Dietary Carbohydrate Levels Research Articles

Modulation of growth, antioxidant status, hepatopancreas morphology, and carbohydrate metabolism mediated by alpha-lipoic acid in juvenile freshwater prawns Macrobrachium nipponense under two dietary carbohydrate levels

Carbohydrate is commonly used in aquatic organism as the cheapest energy source. However, most aquatic animals are low efficient in utilizing dietary carbohydrate for energy provision. Therefore, improving the utilization efficiency of high carbohydrate by aquatic organisms is important for sustainable aquaculture development. Alpha-lipoic acid (α-LA) is a cofactor of key enzymes involved in glucose metabolism. However, its role in regulation of carbohydrate metabolism in aquatic animals is currently unknown. This study investigated the effects of α-LA on growth, antioxidant status, hepatopancreas morphology, and carbohydrate metabolism of freshwater prawns Macrobrachium nipponense under two dietary carbohydrate levels. Six diets were formulated using casein and fish meal as the protein sources, fish oil and soybean oil as the lipid sources, and corn starch as the carbohydrate source, at two carbohydrate levels (15% and 30%) and three concentrations of α-LA supplementation (0, 700, and 1400 mg/kg). Each experimental diet was fed to juvenile prawns (mean weight 0.050 ± 0.003 g), twice daily to apparent satiation, in five replicates. In the 15% (low)-carbohydrate groups, weight gain was significantly reduced in prawns fed 1400 mg/kg α-LA compared with 0 or 700 mg/kg α-LA, but there was no significant effect in the 30% (high)-carbohydrate groups. Survival was significantly higher among prawns fed 700 mg/kg α-LA compared with 0 or 1400 mg/kg α-LA regardless of the carbohydrate level. The levels of dietary carbohydrate and α-LA also significantly affected the activities of key enzymes involved in glycolysis and the citric acid cycle. The activities of hexokinase and pyruvate kinase activities were highest in prawns fed l400 mg/kg α-LA, in both the low- and high-carbohydrate groups. Supplementation with 700 or 1400 mg/kg α-LA significantly increased the activities of 6-phosphofructokinase, pyruvate dehydrogenase, and succinate dehydrogenase regardless of the carbohydrate level. The level of malondialdehyde decreased significantly with increased α-LA supplementation; in contrast, the levels of superoxide dismutase, glutathione peroxidase, and glutathione were significantly higher in prawns fed 700 or 1400 mg/kg α-LA when compare with those fed no α-LA supplement. Dietary α-LA did not affect the overall morphology of the hepatopancreas, but 1400 mg/kg α-LA reduced the number of B (blister-like) cells. Thus, 700 mg/kg α-LA supplementation under either dietary carbohydrate level could improve the antioxidant status, carbohydrate metabolism, and morphology of the hepatopancreas in juveniles of M. nipponense. We conclude that α-LA supplementation can be used to improve the efficiency of carbohydrate utilization when a 30% carbohydrate diet is used for this prawn.

Carbohydrate-restricted diets and Type 1 diabetes mellitus: research considerations.

Type 1 diabetes mellitus (T1DM) is managed via careful control of blood glucose, exogenous insulin, diet, exercise, and other physiologic factors. Interestingly, the dietary recommendations for T1DM have had very little systematic research. Many clinical observations, as well as emerging research studies, have noted that a carbohydrate-restricted diet can lead to normalization of blood glucoses with reduction in hypoglycemic reactions among motivated individuals. In this paper, we review observations of carbohydrate restriction and propose a series of studies to test two levels of dietary carbohydrate intake for the management of individuals affected by T1DM. We recommend that the studies start in otherwise healthy adults with hemoglobin A1c > 8%, and then progress to more complicated populations including children, those with secondary complications and/or good glycemic control. Larger, long-term studies would then address growth in children, and diabetic complications including cardiovascular outcomes. Due to the clinical observations of improvements using carbohydrate-restricted nutrition for T1DM, we recommend that these types of studies addressing the level of dietary carbohydrate be urgently conducted.

Metabolic responses of Chinese perch (Siniperca chuatsi) to different levels of dietary carbohydrate.

