Developmental changes of gut microflora and enzyme activity in rat pups exposed to fat-rich diet

Effects of diet and antibiotics on anastomotic healing: A mouse model study with varied dietary fiber and fat, and pre-operative antibiotics

INTRODUCTION

This study investigated the separate impacts of diet and pre-operative antibiotics on gut microbiome and colonic anastomotic healing using a mouse model.

METHODS

Male C57BL/6J mice were fed either low-fat-high-fibre (SD) or high-fat-low-fiber (WD) groups for 6 weeks, then further received either pre-operative antibiotics or a control sham before a colonic anastomotic procedure was performed. After 7 days, the anastomosis was assessed and microbiota composition and biodiversity were analyzed in anastomotic tissue and stool.

RESULTS

WD-fed mice had shorter survival (5.2 ​± ​2.3 vs. 6.9 ​± ​2.3 days, p ​= ​0.022), increased weight loss (5.55 ​± ​3.80g vs. 2.65 ​± ​2.36g, p ​= ​0.03), and reduced biodiversity compared to SD-fed mice. Pre-operative antibiotics improved anastomotic healing scores (1.33 ​± ​0.65 vs. 2.08 ​± ​0.79, p ​= ​0.02) and reduced Enterococcus faecalis growth in tissue and stool (p ​= ​0.02, p ​= ​0.02). Improved anastomotic healing correlated with lower Enterococcus abundance (p ​= ​0.04) and higher collagen III and IV levels (p ​= ​0.01, 0.04) in anastomotic tissue.

CONCLUSION

SD promotes enhanced post-operative recovery and increased microbiome biodiversity, while pre-operative antibiotics enhance anastomotic healing by suppressing Enterococcus faecalis growth, mitigating collagen III/IV degradation.

Pancreastatin deteriorates hepatic lipid metabolism via elevating fetuin B in ovariectomized rats

Hepatic steatosis is an important mstetabolic complication in women encountering postmenopausal phase of life. Pancreastatin (PST), has previously been investigated in diabetic and insulin resistant rodents. The present study highlighted the role of PST in ovariectomized rats. Female SD rats were ovariectomized and subsequently fed high fructose diet for 12 weeks. PST inhibitor peptide was intraperitoneally administered for 14 days and further examined for insulin resistance, glucose intolerance development, body mass composition, lipid profile detection and hepatic fibrosis. Gut microbial alterations has also been investigated. Results showed development of glucose intolerance in high fructose fed ovariectomized rats with reduced level of reproductive hormones including estradiol and progesterone. Enhanced lipid production was detected in these rats as they showed increased triglycerides, lipid accumulation in liver tissue (determined by HE staining, Oil Red O staining, Nile Red staining). Sirius Red and Masson's trichome analysis depicted positive results for fibrosis development. We also found gut microbiota alterations in fecal samples of these rats. Furthermore, PST inhibition decreased the expression of hepatic Fetuin B and resumed gut microbial diversity. PST deregulates hepatic lipid metabolism which leads to altered expression of Fetuin B in liver and gut dysbiosis in postmenopausal rats.

Effects of Selenium as a Dietary Source on Performance, Inflammation, Cell Damage, and Reproduction of Livestock Induced by Heat Stress: A Review

Heat stress as a result of global warming has harmful consequences for livestock and is thus becoming an urgent issue for animal husbandry worldwide. Ruminants, growing pigs, and poultry are very susceptible to heat stress because of their fast growth, rapid metabolism, high production levels, and sensitivity to temperature. Heat stress compromises the efficiency of animal husbandry by affecting performance, gastrointestinal health, reproductive physiology, and causing cell damage. Selenium (Se) is an essential nutritional trace element for livestock production, which acts as a structural component in at least 25 selenoproteins (SELs); it is involved in thyroid hormone synthesis, and plays a key role in the antioxidant defense system. Dietary Se supplementation has been confirmed to support gastrointestinal health, production performance, and reproductive physiology under conditions of heat stress. The underlying mechanisms include the regulation of nutrient digestibility influenced by gastrointestinal microorganisms, antioxidant status, and immunocompetence. Moreover, heat stress damage to the gastrointestinal and mammary barrier is closely related to cell physiological functions, such as the fluidity and stability of cellular membranes, and the inhibition of receptors as well as transmembrane transport protein function. Se also plays an important role in inhibiting cell apoptosis and reducing cell inflammatory response induced by heat stress. This review highlights the progress of research regarding the dietary supplementation of Se in the mitigation of heat stress, addressing its mechanism and explaining the effect of Se on cell damage caused by heat stress, in order to provide a theoretical reference for the use of Se to mitigate heat stress in livestock.

Dietary fatty acids in gut health: Absorption, metabolism and function

In biological responses, fatty acids (FA) are absorbed and metabolized in the form of substrates for energy production. The molecular structures (number of double bonds and chain length) and composition of dietary FA impact digestion, absorption and metabolism, and the biological roles of FA. Recently, increasing evidence indicates that FA are essentially utilized as an energy source and are signaling molecules that exert physiological activity of gut microbiota and immune responses. In addition, FA could serve as natural ligands for orphan G protein-coupled receptors (GPCR), also called free fatty acid receptors (FFAR), which intertwine metabolic and immune systems via multiple mechanisms. The present review explores the recent findings on FA absorption and its impact on gut health, particularly addressing the mechanism by which dietary FA potentially influences intestinal microbiota and epithelial functions. Also, this work attempts to uncover research ideas for devising future strategies for manipulating the composition of dietary FA to regulate gut health and support a normal immune system for metabolic and immune disorders.

Dietary Betaine Addition Alters Carcass Traits, Meat Quality, and Nitrogen Metabolism of Bama Mini-Pigs

Betaine is widely used as feed additives in animal husbandry as it can cause many benefits such as improving antioxidant ability, growth performance, and carcass traits. However, there are limited studies about the effects of betaine on the Bama mini-pigs. The present study was conducted to evaluate the effects of dietary betaine on carcass traits, meat quality, and nitrogen metabolism of pigs. Twenty-six pregnant Bama mini-pigs and then 104 weaned piglets were assigned for experimental treatments. The plasma and muscle samples were collected at 65-, 95-, and 125-d-old pigs, respectively. The results showed that betaine addition in the sow-offspring diets increased the lean meat rate in the 65-d-old pigs, whereas carcass weight, carcass yield, and loin-eye area were increased in the 95-d-old pigs, and carcass weight and backfat thickness in the 125-d-old pigs. Dietary betaine addition in the sow-offspring diets increased the contents of plasma Asp of 65-d-old, Met of 95- and 125-d-old, and Sar of 125-d-old pigs. Moreover, betaine addition increased the contents of Met, His, Ile, and Phe in Longissimus thoracis et lumborum, whereas those contents were decreased in biceps femoris and psoas major muscles at different stages. Betaine addition in the sow and piglets' diets regulated the muscle fiber-type and myogenic regulatory gene expressions. In summary, betaine addition in the sow and sow-offspring diets could improve the carcass traits and meat quality by altering the plasma biochemical parameters, amino acid composition, and gene expressions of skeletal muscle.

