L-glutamine Supplementation Research Articles

Effect of Oral Supplementation of Putrescine and L-glutamine on the Histomorphology of Small Intestine and Growth Performance in Broiler Chickens

A work was conducted to study the effect of putrescine and L-glutamine supplementation on histomorphology of small intestine in broiler chickens. Five groups of ten chicks each in three replicates reared up to 42 days were used for this study. Putrescine and L-glutamine were orally supplemented at 0% level as control (T1), putrescine 0.05% (T2), putrescine 0.1% (T3), L-glutamine 0.5% (T4) and L-glutamine 1% (T5) from 0 day to 7 days after hatch. At 2nd and 3rd week of age, 3 birds from each groupwere slaughtered and tissue samples from small intestine (duodenum, jejunum and ileum) were collected for histomorphological studies. Statistically significant (p<0.01) increase in duodenal and jejunal villi length, width,crypt length and ileal villi length and width were observed in L-glutamine fed groups than putrescine and control groups. There was no significant difference in duodenal crypt length/width, jejunal crypt width and ileal crypt length/width. It can be inferred that L-glutamine promoted the intestinal villi development during early posthatch life, thus increasing the nutrients absorption and growth performance as body weight gain in broiler chickens.

Effects of Carnitine with and without Glutamine Supplementation on Markers of Muscle Damage and Muscle Soreness among Football Players: A Randomized Controlled Clinical Trial

Background: Exercise-induced muscle damage can affect exercise performance. The purpose of this study is to examine the effects of Carnitine and Glutamine supplementation on markers of muscle damage and muscle soreness after physical exertion on football players.Materials and Methods: Twenty eight healthy male football players aged 21.1±0.7 were recruited in a double blind, randomized, placebo-controlled clinical trial on 3 weeks of supplementation. Before supplementation protocol, each participant had to run on a treadmill for 30 minutes at 75% VO2max. Participants were randomly divided into 4 groups: L-Carnitine, L- Glutamine, L-Carnitine plus L- Glutamine and placebo. Blood samples were obtained pre-exercise and immediately after exercise. Muscle soreness was assessed on both occasions and two days after each exercise.Results: L-Carnitine and L-Glutamine supplementation for 21 days significantly decreased Creatine Kinase activity as a marker of muscle’s damage before (P=0.014) and after exercise (P=0.047), and muscle soreness two days after physical exertion (P=0.057). However, Lactate Dehydrogenase activity was affected by Carnitine supplementation after exercise.Conclusion: Chronic oral supplementation of Carnitine and Glutamine before exercise can reduce chemical markers of muscle tissue damage after exercise. In addition, these supplements may reduce muscle pain after exercise and optimize the processes of muscle tissue repair.[GMJ. 2014;3(4):207-15]

Glycemic effects and safety of L-Glutamine supplementation with or without sitagliptin in type 2 diabetes patients-a randomized study.

Background and AimsL-glutamine is an efficacious glucagon-like peptide (GLP)-1 secretagogue in vitro. When administered with a meal, glutamine increases GLP-1 and insulin excursions and reduces postprandial glycaemia in type 2 diabetes patients. The aim of the study was to assess the efficacy and safety of daily glutamine supplementation with or without the dipeptidyl peptidase (DPP)-4 inhibitor sitagliptin in well-controlled type 2 diabetes patients.MethodsType 2 diabetes patients treated with metformin (n = 13, 9 men) with baseline glycated hemoglobin (HbA1c) 7.1±0.3% (54±4 mmol/mol) received glutamine (15 g bd)+ sitagliptin (100 mg/d) or glutamine (15 g bd) + placebo for 4 weeks in a randomized crossover study.ResultsHbA1c (P = 0.007) and fructosamine (P = 0.02) decreased modestly, without significant time-treatment interactions (both P = 0.4). Blood urea increased (P<0.001) without a significant time-treatment interaction (P = 0.8), but creatinine and estimated glomerular filtration rate (eGFR) were unchanged (P≥0.5). Red blood cells, hemoglobin, hematocrit, and albumin modestly decreased (P≤0.02), without significant time-treatment interactions (P≥0.4). Body weight and plasma electrolytes remained unchanged (P≥0.2).ConclusionsDaily oral supplementation of glutamine with or without sitagliptin for 4 weeks decreased glycaemia in well-controlled type 2 diabetes patients, but was also associated with mild plasma volume expansion.Trial RegistrationClincalTrials.gov NCT00673894

Dietary L-glutamine supplementation modulates microbial community and activates innate immunity in the mouse intestine.

