Changes In Nutrient Metabolism Research Articles

Measuring growth in critically ill neonates and children.

Critical illness increases the risk of malnutrition in both infants and children. Malnutrition risk is multifactorial and includes premorbid factors as well as changes in nutrient metabolism and energy demands during critical illness. Inadequate nutrition has been linked to poor health outcomes and prolonged length of stay in the intensive care unit, demonstrating the importance of both recognizing and addressing malnutrition in this population. Assessing growth and identifying malnutrition requires methodical measurement of growth and a collaborative, multimodal approach to nutrition assessment. Among the nutrition assessment and growth evaluation tools, neonatal, preterm, pediatric, and disease-specific growth charts remain an important component of growth assessment and should be used along with a nutrition-focused physical examination. Routine measurement promotes the identification of potential growth delays that may require interventions. Indirect calorimetry adds an additional layer of detail for a complete picture of each infant or child's unique nutrition status and progress. Quality improvement research on a national level is urgently needed to assess the adequacy and availability of resources in neonatal and pediatric critical care units and to further the development of standard clinical outcome measures for nutrition assessment and intervention in the critically ill neonate and child.

Nutrient-related metabolite profiles explain differences in body composition and size in Nile tilapia (Oreochromis niloticus) from different lakes

This study investigated how metabolite analysis can explain differences in tissue composition and size in fish from different habitats. We, therefore, studied Nile tilapia (Oreochromis niloticus) from three Ethiopian lakes (Gilgel Gibe, Ziway, and Langano) using dried bloodspot (DBS) analysis of carnitine esters and free amino acids. A total of sixty (N = 60) Nile tilapia samples were collected comprising twenty (n = 20) fish from each lake. The proximate composition of the targeted tissues (muscle, skin, gill, gut, and liver) were analyzed. The DBS samples were analyzed for acylcarnitine and free amino acid profiles using quantitative electrospray tandem mass spectrometry. Metabolite ratios were calculated from relevant biochemical pathways that could identify relative changes in nutrient metabolism. The mean weight of Nile tilapia sampled from each lake showed weight variation among the lakes, fish from Lake Ziway were largest (178 g), followed by Gilgel Gibe reservoir (134 g) and Lake Langano (118 g). Fish from Gilgel Gibe showed significantly higher fat composition in all tissues (P < 0.05) except the liver in which no significant variation was observed. The source of fish affected the tissue fat composition. Marked differences were observed in Nile tilapia metabolic activity between the lakes. For instance, the lower body weight and condition of the fish in Lake Langano coincided with several metabolite ratios pointing to a low flow of glucogenic substrate to the citric acid cycle. The low propionyl to acetylcarnitine ratio (C3:C2) in Gilgel Gibe fish is indicating that more of the available acetyl CoA is not led into the citric acid cycle, but instead will be used for fat synthesis. The metabolic markers for lipogenesis and metabolic rate could explain the high-fat concentration in several parts of the body composition of fish from Gilgel Gibe. Our results show that nutrition-related blood metabolite ratios are useful to understand the underlying metabolic events leading to the habitat-dependent differences in the growth of Nile tilapia, and by extension, other species.

Encapsulated Mixture of Methyl Salicylate and Tributyrin Modulates Intestinal Microbiota and Improves Growth Performance of Weaned Piglets.