Potential Use of Gut Microbiota Composition as a Biomarker of Heat Stress in Monogastric Species: A Review

Simple Summary

Heat stress is a significant environmental challenge faced by food animal production worldwide because of its adverse effects on animal performance and productivity. Trillions of microorganisms living in the gut are essential for host health by participating in various digestive, immune, and metabolic activities. At the same time, they are known to be sensitive to changes in the surrounding environment. The present review summarizes current research progress of how the gut microbial community responds to elevated ambient heat in monogastric animal species and discusses the use of the gut microbiota composition as a potential indicator for heat stress.

Abstract

Heat stress is a current challenge for livestock production, and its impact could dramatically increase if global temperatures continue to climb. Exposure of agricultural animals to high ambient temperatures and humidity would lead to substantial economic losses because it compromises animal performance, productivity, health, and welfare. The gut microbiota plays essential roles in nutrient absorption, energy balance, and immune defenses through profound symbiotic interactions with the host. The homeostasis of those diverse gut microorganisms is critical for the host’s overall health and welfare status and also is sensitive to environmental stressors, like heat stress, reflected in altered composition and functionality. This article aims to summarize the research progress on the interactions between heat stress and gut microbiome and discuss the potential use of the gut microbiota composition as a biomarker of heat stress in monogastric animal species. A comprehensive understanding of the gut microbiota’s role in responding to or regulating physiological activities induced by heat stress would contribute to developing mitigation strategies.

Recognizing the Benefits of Pre-/Probiotics in Metabolic Syndrome and Type 2 Diabetes Mellitus Considering the Influence of Akkermansia muciniphila as a Key Gut Bacterium

Metabolic syndrome (MetS) and type 2 diabetes mellitus (T2DM) are diseases that can be influenced by the structure of gut microbiota, whose improvement is often neglected in metabolic pathology. This review highlights the following main aspects: the relationship between probiotics/gut microbes with the pathogenesis of MetS, the particular positive roles of Akkermansia muciniphila supplementation in the onset of MetS, and the interaction between dietary polyphenols (prebiotics) with gut microbiota. Therefore, an extensive and in-depth analysis of the often-neglected correlation between gut microbiota and chronic metabolic diseases was conducted, considering that this topic continues to fascinate and stimulate researchers through the discovery of novel strains and their beneficial properties.

Disturbances in Microbial and Metabolic Communication across the Gut-Liver Axis Induced by a Dioxin-like Pollutant: An Integrated Metagenomics and Metabolomics Analysis

To determine how the aryl hydrocarbon receptor (AhR) signaling acts along the gut-liver axis, we employed an integrated metagenomic and metabolomic approach to comprehensively profile the microbial and metabolic networks. Adult zebrafish were exposed to a model agonist of the AhR: polychlorinated biphenyl (PCB) 126. The metagenomic analysis showed that PCB126 suppressed microbial activities related to primary bile acid metabolism in male intestines. Accordingly, a suite of primary bile acids consistently showed higher concentrations, suggesting that bacterial conversion of primary bile acids was blocked. PCB126 also disturbed bacterial metabolism of bile acids in female intestines, as revealed by higher concentrations of primary bile acids (e.g., chenodeoxycholic acid) and activation of the nuclear farnesoid X receptor signaling. In addition, PCB126 exposure impaired the metabolism of various essential vitamins (e.g., retinol, vitamin B6, and folate). Degradation of vitamin B6 by bacterial enzymes was inhibited in male intestines, resulting in its intestinal accumulation. However, PCB126 suppressed the bacterial metabolism of vitamins in female intestines, causing systematic deficiency of essential vitamins. Overall, we found that PCB126 exposure dysregulated gut microbial activities, consequently interrupting bile acid and vitamin metabolism along the gut-liver axis. The findings provided an insight of the AhR action in microbe-host metabolic communication related to PCBs.

Jejunum: The understudied meeting place of dietary lipids and the microbiota

Although the jejunum is the main intestinal compartment responsible for lipid digestion and absorption, most of the studies assessing the impact of dietary lipids on the intestinal microbiota have been performed in the ileum, colon and faeces. This lack of interest in the jejunum is due to the much lower number of microbes present in this intestinal region and to the difficulty in accessing its lumen, which requires invasive methods. Recently, several recent publications highlighted that the whole jejunal microbiota or specific bacterial members are able to modulate lipid absorption and metabolism in enterocytes. This information reveals new strategies in the development of bacterial- and metabolite-based therapeutic interventions or nutraceutical recommendations to treat or prevent metabolic-related disorders, including obesity, cardiovascular diseases and malnutrition. This review is strictly focused on the following triad: dietary lipids, the jejunal epithelium and the jejunal microbiota. First, we will describe each member of the triad: the structure and functions of the jejunum, the composition of the jejunal microbiota, and dietary lipid handling by enterocytes and by microorganisms. Then, we will present the mechanisms leading to lipid malabsorption in small intestinal bacterial overgrowth (SIBO), a disease in which the jejunal microbiota is altered and which highlights the strong interactions among this triad. We will finally review the recent literature about the interactions among members of the triad, which should encourage research teams to further explore the mechanisms by which specific microbial strains or metabolites, alone or in concert, can mediate, control or modulate lipid absorption in the jejunum.

Effects of acute heat stress on intestinal microbiota in grow-finishing pigs, and associations with feed intake and serum profile

AIMS

This study was conducted to assess the effects of acute heat stress (HS) on intestinal microbiota, and the associations with the changes in feed intake (FI) and serum profile.

METHODS AND RESULTS

Twenty four individually housed pigs (Duroc × Large White × Landrace, 30 ± 1 kg body weight) were randomly assigned to receive one of three treatments (8 pigs/treatment): (i) thermal neutral (TN) conditions (25 ± 1°C), (ii) HS conditions (35 ± 1°C), (iii) pair-feeding (PF) with HS under TN conditions. After 24-h treatment, pigs were monitored to assess FI, and samples of serum and faeces were collected to investigate serum profile, microbial composition and short chain fatty acids (SCFAs). The results showed that HS decreased (P < 0·05) FI compared with the TN group. Compared with TN group, HS changed the serum profile by affecting biochemical parameters and hormones related with energy metabolism and stress response; immune indicators were also altered in HS group. Most of changes in serum profile were independent of FI reduction. Additionally, HS shifted the diversity and composition of faecal microbial community by increasing (P < 0·05) Proteobacteria and decreasing (P < 0·05) Bacteroidetes. Moreover, HS decreased (P < 0·05) the concentrations of propionate, butyrate, valerate, iso-valerate and total SCFAs in faeces in an FI-independent manner. Furthermore, the Spearman correlation analysis implied that changes of serum profile have potential correlation with alterations of faecal microbiota and their SCFAs metabolites in acute HS-treated grow-finishing pigs.

CONCLUSIONS

Metabolism disorders caused by 24-h acute HS associated with changes of faecal microbiota and their SCFAs metabolites in an FI-independent manner in grow-finishing pigs.

SIGNIFICANCE AND IMPACT OF THE STUDY

These results give us a new insight of the intestinal damage caused by acute HS and the underlying mechanisms.