There are great differences in metabolic responses to different levels of carbohydrate among different carnivorous fish species. To explore metabolic responses of Chinese perch to moderate and high level of dietary carbohydrates, three diets containing 7.3% (LC), 17.5% (MC), and 27.5% (HC) of carbohydrates were provided to Chinese perch for 56days. The results showed that MC and HC groups exhibited an increase in weight gain (WG) and hepatic glycogen content, and a decrease in feed conversion efficiency, compared with the LC group. The MC and HC groups also showed the increase in mRNA levels of phosphofructokinase and citrate synthase related to the aerobic oxidation pathway, which might be responsible for the increase in WG. Moreover, compared with the LC group, the HC group exhibited high levels of plasma indices (glucose, pyruvic acid, lactic acid, total triglyceride, total cholesterol, and low-density lipoprotein) and liver lipid resulting from the increased mRNA levels of fatty acid synthesis-related genes (ATP citrate lyase, acetyl-CoA carboxylase α, and fatty acid synthase), low level of crude protein caused by inhibition of TOR pathway, and liver damage induced by low antioxidant capacity and infiltration of inflammatory cells, but the MC group did not. The above results indicated that 17.5% dietary carbohydrate might be utilized effectively in Chinese perch and part carbohydrates were converted into glycogen to maintain glucose homeostasis; 27.5% dietary carbohydrate could not be fully utilized. The 27.5% carbohydrate diet induced the up-regulation of aerobic oxidation, glycogen synthesis, and fat synthesis pathways which might not be sufficient to maintain glucose homeostasis.

Dietary Carbohydrate and Protein Levels Affect the Growth Performance of Juvenile Peanut Worm (Sipunculus nudus): An LC–MS-Based Metabolomics Study

The peanut worm (Sipunculus nudus) is an economically important fishery resource in China. To determine how dietary carbohydrate and protein levels affect the growth performance of juvenile S. nudus and identify the mechanisms underlying observed patterns, five isoenergetic and isolipidic diets with different levels of carbohydrate and protein were formulated and fed to juvenile S. nudus; the experimental groups were referred to as EG1, EG2, EG3, EG4, and EG5, respectively. After 90 days of feeding, S. nudus had significantly lower survival rates when fed D5 compared with other diets (P < 0.05), and the highest survival rate was observed in EG2 individuals. The weight gain rate and specific growth rate were significantly higher in EG2 compared with the other groups (P < 0.05). Metabolomic profiling using liquid chromatography–mass spectrometry revealed 83 significantly differential metabolites (POS: 59; NEG: 24), which were identified via an in-house MS2 database. Pathway analysis indicated that the significantly different metabolites were involved in 22 metabolic pathways (POS: 9; NEG: 13), including tyrosine, phenylalanine, and tryptophan biosynthesis; phenylalanine metabolism; D-glutamate and D-glutamine metabolism; proline and arginine metabolism; aspartate, alanine, and glutamate metabolism; and aminoacyl-tRNA biosynthesis. These analyses implied that the biosynthetic capabilities of juvenile S. nudus were greater in the EG2. The results of this research enhance our understanding of the effects of dietary carbohydrate and protein levels on the growth performance of juvenile S. nudus.

Interactions of dietary carbohydrate and vitamin D3 on growth performance, insulin signaling pathway and glucose metabolism in juvenile abalone Haliotis discus hannai

A 115-day feeding trial was conducted to investigate the effect of dietary carbohydrate and vitamin D3 levels, and their interactions on growth performance, body composition, insulin signaling pathway and glucose metabolism in juvenile abalone Haliotis discus hannai (initial body weight: 2.06 ± 0.01 g). Nine experimental diets in a 3 × 3 two-factor design were formulated with different carbohydrate levels (27.5%, 32% and 36.5%) and vitamin D3 levels (0, 1000 IU/kg and 5000 IU/kg). Results showed that the highest specific growth rate (SGR) of abalone was observed in the treatment with 36.5% of dietary carbohydrate and 1000 IU/kg of vitamin D3. The serum glucose, body crude lipid and muscle glycogen contents of abalone significantly increased with increasing dietary carbohydrate levels (P < 0.05). Diet with 1000 IU/kg of vitamin D3 significantly reduced the serum glucose and body crude lipid content (P < 0.05). Significant interactions between dietary carbohydrate and vitamin D3 were observed in SGR and crude lipid content (P < 0.05). Diet with 36.5% carbohydrate up-regulated the expression of pyruvate kinase, glucose-6-phosphate dehydrogenase (G6PDH), insulin receptor (IR), insulin receptor substrate (IRS), protein kinase B (Akt), glycogen synthase and glycogen phosphorylase (PYG), whereas decreased the phosphoenolpyruvate carboxykinase (PEPCK), glucose-6-phosphatase (G6P) and glycogen synthesis kinase-3β. Diet with 1000 IU/kg of vitamin D3 significantly up-regulated the hexokinase, IR, IRS, Akt and glucose transporter 1 mRNA levels, whereas decreased the G6PDH (P < 0.05). The interaction between dietary carbohydrate and vitamin D3 were significant on PEPCK, G6P, G6PDH and PYG mRNA levels (P < 0.05). In conclusion, dietary carbohydrates and vitamin D3 could affect glucose metabolism by regulating glycolysis, gluconeogenesis and pentose phosphate pathway in abalone. Besides, they triggered the insulin signaling pathway, and further influence glucose transport and glycogen synthesis, which could promote the utilization of carbohydrate in abalone.