This study was conducted to determine effects of dietary supplementation with 1 % L-glutamine for 14 days on the abundance of intestinal bacteria and the activation of intestinal innate immunity in mice. The measured variables included (1) the abundance of Bacteroidetes, Firmicutes, Lactobacillus, Streptococcus and Bifidobacterium in the lumen of the small intestine; (2) the expression of toll-like receptors (TLRs), pro-inflammatory cytokines, and antibacterial substances secreted by Paneth cells and goblet cells in the jejunum, ileum and colon; and (3) the activation of TLR4-nuclear factor kappa B (NF-κB), mitogen-activated protein kinases (MAPK), and phosphoinositide-3-kinases (PI3K)/PI3K-protein kinase B (Akt) signaling pathways in the jejunum and ileum. In the jejunum, glutamine supplementation decreased the abundance of Firmicutes, while increased mRNA levels for antibacterial substances in association with the activation of NF-κB and PI3K-Akt pathways. In the ileum, glutamine supplementation induced a shift in the Firmicutes:Bacteroidetes ratio in favor of Bacteroidetes, and enhanced mRNA levels for Tlr4, pro-inflammatory cytokines, and antibacterial substances participating in NF-κB and JNK signaling pathways. These results indicate that the effects of glutamine on the intestine vary with its segments and compartments. Collectively, dietary glutamine supplementation of mice beneficially alters intestinal bacterial community and activates the innate immunity in the small intestine through NF-κB, MAPK and PI3K-Akt signaling pathways.

Effects of L-glutamine supplementation on maternal and fetal hemodynamics in gestating ewes exposed to alcohol.

Not much is known about effects of gestational alcohol exposure on maternal and fetal cardiovascular adaptations. This study determined whether maternal binge alcohol exposure and L-glutamine supplementation could affect maternal-fetal hemodynamics and fetal regional brain blood flow during the brain growth spurt period. Pregnant sheep were randomly assigned to one of four groups: saline control, alcohol (1.75-2.5g/kg body weight), glutamine (100mg/kg body weight) or alcohol+glutamine. A chronic weekend binge drinking paradigm between gestational days (GD) 99 and 115 was utilized. Fetuses were surgically instrumented on GD 117±1 and studied on GD 120±1. Binge alcohol exposure caused maternal acidemia, hypercapnea, and hypoxemia. Fetuses were acidemic and hypercapnic, but not hypoxemic. Alcohol exposure increased fetal mean arterial pressure, whereas fetal heart rate was unaltered. Alcohol exposure resulted in ~40% reduction in maternal uterine artery blood flow. Labeled microsphere analyses showed that alcohol induced >2-fold increases in fetal whole brain blood flow. The elevation in fetal brain blood flow was region-specific, particularly affecting the developing cerebellum, brain stem, and olfactory bulb. Maternal L-glutamine supplementation attenuated alcohol-induced maternal hypercapnea, fetal acidemia and increases in fetal brain blood flow. L-Glutamine supplementation did not affect uterine blood flow. Collectively, alcohol exposure alters maternal and fetal acid-base balance, decreases uterine blood flow, and alters fetal regional brain blood flow. Importantly, L-glutamine supplementation mitigates alcohol-induced acid-base imbalances and alterations in fetal regional brain blood flow. Further studies are warranted to elucidate mechanisms responsible for alcohol-induced programming of maternal uterine artery and fetal circulation adaptations in pregnancy.

