulatory effects. Findings in this work provide theoretical support for the potential application of Cynomorium songaricum in the field of health food.

Role of the microbiome and its metabolites in ankylosing spondylitis

Ankylosing spondylitis (AS), a chronic condition that commonly influences the spine and sacroiliac joints, usually progresses to stiffness and progressive functional limitation. Its fundamental etiology and pathogenesis are likely multifactorial and remain elusive. As environmental factors, gut microbiota performs critical functions in the pathogenesis of AS through various mechanisms, including interacting with genes, enhancing intestinal permeability, activating the gut mucosa immune system, and affecting the intestinal microbiota metabolites. This review provides an overview of recent advances in investigating gut microbiota in AS pathogenesis and discusses potential methods for future therapeutic intervention.

The Role of Pediatric Nutrition as a Modifiable Risk Factor for Precocious Puberty

Puberty is a critical phase of growth and development characterized by a complex process regulated by the neuroendocrine system. Precocious puberty (PP) is defined as the appearance of physical and hormonal signs of pubertal development at an earlier age than is considered normal. The timing of puberty has important public health, clinical, and social implications. In fact, it is crucial in psychological and physical development and can impact future health. Nutritional status is considered as one of the most important factors modulating pubertal development. This narrative review presents an overview on the role of nutritional factors as determinants of the timing of sexual maturation, focusing on early-life and childhood nutrition. As reported, breast milk seems to have an important protective role against early puberty onset, mainly due to its positive influence on infant growth rate and childhood overweight prevention. The energy imbalance, macro/micronutrient food content, and dietary patterns may modulate the premature activation of the hypothalamic-pituitary-gonadal axis, inducing precocious activation of puberty. An increase in knowledge on the mechanism whereby nutrients may influence puberty will be useful in providing adequate nutritional recommendations to prevent PP and related complications.

Immune-related effects of compound astragalus polysaccharide and sulfated epimedium polysaccharide on newborn piglets

This study aimed to evaluate the immune effects of compound astragalus polysaccharide and sulfated epimedium polysaccharide (APS-sEPS) on the peripheral blood lymphocyte and intestinal mucosa in newborn piglets. A total of 40 newborn piglets were randomly divided into four groups during a 25-day experiment, including APS-sEPS, APS, sEPS and control group. The results showed that supplementation with APS-sEPS to newborn piglets remarkably increased the physiological parameters, especially the WBC. In peripheral blood, piglets that received APS-sEPS showed the highest proliferation of T lymphocytes, the percentage of CD3 + CD4+ and CD3 + CD8+ cells were the highest on days 15 and 25 (p < 0.05). The serum concentrations of IFN-γ on days 7 and 15, and IL-4, IL-10, sIgA on days 7, 15 and 25 in APS-sEPS group were significantly higher than those in the control group (p < 0.05). Furthermore, the villus length and the ratio of villus length to crypt depth in APS-sEPS group were both significantly increased compared to that of control group (p < 0.05). In the duodenum, jejunum and illume, the concentrations of IFN-γ, IL-10, total IgG and sIgA in APS-sEPS group were all significantly higher than that in control group (p < 0.05). In intestinal mucosa, APS-sEPS significantly increased the expression of NF-κB and IRF-3 mRNA in each section of small intestine of piglets. Nevertheless, in the illume segment, the effect of APS-sEPS was more significant than that of APS and sEPS (p < 0.05). The expression of TLR4 was more significant than that of control group in duodenum only. The results from the present research provide evidence that the suckling piglets administered with APS-sEPS supplement exhibited enhanced immune function of peripheral blood lymphocyte and expression of specific antibodies, and ameliorated intestinal morphological development and increased activities of humoral immune response in the small intestine, which would be related to the activation of the TLR4-NF-κB signaling pathway and IRF3.

Are Homemade and Commercial Infant Foods Different? A Nutritional Profile and Food Variety Analysis in Spain

Complementary feeding (CF) is an important determinant of early and later life nutrition with great implications for the health status and the development of an adequate growth. Parents can choose between homemade foods (HMFs) and/or commercial infant foods (CIFs). There is no consistent evidence as to whether HMFs provide a better nutritional profile and variety over CIFs. The aim of this study was to compare the nutritional profiles and food variety of HMFs versus CIFs in the Spanish market targeted for infants (6-11 months) and young children (12-18 months). Thirty mothers with their children aged 6 to 18 months were included in this cross-sectional study, following a 3-day weighed food diary of which HMFs were collected and chemically analyzed. HMFs meals for infant provided significantly lower energy, higher protein and higher fiber, for young children provided significantly higher protein and fiber than CIFs meals. HMFs fruit purees for infant shown significantly higher fiber and for young children provided higher energy than CIFs. HMFs meals contained a significantly greater number of different vegetables than CIFs meals (3.7 vs. 3.3), with carrot as the most frequently used in both. However, in CIFs fruit purees shown higher different fruits than HMFs, in both the banana was the fruit most frequently used. There was a predominance of meat and lack of oily fish and legumes in both HMFs and CIFs meals. HMFs and CIFs were equally characterized by a soft texture and yellow-orange colours. Importantly, our findings emphasize the need for clear guidelines for the preparation of HMFs as well as the promotion of food variety (taste and textures) in both HMFs and CIFs to suit infants' and young children's nutritional and developmental needs.

The Impact of Diet on Microbiota Evolution and Human Health. Is Diet an Adequate Tool for Microbiota Modulation?

The human microbiome is emerging as an interesting field in research into the prevention of health problems and recovery from illness in humans. The complex ecosystem formed by the microbiota is continuously interacting with its host and the environment. Diet could be assumed to be one of the most prominent factors influencing the microbiota composition. Nevertheless, and in spite of numerous strategies proposed to modulate the human microbiota through dietary means, guidelines to achieve this goal have yet to be established. This review assesses the correlation between social and dietary changes over the course of human evolution and the adaptation of the human microbiota to those changes. In addition, it discusses the main dietary strategies for modulating the microbiota and the difficulties of putting them properly into practice.

The use of inulin and wheat bran only during the starter period or during the entire rearing life of broilers: effects on growth performance, small intestinal maturation, and cecal microbial colonization until slaughter age

Inulin and wheat bran were added to broiler diets during the starter period or during the entire rearing period to investigate whether the effects of using these ingredients remained until slaughter age. Diets containing no inulin and no wheat bran (CON), 2% inulin (IN), 10% wheat bran (WB), or 2% inulin + 10% wheat bran (IN+WB) were provided until day 11. Thereafter, each dietary treatment was further divided into a continued diet with supplementation or a control diet, resulting in 7 groups (CON, IN/IN, IN/CON, WB/WB, WB/CON, IN+WB/IN+WB, or IN+WB/CON). On day 40, 12 chickens per group were euthanized. The IN/IN group increased the cecal molar ratio of butyrate but had a lower relative abundance of Lactobacillus (P < 0.05). Additionally, the cecal molar ratio of propionate was higher in the IN/CON group compared to the IN/IN group (P = 0.034). The WB/CON group had the best results on BW and feed conversion ratio (FCR) (P < 0.05). Only the cecal molar ratio of iso-butyrate was higher in the WB/WB group (P = 0.013). Moreover, compared to the CON group, both WB/WB and WB/CON groups reduced the relative abundances of Bifidobacterium and Escherichia coli, and only the WB/WB group reduced the relative abundance of Enterobacteriaceae (P < 0.05). Both IN+WB/IN+WB and IN+WB/CON groups increased BW until day 21 and lowered the relative abundance of Bifidobacterium (P < 0.05). The IN+WB/IN+WB group increased the cecal molar ratio of butyrate but reduced the molar ratio of propionate with a higher relative abundance of Enterobacteriaceae (P < 0.05). In conclusion, the lack of positive effects induced by inulin might be explained by the dose being too high. The beneficial effects on BW, FCR, and microbiota induced by wheat bran during the starter period were lasting when supplementation was stopped, suggesting that wheat bran could be a favorable ingredient during the starter period.