Interactive effects of dietary biotin and carbohydrate on growth performance and glucose metabolism in juvenile turbot Scophthalmus maximus L.

A 10-week feeding trial was conducted to explore the effects of dietary biotin and carbohydrate and their interactions on the growth performance and glucose metabolism in juvenile turbot (Scophthalmus maximus L.). Six isonitrogenous and isolipidic diets from a 2 × 3 factorial design was formulated with two levels of carbohydrate (16% and 25%) and three levels of biotin (0 mg/kg, 0.25 mg/kg and 1.5 mg/kg) respectively. The results showed that juvenile turbots fed with 16% of dietary carbohydrate and 1.5 mg/kg of biotin had the highest specific growth rate (SGR) and higher activities of intestinal amylase and stomach pepsin. Dietary biotin lowered the postprandial plasma glucose at 9 h and 24 h, regardless of dietary carbohydrate levels. However, postprandial plasma glucose at 24 h in groups with 25% of dietary carbohydrate was consistently higher than those in groups with 16% of dietary carbohydrate, regardless of dietary biotin levels. In conclusion, dietary biotin significantly decreased plasma glucose by increasing insulin level in plasma, activating PI3K (phosphoinositide 3-kinase)/AKT (protein kinase b) signaling pathway, promoting glucose transportation, glycolysis, pentose phosphate pathway and glycogen synthesis but inhibiting gluconeogenic pathway. Compared with the increased plasma glucose and growth inhibition in juvenile turbot caused by excessive dietary carbohydrate level (25%), however, the hypoglycemic effect of biotin is limited.

Association of diet diversity score with visceral adiposity in women with polycystic ovarian syndrome

Abstract Aim to investigate dietary intake levels of Saudi females with and without polycystic ovary syndrome)PCOS( and to evaluate their diet diversity and its relationship to visceral adiposity. Methods The present case-control study included 90 PCOS patients and 90 healthy controls whose age and body mass index were matched. Data collected using a structured questionnaire including sociodemographic variables, medical history, food frequency questionnaire, and physical activity records. Anthropometric measures were taken and fasting blood samples were obtained for subsequent metabolic and hormonal assays. Results Lipid accumulation product and visceral adiposity index were significantly higher among patients with PCOS than their control counterparts (p 0.05). Women with PCOS had significantly higher intake levels of dietary energy, carbohydrates, proteins and total fat than their controls (p Conclusions Women with PCOS had more diverse diet and less physical activity compared with controls, highlighting future targets for lifestyle interventions in PCOS.

Dietary taurine modulates hepatic oxidative status, ER stress and inflammation in juvenile turbot (Scophthalmus maximus L.) fed high carbohydrate diets

This study was conducted to explore the beneficial role of taurine against chronic high carbohydrate diet-induced oxidative stress, endoplasmic reticulum (ER) stress and inflammation, and to understand the underlying molecular mechanisms in turbot. Two 10-week feeding trials were simultaneously conducted. For the one, six experimental diets with graded levels of taurine supplementation (0, 0.4%, 0.8%, 1.2%, 1.6% and, 2.0%, respectively) and 15% of carbohydrate were used. For the other one, three graded levels of dietary taurine supplementation (0.4%, 1.2% and 2.0%, respectively) with 21% of carbohydrate were used. The results showed that higher expression level of inflammation cytokines and ER stress related genes were detected in higher dietary carbohydrate group. In both feeding trials, 1.2% of dietary taurine supplementation improved anti-oxidative status by decreasing the content of malondialdehyde, increasing the catalase activity and total anti-oxidative capacities. In feeding trial 1, appropriate taurine supplementation lowered contents of tumour necrosis factor-a, interleukin-6, aspartate aminotransferase and alkaline phosphatase in plasma, and decreased the expressions of pro-inflammatory cytokines, such as interleukin-8 (il-8) and interferon‐γ (ifn-γ). Furthermore, dietary taurine reduced ER stress by decreasing the mRNA levels of activating transcription factor 6, protein kinase R-like endoplasmic reticulum kinase and G protein-coupled receptor 78. The optimal dietary taurine content was estimated as 1.40% based on the analysis of specific growth rate. In feeding trial 2, dietary taurine supplementation attenuated liver inflammation partly referring to significantly down-regulated mRNA levels of nuclear transcription factor‐κB p65, ifn-γ, interleukin1β and up-regulate the transcript of ribosomal protein S6 kinase 1. Dietary taurine supplementation in feeding trial 2 significantly increased the Nrf2-related factor 2 protein level and decreased the NFκB p65 protein level only at 21% of dietary carbohydrate level. Taurine can alleviate the oxidative damage and inflammation caused by 21% of dietary carbohydrate to a certain degree. Overall, the present study confirmed that dietary taurine supplementation improved growth performance and anti-oxidative response, and reduced liver inflammatory and ER stress processes induced by high dietary carbohydrate in turbot.