Associations of Gut Microbiota With Heat Stress-Induced Changes of Growth, Fat Deposition, Intestinal Morphology, and Antioxidant Capacity in Ducks

Accumulating evidence has revealed the dysbiosis of gut/fecal microbiota induced by heat stress (HS) in mammals and poultry. However, the effects of HS on microbiota communities in different intestinal segments of Cherry-Valley ducks (a widely used meat-type breed) and their potential associations with growth performances, fat deposition, intestinal morphology, and antioxidant capacity have not been well evaluated yet. In this study, room temperature (RT) of 25°C was considered as control, and RT at 32°C for 8 h per day was set as the HS treatment. After 3 weeks, the intestinal contents of jejunum, ileum, and cecum were harvested to investigate the microbiota composition variations by 16S ribosomal RNA amplicon sequencing. And the weight gain, adipose indices, intestinal morphology, and a certain number of serum biochemical parameters were also measured and analyzed. The results showed the microbial species at different levels differentially enriched in duck jejunum and cecum under HS, while no significant data were observed in ileum. HS also caused the intestinal morphological changes (villus height and the ratio of villus height to crypt depth) and the reductions of growth speed (daily gain), levels of serum triglyceride (TG) and total cholesterol, and antioxidant activity (higher malondialdehyde (MDA) content and lower total antioxidant). The higher abdominal fat content and serum glucose level were also observed in HS ducks. The Spearman correlation analysis indicated that in jejunum the phyla Firmicutes and Proteobacteria were associated with average daily gain, feed/gain, serum TG and MDA levels, and villus height/crypt depth (P < 0.05). The phylum Firmicutes and genus Acinetobacter were significantly associated with fat deposition and serum glucose level (P < 0.05). The genus Lactobacillus was positively associated with serum total antioxidant (P < 0.05), while some other microbial species were found negatively associated, including order Pseudomonadales, genera Acinetobacter, and unidentified_Mitochondria. However, no significant correlations were observed in cecum. These findings imply the potential roles of duck gut microbiota in the intestinal injuries, fat deposition, and reductions of growth speed and antioxidant capacity caused by HS, although the molecular mechanisms requires further investigation.

Phytoestrogens and the Intestinal Microbiome

The microflora of the digestive tract is composed of a unique set of bacteria, yeasts, viruses and other microorganisms, generally known as the microbiome. The microbiome exhibits considerable inter-individual variability, with up to two-thirds of the microflora differing between individuals. Because of this, the variable intestinal microflora is responsible for many differences in metabolic, hormonal and immunological processes in humans and animals. Significant differences have been observed in the metabolism of phytoestrogens, naturally occurring substances that possess estrogenic or anti-estrogenic activity. These substances occur predominately in legumes, especially in soy and many soy products. Because of their effects, phytoestrogens are used as an alternative therapy for menopausal disorders and benign prostate hyperplasia. In connection with the worldwide expansion of soy products as part of healthy lifestyles including vegetarianism and veganism, phytoestrogens have become a regular part of everyday life. The activity of phytoestrogens is strongly dependent on the microbiome. Their metabolites have stronger estrogenic activity than the natural substances themselves, and because of the variability in microbiomes, there are large differences in the effects of phytoestrogens among individuals.

Effect of dietary fat to starch content on fecal microbiota composition and activity in dogs1

Dietary fat is known to modulate the hindgut microbiota in rodents; however, there is no clear evidence on the impact of high-fat diets on canine gut microbiota. The purpose of this study was to investigate the effect of feeding of diets differing in the amount of ME provided by fat and starch on the composition and activity of canine fecal microbiota. Twelve adult (3 to 7 yr of age) spayed Beagle dogs received a low-fat-high-starch diet (LF-HS; approximately 23%, 42%, and 25% ME provided by fat, starch, and CP, respectively) and a high-fat-low-starch diet (HF-LS; approximately 43%, 22%, and 25% ME provided by fat, starch, and CP, respectively) following a 2-period crossover arrangement. The higher amount of fat in the HF-LS diet was provided by lard, whereas the higher amount of starch in the LF-HS diet was provided primarily by maize and broken rice. Each period lasted 7 wk and included 4 wk for diet adaptation. Dogs were fed to meet their daily energy requirements (set at 480 kJ ME/kg BW0.75). Fecal samples were collected on weeks 5 and 6 of each period for the analysis of bacterial richness, diversity, and composition [by Ion-Torrent next-generation sequencing], bile acids, ammonia, and VFA. Additional fecal samples were collected from four dogs per diet and period to use as inocula for in vitro fermentation using xylan and pectin as substrates. Gas production was measured at 2, 4, 6, 9, 12, and 24 h of incubation. On week 7, blood samples were collected at 0- and 180-min postfeeding for the analysis of bacterial lipopolysaccharide (LPS). Feeding the HF-LS diet led to a greater (P < 0.05) fecal bile acid concentration compared with the LF-HS diet. Bacterial richness and diversity did not differ between diets (P > 0.10). However, dogs showed a lower relative abundance of Prevotella (P < 0.01), Solobacterium (P < 0.05), and Coprobacillus (P ˂ 0.05) when fed of the HF-LS diet. Fecal ammonia and VFA contents were not affected by diet (P > 0.10). Relative to the LF-HS diet, in vitro fermentation of xylan using feces of dogs fed the HF-LS diet produced less gas at 6 h (P < 0.01) and 9 h (P < 0.05). Blood LPS did not increase at 180-min postfeeding with either diet (P < 0.10). These findings indicate that feeding a HF-LS diet to dogs does not affect bacterial diversity or fermentative end products in feces, but may have a negative impact on Prevotella and xylan fermentation.

Association analysis of dietary habits with gut microbiota of a native Chinese community

Environmental exposure, including a high-fat diet (HFD), contributes to the high prevalence of colorectal cancer by changing the composition of the intestinal microbiota. However, data examining the interaction between dietary habits and intestinal microbiota of the Chinese population is sparse. We assessed dietary habits using a food frequency questionnaire (FFQ) in native Chinese community volunteers. Based on the dietary fat content determined using the FFQ, the volunteers were divided into HFD group (≥40% of dietary calories came from fat) or low-fat diet (LFD) group (<40%). Fecal and colonic mucosal microbiota composition was determined using 16S rDNA based methods. In stool matter of HFD group, Prevotella and Abiotrophia showed significantly higher abundance, whereas unclassified genus of S24-7 (family level) of Bacteroidetes, Gemmiger, Akkermansia and Rothia were less abundant. On colonic mucosal tissue testing, unclassified genus of S24-7 showed significantly higher abundance while Bacteroides, Coprobacter, Abiotrophia, and Asteroleplasma were less abundant in HFD group. A high fat and low fiber diet in a native Chinese community may partially contribute to changes of intestinal microbiota composition that may potentially favor the onset and progression of gastrointestinal disorders including inflammatory, hyperplastic and neoplastic diseases.