Effects of early-life lactoferrin intervention on growth performance, small intestinal function and gut microbiota in suckling piglets

The early postnatal stage is a critical period for suckling animals in developing intestinal function and stabilizing gut microbiota. Lactoferrin (LF) plays a critical role in promoting gut development and regulating gut microbiota. This study investigates the impact of early-life lactoferrin (LF) intervention on the growth performance, small intestinal function and gut microbiota in suckling piglets. Sixty suckling piglets (1.51 ± 0.05 kg) obtained from six sows (10 piglets per litter) were assigned to a control (CON) group and an LF group in each litter, which were sow-fed. Piglets in the LF group were orally administered 8-12 mL LF solution (0.5 g per kg body weight per day) for a week, and piglets in the CON group were orally administered the same dose of physiological saline. Six piglets (n = 6) from each group were euthanized on days 8 and 21. The early-life LF intervention increased growth performance, with higher villi height of the jejunum and greater disaccharidase activity of the jejunum and ileum (P < 0.05). Diarrhoea incidence decreased in the LF group from day 1 to day 7 (P < 0.05). Urinary lactulose-mannitol ratios decreased in the LF group, whereas the gene and protein expressions of jejunal occludin increased in the LF group on day 8 and day 21, and higher gene and protein levels of ileal occludin were observed on day 8 (P < 0.05). Additionally, the LF piglets had lower concentrations of IL-1β and TNF-α, and higher concentration of IL-10 in the jejunum (P < 0.05). For the ileum, higher concentration of IL-10 and lower concentration of TNF-α were observed in the LF group (P < 0.05). LF piglets had a greater abundance of Lactobacillus and lower abundance of Veillonella and Escherichia-Shigella in the jejunum on day 8 (P < 0.05). In the ileum, the abundance of Actinobacillus was decreased in the LF piglets on day 8 and day 21 (P < 0.05). The early-life LF intervention enhanced the growth performance and decreased diarrhoea incidence in the suckling piglets by promoting the development of intestinal function and changing the microbiota in the small intestine.

Isolated Rearing at Lactation Increases Gut Microbial Diversity and Post-weaning Performance in Pigs

Environment and diet are two major factors affecting the human gut microbiome. In this study, we used a pig model to determine the impact of these two factors during lactation on the gut microbiome, immune system, and growth performance. We assigned 80 4-day-old pigs from 20 sows to two rearing strategies at lactation: conventional rearing on sow’s milk (SR) or isolated rearing on milk replacer supplemented with solid feed starting on day 10 (IR). At weaning (day 21), SR and IR piglets were co-mingled (10 pens of 4 piglets/pen) and fed the same corn-soybean meal-dried distiller grain with solubles- and antibiotic-free diets for eight feeding phase regimes. Fecal samples were collected on day 21, 62, and 78 for next-generation sequencing of the V4 hypervariable region of the bacterial 16S rRNA gene. Results indicate that IR significantly increased swine microbial diversity and changed the microbiome structure at day 21. Such changes diminished after the two piglet groups were co-mingled and fed the same diet. Post-weaning growth performance also improved in IR piglets. Toward the end of the nursery period (NP), IR piglets had greater average daily gain (0.49 vs. 0.41 kg/d; P < 0.01) and average daily feed intake (0.61 vs. 0.59 kg/d; P < 0.01) but lower feed efficiency (0.64 vs. 0.68; P = 0.05). Consequently, IR piglets were heavier by 2.9 kg (P < 0.01) at the end of NP, and by 4.1 kg (P = 0.08) at market age compared to SR piglets. Interestingly, pigs from the two groups had similar lean tissue percentage. Random forest analysis showed that members of Leuconostoc and Lactococcus best differentiated the IR and SR piglets at weaning (day 21), were negatively correlated with levels of Foxp3 regulatory T cell populations on day 20, and positively correlated with post-weaning growth performance. Our results suggest that rearing strategies may be managed so as to accelerate early-life establishment of the swine gut microbiome to enhance growth performance in piglets.

The effect of inulin and wheat bran on intestinal health and microbiota in the early life of broiler chickens

Inulin and wheat bran were added to the starter diets of broiler chickens to investigate the potential of these ingredients to improve the host's health and growth performance, as well as the underlying mechanisms of their effects. A total of 960 1-day-old chicks were assigned to 4 treatments: control (CON), 2% inulin (IN), 10% wheat bran (WB), and 10% wheat bran +2% inulin (WB+IN). On day 11, 6 chicks per treatment were euthanized. A general linear model procedure with Tukey's multiple range test was performed to compare a series of parameters between treatments. The WB-containing treatments improved BW on day 7, day 11, day 35, and BW gain until day 11 (P < 0.05), but only the WB+IN treatment showed a lower feed conversion ratio than the CON treatment (P = 0.011). Furthermore, the WB+IN treatment showed the highest villus height in the jejunum and ileum (P < 0.05), and the highest jejunal ratio villus height/crypt depth (P = 0.035). The concentration of acetate in the ceca was higher in the CON treatment compared to the IN treatment (P = 0.040). The IN treatment increased the concentration (P = 0.003) and ratio (P = 0.004) of iso-butyrate compared to the WB+IN and the CON treatments (P < 0.05). A clustering result exhibited similar intestinal microbiota profiles in the chicks receiving the IN and the WB+IN diets (P > 0.05), but these profiles were different from those found in chicks receiving the WB and the CON diets (P < 0.05). In conclusion, wheat bran and the combination of wheat bran and inulin ameliorated the growth performance and gut morphology of the starter chicks, which resulted in a higher BW until day 35. Inulin, on the other hand, had a greater ability to influence the microbiota profile. The beneficial results found in relation to BW and gut morphology during the starter period suggested a synergistic effect of inulin and wheat bran.