Tributyrin and essential oils have been used as alternatives to antimicrobials to improve gut health and growth performance in piglets. This study was to evaluate the effects of a dietary supplement with two encapsulated products containing different combinations of tributyrin with oregano or with methyl salicylate on growth performance, serum biochemical parameters related to the physiological status, intestinal microbiota and metabolites of piglets. A total of 108 weaned crossbred piglets (Yorkshire × Landrace, 21 ± 1 d, 8.21 ± 0.04 kg) were randomly divided into three groups. Piglets were fed with one of the following diets for 5 weeks: a basal diet as the control (CON); the control diet supplemented with an encapsulated mixture containing 30% of methyl salicylate and tributyrin at a dosage of 3 kg/t (CMT); and the control diet supplemented with an encapsulated mixture containing 30% of oregano oil and tributyrin at a dosage of 3 kg/t (COT). At the end of the feeding trial, six piglets from each group were slaughtered to collect blood and gut samples for physiological status and gut microbiological analysis. The study found that the CMT group was larger in feed intake (FI) (p < 0.05), average daily gain (ADG) (p = 0.09), total protein (TP), albumin (ALB), glutathione peroxidase (GSH-PX) (p < 0.05), blood total antioxidant capacity (T-AOC) (p < 0.05), and crypt depth in the ileum (p < 0.05) compared with the CON group. The genus abundance of Tissierella and Campylobacter in the CMT group was significantly decreased compared with the CON group. The CMT group also resulted in significantly higher activity in amino acid metabolism and arginine biosynthesis compared with the CON group. The COT group was larger in T-AOC, and the genus abundance of Streptophyta and Chlamydia was significantly increased in the ileum compared with the CON group. Data analysis found a significantly high correlation between the genus abundance of Chlamydia and that of Campylobacter in the ileum. The genus abundance of Campylobacter was also positively correlated with the sorbitol level. In general, the results indicated that the supplementation of both encapsulated mixtures in diet of weaned piglets could improve the animal blood antioxidant capacity. Additionally, the encapsulated mixture of methyl salicylate plus tributyrin improved the growth performance and resulted in certain corresponding changes in nutrient metabolism and in the genus abundance of ileum microbial community.

Measuring seasonal and agro-ecological effects on nutritional status in tropical ranging dairy cows

Despite high numbers of cattle, milk production in many tropical countries such as Ethiopia is very low. Animals are managed traditionally, meaning they mostly depend on seasonal availability of natural pasture, grass, and crop residues with no supplementary feeds. Due to the lack of pasture management, there is overgrazing and soil erosion, and the land still must deal with extremely dry periods. All this has a negative effect on dairy cow productivity. Identification of the specific nutritional deficits would enable targeted interventions to improve milk yield performance, but nutrient and energy intakes are difficult to assess in ranging conditions. The aim of this research was, therefore, to evaluate the nutritional status of ranging dairy cows through blood metabolites, milk yield, and body condition in relation to environmental factors such as agro-ecology and season. The study was performed in a tropical region that is known to be exposed to the above-mentioned situation, the Arba Minch region in the southern Ethiopian Rift Valley. Blood samples were collected from 170 ranging dairy cows in 6 different districts, along a transect extending from the lowlands to the highlands, in both seasons (dry and rainy). Body condition score and milk yield of all cows were also determined for both seasons. Serum urea, creatinine, triglyceride, and nonesterified fatty acid concentrations were quantified spectrophotometrically. Dried serum spots were subject to quantitative electrospray tandem mass spectrometry to estimate changes in nutrient metabolism based on selected free AA and carnitine esters. Based on these measurements, nutritional status varied with season and geographical region. It can also be concluded that extensive metabolite analysis such as mass spectrometry can provide detailed insights, but the simpler spectrophotometric metabolite analysis can estimate the nutritional status of ranging animals.

Effect of Continuous Cropping Soil on the Biosynthesis of Bioactive Compounds and the Antioxidant Activity of Lingzhi or Reishi Medicinal Mushroom, Ganoderma lucidum (Agaricomycetes).