Dietary carbohydrates influence muscle texture of olive flounder Paralichthys olivaceus through impacting mitochondria function and metabolism of glycogen and protein

The present study was conducted to estimate the effects of dietary carbohydrates on muscle quality and the underlying mechanisms. Six isonitrogenous and isolipidic diets were formulated to contain graded levels of carbohydrates (0%, 8%, 12%, 16%, 20% and 24%, respectively). These diets were named as C0, C8, C12, C16, C20 and C24, respectively. After a 10-week feeding trial, results showed that the muscle pH, liquid holding capacity (LHC) and hardness were significantly decreased by the increasing dietary carbohydrate levels. Dietary carbohydrates significantly decreased the muscle fibre diameter, and the highest value was found in the C0 group. Accumulated glycogen and degenerated mitochondrial cristae were observed in the C24 group. Significantly higher contents of protein carbonyls were observed in the C20 group and C24 group (P < 0.05). There was a significant decrease of mtDNA copy number in the C24 group compared with that in the C0 and C8 groups. The AMP/ATP ratio in muscle decreased first and then increased with the increasing dietary carbohydrate levels. The dietary incorporation of carbohydrate significantly reduced the expression of opa1, pygm and genes involved in myogenesis (myf5 and myog). Meanwhile, proteolysis-related genes (murf-1, mafbx, capn2 and ctsl), pro-inflammatory cytokines (il-6 and tnf-α) and mstn were significantly up-regulated. In the C24 group, significant increase of phosphorylation of AMPK (Thr172), up-regulation of PGC-1α and GLUT4 were observed, while the phosphorylation level of S6 (Ser235/236) was significantly decreased. It was concluded that excessive dietary carbohydrate level (24%) had negative impacts on mitochondria function and promoted glycogen accumulation, and thereafter influenced the muscle quality of olive flounder. The activation of AMPK as well as the upregulation of PGC-1α and GLUT4 was the key mechanism.

Alleviation of the Adverse Effect of Dietary Carbohydrate by Supplementation of Myo-Inositol to the Diet of Nile Tilapia (Oreochromis niloticus).