Effects of inulin supplementation to piglets in the suckling period on growth performance, postileal microbial and immunological traits in the suckling period and three weeks after weaning

The aim of this study was to investigate the effect of inulin (IN) supplementation to suckling piglets at and 3 weeks post-weaning. A total of 72 newborn piglets were used. Twenty-four piglets per group received different amounts of IN during the suckling period: (a) CON: no IN; (b) IN-0.5: 0.5 g IN/d on the 1st week, 1 g IN/d on the 2nd week, 1.5 g IN/d on the 3rd week and 2 g IN/d on the 4th week, or (c) IN-0.75: 0.75 g IN/d on the 1st week, 1.5 g IN/d on the 2nd week, 2.25 g IN/d on the 3rd week and 3 g IN/d on the 4th week. Starting at 28 d of age, piglets were weaned and received a post-weaning diet without inulin during the following 3 weeks. At both 28 d and 49 d of age, piglets were euthanised for sampling. Piglets of group IN-0.5 had the highest body weight starting from the 3rd week (p < 0.05), concomitant with the highest villus height and the ratio of villus height/crypt depth in the jejunum and ileum on both sampling days (p < 0.05). At 28 d of age, an increased concentration of propionate, iso-butyrate or total short chain fatty acids was observed between treatment IN-0.5 and the other groups in the caecum or colon (p < 0.05). Moreover, the relative abundance of Escherichia coli (p = 0.05) and Enterobacteriaceae (p = 0.01) in colonic digesta were reduced in IN-0.5-treated piglets, and in both IN-supplemented groups, colonic interleukin-8, tumor necrosis factor-α and toll-like receptor-4 mRNA abundance were decreased compared to the CON group (p < 0.05). However, at 49 d of age, most of these differences disappeared. In conclusion, treatment IN-0.5 improved during the suckling period of piglets development of intestine, but these beneficial effects were not lasting after weaning, when IN supplementation was terminated. Treatment IN-0.75, however, did not display a prebiotic effect.

Physicochemical differences between malanga (Xanthosoma sagittifolium) and potato (Solanum tuberosum) tubers are associated with differential effects on the gut microbiome

Malanga (Xanthosoma sagittifolium) is used as a medicinal food for infant development and gastritis. We compared the physicochemical properties and gut microbial effects of malanga versus potato (Solanum tuberosum) using nutritional analysis, rheometry, in vitro TNO Intestinal Model, and C57Bl/6J mouse models. Malanga was characterized by higher starch (70.7% v. 66.3%), lower amylose:amylopectin (0.33 v. 0.59), higher free sugar (5.44% v. 3.23%), lower viscosity (271.0 v. 863.0 mPa.s), and higher bioaccessible and bioavailable sugar (0.89 v. 0.11 g bioaccessible sucrose per 20 g load in vitro; blood glucose levels of 129.1 v. 95.2 and 133.8 v. 104.3 mg/dL after 20 and 60 min in vivo). Gut microbiota of mice fed a high fat diet containing 20% malanga for 14 d exhibited significantly higher α diversity than those fed 20% potato, indicating that minor physicochemical differences between similar tuber crops are associated with significantly different effects on the gut microbiome.

Effect of Clostridium butyricum supplementation on the development of intestinal flora and the immune system of neonatal mice

The objective of the present study was to examine whether Clostridium butyricum supplementation has a role in the regulation of the intestinal flora and the development of the immune system of neonatal mice. A total of 30 pregnant BALB/c mice, including their offspring, were randomly divided into three groups: In the maternal intervention group (Ba), maternal mice were treated with Clostridium butyricum from birth until weaning at postnatal day 21 (PD21) followed by administration of saline to the offspring at PD21-28; in the offspring intervention group (Ab), breast-feeding maternal mice were supplemented with saline and offspring were directly supplemented with Clostridium butyricum from PD21-28; in the both maternal and offspring intervention group (Bb), both maternal mice and offspring were supplemented with Clostridium butyricum at PD 0-21 and at PD21-28. While mice in the control group were given the same volume of normal saline. Stool samples from the offspring were collected at PD14, -21 and -28 to observe the intestinal flora by colony counts of Enterococcus spp., Enterobacter spp., Bifidobacterium spp. and Lactobacillus spp. Detection of intestinal secreted immunoglobulin A (sIgA) levels and serum cytokine (interferon-γ, and interleukin-12, -4 and -10) levels in offspring was performed to evaluate the effect on their immune system. The results revealed that compared with the control group, offspring in the Ba group displayed significantly decreased stool colony counts of Enterococcus spp. (t=3.123, P<0.01) at PD14 and significantly decreased counts of Enterobacter spp. at PD14 and -21 (t=2.563, P<0.05 and t=2.292, P<0.05, respectively). Compared with the control group, the stool colony counts of Bifidobacterium spp. and Lactobacillus spp. were significantly increased in the Ba group at PD21 (t=3.085, P<0.01 and t=2.8508, P<0.05, respectively). The Ab group had significantly higher stool colony counts of Bifidobacterium spp. and Lactobacillus spp. at PD28, compared with the control group (Q=7.679, P<0.01 and Q=6.149, P<0.01, respectively). There were no significant differences identified in the sIgA levels of the intestinal fluid and serum cytokine levels between the control group and the intervention groups. In conclusion, Clostridium butyricum administered to breast-feeding maternal mice was able to regulate the intestinal flora balance in their offspring. However, due to insignificant effects on sIgA level and the associated cytokines, Clostridium butyricum had a limited influence on the balance of type 1 vs. type 2 T-helper cells. However, using Clostridium butyricum as an invention may be a safe method for improving the balance of intestinal flora and associated processes in offspring.

Ratio of Klebsiella/Bifidobacterium in early life correlates with later development of paediatric allergy

Several studies have reported that intestinal microbial colonisation patterns differ between non-allergic and allergic infants. However, the microbial signature underlying the pathogenesis of allergies remains unclear. We aim to gain insight into the development of the intestinal microbiota of healthy infants and infants who develop allergy in early life, and identify potential microbiota biomarkers of later allergic disease. Using a case-control design in a Chinese sub-cohort of a Singaporean birth cohort (GUSTO), we utilised 16S rRNA gene sequencing to assess intestinal microbial composition and diversity of 21 allergic and 18 healthy infants at 3 weeks, 3 months and 6 months of age, and correlated the microbiota with allergy at ages 18 and 36 months. Pronounced differences in intestinal microbiota composition between allergic and healthy infants were observed at 3 months of age. The intestine of healthy infants was colonised with higher abundance of commensal Bifidobacterium. Conversely, Klebsiella, an opportunistic pathogen, was significantly enriched in the allergic infants. Interestingly, infants with a high Klebsiella/Bifidobacterium (K/B) ratio (above the population median K/B ratio) at age 3 months had an odds ratio of developing allergy by 3 years of age of 9.00 (95% confidence interval 1.46-55.50) compared to those with low K/B ratio. This study demonstrated a relationship between the ratio of genera Klebsiella and Bifidobacterium during early infancy and development of paediatric allergy in childhood. Our study postulates that an elevated K/B ratio in early infancy could be a potential indicator of an increased risk of allergy development. This line of research might enable future intervention strategies in early life to prevent or treat allergy. Our study provides new insights into microbial signatures associated with childhood allergy, in particular, suggests that an elevated K/B ratio could be a potential early-life microbiota biomarker of allergic disease.

Maternal Infections That Would Warrant Antibiotic Use Antepartum or Peripartum Are Not a Risk Factor for the Development of IBD: A Population-Based Analysis

BACKGROUND

We aimed to determine whether maternal antenatal or perinatal infections (and thereby use of antibiotics) increase the risk of developing inflammatory bowel disease (IBD) in their offspring.