High-Fat Diet Induces Dysbiosis of Gastric Microbiota Prior to Gut Microbiota in Association With Metabolic Disorders in Mice

Accumulating evidence suggests that high-fat diet (HFD) induced metabolic disorders are associated with dysbiosis of gut microbiota. However, no study has explored the effect of HFD on the gastric microbiota. This study established the HFD animal model to determine the impact of HFD on the gastric microbiota and its relationship with the alterations of gut microbiota. A total of 40 male C57BL/6 mice were randomly allocated to receive a standard chow diet (CD) or HFD for 12 weeks (12CD group and 12HFD group) and 24 weeks (24CD group and 24HFD group) (n = 10 mice per group). Body weight and length were measured and Lee's index was calculated at different time points. The insulin sensitivity and serum levels of metabolic parameters including blood glucose, insulin and lipid were also evaluated. The gastric mucosa and fecal microbiota of mice were characterized by 16S rRNA gene sequencing. The body weight was much heavier and the Lee's index was higher in 24HFD group than 12HFD. The insulin resistance and serum level of lipid were increased in 24HFD group compared to 12HFD, indicating the aggravation of metabolic disorders as HFD went on. 16S rRNA gene sequencing showed dysbiosis of gastric microbiota with decreased community diversity while no significant alteration in gut microbiota after 12 weeks of HFD. The phyla Firmicutes and Proteobacteria tended to increase whereas Bacteroidetes and Verrucomicrobia decrease in the gastric microbiota of 12HFD mice compared to 12CD. Moreover, a remarkable reduction of bacteria especially Akkermansia muciniphila, which has beneficial effects on host metabolism, was observed firstly in the stomach of 12HFD group and then in the gut of 24HFD group, indicating the earlier alterations of microbiota in stomach than gut after HFD. We also found structural segregation of microbiota in the stomach as well as gut between 12HFD and 24HFD group, which is accompanied by the aggregation of metabolic disorders. These data suggest that HFD affects not only gut microbiota but also gastric microbiota and the disruption of microbial ecosystem in the digestive tract may play a part in the development and progression of metabolic diseases although molecular mechanism requires further investigation.

Amino acid supplements and metabolic health: a potential interplay between intestinal microbiota and systems control

Dietary supplementation of essential amino acids (EAAs) has been shown to promote healthspan. EAAs regulate, in fact, glucose and lipid metabolism and energy balance, increase mitochondrial biogenesis, and maintain immune homeostasis. Basic science and epidemiological results indicate that dietary macronutrient composition affects healthspan through multiple and integrated mechanisms, and their effects are closely related to the metabolic status to which they act. In particular, EAA supplementation can trigger different and even opposite effects depending on the catabolic and anabolic states of the organisms. Among others, gut-associated microbial communities (referred to as gut microbiota) emerged as a major regulator of the host metabolism. Diet and host health influence gut microbiota, and composition of gut microbiota, in turn, controls many aspects of host health, including nutrient metabolism, resistance to infection, and immune signals. Altered communication between the innate immune system and the gut microbiota might contribute to complex diseases. Furthermore, gut microbiota and its impact to host health change largely during different life phases such as lactation, weaning, and aging. Here we will review the accumulating body of knowledge on the impact of dietary EAA supplementation on the host metabolic health and healthspan from a holistic perspective. Moreover, we will focus on the current efforts to establish causal relationships among dietary EAAs, gut microbiota, and health during human development.

Early-life origin of intestinal inflammatory disorders

A growing body of evidence supports the concept of perinatal programming through which the perinatal environment affects the development of the fetus and infant, thereby modifying the risk profile for disease later in life. Increasing attention is focusing on the role of the early environment in the development of chronic intestinal disorders. Epidemiological studies have highlighted the link between perinatal factors, such as breastfeeding, cesarean delivery, and antibiotic use, and an increased risk for inflammatory bowel disease and/or celiac disease. These links are consistent with the concept of perinatal programming of intestinal inflammatory disorders. Animal models have shown that the early-life environment affects the development of the gastrointestinal tract, but further experimental studies are needed to confirm the long-term effects of the perinatal environment on susceptibility to chronic intestinal disorders later in life. Changes in the development and composition of the intestinal microbiota as well as epigenetic changes are emerging as key mechanisms through which the perinatal environment determines susceptibility to intestinal inflammatory disorders.

Effect of Pre- and Post-Weaning High-Fat Dietary Manipulation on Intestinal Microflora and Alkaline Phosphatase Activity in Male Rats

We investigated the impact of a high-fat (HF) diet during pre- and post-weaning periods on the intestinal microbiota and alkaline phosphatase (AP) activity in male rats. Nutrition from birth was influenced by feeding rat dams with either a standard or HF diet. After weaning male pups nursed by control dams continued on a standard diet (CC) or HF diet (C→HF), while offspring nursed by HF dams continued on HF diet (HF) or standard diet (HF→C). The numbers of Bacteroides/Prevotella (BAC) and Lactobacillus/Enterococcus (LAB) in the gut were determined by FISH technique. HF pups displayed enhanced adiposity and increased AP activity (19 %), as well as higher LAB (P<0.001) and lower numbers of BAC (P<0.001) in the jejunum and colon than controls. In HF→C rats, post-weaning lower fat intake resulted in decreased fat deposition accompanied by reduced AP activity (20 %) compared to HF rats. Composition of the intestinal microbiota in these rats was not influenced. In contrast, in comparison with controls, C→HF rats displayed higher LAB (P<0.001) and lower BAC (P<0.001) together with increased adiposity and AP activity (14 %). These results indicate that consumption of diet with different fat content could modulate gut microbial/functional conditions depending on the period when the nutritional manipulation occurs.

The combined effect of Sango sprout juice and caloric restriction on metabolic disorders and gut microbiota composition in an obesity model

The main purpose of this study was to compare the benefits of SSJ supplementation in obese rats with those achieved only by switching the alimentary regimen from high-fat (HFD) to the regular one (RD) in liver, ileum and prostate. Furthermore, changings in caecal chime microbiota were investigated. SSJ was administered to rats in combination with a RD (HFD-RD + SSJ). The switch from HFD to RD led to a weight loss of almost 9.8 g, and the total cholesterol was found to be significantly lower. In the HFD-RD + SSJ group, all values were improved compared with the HFD control, and the weight decrement was higher (-23.29 g) with respect to HFD-RD. HFD led to a widespread increment of oxidative stress (OS) markers in liver, ileum and prostate. SSJ has shown to improve the results achieved by the suspension of HFD and it has proven effective wherever the only switch in diet regimen failed.

Helicobacter pylori Infection Aggravates Diet-induced Insulin Resistance in Association With Gut Microbiota of Mice

Emerging evidence suggests that Helicobacter pylori infection is associated with insulin resistance (IR) yet the underlying mechanisms are still obscure. The vital role of gut microbiota in triggering IR has been increasingly reported, however, no study has explored the correlation of gut microbiota and H. pylori-associated IR. Using H. pylori-infected mice model fed different diet structures, we demonstrated that H. pylori infection significantly aggravated high-fat diet (HFD)-induced metabolic disorders at the early stage, the extent of which was close to the effect of long-term HFD. Interestingly, we observed dynamic alterations in gut microbiota that were consistent with the changes in the metabolic phenotype induced by H. pylori and HFD. There may be an interaction among H. pylori, diet and gut microbiota, which dysregulates the host metabolic homeostasis, and treatment of H. pylori may be beneficial to the patients with impaired glucose tolerance in addition to diet control.