Simple SummaryRecently, the price escalation of fishmeal has made aquaculture nutritionists to consider using carbohydrate in aquafeed to spare the use of dietary protein. However, the high carbohydrate diet could induce lipid metabolism disorder, impair antioxidant capacity, reduce nonspecific immunity and decrease resistance to a pathogen in farmed fish. Myo-inositol is regarded as a vitamin-like essential nutrient for most aquatic animals. Previous studies have shown that dietary supplementation with myo-inositol can reduce lipid accumulation in tissues and decrease the chance of becoming a fatty liver. To explore the mechanism of myo-inositol on alleviating the adverse effect of the high carbohydrate diet in Nile tilapia, six diets contained either low carbohydrate (30%) or high carbohydrate (45%) with three levels of myo-inositol supplementation (0, 400 and 1200 mg/kg diet) to each level of the carbohydrate diet. After an 8-week trial, the result showed that additive myo-inositol in the diet could significantly improve the growth performance and increase the crude protein content of fish. The addition of myo-inositol could effectively decrease the lipid accumulation induced by the high carbohydrate diet by accelerating the transportation of cholesterol back to the liver and promoting the lipid decomposition.This study investigated the effect of dietary myo-inositol (MI) on alleviating the adverse effect of the high carbohydrate diet in Nile tilapia (Oreochromis niloticus). Six diets contained either low carbohydrate (LC 30%) or high carbohydrate (HC 45%) with three levels of MI supplementation (0, 400 and 1200 mg/kg diet) to each level of the carbohydrate diet. After an 8-week trial, the fish fed 400 mg/kg MI under HC levels had the highest weight gain and fatness, but the fish fed 1200 mg/kg MI had the lowest hepatosomatic index, visceral index and crude lipid in the HC group. The diet of 1200 mg/kg MI significantly decreased triglyceride content in the serum and liver compared with those fed the MI supplemented diets regardless of carbohydrate levels. Dietary MI decreased triglyceride accumulation in the liver irrespective of carbohydrate levels. The content of malondialdehyde decreased with increasing dietary MI at both carbohydrate levels. Fish fed 1200 mg/kg MI had the highest glutathione peroxidase, superoxide dismutase, aspartate aminotransferase and glutamic-pyruvic transaminase activities. The HC diet increased the mRNA expression of key genes involved in lipid synthesis (DGAT, SREBP, FAS) in the fish fed the diet without MI supplementation. Dietary MI significantly under expressed fatty acid synthetase in fish fed the HC diets. Moreover, the mRNA expression of genes related to lipid catabolism (CPT, ATGL, PPAR-α) was significantly up-regulated with the increase of dietary MI levels despite dietary carbohydrate levels. The gene expressions of gluconeogenesis, glycolysis and MI biosynthesis were significantly down-regulated, while the expression of the pentose phosphate pathway was up-regulated with the increase of MI levels. This study indicates that HC diets can interrupt normal lipid metabolism and tend to form a fatty liver in fish. Dietary MI supplement can alleviate lipid accumulation in the liver by diverging some glucose metabolism into the pentose phosphate pathway and enhance the antioxidant capacity in O. niloticus.

Responses of glycolysis, glycogen accumulation and glucose-induced lipogenesis in grass carp and Chinese longsnout catfish fed high-carbohydrate diet

This study investigated the different adaptive metabolic strategies of grass carp (Ctenopharyngodon idellus) and Chinese longsnout catfish (Leiocassis longirostris Günther) to a high-carbohydrate diet (HCD). Two dietary carbohydrate levels were formulated for grass carp (normal-carbohydrate diet [NCD]: 30%; HCD: 50%) and Chinese longsnout catfish (NCD: 8%; HCD: 20%). Based on transcriptome data, the top twenty KEGG pathway enrichment analyses indicated that five pathways related to carbohydrate metabolism were enriched in grass carp that were fed an HCD, but were not in Chinese longsnout catfish. After 56 d, compared to the fish in the NCD group, grass carp fed an HCD exhibited significant increase in their whole-body lipid content and glucose-induced lipogenesis, including fatty acid synthase content and transcriptional levels of acetyl-CoA carboxylase, sterol regulatory element-binding protein-1, and carbohydrate response element-binding protein. Raised hepatic glycogen content was observed in both grass carp and Chinese longsnout catfish that were fed an HCD. The enhanced glycogen synthesis, including induced glycogen synthase activity and upregulation of mRNA levels of glycogen synthase and serine/threonine-protein phosphatase PP1-beta catalytic subunit, led to accumulation of glycogen in grass carp. However, reduced glycogenolysis with downregulation of the transcriptional levels of phosphorylase kinase regulatory subunit alpha and glycogen phosphorylase caused accumulation of glycogen in Chinese longsnout catfish. In addition, significantly increased intestinal amylase activity and induced glycolysis of glucokinase and pyruvate kinase were observed in grass carp that were fed an HCD. The results indicated that grass carp responded effectively to an HCD by induction of glycolysis, glycogen accumulation and glucose-induced lipogenesis, while Chinese longsnout catfish did not.

Effects of dietary carbohydrate level on growth performance, innate immunity, antioxidant ability and hypoxia resistant of brook trout Salvelinus fontinalis

Effects of dietary carbohydrate level on growth performance, innate immunity, antioxidant ability and hypoxia resistant of brook trout <i>Salvelinus fontinalis</i>

COVID-19: Proposing a Ketone-Based Metabolic Therapy as a Treatment to Blunt the Cytokine Storm.