METHODS

The University of Manitoba IBD Epidemiology Database contains records of all Manitobans diagnosed with IBD from 1984 to 2010. Each individual with IBD is matched to 10 controls. Subjects' medical system contacts are identified using a unique deidentified personal health identification number. Individuals born in 1970 and later are linkable to their mothers through a 6-digit family health registration number and cross referencing of mothers' personal health identification number with the child's birth record. We assessed antenatal (30 days and 9 months before delivery) and peripartum (in hospital) maternal infections identified by ICD-8 and ICD-9 codes as a proxy for antibiotic use.

RESULTS

Of the 2487 IBD cases born after 1970, 1758 were born in Manitoba, of which 1671 were linkable to mothers (Crohn's disease = 973 and ulcerative colitis = 698). From 1615 families, 10488 matched controls and 1740 siblings were identified. Maternal infections occurred with equal rates in mothers of IBD cases and mothers of controls: within 9 months antepartum, 21.7% versus 23.2% (odds ratio = 0.96 [0.84-1.09]); within 30 days antepartum 11.4% versus 12.4% (odds ratio = 0.97, 0.82-1.14); peripartum 5.5% versus 7.5% (odds ratio = 0.86, 0.68-1.09). There was also no difference in the occurrence of antepartum or peripartum infections among mothers of IBD cases versus unaffected siblings.

CONCLUSIONS

Maternal infections (and therefore antibiotic use) in the antepartum and peripartum periods do not affect the risk of development of IBD in offspring.

Anticlostridial agent 8-hydroxyquinoline improves the isolation of faecal bifidobacteria on modified Wilkins-Chalgren agar with mupirocin

The need for suitable selective cultivation media for the isolation of Bifidobacterium spp. continues to be a real concern in the field of intestinal microbiology. Isolation of bifidobacteria from human and animal faecal samples using selective agar plating may be problematic especially in samples with increased clostridial counts than bifidobacterial counts. Due to the absence of anticlostridial agents in existing selective media, clostridia can displace bifidobacteria resulting in incorrect estimation of their counts. Therefore, we supplemented the existing selective medium 'modified Wilkins Chalgren agar with mupirocin' (MWM) with 90 mg l(-1) of 8-hydroxyquinoline (8HQ), which was recently proved to act selectively against clostridia. The newly composed 'modified Wilkins-Chalgren agar with 8HQ' (MWMQ) was tested on pure bifidobacterial and clostridial strains, their mixtures, and using faecal samples of mammalian origin; its selectivity was evaluated by genus-specific identification of isolates. The results demonstrated that the presence of 8HQ in this agar eliminated the growth of nonbifidobacterial strains on MWMQ compared to that on MWM, whereas the recovery of bifidobacterial counts was at satisfactory levels. In conclusion, MWMQ could be recommended for bifidobacterial isolation from human and animal faeces especially when bifidobacteria are not numerically dominant and there are chances of clostridial contamination.

SIGNIFICANCE AND IMPACT OF THE STUDY

Routine isolation of bifidobacteria from mammalian faeces does not use a reliable selective agar with an anticlostridial agent. Overgrowth of clostridia may result in incorrect estimation of bifidobacterial counts. Thus, in order to improve the selectivity of existing media for bifidobacterial isolation, we chose the modified Wilkins-Chalgren agar with mupirocin and supplemented it with 8-hydroxyquinoline (8HQ), a molecule that shows anticlostridial activity without affecting the growth of bifidobacteria. This newly composed medium showed enhanced selectivity and specificity compared to the original medium and therefore, can be recommended for the isolation of bifidobacteria from mammal faeces.

Nutrition in the First 1000 Days: The Origin of Childhood Obesity

Childhood obesity is a major global issue. Its incidence is constantly increasing, thereby offering a threatening public health perspective. The risk of developing the numerous chronic diseases associated with this condition from very early in life is significant. Although complex and multi-factorial, the pathophysiology of obesity recognizes essential roles of nutritional and metabolic aspects. Particularly, several risk factors identified as possible determinants of later-life obesity act within the first 1000 days of life (i.e., from conception to age 2 years). The purpose of this manuscript is to review those key mechanisms for which a role in predisposing children to obesity is supported by the most recent literature. Throughout the development of the human feeding environment, three different stages have been identified: (1) the prenatal period; (2) breast vs. formula feeding; and (3) complementary diet. A deep understanding of the specific nutritional challenges presented within each phase might foster the development of future preventive strategies.

Targeting gut-liver axis for the treatment of nonalcoholic steatohepatitis: translational and clinical evidence

Nonalcoholic fatty liver disease (NAFLD) is widely emerging as the most prevalent liver disorder and is associated with increased risk of liver-related and cardiovascular mortality. Recent experimental and clinical studies have revealed the pivotal role played by the alteration of gut-liver axis in the onset of fatty liver and related metabolic disturbances. Gut-liver cross talk is implicated not only in the impairment of lipid and glucose homeostasis leading to steatogenesis, but also in the initiation of inflammation and fibrogenesis, which characterize nonalcoholic steatohepatitis (NASH), the evolving form of NAFLD. The gut microbiota has been recognized as the key player in the gut-liver liaison and because of its complexity can act as a villain or a victim. Gut microbiota not only influences absorption and disposal of nutrients to the liver, but also conditions hepatic inflammation by supplying toll-like receptor ligands, which can stimulate liver cells to produce proinflammatory cytokines. Thus, the modification of intestinal bacterial flora by specific probiotics has been proposed as a therapeutic approach for the treatment of NASH. In this review, we summarized the evidence regarding the role of gut-liver axis in the pathogenesis of NASH and discussed the potential therapeutic role of gut microbiota modulation in the clinical setting.

Cesarean Section Delivery Is Not a Risk Factor for Development of Inflammatory Bowel Disease: A Population-based Analysis

BACKGROUND & AIMS

Mode of birth affects development of the intestinal microbiota, and microbial dysbiosis has been associated with inflammatory bowel disease (IBD). We performed a population-based analysis to determine whether mode of delivery (cesarean section vs. vaginal delivery) affects risk of IBD.

METHODS

We collected data from the University of Manitoba IBD Epidemiology Database, which contains records on all Manitobans diagnosed with IBD from 1984 through 2010. Starting in 1970, 6-digit family health registration numbers were used in Manitoba to link mothers with their offspring. Maternal health records, including dates and modes of delivery and siblings of individuals with IBD, were identified.

RESULTS

We obtained data on 1671 individuals with IBD and 10,488 controls (individuals without IBD, matched by age, sex, and area of residence at IBD diagnosis) linked to mothers' obstetrical records. Higher proportions of urban than rural residents were delivered by cesarean section for IBD cases (12.8% vs. 9.7%, P = .05) and controls (13.3% vs. 9.4%, P < .0001). A higher percentage of men with Crohn's disease than women with Crohn's disease were born via cesarean section (13.5% vs. 8.4%, P = .01). Overall, there was no difference in the percentage of IBD cases born by cesarean section (11.6%) vs. controls (11.7%, P = .93). In multivariate analysis, birth by cesarean section was not associated with an increased risk of subsequent IBD, controlling for age, sex, urban residence, and income (odds ratio, 1.04; 95% confidence interval, 0.89-1.23). Persons with IBD were no more likely to have been born by cesarean section than their siblings without IBD (1740 siblings from 1615 families) (11.6% vs. 11.3%; odds ratio, 1.14; 95% confidence interval, 0.72-1.80; P = .79).