Continuous monoculture can increase plant morbidity and reduce crop yields. However, the Ganoderma lucidum mushroom possesses unique nutrient acquisition methods and displays an altered response to the generation of reactive oxygen species (ROS). The effects of continuous cropping on G. lucidum remain unclear. Here, we investigated the effects of consecutive monoculture soil on the yield, bioactive components, antioxidant properties, nutrient metabolism, and enzyme activity of G. lucidum. The results showed no significant differences in terms of yield between the control check and treatment groups after 2 years. However, the content of polysaccharides and triterpenoids after 2 years of treatment and the content of total phenols and flavonoids after 3 years of treatment significantly increased. Moreover, the antioxidant activity (AOA) of the polysaccharides under consecutive monoculture soil treatments also significantly increased. These differences were caused by changes in nutrient metabolism and the activities of antioxidant and ligninolytic enzymes. Under continuous monoculture soil treatment, the content of reducing sugars, water-soluble sugars, free amino acids, and water-soluble proteins significantly increased. The activities of superoxide dismutase, manganese peroxidase, and lignin peroxidase increased with the time of continuous monoculture, while the activities of peroxidase, catalase, and laccase decreased. The increase in ligninolytic enzymes was postulated to mediate the ROS scavenging ability of G. lucidum. In conclusion, continuous cropping soil could increase the levels of bioactive components and AOAs of G. lucidum.

Crohn Hastalığında Gelişen Komplikasyonlara Göre Değişen Tıbbi Beslenme Tedavisi: Bir Olgu Sunumu

İnflamatuvar bağırsak hastalıkları (İBH), iki temel formuyla Crohn hastalığı (CH) ve Ülseratif Kolit (ÜK) olup gastrointestinal sistemde kronik, tekrarlayıcı inflamasyona neden olurlar. Bu hastalıklar genetik yatkınlık, çevresel ve immünolojik etmenlerin bir araya gelmesi sonucu, gastrointestinal florayı, barsağın tüm katmanlarını etkileyen, uyumsuz immün yanıtların tetiklendiği inflamatuvar olaylar dizisidir. CH ağız, özefagus, mide, bağırsak ve anüse kadar olan bölgede inflamatuvar aktivitelerle mukozayı etkilerken, ÜK yalnızca kolonik mukozayı etkiler. CH’ın etiyopatogenezi tam olarak anlaşılmamakla birlikte çevresel etmenlerden, sigara, enfeksiyon, apendektomi, emzirme süresi, beslenme alışkanlıkları, ilaçlar, sosyoekonomik etmenler ve stresle ilişkilidir. Bağışıklık sistemde önemli rol oynayan gen mutasyonunun otoimmün hastalıklara ve İBH’a neden olduğu bilinmektedir. Genellikle 15-30 yaş arası görülen CH, fistül, bağırsak tıkanıklığı ve karın içi abse gibi ciddi komplikasyonlar oluşturmaktadır. Hastaneye yatan CH’da %75 beslenme yetersizliği ve ağır mikrobesin ögesi kayıpları görülür, özellikle emilim bozukluğu, intestinal kayıplar, besin metabolizmasındaki değişiklikler, inflamasyon şiddeti, bulantı, kusma, karın ağrısına bağlı tüketimin azalması/gereksinmenin artması, steroidlerin vitamin ve minerallere olumsuz etkisi, GI’in tutulum yeri, hastalıklı barsağın uzunluğu, rezeke edilmesi ve yine hastalığın alevlenme süresi/sıklığı, beslenme yetersizliğine, protein, vitamin, mineral, eser element kayıplarına neden olmaktadır. CH’ın beslenme tedavisi remisyon ve aktif döneme, gelişen komplikasyonlara göre, cerrahi öncesi ve sonrasında değişkenlik arz eder ve dinamik bir süreçtir. Beslenme tedavisinin amacı atakları azaltmak, aktif dönemde vücut bileşimini korumak, makro ve mikrobesin ögeleri kayıplarını önlemek ve yerine koymak, yaşam kalitesini arttırmak olmalıdır. Bu makalede CH tanısı alan bir hastanın gelişen komplikasyonlara göre farklı beslenme tedavi stratejilerinin gerçekleştirildiği olgu tartışılmaktadır.

