Fructan supplementation of senior cats affects stool metabolite concentrations and fecal microbiota concentrations, but not nitrogen partitioning in excreta.

Fructan supplementation of a commercially available canned cat food was evaluated using senior (≥ 9 yr) cats to assess nitrogen (N) partitioning in excreta and stool metabolite and microbiota concentrations. Oligofructose (OF) or SynergyC (OF+IN) were added to the diet individually at 1% (dry weight basis). Cats were acclimated to the control diet for 7 d and then were randomly assigned to 1 of 3 treatment groups for 21 d (n = 6). Feces and urine were collected on d 22 through 28. No differences were observed in food intake; fecal output, DM percentage, score, pH, or short- or branched-chain fatty acids, fecal and urinary ammonia output, urinary felinine concentrations, or N retention. Supplemental OF+IN tended to decrease N digestibility (P = 0.102) and Bifidobacteria spp. (P = 0.073) and decrease fecal indole (P < 0.05), tyramine (P < 0.05), and Escherichia coli (P < 0.05) concentrations. Both fructan-supplemented treatments decreased (P < 0.05) fecal histamine concentrations. The tendency to a lower apparent N digestibility was likely due to increased colonic microbial protein synthesis of fructan-supplemented cats. Fructan supplementation may benefit senior cats as it modulates stool odor-forming compounds and decreases some protein catabolites and pathogenic gut microbiota concentrations without affecting N retention.

Inflammatory disease processes and interactions with nutrition.

Inflammation is a stereotypical physiological response to infections and tissue injury; it initiates pathogen killing as well as tissue repair processes and helps to restore homeostasis at infected or damaged sites. Acute inflammatory reactions are usually self-limiting and resolve rapidly, due to the involvement of negative feedback mechanisms. Thus, regulated inflammatory responses are essential to remain healthy and maintain homeostasis. However, inflammatory responses that fail to regulate themselves can become chronic and contribute to the perpetuation and progression of disease. Characteristics typical of chronic inflammatory responses underlying the pathophysiology of several disorders include loss of barrier function, responsiveness to a normally benign stimulus, infiltration of inflammatory cells into compartments where they are not normally found in such high numbers, and overproduction of oxidants, cytokines, chemokines, eicosanoids and matrix metalloproteinases. The levels of these mediators amplify the inflammatory response, are destructive and contribute to the clinical symptoms. Various dietary components including long chain omega-3 fatty acids, antioxidant vitamins, plant flavonoids, prebiotics and probiotics have the potential to modulate predisposition to chronic inflammatory conditions and may have a role in their therapy. These components act through a variety of mechanisms including decreasing inflammatory mediator production through effects on cell signaling and gene expression (omega-3 fatty acids, vitamin E, plant flavonoids), reducing the production of damaging oxidants (vitamin E and other antioxidants), and promoting gut barrier function and anti-inflammatory responses (prebiotics and probiotics). However, in general really strong evidence of benefit to human health through anti-inflammatory actions is lacking for most of these dietary components. Thus, further studies addressing efficacy in humans linked to studies providing greater understanding of the mechanisms of action involved are required.

Selected nondigestible carbohydrates and prebiotics support the growth of probiotic fish bacteria mono-cultures in vitro.

AIMS: To search for nondigestible but fermentable (NDF) carbohydrates and prebiotics with a potency to promote the growth of selected bacteria in vitro. METHODS AND RESULTS: The growth of three reference bacteria strains Bacillus subtilis LMG 7135(T), Carnobacterium piscicola LMG 9839, Lactobacillus plantarum LMG 9211 and one candidate probiotic bacteria Lactobacillus delbrueckii subsp. lactis was investigated over a minimum period of 48 h in the presence of beta-glucan, xylo-oligosaccharide, arabinoxylo-oligosaccharide, inulin, oligofructose and glucose. Besides the capability to grow on inulin and oligofructose containing media, a distinct high growth in beta-glucan based substrates and a low growth in (arabino)xylooligosaccharide containing media were evident for most bacteria tested. With the exception of B. subtilis and L. plantarum, other bacteria grew equally well or even better on different substrates than on glucose. The fermentation of studied carbohydrates by these micro-organisms was dominated by the production of acetic acid as the main short chain fatty acid. CONCLUSIONS: Selected bacteria are able to ferment and grow on NDF and prebiotic carbohydrates but in a substrate dependent manner. SIGNIFICANCE AND IMPACT OF THE STUDY: This study delivers a first screening of which NDF or prebiotic carbohydrates are the most promising for aquaculture feed supplementations.