L-Glutamine Supplementation Prevents the Development of Experimental Diabetic Cardiomyopathy in Streptozotocin-Nicotinamide Induced Diabetic Rats

The objective of the present investigation was to evaluate the effect of L-glutamine on cardiac myopathy in streptozotocin-nicotinamide induced diabetic rats. Diabetes was induced in overnight fasted Sprague Dawely rats by using intraperitonial injection of streptozotocin (55 mg/kg). Nicotinamide (100 mg/kg, i.p.) was administered 20 min before administration of streptozotocin. Experimental rats were divided into Group I: non-diabetic control (distilled water; 10 ml/kg, p.o.), II: diabetic control (distilled water, 10 ml/kg, p.o.), III: L-glutamine (500 mg/kg, p.o.) and IV: L-glutamine (1000 mg/kg, p.o.). All groups were diabetic except group I. The plasma glucose level, body weight, electrocardiographic abnormalities, hemodynamic changes and left ventricular contractile function, biological markers of cardiotoxicity, antioxidant markers were determined after 4 months after STZ with nicotinamide injection. Histopathological changes of heart tissue were carried out by using H and E stain. L-glutamine treatment improved the electrocardiographic, hemodynamic changes; LV contractile function; biological markers; oxidative stress parameters and histological changes in STZ induced diabetic rats. Results from the present investigation demonstrated that L-glutamine has seemed a cardioprotective activity.

Serum Amino Acids Profile and the Beneficial Effects of L-Arginine or L-Glutamine Supplementation in Dextran Sulfate Sodium Colitis

This study was conducted to investigate serum amino acids profile in dextran sulfate sodium (DSS)-induced colitis, and impacts of graded dose of arginine or glutamine supplementation on the colitis. Using DSS-induced colitis model, which is similar to human ulcerative colitis, we determined serum profile of amino acids at day 3, 7, 10 and 12 (5 days post DSS treatment). Meanwhile, effects of graded dose of arginine (0.4%, 0.8%, and 1.5%) or glutamine (0.5%, 1.0% and 2.0%) supplementation on clinical parameters, serum amino acids, colonic tight junction proteins, colonic anti-oxidative indicators [catalase, total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px)], colonic pro-inflammatory cytokines [interleukin-1 beta (IL-1β), IL-6, IL-17 and tumor necrosis factor alpha (TNF-α)] in DSS-induced colitis were fully analyzed at day 7 and 12. Additionally, the activation of signal transduction pathways, including nuclear factor kappa B (NF-κB), mitogen-activated protein kinases (MAPK), phosphoinositide-3-kinases (PI3K)/PI3K-protein kinase B (Akt), and myosin light chain kinase (MLCK)- myosin light chain (MLC20), were analyzed using immunoblotting. Serum amino acids analysis showed that DSS treatment changed the serum contents of amino acids, such as Trp, Glu, and Gln (P<0.05). Dietary arginine or glutamine supplementation had significant (P<0.05) influence on the clinical and biochemical parameters (T-SOD, IL-17 and TNF-α) in colitis model. These results were associated with colonic NF-κB, PI3K-Akt and MLCK signaling pathways. In conclusion, arginine or glutamine could be a potential therapy for intestinal inflammatory diseases.

Surface Electromyography Assessments of the Vastus medialis and Rectus femoris Muscles and Creatine Kinase after Eccentric Contraction Following Glutamine Supplementation.

L-glutamine is the most abundant amino acid found in human muscle and plays an important role in protein synthesis and can reduce the levels of inflammation biomarkers and creatine kinase (CK) after training sessions. Delayed onset muscle soreness (DOMS) develops after intense exercise and is associated with an inflammatory response. The purpose of this study was to investigate the effect of glutamine supplementation on surface electromyography activity of the vastus medialis muscle (VMM) and rectus femoris muscle (RFM) and levels of creatine kinase after an eccentric contraction. SEVENTEEN HEALTHY MEN (AGE: 22.35±2.27yr; body mass: 69.91± 9.78kg; height: 177.08±4.32cm) were randomly assigned to experimental (n=9) and control groups (n=8) in a double-blind manner. In both groups, subjects were given L-glutamine supplementation (0.1g.kg(-1)) or placebo three times a week for 4 weeks. Median frequency (MDF) and mean power frequency (MPF) for VMM and RFM muscles and also CK measurements were performed before, 24h and 48 h after a resistance training session. The resistance training included 6 sets of eccentric leg extensions to exhaustion with 75% of 1RM. There was no significant difference between groups for MDF or MPF in VMM and RFM. The difference of CK level between the groups was also not significant. The results of this study indicate that glutamine supplementation has no positive effect on muscle injury markers after a resistance training session.