Muscle catabolic capacities and global hepatic epigenome are modified in juvenile rainbow trout fed different vitamin levels at first feeding

Based on the concept of nutritional programming in mammals, we tested whether a short term hyper or hypo vitamin stimulus during first-feeding could induce long-lasting changes in nutrient metabolism in rainbow trout. Trout alevins received during the 4 first weeks of exogenous feeding a diet either without supplemental vitamins (NOSUP), a diet supplemented with a vitamin premix to satisfy the minimal requirement in all the vitamins (NRC) or a diet with a vitamin premix corresponding to an optimal vitamin nutrition (OVN). Following a common rearing period on the control diet, all three groups were then evaluated in terms of metabolic marker gene expressions at the end of the feeding period (day 119). Whereas no gene modifications for proteins involved in energy and lipid metabolism were observed in whole alevins (short-term effect), some of these genes showed a long-term molecular adaptation in the muscle of juveniles (long-term effect). Indeed, muscle of juveniles subjected at an early feeding of the OVN diet displayed up-regulated expression of markers of lipid catabolism (3-hydroxyacyl-CoA dehydrogenase – HOAD - enzyme) and mitochondrial energy metabolism (Citrate synthase - cs, Ubiquitinol cytochrome c reductase core protein 2 - QCR2, cytochrome oxidase 4 - COX4, ATP synthase form 5 - ATP5A) compared to fish fed the NOSUP diet. Moreover, some key enzymes involved in glucose catabolism (Muscle Pyruvate kinase - PKM) and amino acid catabolism (Glutamate dehydrogenase - GDH3) were also up regulated in muscle of juvenile fish fed with the OVN diet at first-feeding compared to fish fed the NOSUP diet. We researched if these permanently modified gene expressions could be related to global modifications of epigenetic marks (global DNA methylation and global histone acetylation and methylation). There was no variation of the epigenetic marks in muscle. However, we found changes in hepatic DNA methylation, global H3 acetylation and H3K4 methylation, dependent on the vitamin intake at early life. In summary, our data show, for the first time in fish, that a short-term vitamin-stimulus during early life may durably influence muscle energy and lipid metabolism as well as some hepatic epigenetic marks in rainbow trout. Statement of relevanceProgramming at first feeding with different levels of vitamins was successfully tested in fish for the first time. These data proove one more time the importance of the early life on the fish metabolism in adults.

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 (3days 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 [14C] 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. Statement of relevanceCarnivorous fish, such as rainbow trout and gilthead seabream exhibit a poor utilization of dietary carbohydrates as energy substrates. The concept of nutritional programming raises the possibility of tailoring specific metabolic pathways or functions in fish, for example to improve the use of dietary carbohydrates and promote the development of cereal based-diets for a more sustainable aquaculture.

Abstract 386: The Role of GAPDH in the Cardio-metabolic Response to Ischemia

Fundamental changes in nutrient metabolism underlie many disease processes, including obesity, diabetes, and cancer. Metabolic derangements are also a hallmark of heart disease, both in the context of failure and ischemia, and likely contributors to its etiology. For example, while the healthy heart favors fats as a fuel, failing hearts will consume more glucose; but it is unclear if this is pathological or protective. It is very likely that manipulation of metabolic pathways can affect, and possibly augment and protect, heart function. Yet no drug therapy exists that targets cardiac metabolism. Staples of ischemic disease management largely focus on anti-platelet, cholesterol-lowering, and beta-adrenergic blocking regimens. Heart failure medicines focus on maladaptive neuro-hormonal responses, a strategy several decades old. Our goal here is to delineate exactly how critical aspects of metabolism are altered in cardiac ischemia, and to identify new targets of pharmacological intervention. Metabolism largely remains unexplored because of its intricate network of regulation, compounded by the fact that variations in this network will often escape traditional methods of gene expression profiling. But by using high throughput metabolomic and proteomic platforms, we have striking evidence that the glycolytic enzyme glyceraldehyde 3-phosphate dehydrogenase (GAPDH) is instrumental in the heart’s response to ischemia. Dynamic, real-time metabolomic flux using heavy carbon isotope labeling points toward a partial shift of glycolytic intermediates toward lipid synthesis during ischemic stress in cardiomyocytes, precisely at the step catalyzed by GAPDH. Expansive phospho-proteomic analyses from Langendorff ex vivo hanging heart experiments show that this shift in metabolism may be triggered by an inhibitory phosphorylation of GAPDH. Our hypothesis that glycolysis is in part rerouted toward triglyceride synthesis is a revolutionary departure from decades-old perceptions of energy management. Modulating GAPDH function, either directly or indirectly via partner proteins, may offer insight into untapped areas of therapy. Our early attempts with chemicals that inhibit GAPDH already show heart cells with improved survival under ischemia.