Human SARS-CoV-2 infection is characterized by a high mortality rate due to some patients developing a large innate immune response associated with a cytokine storm and acute respiratory distress syndrome (ARDS). This is characterized at the molecular level by decreased energy metabolism, altered redox state, oxidative damage, and cell death. Therapies that increase levels of (R)-beta-hydroxybutyrate (R-BHB), such as the ketogenic diet or consuming exogenous ketones, should restore altered energy metabolism and redox state. R-BHB activates anti-inflammatory GPR109A signaling and inhibits the NLRP3 inflammasome and histone deacetylases, while a ketogenic diet has been shown to protect mice from influenza virus infection through a protective γδ T cell response and by increasing electron transport chain gene expression to restore energy metabolism. During a virus-induced cytokine storm, metabolic flexibility is compromised due to increased levels of reactive oxygen species (ROS) and reactive nitrogen species (RNS) that damage, downregulate, or inactivate many enzymes of central metabolism including the pyruvate dehydrogenase complex (PDC). This leads to an energy and redox crisis that decreases B and T cell proliferation and results in increased cytokine production and cell death. It is hypothesized that a moderately high-fat diet together with exogenous ketone supplementation at the first signs of respiratory distress will increase mitochondrial metabolism by bypassing the block at PDC. R-BHB-mediated restoration of nucleotide coenzyme ratios and redox state should decrease ROS and RNS to blunt the innate immune response and the associated cytokine storm, allowing the proliferation of cells responsible for adaptive immunity. Limitations of the proposed therapy include the following: it is unknown if human immune and lung cell functions are enhanced by ketosis, the risk of ketoacidosis must be assessed prior to initiating treatment, and permissive dietary fat and carbohydrate levels for exogenous ketones to boost immune function are not yet established. The third limitation could be addressed by studies with influenza-infected mice. A clinical study is warranted where COVID-19 patients consume a permissive diet combined with ketone ester to raise blood ketone levels to 1 to 2 mM with measured outcomes of symptom severity, length of infection, and case fatality rate.

Effect of different carbohydrate-to-lipid ratios elicits growth, feed utilization, lipid deposition and lipogenic enzyme activity in striped catfish (Pangasianodon hypophthalmus, Sauvage, 1878) fingerlings

This study evaluated the effects of diets containing various carbohydrate-to-lipid (CHO L-1) ratios on growth performance, nutrient utilization body indices and hepatic lipogenic enzyme (malic enzyme, 6-phosphogluconate dehydrogenase and fatty acid synthase) activities. Triplicate groups of Pangasianodon hypophthalmus fingerlings were fed eight isoenergetic and isonitrogenous diets with different carbohydrate-to-lipid ratios (0.51, 0.79, 1.12, 1.79, 2.41, 3.24, 4.43 and 7.62). Higher body fat deposition and lower growth performance were observed in P. hypophthalmus fingerlings fed with high-lipid diet than those fed with high-carbohydrate diet. The fish fed the diet with 7.62 CHO L-1 ratio exhibited significantly (p<0.05) higher hepatosomatic index compared to those fed higher lipid diets (0.51 and 0.79). High dietary carbohydrate level significantly increased (p<0.05) the activities of malic, 6-phosphogluconate dehydrogenase and fatty acid synthase enzyme. Based on the second-order polynomial regression analysis of weight gain, the optimal dietary carbohydrate and lipid contents for P. hypophthalmus fingerling were 304 and 103 g kg−1, respectively, which correspond to a dietary CHO L-1 ratio of 2.95.

Effects of dietary carbohydrate levels on growth, body composition, and gene expression of key enzymes involved in hepatopancreas metabolism in mud crab Scylla paramamosain

This study estimated the effects of different dietary carbohydrate levels on growth performance, feed utilization, body composition, and the gene expression of key enzymes involved in hepatopancreas lipogenesis and glucose metabolism in mud crab Scylla paramamosain. Crabs with an initial mean weight of 1.84 ± 0.06 g were used in an 8-week experiment to test five diets (C6, C12, C18, C24, C30) formulated to contain increasing levels of carbohydrate, measured as 8.55%, 13.36%, 17.76%, 25.64% and 32.50%, respectively. The results showed that the levels 25.64% and 32.50% improved growth performance, with the best gains at 25.64%. The highest dietary carbohydrate level led to higher hemolymph glucose concentrations and more fat deposition in the body. Furthermore, real-time quantitative PCR analysis revealed that the mRNA expression of key enzymes in glycolytic and lipogenic metabolism (i.e. glucokinase, fructose-2,6-diphosphatase, and fatty acid synthetase) were significantly affected by the dietary carbohydrate level. The mRNA expression of glucokinase was lowest in the group fed the carbohydrate-rich C30 diet, and the mRNA of fructose-2 and 6-diphosphatase were remarkably expressed in the C24 group (P < .05). The mRNA expression of fatty acid synthase at the dietary carbohydrate levels 32.50% and 25.64% were respectively 10-fold and 5-fold greater than with 8.55% dietary carbohydrate. The overall data suggest that S. paramamosain can be fed 25.64%–32.50% carbohydrate to achieve satisfactory growth performance. A two-slope broken-line regression analysis of weight gain showed that 24.08% dietary carbohydrate would be optimal for this species reared under similar conditions.