CONCLUSIONS

People with IBD were not more likely to have been born via cesarean section than controls or siblings without IBD. These findings indicate that events of the immediate postpartum period that shape the developing intestinal microbiome do not affect risk for IBD.

Antimicrobial Activity of Lactobacillus spp. Isolated From Fecal Flora of Healthy Breast-Fed Infants Against Diarrheagenic Escherichia coli

Background:

Among the enteric pathogens, diarrheagenic Escherichia coli are important causes of diarrhea in children in both developing and industrialized countries. Some Lactobacillus species are commonly used as probiotics, with effects especially against acute diarrhea in childhood.

Objectives:

The aim of this study was to explore antimicrobial activity of Lactobacillus strains isolated from fecal flora of healthy breast-fed infants against five diarrheagenic E. coli pathotypes such as enteroaggregative E. coli (EAEC), enterohaemorrhagic E. coli (EHEC) enteroinvasive E. coli (EIEC), enteropathogenic E. coli (EPEC) and enterotoxigenic E. coli (ETEC).

Materials and Methods:

Fecal samples were collected from seven healthy breast-fed infants between 1 to 18 months of age in Tehran city, Iran. Identification of Lactobacillus isolates was performed by biochemical and 16S rRNA gene sequencing methods. An agar well diffusion assay was used for detection of antimicrobial activity of Lactobacillus isolates against five diarrheagenic E. coli pathotypes.

Results:

A total of 20 Lactobacillus isolates were identified from stool samples. Lactobacillus fermentum was the most frequently isolated strain, followed by L. plantarum and L. rhamnosus. Seven Lactobacillus strains including L. fermentum (four isolates), L. paracasei (one isolate), L. plantarum (one isolate) and L. rhamnosus (one isolate) had a mild inhibitory activity against diarrheagenic E. coli. The mechanism of inhibitory activity of Lactobacillus strains appeared to be due to the production of organic acids or hydrogen peroxide.

Conclusions:

Our findings show that Lactobacillus strains with human origin had a mild inhibitory activity against the diarrheagenic E. coli, and these strains may be useful as probiotic candidates in prevention of intestinal infections caused by diarrheagenic E. coli.

Dynamics of the nasal microbiota in infancy: a prospective cohort study

BACKGROUND

Understanding the composition and dynamics of the upper respiratory tract microbiota in healthy infants is a prerequisite to investigate the role of the microbiota in patients with respiratory diseases. This is especially true in early life, when the immune system is in development.

OBJECTIVE

We sought to describe the dynamics of the upper respiratory tract microbiota in healthy infants within the first year of life.

METHODS

After exclusion of low-quality samples, microbiota characterization was performed by using 16S rDNA pyrosequencing of 872 nasal swabs collected biweekly from 47 unselected infants.

RESULTS

Bacterial density increased and diversity decreased within the first year of life (R(2) = 0.95 and 0.73, respectively). A distinct profile for the first 3 months of life was found with increased relative abundances of Staphlyococcaceae and Corynebacteriaceae (exponential decay: R(2) = 0.94 and 0.96, respectively). In addition, relative bacterial abundance and composition differed significantly from summer to winter months. The individual composition of the microbiota changed with increasing time intervals between samples and was best modeled by an exponential function (R(2) = 0.97). Within-subject dissimilarity in a 2-week time interval was consistently lower than that between subjects, indicating a personalized microbiota.

CONCLUSION

This study reveals age and seasonality as major factors driving the composition of the nasal microbiota within the first year of life. A subject's microbiota is personalized but dynamic throughout the first year. These data are indispensable to interpretation of cross-sectional studies and investigation of the role of the microbiota in both healthy subjects and patients with respiratory diseases. They might also serve as a baseline for future intervention studies.

High abundance of Escherichia during the establishment of fecal microbiota in Brazilian children

The sequence of bacterial events that occurs during the colonization of the gastrointestinal tract may affect the future health of the host. A clear understanding of the colonization process of the human neonatal gut in developing countries is lacking because the few available studies were mostly performed using culture techniques. Using molecular approaches, this study analyzed the fecal microbiota of children of low socioeconomic status in São Paulo, Brazil, during their first year of life. We collected fecal samples of healthy children at 3, 6, and 12 months of life. Total DNA was extracted directly from feces, and the bacteria-specific primers 27F-1492R were used to construct 16S rRNA libraries. Clones were randomly selected and partially sequenced. The main phylogenetic groups identified at 3 months were Streptococcus, unidentified bacteria, and Escherichia. At 6 months, Escherichia remained predominant, while the unidentified bacterial population increased significantly. At 12 months, a more complex composition of fecal microbiota was observed, represented by unidentified bacteria and microorganisms found at low rates at earlier ages. The genus Escherichia remained the most abundant microorganism (34% relative abundance and 75% prevalence). Principal component analysis (PCA) revealed changes in the composition of the microbiota at 6 months and an increase of diversity at 12 months of life. Bifidobacterium was identified by quantitative PCR (qPCR) and showed a high incidence in the microbiota at 3 months. The present results corroborate the global observation of inter-individual variability with an early establishment of microbial complexity at the end of the first year of life and highlight the presence of the Escherichia as abundant in microbiota composition of this group of children.

Establishment of intestinal microbiota during early life: a longitudinal, explorative study of a large cohort of Danish infants

Fecal samples were obtained from a cohort of 330 healthy Danish infants at 9, 18, and 36 months after birth, enabling characterization of interbacterial relationships by use of quantitative PCR targeting 31 selected bacterial 16S rRNA gene targets representing different phylogenetic levels. Nutritional parameters and measures of growth and body composition were determined and investigated in relation to the observed development in microbiota composition. We found that significant changes in the gut microbiota occurred, particularly from age 9 to 18 months, when cessation of breastfeeding and introduction of a complementary feeding induce replacement of a microbiota characterized by lactobacilli, bifidobacteria, and Enterobacteriaceae with a microbiota dominated by Clostridium spp. and Bacteroides spp. Classification of samples by a proxy enterotype based on the relative levels of Bacteroides spp. and Prevotella spp. showed that enterotype establishment occurs between 9 and 36 months. Thirty percent of the individuals shifted enterotype between 18 and 36 months. The composition of the microbiota was most pronouncedly influenced by the time of cessation of breastfeeding. From 9 to 18 months, a positive correlation was observed between the increase in body mass index and the increase of the short-chain-fatty-acid-producing clostridia, the Clostridum leptum group, and Eubacterium hallii. Considering previously established positive associations between rapid infant weight gain, early breastfeeding discontinuation, and later-life obesity, the corresponding microbial findings seen here warrant attention.