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H. pylori infection aggravates high-fat diet induced metabolic disorders at the early stage in C57BL/6 mice.

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H. pylori infection in high-fat diet induces dynamic alterations of gut microbiota consistent with the metabolic phynotype.

H. pylori is one of the most common human bacterial pathogens which causes gastric disorders. Epidemiological studies show that its infection is associated with insulin resistance although the mechanism is obscure. Our study demonstrates that H. pylori infection significantly aggravates high-fat diet induced metabolic disorders at the early stage, accompanied by dramatic alterations of gut microbiota. Moreover, the changes of gut microbiota are consistent with the metabolic phynotype, indicating an interaction among H. pylori, diet and gut microbiota. Thus, the treatment of H. pylori may be beneficial to the patients with impaired glucose tolerance in addition to diet control.

Comprehensive insights into microcystin-LR effects on hepatic lipid metabolism using cross-omics technologies

Microcystin-LR (MC-LR) can induce hepatic tissue damages and molecular toxicities, but its effects on lipid metabolism remain unknown. This study investigated the effects of MC-LR exposure on mice lipid metabolism and uncovered the underlying mechanism through metabonomic, transcriptomic and metagenomic analyses after administration of mice with MC-LR by gavage for 28 d. Increased liver weight and abdominal fat weight, and evident hepatic lipid vacuoles accumulation were observed in the mice fed with 0.2mg/kg/d MC-LR. Serum nuclear magnetic resonance analysis showed that MC-LR treatment altered the levels of serum metabolites including triglyceride, unsaturated fatty acid (UFA) and very low density lipoprotein. Digital Gene Expression technology was used to reveal differential expression of hepatic transcriptomes, demonstrating that MC-LR treatment disturbed hepatic UFA biosynthesis and activated peroxisome proliferator-activated receptor (PPAR) signaling pathways via Pparγ, Fabp1 and Fabp2 over-expression. Metagenomic analyses of gut microbiota revealed that MC-LR exposure also increased abundant ratio of Firmicutes vs. Bacteroidetes in gut and altered biosynthetic pathways of various microbial metabolic and pro-inflammatory molecules. In conclusion, oral MC-LR exposure can induce hepatic lipid metabolism disorder mediated by UFA biosynthesis and PPAR activation, and gut microbial community shift may play an important role in the metabolic disturbance.

Relationship between small intestinal microbiota and bowel and metabolic diseases

Microbiota plays a vital role in human health and diseases. Colonic microbiota has been deeply studied because it is abundant and easy to get. The small intestine is the main place where most nutrients are digested and absorbed, and the microbiota which dwells in the small intestine has also profound effects on the host. As it is difficult to obtain samples from the small intestine, small intestinal microbiota composition is seldom reported. A few recent studies show that a significant distinction exists in microbiota between the small intestine and colon. The small intestinal microbiota participates in energy storage, intestinal endocrine function and immune maturation of the host. Therefore, more and more studies are focusing on the small intestinal microbiota. This paper reviews recent advances in understanding the relationship between small intestinal microbiota and related diseases.

Evaluation of feed grade sodium bisulfate impact on gastrointestinal tract microbiota ecology in broilers via a pyrosequencing platform

The gastrointestinal microbial community in broiler chickens consists of many different species of bacteria, and the overall microbiota can vary from bird to bird. To control pathogenic bacteria in broilers and improve gut health, numerous potential dietary amendments have been used. In this study, we used a pyrosequencing platform to evaluate the effect of sodium bisulfate on microbiota of the crop, cecum, and ileum of broiler chickens grown over several weeks. The diversity information in each digestive organ sample exhibited considerable variation and was clearly separable, suggesting distinct bacterial populations. Although no apparent microbial clustering occurred between the control and the dietary treatments, we did observe shifts in overall microbiota populations in the crop, ileum, and ceca as well as changes in specific microorganisms such as Bacteroides, Clostridium, and Lactobacillus species that were identified as birds became older.

Correlations of Gut Microbial Community Shift with Hepatic Damage and Growth Inhibition of Carassius auratus Induced by Pentachlorophenol Exposure

Goldfish (Carassius auratus) were exposed to 0-100 μg/L pentachlorophenol (PCP) for 28 days to investigate the correlations of fish gut microbial community shift with the induced toxicological effects. PCP exposure caused accumulation of PCP in the fish intestinal tract in a time- and dose-dependent manner, while hepatic PCP reached the maximal level after a 21 day exposure. Under the relatively higher PCP stress, the fish body weight and liver weight were reduced and hepatic CAT and SOD activities were inhibited, demonstrating negative correlations with the PCP levels in liver and gut content (R < -0.5 and P < 0.05 each). Pyrosequencing of the 16S rRNA gene indicated that PCP exposure increased the abundance of Bacteroidetes in the fish gut. Within the Bacteroidetes phylum, the Bacteroides genus had the highest abundance, which was significantly correlated with PCP exposure dosage and duration (R > 0.5 and P < 0.05 each). Bioinformatic analysis revealed that Bacteroides showed quantitatively negative correlations with Chryseobacterium, Microbacterium, Arthrobacter, and Legionella in the fish gut, and the Bacteroidetes abundance, Bacteroides abundance, and Firmicutes/Bacteroidetes ratio played crucial roles in the reduction of body weight and liver weight under PCP stress. The results may extend our knowledge regarding the roles of gut microbiota in ecotoxicology.

Lean rats gained more body weight than obese ones from a high-fibre diet

There is controversy over previous findings that a high ratio of Firmicutes to Bacteriodetes helps obese animals harvest energy from the diet. To further investigate the relationship between microbial composition and energy harvest, microbial adaptation to diet and time should be considered. In this study, lean and obese rats were successfully induced with low-fat and high-fat diets. An 8-week high soyabean fibre (HSF)-containing diet was then fed to investigate the interaction between the diet and the rats’ gut microbiota, as well as their influence on rats’ growth. Rats’ body weight (BW) was recorded weekly; their plasma lipids and their gut microbiota at week 11, 15 and 19 were analysed. After the consumption of the HSF diet, BW of lean rats increased significantly (P<0·05), but no significant alteration in BW was found in obese rats. The average content of plasma cholesterol was lowered and that of TAG was upgraded in both the groups when fed the HSF diet. There was no significant difference observed at each period between lean and obese rats. In the group of lean rats, the diversity of gut microbiota was elevated strongly (P<0·01), and bacteria from phylum Firmicutes and Bacteroidetes were both increased largely (P<0·01); however, the bacterial diversity and composition in obese rats were less altered after the HSF diet control. In conclusion, the increased Firmicutes and Bacteriodetes might relate to lean rats’ higher BW gain; ‘obese microbiota’ could not help the hosts harvest more energy from the HSF diet.