Data on PCR primer design for glucose 6-phosphate dehydrogenase gene and the effects of dietary carbohydrate levels on its expression in the liver of Malaysian mahseer (Tor tambroides).

The enzyme glucose-6-phosphate dehydrogenase (G6PD) catalyses the metabolite glucose-6-phosphate in producing NADPH during the first phase of pentose-phosphate pathway thus provides reducing power to all cells for cellular growth, antioxidant defence, and biosynthetic reactions in all living organism. The deliberate inclusion of starch as carbohydrate source in commercial feed however may affect the G6PD hepatic activity in cultured fish. We designed a set of primers to target G6PD gene in the popular Malaysian aquaculture species, Tor tambroides. For this dataset, the molecular characteristics of obtained T. tambroides G6PD (TtG6PD) nucleotide sequence was analysed using multiple alignments and phylogenetic analyses of the deduced amino acids. The set of primers obtained were then used in a study to evaluate the effect of different dietary carbohydrate inclusion levels on the hepatic TtG6PD mRNA expression of the T. tambroides fingerlings. Four groups of fish were given a dietary treatment of 15%, 20%, 25% and 30% starch at the optimal inclusion level of 23.4% for 10 weeks. The TtG6PD mRNA transcripts were measured using real-time-PCR assays and its expression normalized against β-actin, which acts as the internal control gene. This article provides supportive data in relation between hepatic TtG6PD mRNA gene expression in T. tambroides and how it is influenced by its dietary carbohydrate intake. These data will also assist in further nutritional genomic studies of carbohydrate and energy utilization for all species in the mahseer family.

Interactions of Blood Serum, Urine and Fecal Metabolites of Cats Fed by Different Dietary Protein and Carbohydrate Levels

Abstract Objectives Because dietary protein and carbohydrate levels impact the gastrointestinal (GI) microbiome and host metabolism, this study evaluated their effect on serum, urine and fecal metabolites. Methods Three complete and balanced isocaloric foods (mean 3940 kcals/kg) were used. Their protein (P) and carbohydrate (CHO) levels were: LP (P: 25.84%, CHO: 46.9%), MP (P: 32.0%, CHO: 39.9%) and HP (P: 50.67%, CHO: 21.2%). The study used 30 adult healthy cats and a balanced Latin-Square design. Food offering was adjusted to maintain weight; cats were fed for 80 days before receiving the next food. This study was reviewed and approved by IACUC and all cats included in this study were allowed routine social activities. Serum (S), urine (U) and fecal (F) samples were collected at the end of each treatment period and analyzed for non-targeted metabolomics by Metabolon Inc. (Morrisville, NC). Data analysis was performed by using JMP v14.0. Variables with significance at P &amp;lt; 0.05 are reported. Results PCA analysis of S, U and F metabolites together shows that the cats fed HP clustered separately from the cats fed LP and MP foods. Independent PCA analysis of S, U and F metabolites revealed that F metabolites show clear separation from the cats fed HP compared with LP and MP foods. However, S and U metabolites did not show this. Fecal samples showed that carbohydrates, acylglycerols, endocannabinoids and bile acids metabolism was significantly impacted by HP when compared with LP and MP foods. This resulted in elevations of a number of toxic metabolites (e.g., 3-indoxyl sulfate, p-cresol sulfate and trimethylamine N-oxide). The F concentration of these metabolites was positively correlated to that of S and U. This positive relationship in all three sample types was not observed for acylglycerols, endocannabinoids and sugars suggesting that those metabolites were not absorbed and excreted as were the mentioned toxins. Conclusions Dietary P and CHO levels influence cat's GI metabolism with impacting specific urine and serum metabolites. Cats fed HP food had F increases of toxic metabolites related to renal and cardiovascular disorders and these metabolites were positively associated with S and U concentrations. Dietary P and CHO levels may directly impact renal and cardiovascular disorders. Funding Sources Hill's Pet Nutrition, Inc.

