Isotopic and genetic methods reveal the role of the gut microbiome in mammalian host essential amino acid metabolism.

Intestinal microbiota perform many functions for their host, but among the most important is their role in metabolism, especially the conversion of recalcitrant biomass that the host is unable to digest into bioavailable compounds. Most studies have focused on the assistance gut microbiota provide in the metabolism of carbohydrates, however, their role in host amino acid metabolism is poorly understood. We conducted an experiment on Mus musculus using 16S rRNA gene sequencing and carbon isotope analysis of essential amino acids (AAESS) to quantify the community composition of gut microbiota and the contribution of carbohydrate carbon used by the gut microbiome to synthesize AAESS that are assimilated by mice to build skeletal muscle tissue. The relative abundances of Firmicutes and Bacteroidetes inversely varied as a function of dietary macromolecular content, with Firmicutes dominating when mice were fed low-protein diets that contained the highest proportions of simple carbohydrates (sucrose). Mixing models estimated that the microbial contribution of AAESS to mouse muscle varied from less than 5% (threonine, lysine, and phenylalanine) to approximately 60% (valine) across diet treatments, with the Firmicute-dominated microbiome associated with the greatest contribution. Our results show that intestinal microbes can provide a significant source of the AAESS their host uses to synthesize structural tissues. The role that gut microbiota play in the amino acid metabolism of animals that consume protein-deficient diets is likely a significant but under-recognized aspect of foraging ecology and physiology

High-glucose feeding of gilthead seabream (Sparus aurata) larvae: effects on molecular and metabolic pathways

Nutritional programming has begun to arouse interest as a novel tool to alter specific metabolic pathways or functions in farmed animals. The aim of the present study was to explore the potential of early glucose stimuli to induce changes in nutrient metabolism of gilthead seabream. Nutritional conditioning was performed by delivering glucose-rich feed at three distinct recurrent periods of larval feeding regime: during first-feeding with rotifers (3 days after hatching, DAH) and mid-feeding with Artemia metanauplii (20DAH) and the beginning of inert diet feeding (30DAH), called the Recurrent treatment (REC). As opposed, the control treatment (CTRL) did not experience any glucose stimuli. At post-larval stage (from 50 to 60DAH), both treatments were challenged with a high-carbohydrate diet (50%). The immediate response to the early stimuli was assessed through gene expression of metabolic markers and by nutrient metabolism using [C-14] tracers. Each dietary stimulus induced metabolic changes on REC larvae, shown by altered expression of some genes, including those involved in glycolysis, and by a different pattern of glucose utilization. However, none of the molecular adaptations (except G6PDH gene) were persistent in the viscera and muscle of challenged post-larvae from REC group. In contrast, the glucose metabolism of challenged REC post-larvae revealed a shift towards a higher catabolism and lower glucose retention in tissues, compared to the CTRL group, suggesting an improvement of glucose oxidation pathways. In addition, the REC group showed a higher bio-conversion of glucose into lipids, indicating enhanced hepatic lipogenesis. The early stimuli did not affect the relative retention or use of amino acids or the growth and survival of challenged fish, up to 60DAH. In summary, although not substantiated at a molecular level, our data reveal that a recurrent high-glucose stimulus during larval stages affects the short-term modulation of pathways for glucose utilization in gilthead seabream. (C) 2015 Elsevier B.V. All rights reserved

Nutrient digestibility and growth response of rainbow trout (Salmo gairdneri ) fed different carbohydrate types

Seven groups of fingerling rainbow trout (S. gairdneri ) were fed for 10 weeks on 0%, 10%, 20% and 30% of cassava or rice in isonitrogenous diets. Optimum growth and food utilization was at 20% dietary cassava. High fiber content of the control diet did not suppress protein digestibility in this group. Rather, at all levels, protein digestibility was good and remained between 84.4% and 90.1%. However, in the control group, carbohydrate digestibility was very poor. The cassava diets which had the highest digestible energy as carbohydrate produced the best growth performance, food utilization and protein sparing. At the levels studied, the dietary carbohydrates produced no hyperglycamic effect on the fis