Changes in gut microbiota in rats fed a high fat diet correlate with obesity-associated metabolic parameters

The gut microbiota is emerging as a new factor in the development of obesity. Many studies have described changes in microbiota composition in response to obesity and high fat diet (HFD) at the phylum level. In this study we used 16s RNA high throughput sequencing on faecal samples from rats chronically fed HFD or control chow (n = 10 per group, 16 weeks) to investigate changes in gut microbiota composition at the species level. 53.17% dissimilarity between groups was observed at the species level. Lactobacillus intestinalis dominated the microbiota in rats under the chow diet. However this species was considerably less abundant in rats fed HFD (P<0.0001), this being compensated by an increase in abundance of propionate/acetate producing species. To further understand the influence of these species on the development of the obese phenotype, we correlated their abundance with metabolic parameters associated with obesity. Of the taxa contributing the most to dissimilarity between groups, 10 presented significant correlations with at least one of the tested parameters, three of them correlated positively with all metabolic parameters: Phascolarctobacterium, Proteus mirabilis and Veillonellaceae, all propionate/acetate producers. Lactobacillus intestinalis was the only species whose abundance was negatively correlated with change in body weight and fat mass. This species decreased drastically in response to HFD, favouring propionate/acetate producing bacterial species whose abundance was strongly correlated with adiposity and deterioration of metabolic factors. Our observations suggest that these species may play a key role in the development of obesity in response to a HFD.

Effect of repeated fasting/refeeding on obesity development and health complications in rats arising from reduced nest

BACKGROUND

Overnutrition during postnatal life represents a risk factor for later obesity and associated metabolic disorders.

AIM

We investigated the interaction between postnatal and later-life nutrition on body composition, blood pressure and the jejunal enzyme activities in male Sprague-Dawley rats.

METHODS

From birth, we adjusted the number of pups in the nest to 4 (small litters-SL; overfeeding) or to 10 pups (normal litters-NL; controls), and from day 50 until 70, the SL (SL-R) and NL (NL-R) rats were subjected to 1 day fasting and 1 day refeeding cycles (RFR). Their body composition was determined by magnetic resonance imaging, and enzyme activity was assayed histochemically.

RESULTS

At 50 and 70 days, SL rats were found to be overweight (p < 0.001), with higher adiposity (p < 0.001) and blood pressure (p < 0.01). Moreover, despite significantly decreased daily food intake during RFR (SL-R 39 %, NL-R 23 %), higher fat deposition (p < 0.001) and blood pressure (p < 0.05) was detected in SL-R rats. Activity of alkaline phosphatase (AP) functionally involved in lipid absorption was significantly higher in SL than NL rats (p < 0.001) but substantially decreased in RFR groups (SL-R p < 0.001, NL-R p < 0.01). However, despite these enzymatic adaptations to reduced food intake, the SL-R rats displayed significantly higher AP activity in comparison with NL-R rats (p < 0.01) on day 70.

CONCLUSIONS

Our results demonstrate that postnatal overfeeding predisposes the ontogeny of intestinal function, which may promote the probability of obesity risk. Accordingly, in these animals, efficient fat deposition and elevated blood pressure were not diminished in response to dietary restrictions in later life.

The gut microbiota of Colombians differs from that of Americans, Europeans and Asians

BACKGROUND

The composition of the gut microbiota has recently been associated with health and disease, particularly with obesity. Some studies suggested a higher proportion of Firmicutes and a lower proportion of Bacteroidetes in obese compared to lean people; others found discordant patterns. Most studies, however, focused on Americans or Europeans, giving a limited picture of the gut microbiome. To determine the generality of previous observations and expand our knowledge of the human gut microbiota, it is important to replicate studies in overlooked populations. Thus, we describe here, for the first time, the gut microbiota of Colombian adults via the pyrosequencing of the 16S ribosomal DNA (rDNA), comparing it with results obtained in Americans, Europeans, Japanese and South Koreans, and testing the generality of previous observations concerning changes in Firmicutes and Bacteroidetes with increasing body mass index (BMI).

RESULTS

We found that the composition of the gut microbiota of Colombians was significantly different from that of Americans, Europeans and Asians. The geographic origin of the population explained more variance in the composition of this bacterial community than BMI or gender. Concerning changes in Firmicutes and Bacteroidetes with obesity, in Colombians we found a tendency in Firmicutes to diminish with increasing BMI, whereas no change was observed in Bacteroidetes. A similar result was found in Americans. A more detailed inspection of the Colombian dataset revealed that five fiber-degrading bacteria, including Akkermansia, Dialister, Oscillospira, Ruminococcaceae and Clostridiales, became less abundant in obese subjects.

CONCLUSION

We contributed data from unstudied Colombians that showed that the geographic origin of the studied population had a greater impact on the composition of the gut microbiota than BMI or gender. Any strategy aiming to modulate or control obesity via manipulation of this bacterial community should consider this effect.

Jussara (Euterpe edulis Mart.) supplementation during pregnancy and lactation modulates the gene and protein expression of inflammation biomarkers induced by trans-fatty acids in the colon of offspring

Maternal intake of trans-fatty acids (TFAs) in the perinatal period triggers a proinflammatory state in offspring. Anthocyanins contained in fruit are promising modulators of inflammation. This study investigated the effect of Jussara supplementation in the maternal diet on the proinflammatory state of the colon in offspring exposed to perinatal TFAs. On the first day of pregnancy rats were divided into four groups: control diet (C), control diet with 0.5% Jussara supplementation (CJ), diet enriched with hydrogenated vegetable fat, rich in TFAs (T), or T diet supplemented with 0.5% Jussara (TJ) during pregnancy and lactation. We showed that Jussara supplementation in maternal diet (CJ and TJ groups) reduced carcass lipid/protein ratios, serum lipids, glucose, IL-6, TNF-α, gene expression of IL-6R, TNF-αR (P < 0.05), TLR-4 (P < 0.01), and increase Lactobacillus spp. (P < 0.05) in the colon of offspring compared to the T group. The IL-10 (P = 0.035) and IL-10/TNF-α ratio (P < 0.01) was higher in the CJ group than in the T group. The 0.5% Jussara supplementation reverses the adverse effects of perinatal TFAs, improving lipid profiles, glucose levels, body composition, and gut microbiota and reducing low-grade inflammation in the colon of 21-day-old offspring, and could contribute to reducing chronic disease development.

Resistant starch and energy balance: impact on weight loss and maintenance

The obesity epidemic has prompted researchers to find effective weight-loss and maintenance tools. Weight loss and subsequent maintenance are reliant on energy balance--the net difference between energy intake and energy expenditure. Negative energy balance, lower intake than expenditure, results in weight loss whereas positive energy balance, greater intake than expenditure, results in weight gain. Resistant starch has many attributes, which could promote weight loss and/or maintenance including reduced postprandial insulinemia, increased release of gut satiety peptides, increased fat oxidation, lower fat storage in adipocytes, and preservation of lean body mass. Retention of lean body mass during weight loss or maintenance would prevent the decrease in basal metabolic rate and, therefore, the decrease in total energy expenditure, that occurs with weight loss. In addition, the fiber-like properties of resistant starch may increase the thermic effect of food, thereby increasing total energy expenditure. Due to its ability to increase fat oxidation and reduce fat storage in adipocytes, resistant starch has recently been promoted in the popular press as a "weight loss wonder food". This review focuses on data describing the effects of resistant starch on body weight, energy intake, energy expenditure, and body composition to determine if there is sufficient evidence to warrant these claims.