Trehalose metabolism confers developmental robustness and stability in Drosophila by regulating glucose homeostasis

Organisms have evolved molecular mechanisms to ensure consistent and invariant phenotypes in the face of environmental fluctuations. Developmental homeostasis is determined by two factors: robustness, which buffers against environmental variations; and developmental stability, which buffers against intrinsic random variations. However, our understanding of these noise-buffering mechanisms remains incomplete. Here, we showed that appropriate glycemic control confers developmental homeostasis in the fruit fly Drosophila. We found that circulating glucose levels are buffered by trehalose metabolism, which acts as a glucose sink in circulation. Furthermore, mutations in trehalose synthesis enzyme (Tps1) increased the among-individual and within-individual variations in wing size. Whereas wild-type flies were largely resistant to changes in dietary carbohydrate and protein levels, Tps1 mutants experienced significant disruptions in developmental homeostasis in response to dietary stress. These results demonstrate that glucose homeostasis against dietary stress is crucial for developmental homeostasis.

The effect of dietary protein, lipid, and carbohydrate levels on the performance, metabolic rate and nitrogen retention in juvenile European lobster (Homarus gammarus, L.)

Releasing hatchery-reared juveniles in the wild can mitigate the general decline in the natural stocks of European lobster, Homarus gammarus, L.. However, growth and survival rates in lobster culture are low, presumably due to suboptimal nutrition and feeding. With the aim of determining appropriate nutrient levels, we tested different formulated extruded feeds for the culture of juvenile European lobster. Baseline metabolism (standard metabolic rate, SMR), in combination with the metabolic cost of feeding (specific dynamic action, SDA), and nitrogen retention during digestion and assimilation was investigated for six experimental diets. Diets were formulated to contain two different levels of protein (400 and 500 g kg−1), with three lipid to carbohydrate (L:CHO) ratios (low, medium, and high). These experimental diets were tested over a 32-day period, against a conventional control diet (Antarctic krill, Euphausia superba). During this period, the growth performance of the juveniles was assessed as molting frequency, increments in carapace length and whole body wet weight. At the end of the growth performance trial, oxygen consumption (MO2) and nitrogen excretion rates of individual lobsters were determined prior to and following the ingestion of a single meal. Molting occurred more frequently in juveniles fed with krill and krill resulted in a significantly higher specific growth rate than experimental dry feeds except for the 500-low diet. However, lobsters fed any of the three 500 and the 400-low diets had carapace length increments, SMR, SDA, and nitrogen retention similar to those fed the krill diet. Results suggest that protein is an important macronutrient for juveniles of this species and must be included above 40%. Also, lobsters have a dietary requirement for carbohydrates ranging from 24% to 35% probably related to the need for glycogen in chitin synthesis. The lower the protein content, the higher the requirement in carbohydrates.

Early feeding with hyperglucidic diet during fry stage exerts long-term positive effects on nutrient metabolism and growth performance in adult tilapia (Oreochromis niloticus)

The present study aimed to investigate nutritional programming of carbohydrate metabolism in Nile tilapia. Early nutritional intervention stimulus was achieved by feeding fry with high-protein/low-carbohydrate (HP/LC) or low-protein/high-carbohydrate (LP/HC) diet since first feeding for 4 weeks, and the effect of nutritional stimulus on carbohydrate and its related metabolism was evaluated through the adult stage. Our findings indicated that at week 1, LP/HC diet-fed fry had lower levels of mRNA for genes coding gluconeogenesis and amino acid catabolism and higher levels of hk2 (P < 0⋅05). As expected, in adult tilapia, although LP/HC diet-fed fish had poorer growth (end of stimulus), the fish showed compensatory growth. There were permanent effects of early high-carbohydrate (HC) intake on several parameters, including (1) modulating hepatic composition, (2) increased muscle glycogen, (3) lower levels of enzymes involved in amino acid catabolism and (4) higher levels of glycolytic enzymes in glycolysis. Finally, HP/LC diet- and LP/HC diet-fed fish were challenged with different dietary carbohydrate levels. Irrespective of challenging diets, the early HC stimulus had significant effects on adult tilapia by (1) promoting utilisation of glucose, which had protein-sparing effects for better growth, (2) inducting lipogenesis and (3) decreasing amino acid catabolism. Taken together, for the first time, we demonstrated that early HC feeding was effective for positive nutritional programming of metabolism in Nile tilapia (an omnivorous fish). It led to the improvement of growth performance in adult fish associated with early feeding, which is linked to a better ability to use glucose, to induce lipogenesis, and to suppress amino acid catabolism.