Oral and intestinal sweet and fat tasting: impact of receptor polymorphisms and dietary modulation for metabolic disease.

The human body has evolved with a disposition for nutrient storage, allowing for periods of irregular food availability and famine. In contrast, the modern diet is characterized by excessive consumption of fats and sugars, resulting in a surge in the rates of obesity and type 2 diabetes. Although these metabolic disorders arise from a complex interaction of genetic, social, and environmental factors, evidence now points to fundamental changes in nutrient metabolism at the cellular level contributing to the underlying pathology. Taste receptors detect nutrients in the oral cavity and gastrointestinal tract and can influence the hormonal response to nutrients; they may also become maladaptive in conditions of excess fat or sugar consumption. Precise links between taste receptor activity, and downstream effects on energy intake and glycemia are not well defined. This review outlines the candidate taste receptors for carbohydrates and fats in the oral cavity and within the small intestine, highlighting the contributions of underlying genetics (polymorphisms) and sensory challenges (e.g., a high-fat diet) to the development of obesity and type 2 diabetes.

High or low dietary carbohydrate:protein ratios during first-feeding affect glucose metabolism and intestinal microbiota in juvenile rainbow trout.

Based on the concept of nutritional programming in mammals, we tested whether an acute hyperglucidic-hypoproteic stimulus during first feeding could induce long-term changes in nutrient metabolism in rainbow trout. Trout alevins received during the five first days of exogenous feeding either a hyperglucidic (40% gelatinized starch + 20% glucose) and hypoproteic (20%) diet (VLP diet) or a high-protein (60%) glucose-free diet (HP diet, control). Following a common 105-day period on a commercial diet, both groups were then challenged (65 days) with a carbohydrate-rich diet (28%). Short- and long-term effects of the early stimuli were evaluated in terms of metabolic marker gene expressions and intestinal microbiota as initial gut colonisation is essential for regulating the development of the digestive system. In whole alevins (short term), diet VLP relative to HP rapidly increased gene expressions of glycolytic enzymes, while those involved in gluconeogenesis and amino acid catabolism decreased. However, none of these genes showed persistent molecular adaptation in the liver of challenged juveniles (long term). By contrast, muscle of challenged juveniles subjected previously to the VLP stimulus displayed downregulated expression of markers of glycolysis and glucose transport (not seen in the short term). These fish also had higher plasma glucose (9 h postprandial), suggesting impaired glucose homeostasis induced by the early stimulus. The early stimulus did not modify the expression of the analysed metabolism-related microRNAs, but had short- and long-term effects on intestinal fungi (not bacteria) profiles. In summary, our data show that a short hyperglucidic-hypoproteic stimulus during early life may have a long-term influence on muscle glucose metabolism and intestinal microbiota in trout.

Microgravity alters the physiological characteristics of Escherichia coli O157:H7 ATCC 35150, ATCC 43889, and ATCC 43895 under different nutrient conditions.