The gut microbiota and obesity: from correlation to causality

The gut microbiota has been linked with chronic diseases such as obesity in humans. However, the demonstration of causality between constituents of the microbiota and specific diseases remains an important challenge in the field. In this Opinion article, using Koch's postulates as a conceptual framework, I explore the chain of causation from alterations in the gut microbiota, particularly of the endotoxin-producing members, to the development of obesity in both rodents and humans. I then propose a strategy for identifying the causative agents of obesity in the human microbiota through a combination of microbiome-wide association studies, mechanistic analysis of host responses and the reproduction of diseases in gnotobiotic animals.

Effect of antibiotic treatment on intestinal microbial and enzymatic development in postnatally overfed obese rats

OBJECTIVE

To investigate the effect of the microbiota-induced changes and early overfeeding after amoxicillin administration (a) in suckling pups via their dams up to 15 days of lactation and (b) in weaned pups on intestinal microbial/functional adaptability and obesity development in male Sprague-Dawley rats.

DESIGN AND METHODS

Postnatal nutrition was elicited by adjusting the number of pups in the nest to 4 (small litters [SLs]) and 10 (normal litters [NLs]), while from days 21 to 40, both groups were fed with a standard diet. The numbers of Bacteroides/Prevotella (BAC) and Lactobacillus/Enterococcus (LAB) in the jejunum and colon were determined by fluorescence in situ hybridization technique, and jejunal alkaline phosphatase (AP), α-glucosidase and aminopeptidase activity was assayed histochemically.

RESULTS

On day 40, the SL in comparison with NL animals displayed excess weight/fat gain accompanied by higher LAB and lower numbers of BAC, and with permanently higher AP activity. Moreover, these acquired changes continued in SL vs. NL rats and were not influenced by antibiotic treatment, which induced significant decrease in the quantity of LAB and BAC.

CONCLUSIONS

These findings highlight the role of early life overfeeding upon the gut microbial/functional ontogeny and allow to distinguish their potential involvement in later risk of obesity.

Is bile acid a determinant of the gut microbiota on a high-fat diet?

Recently, we discovered that bile acid, a main component of bile, is a host factor that regulates the composition of the cecal microbiota in rats. Because bile secretion increases on a high-fat diet and bile acids generally have strong antimicrobial activity, we speculated that bile acids would be a determinant of the gut microbiota in response to a high-fat diet. The observed changes in the rat cecal microbiota triggered by cholic acid (the most abundant bile acid in human biliary bile) administration resemble those found in animals fed high-fat diets. Here, we discuss the rationale for this hypothesis by evaluating reported diet-induced gut microbiota alterations based on the postulate that bile acids worked as an underlying determinant. The identification of host factors determining the gut microbiota greatly contributes to understanding the causal relationships between changes in the gut microbiota and disease development, which remain to be elucidated.

Diet-induced dysbiosis of the intestinal microbiota and the effects on immunity and disease

The gastrointestinal (GI) microbiota is the collection of microbes which reside in the GI tract and represents the largest source of non-self antigens in the human body. The GI tract functions as a major immunological organ as it must maintain tolerance to commensal and dietary antigens while remaining responsive to pathogenic stimuli. If this balance is disrupted, inappropriate inflammatory processes can result, leading to host cell damage and/or autoimmunity. Evidence suggests that the composition of the intestinal microbiota can influence susceptibility to chronic disease of the intestinal tract including ulcerative colitis, Crohn’s disease, celiac disease and irritable bowel syndrome, as well as more systemic diseases such as obesity, type 1 diabetes and type 2 diabetes. Interestingly, a considerable shift in diet has coincided with increased incidence of many of these inflammatory diseases. It was originally believed that the composition of the intestinal microbiota was relatively stable from early childhood; however, recent evidence suggests that diet can cause dysbiosis, an alteration in the composition of the microbiota, which could lead to aberrant immune responses. The role of the microbiota and the potential for diet-induced dysbiosis in inflammatory conditions of the GI tract and systemic diseases will be discussed.

Effects of rice bran oil on the intestinal microbiota and metabolism of isoflavones in adult mice

This study examined the effects of rice bran oil (RBO) on mouse intestinal microbiota and urinary isoflavonoids. Dietary RBO affects intestinal cholesterol absorption. Intestinal microbiota seem to play an important role in isoflavone metabolism. We hypothesized that dietary RBO changes the metabolism of isoflavonoids and intestinal microbiota in mice. Male mice were randomly divided into two groups: those fed a 0.05% daidzein with 10% RBO diet (RO group) and those fed a 0.05% daidzein with 10% lard control diet (LO group) for 30 days. Urinary amounts of daidzein and dihydrodaidzein were significantly lower in the RO group than in the LO group. The ratio of equol/daidzein was significantly higher in the RO group (p < 0.01) than in the LO group. The amount of fecal bile acids was significantly greater in the RO group than in the LO group. The composition of cecal microbiota differed between the RO and LO groups. The occupation ratios of Lactobacillales were significantly higher in the RO group (p < 0.05). Significant positive correlation (r = 0.591) was observed between the occupation ratios of Lactobacillales and fecal bile acid content of two dietary groups. This study suggests that dietary rice bran oil has the potential to affect the metabolism of daidzein by altering the metabolic activity of intestinal microbiota.

The suckling rat as a model for immunonutrition studies in early life

Diet plays a crucial role in maintaining optimal immune function. Research demonstrates the immunomodulatory properties and mechanisms of particular nutrients; however, these aspects are studied less in early life, when diet may exert an important role in the immune development of the neonate. Besides the limited data from epidemiological and human interventional trials in early life, animal models hold the key to increase the current knowledge about this interaction in this particular period. This paper reports the potential of the suckling rat as a model for immunonutrition studies in early life. In particular, it describes the main changes in the systemic and mucosal immune system development during rat suckling and allows some of these elements to be established as target biomarkers for studying the influence of particular nutrients. Different approaches to evaluate these immune effects, including the manipulation of the maternal diet during gestation and/or lactation or feeding the nutrient directly to the pups, are also described in detail. In summary, this paper provides investigators with useful tools for better designing experimental approaches focused on nutrition in early life for programming and immune development by using the suckling rat as a model.

Current and emerging concepts on the role of peripheral signals in the control of food intake and development of obesity

The gastrointestinal peptides are classically known as short-term signals, primarily inducing satiation and/or satiety. However, accumulating evidence has broadened this view, and their role in long-term energy homeostasis and the development of obesity has been increasingly recognised. In the present review, the recent research involving the role of satiation signals, especially ghrelin, cholecystokinin, glucagon-like peptide 1 and peptide YY, in the development and treatment of obesity will be discussed. Their activity, interactions and release profile vary constantly with changes in dietary and energy influences, intestinal luminal environment, body weight and metabolic status. Manipulation of gut peptides and nutrient sensors in the oral and postoral compartments through diet and/or changes in gut microflora or using multi-hormone 'cocktail' therapy are among promising approaches aimed at reducing excess food consumption and body-weight gain.