Inulin and oligofructose as prebiotics in the prevention of intestinal infections and diseases.

Health and wellbeing are challenged constantly by pathogens. A number of defence mechanisms exist to protect the body from pathogen colonisation and invasion, with an important role to play for the natural intestinal bacterial flora (mainly by bifidobacteria and lactobacilli). The present paper reviews the evidence on the effects of inulin and oligofructose on colonisation and translocation of pathogens and the prevention of intestinal diseases. In vitro experiments have shown that lactic acid-producing bacteria have antagonistic (antibacterial) activity against pathogens partly because of the production of organic acids which are the endproducts of inulin and oligofructose fermentation. In addition, studies with epithelial layers have shown that inulin and oligofructose inhibit pathogen colonisation and that endproducts of their fermentation have the ability to support barrier function. Furthermore, studies in various animal models have shown that inulin and oligofructose accelerate the recovery of beneficial bacteria, slow down pathogen growth, decreasing pathogen colonisation and systemic translocation. Finally, data from human intervention trials either in patients with intestinal disorders or disease, or prone to critical illness, found that inulin and oligofructose restore the balance when the gut microbial community is altered, inhibit the progression of disease or prevent it from relapsing and/or developing. To conclude, the dietary use of inulin and oligofructose offers a promising approach to restore microbial communities and to support barrier function of the epithelia by their prebiotic action. This may offer the host protection against invasion and translocation of pathogens (endogenous and/or exogenous) and in the prevention of gastrointestinal diseases.

Molecular biological methods for studying the gut microbiota: the EU human gut flora project.

Seven European laboratories co-operated in a joint project (FAIR CT97-3035) to develop, refine and apply molecular methods towards facilitating elucidation of the complex composition of the human intestinal microflora and to devise robust methodologies for monitoring the gut flora in response to diet. An extensive database of 16S rRNA sequences for tracking intestinal bacteria was generated by sequencing the 16S rRNA genes of new faecal isolates and of clones obtained by amplification with polymerase chain reaction (PCR) on faecal DNA from subjects belonging to different age groups. The analyses indicated that the number of different species (diversity) present in the human gut increased with age. The sequence information generated, provided the basis for design of 16S rRNA-directed oligonucleotide probes to specifically detect bacteria at various levels of phylogenetic hierarchy. The probes were tested for their specificity and used in whole-cell and dot-blot hybridisations. The applicability of the developed methods was demonstrated in several studies and the major outcomes are described.

Experimental evidences on the potential of prebiotic fructans to reduce the risk of colon cancer.

Inulin is extracted from the chicory root. It is a set of fructans with its monomers linked by means of beta(2-1) bonds. This linkage cannot be hydrolysed by either pancreatic or by brush border digestive enzymes in the upper intestinal tract of humans. As such the carbohydrates arrive in the colon, where they are fermented by bifidobacteria and other lactic acid producing bacteria, thus enhancing their relative populations in the gut. Recent research in experimental animal models revealed that inulin has significant anticarcinogenic properties. It acts chemopreventively by reducing the incidence of azoxymethane (AOM) - induced aberrant crypt foci and tumours in the colon. These effects may be due to the stimulation of bifidobacteria, which themselves have been shown to act as antigenotoxic in the colon and to reduce AOM-induced tumours. Also fermentation products, including the short-chain fatty acid butyrate, could contribute to the protective effects. In this case a mechanism may be the induction of apoptosis of already transformed cells. The experimental evidence from animal studies and from studies elucidating potential mechanisms strongly supports the possibility that inulin will contribute to reducing risks for colon cancer in humans. In order to obtain more insight into this possibility, human dietary intervention studies relating biomarkers of reduced risk to inulin consumption are needed.

Study of the regulation by nutrients of the expression of genes involved in lipogenesis and obesity in humans and animals.