The effects of antimicrobials and exposure to smoking on bacterial interference in the upper respiratory tract of children

Interactions between micro-organisms that include antagonism (interference) and synergism maintain balance between members of the normal endogenous flora, and play a role in preventing colonization by potential pathogens. Bacteria with interference capability of potential respiratory tract pathogens include alpha-hemolytic streptococci, non-hemolytic streptococci, Prevotella spp. and Peptostreptococcus spp. The role of bacterial interference in the occurrence of upper respiratory tract infections and its effect on their eradication is discussed. The infections include otitis media, sinusitis and pharyngo-tonsillitis. Treatment with antimicrobial agents and direct and indirect exposure to smoking, can affect the balance between the interfering organisms and potential pathogens. Introduction into the indigenous microflora of low virulence bacterial strains that are capable of interfering with colonization and infection with virulent organisms has been used to prevent the failure of antimicrobials in the treatment of pharyngo-tonsillitis and otitis media.

Modulation of gut microbiota downregulates the development of food allergy in infancy

In humans, microbial colonisation of the intestine begins just after birth. However, development of the normal flora is a gradual process, which is initially determined by factors such as genetic aspects, the maternal-foetal interaction, place and mode of delivery, early feedings strategies, and the use of antibiotics. Current knowledge on the significance and impact of the gut microflora on the development of the gut immune system indicates that a close relationship between allergic sensitisation and the development of the intestinal microflora may occur in infancy. Intestinal micro-organisms could downregulate the allergic inflammation by counterbalancing type 2 T-helper cell responses and by enhancing allergen exclusion through an immunological response.

Beyond the Paleolithic prescription: incorporating diversity and flexibility in the study of human diet evolution

Evolutionary paradigms of human health and nutrition center on the evolutionary discordance or "mismatch" model in which human bodies, reflecting adaptations established in the Paleolithic era, are ill-suited to modern industrialized diets, resulting in rapidly increasing rates of chronic metabolic disease. Though this model remains useful, its utility in explaining the evolution of human dietary tendencies is limited. The assumption that human diets are mismatched to the evolved biology of humans implies that the human diet is instinctual or genetically determined and rooted in the Paleolithic era. This review looks at current research indicating that human eating habits are learned primarily through behavioral, social, and physiological mechanisms that start in utero and extend throughout the life course. Adaptations that appear to be strongly genetic likely reflect Neolithic, rather than Paleolithic, adaptations and are significantly influenced by human niche-constructing behavior. Several examples are used to conclude that incorporating a broader understanding of both the evolved mechanisms by which humans learn and imprint eating habits and the reciprocal effects of those habits on physiology would provide useful tools for structuring more lasting nutrition interventions.

Effect of high β-palmitate content in infant formula on the intestinal microbiota of term infants

OBJECTIVES

Palmitic acid (PA) constitutes 17% to 25% of the human milk fatty acids, and ~70% is esterified in the sn-2 position of triglycerides (β-palmitate). In the sn-2 position, PA is not hydrolyzed and thus is efficiently absorbed. The PA in palm oils, commonly used in infant formulas, is esterified in the sn-1 and sn-3 positions. In these positions, PA is hydrolyzed and forms poorly absorbed calcium complexes. The present study assessed whether high β-palmitate in infant formulas affects the intestinal flora.

METHODS

Thirty-six term infants were enrolled: 14 breast-fed (BF group) and 22 formula-fed infants who were randomly assigned to receive formula containing high β-palmitate (HBP group, n=14), or low β-palmitate (LBP group, n=8), where 44% and 14% of the PA was β-palmitate, respectively. The total amount of PA in the formulas was 19% and 22% in the LBP and HBP groups, respectively. Neither formula contained pre- or probiotics. Stool samples were collected at enrollment and at 6 weeks for the quantification of bacteria.

RESULTS

At 6 weeks, the HBP and BF groups had higher Lactobacillus and bifidobacteria counts than the LBP group (P<0.01). The Lactobacillus counts at 6 weeks were not significantly different between the HBP and BF groups. Lactobacillus counts were 1.2×10¹⁰, 1.2×10¹¹, and 5.6×10¹⁰ CFU/g for LBP, HBP, and BF groups, respectively. Bifidobacteria counts were 5.1×10⁹, 1.2×10¹¹, and 3.9×10¹⁰ CFU/g for LBP, HBP, and BF groups, respectively.

CONCLUSIONS

HBP formula beneficially affected infant gut microbiota by increasing the Lactobacillus and bifidobacteria counts in fecal stools.

Environmental factors and inflammatory bowel disease: elusive or nonexistent?

Although abundant indirect evidence suggests that environmental factors contribute to the pathogenesis of inflammatory bowel disease (IBD), the search for specific etiological agents has been largely disappointing. Early life factors have been hypothesized to influence the risk of IBD; however, new data from the Nurses Health Study showed no associations between breastfeeding, gestational age, and birthweight and adult-onset IBD.

Bacterial carbohydrate-degrading capacity in foal faeces: changes from birth to pre-weaning and the impact of maternal supplementation with fermented feed products

The present study aimed at (1) describing age-related changes in faecal bacterial functional groups involved in carbohydrate degradation and in their activities in foals (n10) from birth (day (d) 0) to 6 months (d180) and (2) investigating the effect of maternal supplementation (five mares per treatment) from d − 45 to d60 with fermented feed products on response trends over time of the foal bacterial carbohydrate-degrading capacity. Maternal supplementation with fermented feed products stimulated foal growth from d0 to d60 and had an impact on the establishment of some digestive bacterial groups and their activities in foals from d0 to d5 but not in the longer term. Irrespective of the maternal treatment, total bacteria, total anaerobic, lactate-utilising and amylolytic bacteria were established immediately after birth (P< 0·05) and were active as shown by the significant increase in total volatile fatty acids. In the foals of supplemented mares, total anaerobes and lactate utilisers were established rapidly between d0 and d2 (P= 0·021 and 0·066, respectively) and the increase in the percentage of propionate occurred earlier (P= 0·013). Maternal supplementation had no effect on the establishment of fibrolytic bacteria and their activity. Cellulolytic bacteria andFibrobacter succinogenesfirst appeared at d2 and d5, and increased progressively, reaching stable values at d30 and d60, respectively. From the second week of life, the increase in the molar percentage of acetate and the ratio (acetate+butyrate):propionate (P< 0·05) suggested that fibrolytic activity had begun. From d60, only minor changes in bacterial composition and activities occurred, showing that the bacterial carbohydrate-degrading capacity was established at 2 months of age.