The aim of this study is to provide understanding of microgravity effects on important food-borne bacteria, Escherichia coli O157:H7 ATCC 35150, ATCC 43889, and ATCC 43895, cultured in nutrient-rich or minimal medium. Physiological characteristics, such as growth (measured by optical density and plating), cell morphology, and pH, were monitored under low-shear modeled microgravity (LSMMG; space conditions) and normal gravity (NG; Earth conditions). In nutrient-rich medium, all strains except ATCC 35150 showed significantly higher optical density after 6 h of culture under LSMMG conditions than under NG conditions (P < 0.05). LSMMG-cultured cells were approximately 1.8 times larger than NG-cultured cells at 24 h; therefore, it was assumed that the increase in optical density was due to the size of individual cells rather than an increase in the cell population. The higher pH of the NG cultures relative to that of the LSMMG cultures suggests that nitrogen metabolism was slower in the latter. After 24 h of culturing in minimal media, LSMMG-cultured cells had an optical density 1.3 times higher than that of NG-cultured cells; thus, the higher optical density in the LSMMG cultures may be due to an increase in both cell size and number. Since bacteria actively grew under LSMMG conditions in minimal medium despite the lower pH, it is of some concern that LSMMG-cultured E. coli O157:H7 may be able to adapt well to acidic environments. These changes may be caused by changes in nutrient metabolism under LSMMG conditions, although this needs to be demonstrated in future studies.

GPR43 regulates metabolic function in skeletal muscle cells

Introduction: Preliminary data suggests a putative role for GPR43 in regulating systemic health via processes including adipogenesis, inflammation and secretion of gastrointestinal peptides. This suggests GPR43 may have a role in weight control. Given muscle is a major determinant of systemic metabolic health and energy balance, we sought to characterise the effect of activating GPR43 in skeletal and cardiac muscle cells. Methods: C2C12 skeletal muscle myotubes and H9c2 cardiac muscle myoblasts were exposed to a GPR43 specific phenylacetamide (PA) agonist (70 nM to 7 M) for 15min (n = 5—8/group). Protein expression was quantified by Western blotting. Metabolic activity of C2C12 and H9c2 cells treated with PA was determined via MTT assay (n = 10—12/group). Results: In C2C12 myotubes 70 nM PA significantly up-regulated total JNK and AMPK proteins compared to control (p≤ 0.05). There was no change in the phosphorylation of these markers or the abundance of total or phosphorylated ERK1/2 protein at any dose used. Metabolic activity in C2C12 myotubes was decreased at 70 nM and 7 M PA compared to control (p≤ 0.05). Interestingly, PA treatment did not alter protein expression or metabolic activity in H9c2 myoblasts. Conclusion: These data suggest GPR43 may have a specific role in mediating skeletal muscle metabolic function. Decrements in metabolic activity in C2C12 myotubes imply GPR43 agonism may impinge upon nutrient metabolism in skeletal muscle. This has the potential to promote aberrations of systemic metabolic health. Thus, targeting GPR43 may form a novel means of treating obesity and type 2 diabetes mellitus in which skeletal muscle fatty acid and glucose metabolism is perturbed. Further work is needed to clarify the signaling pathways mediating decreased metabolic activity and how this relates to functional changes in nutrient metabolism. LMC was supported by a scholarship (PB 10M 5472) from the National Heart Foundation of Australia.

Immunity lessons and actions: Practical implications

Nutritional approaches can be used to improve disease resistance while mitigating the negative impact of immunity on bird performance. Supplying dietary nutrients at the appropriate times and amounts is critical for the development, maintenance, and function of the immune system. The immune system consists of multiple tissues and cell types, and when combined with the diversity of pathogens and routes of infection, the complexity of assigning nutrient requirements for immunity becomes apparent. Activation of the immune system reduces bird performance because of decreased food intake and changes in nutrient metabolism. Understanding the purpose of altered nutrient metabolism may help researchers develop nutritional strategies that complement, or support, the purpose of these catabolic responses to infection. Consequently, providing nutritional support to the immune system during times of critical need may help to mitigate the overall catabolic response to infection. To do so, the proper tools are needed for assessment and understanding of the desired responses from the immune system to particular pathogens. The immune system is dynamic and complex and requires proper care and feeding.