Dietary digestible carbohydrates are able to modulate lipogenesis, by modifying the expression of genes coding for key lipogenic enzymes, like fatty acid synthase. The overall objective of the Nutrigene project (FAIR-CT97-3011) was to study the efficiency of various carbohydrates to modulate the lipogenic capacity and relevant gene expression in rat and human species (control and obese subjects) and to understand the underlying molecular mechanisms involved in the regulation of lipogenic genes by carbohydrates. Key cellular mediators (namely SREBP-1c and 2, AMP activated protein kinase, cholesterol content) of the regulation of lipogenic gene expression by glucose and/or insulin were identified and constitute new putative targets in the development of plurimetabolic syndrome associated with obesity. In humans, hepatic lipogenesis and triglyceride synthesis, assessed in vivo by the use of stable isotopes, was promoted by a high-carbohydrate diet in non obese subjects, and in non alcoholic steatotic patients, but was not modified in the adipose tissue of obese subjects. Non digestible/fermentable carbohydrates, such as fructans, were shown to decrease hepatic lipogenesis in non obese rats, and to lessen hepatic steatosis and body weight in obese Zucker rats. If confirmed in obese humans, this would allow the development of functional food able to counteract the metabolic disturbances linked to obesity.

Evaluation in human volunteers of the potential anticarcinogenic activities of novel nutritional concepts: prebiotics, probiotics and synbiotics (the SYNCAN project QLK1-1999-00346).

Prebiotics is a recent novel food concept that includes food ingredients that are not digested in the human upper intestinal tract and hence arrive in the colon where they are selectively fermented by a limited number of colonic bacteria. Amongst these are bifidobacteria and lactobacilli, which are considered indicators of a well-balanced intestinal flora. Probiotics are bacteria that, while passing through the intestine, may exert specific beneficial effects on the host's physiology. In general, probiotics are members of the group of the lactic acid-producing bacteria. By means of a variety of experimental models it was demonstrated that prebiotic carbohydrates and probiotics consistently reduced processes of carcinogenesis and tumorigenesis. Synergistic chemopreventive actions were observed with combinations of the two, which together are called synbiotics. One of the most important causes of death in the ageing western population is colon cancer, which is typically associated with a western-style diet. On the basis of the available experimental data, an EU-funded research project (the SYNCAN project QLK1-1999-00346) was set up to evaluate whether synbiotics and prebiotics can be added to food without detriment to (and hopefully eventually improving) organoleptic properties. They are, as such, a good vector for importing nutritionally interesting properties into our diet.

Functional food properties of non-digestible oligosaccharides: a consensus report from the ENDO project (DGXII AIRII-CT94-1095).

This paper results from the final phase of the ENDO project (DGXII AIRII-CT94-1095), a European Commission-funded project on non-digestible oligosaccharides (NDO). All participants in the programme met to perform a consensus exercise on the possible functional food properties of NDO. Topics studied during the project (including a workshop on probiotics and prebiotics) and related aspects, for which considerable evidence has been generated recently, were evaluated on the basis of existing published scientific evidence. There was a general consensus that: (1) there is strong evidence for a prebiotic effect of NDO in human subjects. A prebiotic effect was defined as a food-induced increase in numbers and/or activity predominantly of bifidobacteria and lactic acid bacteria in the human large intestine; (2) there is strong evidence for the impact that NDO have on bowel habit; (3) there is promising evidence that consumption of inulin-type fructans may result in increased Ca absorption in man; (4) there are preliminary indications that inulin-type fructans interact with the functioning of lipid metabolism; (5) there is preliminary evidence in experimental animals of a preventive effect against colon cancer. Human nutrition studies are needed to substantiate these findings. It was concluded that the nutritional properties of NDO may prove to be a key issue in nutritional research in the future.

The bifidogenic nature of chicory inulin and its hydrolysis products.

Research data on the bifidogenic effect of beta(2-1)fructans, which at present are commercialized in the U.S., Japan and Europe as food ingredients, are presented. These food ingredients originate from two different sources. Short-chain fructo-oligosaccharides are synthesized from sucrose and are composed of GFn [n beta(2-1) linked fructose moieties bound to a glucose molecule; 2 10 are fermented on average half as quickly as molecules with a DP < 10. All beta(2-1)fructans are bifidogenic and classified as biobiotics.

On the presence of inulin and oligofructose as natural ingredients in the western diet.