Eleutherine americana as a growth promotor for infant intestinal microbiota

Eleutherine americana extract and its oligosaccharides extract were demonstrated for their growth-promoting activities on mixed infant intestinal microbiota and individual bacterial species including Bacteroides, bifidobacteria, clostridia, and lactobacilli. Fermentation of all the substrates resulted in about 1-2 log increase in the numbers of bifidobacteria belonging to the dominant infant gut microbiota. The highest levels of the bacterial populations were resulted from the oligosaccharides extract. The oligosaccharides extract stimulated the growth of bifidobacteria in mixed and individual populations by increasing their numbers from 9.63 to 12.08 and 5.80 to 8.85 log cfu/ml, respectively within 48 h. In addition, Bacteroides populations were enhanced by fermentation of E. americana extract. Increase in lactobacilli level was observed from fermentation by a single bacterial species, but not from the mixed cultures. Fermentation of the extract, oligosaccharides extract, and commercial fructo-oligosaccharides by both mixed and individual intestinal microbiota resulted in increase in the production of short chain fatty acids. Acetic acid production was predominant, followed by lactic acid and minor amount of propionic and butyric acids. The highest production of acetic acid was resulted from the oligosaccharides extract. Increase in the acetic acid in mixed and individual species of bifidobacterial populations ranged from 1.21 to 34.26 and 1.02-25.21 mM, respectively. This study showed that E. americana can be considered as a potential prebiotic which may be supplemented as an ingredient in functional foods.

Continuous surveillance to reduce extended-spectrum β-lactamase Klebsiella pneumoniae colonization in the neonatal intensive care unit

BACKGROUND

Clinical illness caused by resistant bacteria usually represents a wider problem of asymptomatic colonization. Active surveillance with appropriate institution of isolation precautions represents a potential mechanism to control colonization and reduce infection. The neonatal intensive care unit (NICU) is an environment particularly appropriate for such interventions. Neonates are rarely colonized by resistant bacteria on admission and staff enthusiasm for infection control is high.

OBJECTIVE

To reduce extended-spectrum β-lactamase-producing Klebsiella pneumoniae (ESBL-KP) acquisition amongst neonates through a continuous active surveillance intervention.

METHODS

Fecal ESBL-KP cultures were performed weekly on all neonates over 4 years. Neonates with positive cultures were managed with contact precautions by dedicated nurses separately from other neonates. ESBL-KP acquisition amongst neonates staying >7 days was compared for the consecutive years. A subset of ESBL-KP isolates was typed with pulsed-field gel electrophoresis (PFGE).

RESULTS

Surveillance cultures were obtained from 1,482/1,763 (84%) neonates over 4 years. ESBL-KP acquisition decreased continuously from 94/397 (24%) neonates in 2006 to 33/304 (11%) in 2009 (p < 0.001, hazard ratio 0.75, 95% confidence interval 0.66-0.85, p < 0.001 for comparison of years). Hospital-wide ESBL-KP acquisition did not decrease outside the NICU. PFGE identified identical ESBL-KP strains from multiple neonates on six occasions and different strains from single neonates on seven occasions.

CONCLUSIONS

ESBL-KP is probably both imported into and spread within the NICU. Continuous long-term surveillance with cohorting was associated with a decrease in ESBL-KP acquisition within the NICU. This low-risk intervention should be considered as a means to decrease neonatal acquisition of resistant bacteria.

Water as the Earth’s Buffer and Immune System

A comprehensive review on water as a buffer of the planet and its immune system is presented. The relationship between the quality of drinking water, the level of development of human intelligence, and its health is highlighted. The problems of obtaining cytogenetically and physiologically safe high-quality drinking water are discussed along with the problems of its decontamination. The solutions to maintain stable development of aquatic ecosystems are proposed. It is shown that tap water is the habitat of multiresistant genetically-mutated microorganisms.

Impact of probiotic feeding during weaning on the serum lipid profile and plasma metabolome in infants

The gut microbiome interacts with the host in the metabolic response to diet, and early microbial aberrancies may be linked to the development of obesity and metabolic disorders later in life. Probiotics have been proposed to affect metabolic programming and blood lipid levels, although studies are lacking in infants. Here, we report on the lipid profile and global metabolic response following daily feeding of probiotics during weaning. A total of 179 healthy, term infants were randomised to daily intake of cereals with (n89) or without (n90) the addition ofLactobacillus paracaseissp.paracaseiF19 (LF19) 108colony-forming units per serving from 4 to 13 months of age. Weight, length and skinfold thickness were monitored. Venous blood was drawn at 5·5 and 13 months of age for analysis of the serum lipid profile. In a subsample, randomly selected from each group, GC-time-of-flight/MS was used to metabolically characterise plasma samples from thirty-seven infants. A combination of multi- and univariate analysis was applied to reveal differences related to LF19 treatment based on 228 putative metabolites, of which ninety-nine were identified or classified. We observed no effects of probiotic feeding on anthropometrics or the serum lipid profile. However, we detected significantly lower levels of palmitoleic acid (16 : 1) (P< 0·05) and significantly higher levels of putrescine (P< 0·01) in LF19-treated infants. Palmitoleic acid is a major MUFA strongly linked to visceral obesity, while putrescine is a polyamine with importance for gut integrity. Whether the observed differences will have long-term health consequences are being followed.

Persistence of orally administered lactobacillus strains in the gut of infant mice

The present study tested the persistence of orally administered bacteria in the gut of suckling mice. We used three bacterial strains: one strain of Lactobacillus johnsonii (designated strain Ms1) that was previously isolated from the mouse stomach, and two strains of L. plantarum, (strain No. 14 and JCM 1149(T)). We detected L. johnsonii Ms1, but neither strain of L. plantarum, in the gut 7 days after administration when the organisms were administered on days 0, 1, 3 or 7 of neonatal life. None of the strains was detected in the gut 7 days after the administration on days 14 or 28 of neonatal life. L. johnsonii Ms1 and L. plantarum JCM 1149(T) exhibited similar levels of in vitro association with gut tissues, with both strains showing association that was significantly higher than that of L. plantarum No. 14. In a separate experiment, the number of total bacteria and lactobacilli in the gut, as estimated by real-time quantitative PCR, was significantly higher in 14- and 21-day-old mice than in 0- and 7-day-old mice. In addition, the number of total bacteria was higher in 21-day-old mice than in 14-day-old mice, and the number of lactobacilli was higher in 7-day-old mice than in 0-day-old mice. These results suggest that gut persistence of administered bacteria in infant mice is species- or strain-specific and is affected by the development of indigenous microbiota. In addition, gut persistence of administered bacteria may not always depend on the tissue association capacity.

Quantitative analysis of intestinal bacterial populations from term infants fed formula supplemented with fructo-oligosaccharides

OBJECTIVES

Previous studies of infant formulas supplemented with oligosaccharides reported mixed results regarding the impact on intestinal microbial populations. The objective of this study was to examine the effect of supplementation of an infant formula with fructo-oligosaccharides (FOS) on select groups of intestinal bacteria in term infants.

METHODS

Four groups of infants were enrolled and fed human milk, a commercially available milk-based infant formula, or infant formula supplemented with 2.0 or 3.0 g/L FOS. Dietary intake, stool, and tolerance events were recorded. Fresh stool samples were collected approximately 27 days after feeding the diets (approximately 32 days after birth). Total bacteria, Bacteroides (as commensal bacteria), Bifidobacterium and Lactobacillus, and Clostridium difficile and Escherichia coli were quantified using respective specific real-time PCR assays.