Association between Dietary Carbohydrates and Body Weight

The role of dietary carbohydrates in weight loss has received considerable attention in light of the current obesity epidemic. The authors investigated the association of body mass index (weight (kg)/height (m)2) with dietary intake of carbohydrates and with measures of the induced glycemic response, using data from an observational study of 572 healthy adults in central Massachusetts. Anthropometric measurements, 7-day dietary recalls, and physical activity recalls were collected quarterly from each subject throughout a 1-year study period. Data were collected between 1994 and 1998. Longitudinal analyses were conducted, and results were adjusted for other factors related to body habitus. Average body mass index was 27.4 kg/m2 (standard deviation, 5.5), while the average percentage of calories from carbohydrates was 44.9 (standard deviation, 9.6). Mean daily dietary glycemic index was 81.7 (standard deviation, 5.5), and glycemic load was 197.8 (standard deviation, 105.2). Body mass index was found to be positively associated with glycemic index, a measure of the glycemic response associated with ingesting different types of carbohydrates, but not with daily carbohydrate intake, percentage of calories from carbohydrates, or glycemic load. Results suggest that the type of carbohydrate may be related to body weight. However, further research is required to elucidate this association and its implications for weight management

The Role of Dietary Carbohydrates in Gestational Diabetes

Gestational diabetes (GDM) is hyperglycemia that is recognized for the first time during pregnancy. GDM is associated with a wide range of short- and long-term adverse health consequences for both mother and offspring. It is a complex disease with a multifactorial etiology, with disturbances in glucose, lipid, inflammation and gut microbiota. Consequently, its management is complex, requiring patients to self-manage their diet, lifestyle and self-care behaviors in combination with use of insulin. In addition to nutritional recommendations for all pregnant women, special attention to dietary carbohydrate (CHO) amount and type on glucose levels is especially important in GDM. Dietary CHO are diverse, ranging from simple sugars to longer-chain oligo- and poly- saccharides which have diverse effects on blood glucose, microbial fermentation and bowel function. Studies have established that dietary CHO amount and type can impact maternal glucose and nutritional recommendations advise women with GDM to limit total intake or choose complex and low glycemic CHO. However, robust maternal and infant benefits are not consistently shown. Novel approaches which help women with GDM adhere to dietary recommendations such as diabetes-specific meal replacements (which provide a defined and complete nutritional composition with slowly-digested CHO) and continuous glucose monitors (which provide unlimited monitoring of maternal glycemic fluctuations) have shown benefits on both maternal and neonatal outcomes. Continued research is needed to understand and develop tools to facilitate patient adherence to treatment goals, individualize interventions and improve outcomes

Helminth parasites in pigs: New challenges in pig production and current research highlights

Helminths in pigs have generally received little attention from veterinary parasitologists, despite Ascaris suum, Trichuris suis, and Oesophagostomum sp. being common worldwide. The present paper presents challenges and current research highlights connected with these parasites. In Danish swine herds, new indoor production systems may favour helminth transmission and growing knowledge on pasture survival and infectivity of A. suum and T. suis eggs indicates that they may constitute a serious threat to outdoor pig production. Furthermore, it is now evident that A. suum is zoonotic and the same may be true for T. suis. With these ‘new’ challenges and the economic impact of the infections, further research is warranted. Better understanding of host–parasite relationships and A. suum and T. suis egg ecology may also improve the understanding and control of human A. lumbricoides and T. trichiura infections. The population dynamics of the three parasites are well documented and may be used to study phenomena, such as predisposition and worm aggregation. Furthermore, better methods to recover larvae have provided tools for quantifying parasite transmission. Thus, an on-going study using helminth naïve tracer pigs has surprisingly demonstrated that soil infectivity with A. suum and T. suis increases during the first 2–3 years after pasture contamination. Though all three helminth species stimulate the Th2 arm of the immune system, Oesophagostomum seems weakly immunogenic, perhaps via specific modulation of the host immune system. A. suum and T. suis potently modulate the host immune response, up-regulating Th2 and down-regulating Th1. As a consequence, A. suum may compromise the efficacy of certain bacterial vaccines, whereas T. suis, which establish only short-term in humans, is a favourite candidate for down-regulating autoimmune Th1-related diseases in man. Some basic research findings have offered new possibilities for future sustainable control measures. For example, the heredity of host resistance to A. suum and T. suis is so high that breeding for resistant pigs may be a possibility. Experimental studies have demonstrated that fermentable dietary carbohydrates have an antagonistic effect on Oesophagostomum and to a lesser extent on T. suis and A. suum, whereas egg-destroying microfungi may be used to inactivate the hard-shelled A. suum and T. suis eggs in the environment. Helminth control in Denmark has previously relied solely on anthelmintic treatment in herds with low helminth transmission. When indoor transmission rates increase, or in outdoor herds with high pasture contamination levels, medication may advantageously be combined with sustainable control measures, such as selected pig genomes, bioactive forages, and egg-destroying microfungi. © 2011 Elsevier B.V. All rights reserved