Gut Microbiota and Obesity

The current obesity epidemic clearly has many causes, including the impact of our modern world on both our diet and our lifestyle/physical activity. Although many interventions have been recommended, the prevalence of obesity continues to rise and has forced a re-evaluation of the potential interventions that could have an impact. In recent years it has been definitively shown that microbiota in the gastrointestinal tract are altered in obese individuals. Recent data provide a potential mechanistic understanding of the interactions between microbiota and obesity and allow potential new interventions to the control of obesity to be proposed.

Management of metabolic syndrome through probiotic and prebiotic interventions

Metabolic syndrome is a complex disorder caused by a cluster of interrelated factors that increases the risk of cardiovascular diseases and type 2 diabetes. Obesity is the main precursor for metabolic syndrome that can be targeted in developing various therapies. With this view, several physical, psychological, pharmaceutical and dietary therapies have been proposed for the management of obesity. However, dietary strategies found more appropriate without any adverse health effects. Application of probiotics and prebiotics as biotherapeutics is the new emerging area in developing dietary strategies and many people are interested in learning the facts behind these health claims. Recent studies established the role of probiotics and prebiotics in weight management with possible mechanisms of improved microbial balance, decreased food intake, decreased abdominal adiposity and increased mucosal integrity with decreased inflammatory tone. Hence, the above "Pharmaco-nutritional" approach has been selected and extensively reviewed to gain thorough knowledge on putative mechanisms of probiotic and prebiotic action in order to develop dietary strategies for the management of metabolic syndrome.

Lactobacillus species shift in distal esophagus of high-fat-diet-fed rats

AIM: To analyze the microbiota shift in the distal esophagus of Sprague-Dawley rats fed a high-fat diet.

METHODS: Twenty Sprague-Dawley rats were divided into high-fat diet and normal control groups of 10 rats each. The composition of microbiota in the mucosa from the distal esophagus was analyzed based on selective culture. A variety of Lactobacillus species were identified by molecular biological techniques. Bacterial DNA from Lactobacillus colonies was extracted, and 16S rDNA was amplified by PCR using bacterial universal primers. The amplified 16S rDNA products were separated by denaturing gradient gel electrophoresis (DGGE). Every single band was purified from the gel and sent to be sequenced.

RESULTS: Based on mucosal bacterial culturing in the distal esophagus, Staphylococcus aureus was absent, and total anaerobes and Lactobacillus species were decreased significantly in the high-fat diet group compared with the normal control group (P < 0.01). Detailed DGGE analysis on the composition of Lactobacillus species in the distal esophagus revealed that Lactobacillus crispatus, Lactobacillus gasseri (L. gasseri) and Lactobacillus reuteri (L. reuteri) comprised the Lactobacillus species in the high-fat diet group, while the composition of Lactobacillus species in the normal control group consisted of L. gasseri, Lactobacillus jensenii and L. reuteri.

CONCLUSION: High-fat diet led to a mucosal microflora shift in the distal esophagus in rats, especially the composition of Lactobacillus species.

The human microbiome and surgical disease

OBJECTIVE

The purpose of this review article is to summarize what is currently known about microbes associated with the human body and to provide examples of how this knowledge impacts the care of surgical patients.

BACKGROUND

Pioneering research over the past decade has demonstrated that human beings live in close, constant contact with dynamic communities of microbial organisms. This new reality has wide-ranging implications for the care of surgical patients.

METHODS AND RESULTS

Recent advances in the culture-independent study of the human microbiome are reviewed. To illustrate the translational relevance of these studies to surgical disease, we discuss in detail what is known about the role of microbes in the pathogenesis of obesity, gastrointestinal malignancies, Crohn disease, and perioperative complications including surgical site infections and sepsis. The topics of mechanical bowel preparation and perioperative antibiotics are also discussed.

CONCLUSIONS

Heightened understanding of the microbiome in coming years will likely offer opportunities to refine the prevention and treatment of a wide variety of surgical conditions.

Developmental Changes in Gut Microbiota and Enzyme Activity Predict Obesity Risk in Rats Arising From Reduced Nests

The aim of the study was to assess the impact of preweaning overnutrition upon the ontogeny of intestinal microbiota, alkaline phosphatase activity (AP) and parameters of growth and obesity in male Sprague-Dawley rats. We tested whether intestinal characteristics acquired in suckling pups could programme the development of enhanced fat deposition during normalized nutrition beyond weaning. Postnatal nutrition was manipulated by adjusting the number of pups in the nest to 4 (small litters - SL) and 10 (normal litters - NL). In the postweaning period both groups were fed with a standard diet. The jejunal and colonic Lactobacillus/Enterococcus (LAB) and the Bacteroides/Prevotella (BAC) were determined using the FISH technique, and the jejunal AP activity was assayed histochemically. At 15 and 20 days of age the SL pups became heavier, displayed increased adiposity accompanied by significantly higher LAB and lower numbers of BAC and with higher AP activity in comparison with rats nursed in NL nests. These differences persisted to day 40 and withdrawal of the previous causal dietary influence did not prevent the post-weaning fat accretion. These results reveal the significance of early nutritional imprint upon the gut microbial/functional development and allow better understanding of their involvement in the control of obesity.

Development of gut microflora in obese and lean rats

The influence was evaluated of post-weaning normal nutrition and over-nutrition upon the development of the intestinal microbiota, the alkaline phosphatase activity (AP) and occurrence of obesity in male Sprague-Dawley rats (from days 21 to 40 the control rats were submitted to ad libitum intake of a standard laboratory diet whereas overfed rats received the same diet supplemented with milk-based high fat liquid diet). The jejunal numbers of two dominant divisions of bacteria, i.e. Firmicutes (Lactobacillus/ Enterococcus--LAB) and the Bacteroidetes (Bacteroides/Prevotella--BAC), were determined using the fluorescent in situ hybridization (FISH) method, and the jejunal AP activity was assayed histochemically. On day 40, the overfed rats in comparison with control animals displayed increased adiposity accompanied by enhanced AP activity, abundance of LAB, lower amounts of BAC and, thereafter, higher LAB/BAC ratio (L/B). The numbers of LAB and L/B index positively correlated with body fat, energy intake and AP activity, whereas numbers of BAC showed an opposite tendency. These results revealed the significance of nutritional imprint upon the post-weaning development of intestinal microbial and functional axis and contribute to better understanding of their involvement in energy-balance control and in adverse and/or positive regulation of adiposity.

Complex links between dietary lipids, endogenous endotoxins and metabolic inflammation

Metabolic diseases such as obesity are characterized by a subclinical inflammatory state that contributes to the development of insulin resistance and atherosclerosis. Recent reports also indicate that (i) there are alterations of the intestinal microbiota in metabolic diseases and (ii) absorption of endogenous endotoxins (namely lipopolysaccharides, LPS) can occur, particularly during the digestion of lipids. The aim of the present review is to highlight recently gained knowledge regarding the links between high fat diets, lipid digestion, intestinal microbiota and metabolic endotoxemia & inflammation.