RESULTS

The formula feeding groups did not differ in stool consistency and stool frequency or frequency of spit-up or vomit during the entire study. The formula-fed infants tended to have more total bacteria in their stool samples than the human milk-fed infants. The formula-fed infants harbored a greater abundance of C difficile and E coli than the human milk-fed infants, but had a similar abundance of Bacteroides, Bifidobacterium, and Lactobacillus. The FOS supplementation at either dose did not significantly increase the bifidobacterial or lactobacilli populations, or decrease the populations of C difficile, E coli, or Bacteroides.

CONCLUSIONS

The milk-based formula used in this study supported bifidobacterial and lactobacilli populations comparable with the human milk group; however, this formula did not suppress E coli or C difficile as effectively as human milk.

New insights in gut microbiota establishment in healthy breast fed neonates

The establishment of a pioneer gut microbiota is increasingly recognized as a crucial stage in neonatal development influencing health throughout life. While current knowledge is mainly based on either culture or molecular analysis of feces, we opted for a comprehensive approach complementing culture with state-of-the-art molecular methods. The bacterial composition in feces from seven healthy vaginally-delivered, breast-fed neonates was analyzed at days 4-6, 9-14 and 25-30 postnatal, using culture, 16S rRNA gene sequencing of isolates, quantitative PCR and pyrosequencing. Anaerobes outnumbered facultative anaerobes in all seven neonates within the first days of life, owing to high levels of Bifidobacterium and unexpectedly also Bacteroides, which were inversely correlated. Four neonates harbored maternal Bacteroides levels, comprising typical adult species, throughout the neonatal period, while in three only subdominant levels were detected. In contrast, the major adult-type butyrate-producing anaerobic populations, Roseburia and Faecalibacterium, remained undetectable during the neonatal period. The presence of Bacteroidetes as pioneer bacteria in the majority of neonates studied demonstrates that adult-type strict anaerobes may reach adult-like population densities within the first week of life. Consequently the switch from facultative to strict anaerobes may occur earlier than previously assumed in breast-fed neonates, and the establishment of the major butyrate-producing populations may be limited by other factors than the absence of anaerobic conditions. The impact of breast milk components on the timing of establishment of anaerobic pioneer bacteria, as well as opportunistic pathogens should be further studied in regard to priming of the gut-associated immune system and consequences on later health.

Hydrolyzed caseinomacropeptide conjugated galactooligosaccharides support the growth and enhance the bile tolerance in Lactobacillus strains

In this study bioactive caseinomacropeptide was conjugated with prebiotic galactooligosaccharides (hCMP:GOS) by Maillard reaction to synthesize value added prebiotic compounds to Lactobacillus strains. Growth study showed the ability of hCMP:GOS to serve as a sole carbon source for Lactobacillus strains. A significant amount of acetate and lactate was detected in cell free culture supernatant by HPLC. It demonstrated the ability of Lactobacillus strains to ferment the hCMP:GOS as a carbon source. In addition, hCMP:GOS grown Lactobacillus cells exhibited enhanced bile tolerance and retained 90% viability. Overall results of this study indicate that the hCMP conjugated GOS can be potential multipurpose prebiotic substrates to enhance the growth and bile tolerance in Lactobacillus strains and serve as a fermentable substrate to produce beneficial metabolites in the host.

Effect of soy flour addition and heat-processing method on nutritional quality and consumer acceptability of cassava complementary porridges

BACKGROUND

The nutritional quality of cassava complementary porridge was improved through extrusion cooking and compositing with either defatted or full fat soy flour (65:35 w/w), and product acceptability by mothers with children of the target population was evaluated.

RESULTS

The protein digestibility-corrected amino acid score (PDCAAS) of extrusion- and conventionally cooked composite porridges was within the recommendations for complementary foods. The kinetics of starch digestibility showed that all porridges had a rapid rate of starch digestibility, but the rate was lower when defatted soy flour was added and lowest when full fat soy flour was added. The formation of amylase-lipid complexes as shown by X-ray diffraction and differential scanning calorimetry can be attributed to the lower digestibility of extrusion-cooked porridge with full fat soy flour. If fed thrice per day, extrusion-cooked porridge with defatted or full fat soy flour would meet the energy, protein and available lysine requirements of a child aged 6-8 months receiving low or average nutrients from breast milk. All porridges were well received by Mozambican mothers who use cassava as a staple food. The mean scores for sensory liking of all porridges were 3 and above on a five-point hedonic scale.

CONCLUSION

Extrusion-cooked cassava/soy flour porridges have good potential for use as high-energy/high-protein complementary foods and have acceptable sensory properties.

Composition of the early intestinal microbiota: knowledge, knowledge gaps and the use of high-throughput sequencing to address these gaps

The colonization, development and maturation of the newborn gastrointestinal tract that begins immediately at birth and continues for two years, is modulated by numerous factors including mode of delivery, feeding regime, maternal diet/weight, probiotic and prebiotic use and antibiotic exposure pre-, peri- and post-natally. While in the past, culture-based approaches were used to assess the impact of these factors on the gut microbiota, these have now largely been replaced by culture-independent DNA-based approaches and most recently, high-throughput sequencing-based forms thereof. The aim of this review is to summarize recent research into the modulatory factors that impact on the acquisition and development of the infant gut microbiota, to outline the knowledge recently gained through the use of culture-independent techniques and, in particular, highlight advances in high-throughput sequencing and how these technologies have, and will continue to, fill gaps in our knowledge with respect to the human intestinal microbiota.

Microbial composition and in vitro fermentation patterns of human milk oligosaccharides and prebiotics differ between formula-fed and sow-reared piglets

The microbial composition and in vitro fermentation characteristics of human milk oligosaccharides (HMO), lacto-N-neotetraose (LNnT), a 2:1 mixture of polydextrose (PDX) and galactooligosaccharides (GOS), and short-chain fructooligosaccharides (scFOS) by pooled ascending colonic microbiota from 9- and 17-d-old formula-fed (FF) and sow-reared (SR) piglets were assessed. pH change and gas, SCFA, and lactate production were determined after 0, 2, 4, 8, and 12 h of incubation. In most donor groups, the pH change was greater for scFOS fermentation and lower for PDX/GOS than for other substrates. LNnT fermentation produced larger amounts of gas, total SCFA, acetate, and butyrate than did the other substrates, whereas HMO and scFOS produced higher amounts of propionate and lactate, respectively. In general, pH change, total SCFA, acetate, and propionate production were greater in pooled inoculum from FF and 9-d-old piglets, whereas SR-derived inoculum produced higher amounts of butyrate and lactate after 4 h fermentation. Gut microbiota were assessed by 16S ribosomal RNA V3 gene denaturing gradient gel electrophoresis analysis and real-time qPCR. Microbial structures differed among the 4 groups before fermentation, with higher counts of Bifidobacterium in SR piglets and higher counts of Clostridium cluster IV, XIVa, and Bacteroides vulgatus in FF piglets. Lactobacillus counts were higher in 9-d-old piglets than in 17-d-old piglets, regardless of diet. Bifidobacterium, Bacteroides, and clostridial species increased after 8 and 12 h fermentation on most substrates. In summary, piglet diet and age affect gut microbiota, leading to different fermentation patterns. HMO have potential prebiotic effects due to their effects on SCFA production and microbial modulation.