Dietary carbohydrate requirement of Heterobranchus longifilis

The dietary carbohydrate requirement of Heterobranchus longifilis was evaluated in two separate experiments.In the first experiment, varying levels of carbohydrate ranging from 28, 24 to58 72% were fed to the fish of mean weight 1.83~c0.02g. Results revealed that the polynomial regression curve for the mean weight gain and the carbohydrate levels did not present a point where Y-max is equal to X-max and so the requirement was not obtained. The second experiment was therefore, conducted with lower levels of carbohydrate ranging from 17.00 to 20.86% and fed to fish with mean weight 0.49~c0.02g. Based on growth and feed efficiency data the carbohydrate requirement was determined to be 19.5

Dietary carbohydrates and fats in nonalcoholic fatty liver disease

This Review discusses the role of dietary fats and carbohydrates in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). Studies on the dietary habits of patients with NAFLD, and the effect on liver fat accumulation of altering dietary macronutrients, are also reviewed. The global prevalence of nonalcoholic fatty liver disease (NAFLD) has dramatically increased in parallel with the epidemic of obesity. Controversy has emerged around dietary guidelines recommending low-fat-high-carbohydrate diets and the roles of dietary macronutrients in the pathogenesis of metabolic disease. In this Review, the topical questions of whether and how dietary fats and carbohydrates, including free sugars, differentially influence the accumulation of liver fat (specifically, intrahepatic triglyceride (IHTG) content) are addressed. Focusing on evidence from humans, we examine data from stable isotope studies elucidating how macronutrients regulate IHTG synthesis and disposal, alter pools of bioactive lipids and influence insulin sensitivity. In addition, we review cross-sectional studies on dietary habits of patients with NAFLD and randomized controlled trials on the effects of altering dietary macronutrients on IHTG. Perhaps surprisingly, evidence to date shows no differential effects between free sugars, with both glucose and fructose increasing IHTG in the context of excess energy. Moreover, saturated fat raises IHTG more than polyunsaturated or monounsaturated fats, with adverse effects on insulin sensitivity, which are probably mediated in part by increased ceramide synthesis. Taken together, the data support the use of diets that have a reduced content of free sugars, refined carbohydrates and saturated fat in the treatment of NAFLD.Peer reviewe

Glycaemic and insulinemic response to dietary carbohydrates in horses

BACKGROUND: Dietary sugar and starch affect plasma glucose and insulin concentrations. Little information is available about the effect of dietary fibre on plasma glucose and insulin concentration. It is hypothesized that different dietary fibre compositions will alter post-prandial glycaemic- and insulinemic index of test meals. The objective was to measure postprandial glucose and insulin concentrations in horses fed meals of different fibre compositions. METHODS: Blood was drawn via jugular vein puncture and the glycaemic and insulinemic index were calculated. RESULTS: The meal effect on glycaemic and insulinemic response followed the expected pattern, where plasma concentrations increased after feeding and declined after peak concentration. Glycaemic index was 100 (H), 102 (OB), 102 (BB) and 106 (M) and did not differ significantly between meals. Insulinemic index was 100 (H), 140 (OB), 121 (BB) and 125 (M) and did not differ significantly between meals. CONCLUSIONS: In conclusion, meals containing different fibre compositions did not affect the glycaemic- and insulinemic index in horses