Oral supplementations with free and dipeptide forms of l-glutamine in endotoxemic mice: effects on muscle glutamine-glutathione axis and heat shock proteins

Sepsis is a leading cause of death in intensive care units worldwide. Low availability of glutamine contributes to the catabolic state of sepsis. l-Glutamine supplementation has antioxidant properties and modulates the expression of heat shock proteins (HSPs). This study investigated the effects of oral supplementation with l-glutamine plus l-alanine (GLN+ALA), both in the free form and l-alanyl-l-glutamine dipeptide (DIP), on glutamine-glutathione (GSH) axis and HSPs expression in endotoxemic mice. B6.129F2/J mice were subjected to endotoxemia (lipopolysaccharides from Escherichia coli, 5 mg.kg−1, LPS group) and orally supplemented for 48 h with either l-glutamine (1 g.kg−1) plusl-alanine (0.61 g.kg−1) (GLN+ALA-LPS group) or 1.49 g.kg−1 of DIP (DIP-LPS group). Endotoxemia reduced plasma and muscle glutamine concentrations [relative to CTRL group] which were restored in both GLN+ALA-LPS and DIP-LPS groups (P<.05). In supplemented groups were re-established GSH content and intracellular redox status (GSSG/GSH ratio) in circulating erythrocytes and muscle. Thiobarbituric acid reactive substance was 4-fold in LPS treated mice relative to the untreated CTRL group, and plasma TNF-α and IL-1β levels were attenuated by the supplements. Heat shock proteins 27, 70 and 90 (protein and mRNA) were elevated in the LPS group and were returned to basal levels (relative to CTRL group) in both GLN+ALA-LPS and DIP-LPS groups. Supplementations to endotoxemic mice resulted in up-regulation of GSH reductase, GSH peroxidase and glutamate cysteine ligase mRNA expression in muscle. In conclusion, oral supplementations with GLN+ALA or DIP are effective in reversing the conditions of LPS-induced deleterious impact on glutamine-GSH axis in mice under endotoxemia.

Effect of l-glutamine on myenteric neuron and of the mucous of the ileum of diabetic rats

The objective of this work was to investigate the effect of the L-glutamine supplementation to prevent - diabetes induced changes in myenteric neurons and also to verify the effect on the mucosa of the ileum of Wistar rats. The animals were divided in five groups (n = 5): untreated normoglycaemic (UN), normoglycaemic treated with L-glutamine (NG), untreated diabetics (UD), diabetics treated with L-glutamine, starting on the 4th (DG4) or 45th day following diabetes induction (DG45). The amino acid was added to the diet at 1%. The density and size of neurons, the metaphasic index in the crypt, the height of the villus, the depth of the crypt and the number of globet cells were determined. There was no difference in the neuronal density and in the cellular body area of the myosin-stained myenteric neurons of groups DG4 and DG45 when compared to group D. The metaphase index and the number of goblet cells showed no significant differences when all groups were compared (P > 0.05). The villi height of groups DG4 and DG45 were 45.5% (P < 0.05) and 32.4% (P > 0.05) higher than those in group UD, respectively. The analyzed crypts showed similar depth for all studied groups.

Dietary l-glutamine supplementation increases Pasteurella multocida burden and the expression of its major virulence factors in mice

This study was conducted to determine the effects of graded doses of L-glutamine supplementation on the replication and distribution of Pasteurella multocida, and the expression of its major virulence factors in mouse model. Mice were randomly assigned to the basal diet supplemented with 0, 0.5, 1.0 or 2.0% glutamine. Pasteurella multocida burden was detected in the heart, liver, spleen, lung and kidney after 12h of P. multocida infection. The expression of major virulence factors, toll-like receptors (TLRs), proinflammatory cytokines (interleukin-1 beta, interleukin-6, and tumor necrosis factor alpha) and anti-oxidative factors (GPX1 and CuZnSOD) was analyzed in the lung and spleen. Dietary 0.5% glutamine supplementation has little significant effect on these parameters, compared to those with basal diet. However, results showed that a high dose of glutamine supplementation increased the P. multocida burden (P<0.001) and the expression of its major virulence factors (P<0.05) as compared to those with a lower dose of supplementation. In the lung, high dose of glutamine supplementation inhibited the proinflammatory responses (P<0.05) and TLRs signaling (P<0.05). In the spleen, the effect of glutamine supplementation on different components in TLR signaling depends on glutamine concentration, and high dose of glutamine supplementation activated the proinflammatory response. In conclusion, glutamine supplementation increased P. multocida burden and the expression of its major virulence factors, while affecting the functions of the lung and spleen.