The effects of anAspergillus oryzaeextract containing alpha-amylase activity on ruminal fermentation and milk production in lactating Holstein cows

AbstractThe effects of anAspergillus oryzaeextract containing alpha-amylase activity (Amaize™, Alltech Inc., Nicholasville, KY) were examinedin vivoandin vitro. A lactating cow study employed 20 intact and four ruminally fistulated Holstein cows in a replicated 4 × 4 Latin-square design to examine the effects of four concentrations of dietary Amaize™ extract on milk production and composition, ruminal fermentation and serum metabolite concentrations. The treatment diets contained 0, 240, 480 or 720 alpha-amylase dextrinizing units (DU) per kg of total mixed ration (TMR) (dry-matter basis). The supplemental alpha-amylase increased the yields of milk (P= 0·02), fat (P= 0·02) and protein (P= 0·06) quadratically. The maximum milk yield was obtained when 240 DU per kg of TMR were offered. Ruminalin situstarch disappearance was not affected by alpha-amylase supplementation in lactating cows or ruminally cannulated steers. Supplemental alpha-amylase extract reduced the molar proportion of propionate in the rumen of steers (P= 0·08) and lactating cows (P= 0·04), and in rumen-simulating cultures (P= 0·04). The supplement also increased the molar proportions of acetate (P= 0·06) and butyrate (P= 0·05), and the serum beta-hydroxybutyrate (P= 0·01) and non-esterified fatty acid (P= 0·03) concentrations in lactating cows. The improvements in milk production appear to be a consequence of the effects of alpha-amylase on ruminal fermentation and the potential changes in nutrient metabolism that result from them. We conclude that supplemental alpha-amylase may be given to modify ruminal fermentation and improve milk and component yield in lactating Holstein cattle.

Cloning and establishment of a line of rats for high levels of voluntary wheel running

We generated an original Wistar line of rats that displayed increased levels of wheel running, which we named SPORTS (Spontaneously-Running-Tokushima-Shikoku). Male SPORTS rats ran voluntarily in a running wheel almost six times longer than male control Wistar rats, established without selection for their running activity. The running phenotype of female SPORTS rats was the same as female control Wistar rats. However, male offspring from the cross-mating between a female SPORTS rat and a male control rat also showed a similar level of hyper-running activity as the original SPORTS line. Compared to control rats, male SPORTS rats had lower levels of mean body weight, abdominal fat and plasma insulin after 4 weeks of running. It is likely that all these beneficial changes observed in the SPORTS rats reflected the increases in glucose disposal we observed in oral glucose tolerance tests carried out on the animals. We also found hyper-running caused a significant increase in skeletal muscle oxidative capacity, measured as the ratio of malate dehydrogenase to phosphofructokinase activity, an index of aerobic metabolism. These results indicate that the SPORTS rat may be a good animal model for determining the mechanisms responsible for up-regulation of running motivation, in addition to investigating changes in nutrient metabolism induced by high intensity exercise.

Modulation of nutrient metabolism and homeostasis by the immune system

Interactions between nutrition and immunity are diverse and have profound implications on animal growth and productivity. The innate immune system provides protection during the initial stages of infection and is responsible for mediating many of the alterations in nutrient metabolism. The macrophage is the key sensory and regulatory cell of the innate immune system. Their pro-inflammatory cytokines coordinate local immunity to pathogens, yet also act systemically to alter metabolic homeostasis and decrease food intake and growth rate. Altered energy, amino acid, lipid, and mineral metabolism have nutritionally important implications. For example, an innate immune response results in decreased uptake of amino acids by skeletal muscles and a corresponding increase in uptake by the liver and to a lesser extent by leukocytes. The net result is a decrease in amino acid requirements with no change in the efficiency of their use for growth. The shift in the priority of individual tissues for nutrients appears to be accomplished by changes in the types and amounts of their nutrient transporters and storage proteins. Adaptive immune responses result in considerably more subtle changes in nutrient metabolism than innate responses.