The classic definitions of inulin and oligofructose are constructively criticized. It is observed that inulin cannot unequivocally be described as a polydisperse 1-kestose-based (GFn) beta (2-->1) linear fructan chain, but that inulin always contains small amounts of Fm and branched molecules. This review article describes the presence of inulin and oligofructose in common foodstuffs. Historical data on human consumption add an extra dimension. Modern analytical techniques (HPLC, LGC, HPAEC-PAD) are used to check the variety of data mentioned in the literature throughout the past century. Methods to determine inulin and oligofructose in natural foodstuffs (cereals, fruit, and vegetables) are optimized and used to determine the loss of inulin during storage and during preparation of the food. These findings allow quantification of the amount of inulin and oligofructose in the average daily western diet. The daily per capita intake is estimated to range from 1 to 10 g, depending on geographic, demographic, and other related parameters (age, sex, season, etc.). Inulin and oligofructose are not measured by classic methods of dietary fiber analysis and consequently are often not mentioned in food tables. Their significant contribution (1 to 10 g/d/per capita) to the dietary fiber fraction (recommended at 25 g/d/per capita) is not taken into account in any nutritional recommendations. In view of this, inulin and oligofructose deserve more attention, both in food composition tables and in diet or nutrition studies.

Dynamics and regulation of sucrose phosphorylase formation in Leuconostoc mesenteroides fermentations.

The production of Leuconostoc mesenteroides sucrose phosphorylase has been studied in 10- and 20-L batch fermentations. A fermentation medium was devised combining rapid growth, high cell yield, and high enzyme levels. Overall fermentation dynamics and enzyme fermentation patterns are elucidated here in detail. Sucrose is phosphorolyzed into fructose and glucose-1-phosphate (G-1-P) with G-1-P preferentially utilized (thus saving ATP). Subsequently, fructose is gradually metabolized and is also converted to mannitol. Invertase activity is absent. Sucrose phosphorylase is formed transitorily with peak levels toward the end of active growth; a sharp decline in enzyme activity occurs upon further fermentation. The moment of cell (enzyme) harvest is thus critical in view of obtaining active cell or enzyme preparations for sucrose phosphorolysis. Microaerophilic and strictly anaerobic fermentations displayed no appreciable difference in sucrose phosphorylase formation profile. The enzyme is intracellularly located. It is constitutively formed in the absence of sucrose, contrary to that of Pseudomonas species; other disaccharide phosphorylases are not formed.

Twenty-five minutes between blood pressure readings: the influence on prevalence rates of isolated systolic hypertension.

The aim of the present study was to investigate the influence of a 25-min time interval between the first and the last reading of a series of six, on systolic (SBP) and Phase V diastolic (DBP) blood pressure and its implications for prevalence rates of hypertension. Readings were taken from 5999 persons (2889 men and 3110 women) by two observers using a Hawksley random-zero sphygmomanometer. The first reading was taken 5 min after entering the examining room. The study showed a considerable fall in mean SBP (men, 10.3 mmHg; women, 10.4 mmHg) and hardly a difference in mean DBP (men, 0.8 mmHg; women, 0.1 mmHg) between the first and sixth reading. The fall in SBP was independent of observer and sex and hardly correlated with age or Quetelet's index. The study also showed the implications for the classification of hypertension. Prevalence rates of isolated systolic hypertension dropped remarkably (men, 4.0 to 0.5%; women, 0.9 to 0.1%) between both readings while prevalence rates of severe, moderate and mild diastolic hypertension were nearly similar for the first and sixth reading.

Adverse effect of excess methionine or methionine hydroxy analog on feed consumption in cattle.

The toxicity of DL-methionine and methionine hydroxy analog infused into the rumen or abomasum was gauged by relative feed consumption. A continuous intraruminal infustion of at least 3 days' duration of DL-methionine equalent to about 2.5% or more of dietary dry matter intake was required to reach a toxic amount. This was approximately four times the amount necessary when it was infused into the abomasum. Methionine hydroxy analog equalent to about 1% or more of dietary dry matter intake was toxic when infused into either rumen or abomasum. This is in large excess of suggested amounts of analog supplementation. Reduced palatability is likely to occur in advance of reduced intake due to toxicity.