Modulation of nutrient metabolism and homeostasis by the immune system

Interactions between nutrition and immunity are diverse and have profound implications on animal growth and productivity. The innate immune system provides protection during the initial stages of infection and is responsible for mediating many of the alterations in nutrient metabolism. The macrophage is the key sensory and regulatory cell of the innate immune system. Their pro-inflammatory cytokines coordinate local immunity to pathogens, yet also act systemically to alter metabolic homeostasis and decrease food intake and growth rate. Altered energy, amino acid, lipid, and mineral metabolism have nutritionally important implications. For example, an innate immune response results in decreased uptake of amino acids by skeletal muscles and a corresponding increase in uptake by the liver and to a lesser extent by leukocytes. The net result is a decrease in amino acid requirements with no change in the efficiency of their use for growth. The shift in the priority of individual tissues for nutrients appears to be accomplished by changes in the types and amounts of their nutrient transporters and storage proteins. Adaptive immune responses result in considerably more subtle changes in nutrient metabolism than innate responses.

Characterization of the Fasting-induced Adipose Factor FIAF, a Novel Peroxisome Proliferator-activated Receptor Target Gene

Fasting is associated with significant changes in nutrient metabolism, many of which are governed by transcription factors that regulate the expression of rate-limiting enzymes. One factor that plays an important role in the metabolic response to fasting is the peroxisome proliferator-activated receptor alpha (PPARalpha). To gain more insight into the role of PPARalpha during fasting, and into the regulation of metabolism during fasting in general, a search for unknown PPARalpha target genes was performed. Using subtractive hybridization (SABRE) comparing liver mRNA from wild-type and PPARalpha null mice, we isolated a novel PPARalpha target gene, encoding the secreted protein FIAF (for fasting induced adipose factor), that belongs to the family of fibrinogen/angiopoietin-like proteins. FIAF is predominantly expressed in adipose tissue and is strongly up-regulated by fasting in white adipose tissue and liver. Moreover, FIAF mRNA is decreased in white adipose tissue of PPARgamma +/- mice. FIAF protein can be detected in various tissues and in blood plasma, suggesting that FIAF has an endocrine function. Its plasma abundance is increased by fasting and decreased by chronic high fat feeding. The data suggest that FIAF represents a novel endocrine signal involved in the regulation of metabolism, especially under fasting conditions.

Effects of three neurochemical stimuli on delayed feeding and energy metabolism

Infusions of norepinephrine (NE), the gamma-aminobutyric acid agonist, muscimol (MUS), or neuropeptide Y (NPY) into the paraventricular nucleus (PVN) of the hypothalamus all increase food intake. Such feeding may be due to direct activation of behavioral processes driving ingestion and/or to alterations in nutrient metabolism that feeding serves to normalize. To examine these possibilities, male Sprague–Dawley rats received PVN infusions of vehicle, 20 nmol NE, 1 nmol MUS or 100 pmol NPY at dark onset, then food intake was measured under three feeding conditions: (1) 1 and 2 h immediately after injections, (2) 1 h after a 1 h delay between injections and access to food, and (3) 1 h after a 1 h feeding delay, but with injections occurring just before presenting food. Measures of energy expenditure (EE) and respiratory quotients (RQs) in the absence of food were made over 2 h in parallel experiments. Results confirmed that NE, MUS and NPY all increased dark-onset feeding, but only NPY increased intake above control levels after a 1 h feeding delay. No neurochemically-induced changes in EE were observed, nor were there changes in RQs after NE or MUS. However, NPY reliably enhanced RQs from 30 to 120 min of testing. Our findings imply that NE and MUS initiate relatively immediate, short-term feeding that is not associated with changes in nutrient metabolism and does not summate with cues stimulated by delayed access to food. NPY initiates more protracted feeding temporally linked to enhanced carbohydrate metabolism. This may indicate that part of NPY’s feeding stimulatory effects are secondary to physiological processes driving ingestion.