Effect of L-glutamine supplementation on electromyographic activity of the quadriceps muscle injured by eccentric exercise.

The purpose of the present study was to examine the effects of L-glutamine on electromyographic (EMG) activity of the quadriceps muscle injured by eccentric exercise (EE). Seventeen healthy men (age: 22.35±2.27 yr; body mass: 69.91±9.78 kg; height: 177.08±4.32 cm) were randomly and double-blind study with subjects assigned to either an L-glutamine supplementation (n=9) or placebo (n=8) group. The subjects in two groups were asked to take three times during a week for 4 weeks. Each subject was screened for dietary habits before inclusion into the study. Participants performed 6 set to exhaustion eccentric leg extensions at 75% of 1RM and rest intervals were 3 min among sets. Pain Assessment Scale (PAS), EMG activity and range of motion (ROM) measurements were taken before exercise protocol and 24 and 48 hr afterwards. There was no statistically significant difference between groups in perceived muscle soreness (SOR), ROM and EMG activity (P < 0.05). The results indicate that L-glutamine supplementation has no significant effect on muscle injury markers in between groups, although glutamine supplementation attenuated delayed onset muscle soreness (DOMS) effects in sup group.

Improved performance and small intestinal development of broiler chickens by dietary L-glutamine supplementation

An experiment was conducted to evaluate the effect of L-glutamine (Gln) supplementation on performance and intestinal morphology of broiler chickens. A total of 192 day-old male broilers (Ross 308) were used in a completely randomised design with four treatments and four replicates of 12 birds each. Four experimental diets were formulated to be isonitrogenous and isocaloric with different levels of Gln supplementation (0, 0.5, 1.0 and 1.5%) in control and treatment groups, respectively and were fed for the first 3 weeks of life. On days 21 and 42, one bird from each replicate was slaughtered and morphometric indices of the small intestine were evaluated. Results obtained on days 21 and 42 showed increased ADWG in the birds that consumed 1% Gln supplemented diet compared to the control birds fed a standard corn-SBM diet (P≤0.05). On day 21, birds fed diets supplemented with 1 or 1.5% Gln had a significantly heavier duodenum and jejunum relative weight compared to the control birds (P≤0.05). Morphological assays showed that villus height and villus surface area of the duodenum and jejunum were significantly increased at both 21 and 42 days of age, as 1 or 1.5% Gln was supplemented in broiler diets (P≤0.05). The results of this study indicated that addition of 1% Gln to the diet for 21 days improved growth performance and small intestinal development of broiler chickens at the end of the starter (day 21) and grower (day 42) period.

Protective effects of l-glutamine on the bladder wall of rats submitted to pelvic radiation

Radiotherapy is often used to treat prostate tumors, but the normal bladder is usually adversely affected. Using an animal model of pelvic radiation, we investigated whether glutamine nutritional supplementation can prevent radiation-induced damage to the bladder, especially in its more superficial layers. Male rats aged 3–4 months were divided into groups of 8 animals each: controls, which consisted intact animals; radiated-only rats, which were sacrificed 7 (R7) or 15 (R15) days after a radiation session (10Gy aimed at the pelvico-abdominal region); and radiated rats receiving l-glutamine supplementation (0.65g/kg body weight/day), which were sacrificed 7 (RG7) or 15 (RG15) days after the radiation session. Cells and blood vessels in the vesical lamina propria, as well as the urothelium, were then measured using histological methods. The effects of radiation were evaluated by comparing controls vs. either R7 or R15, while a protective effect of glutamine was assessed by comparing R7 vs. RG7 and R15 vs. RG15. The results showed that, in R7, epithelial thickness, epithelial cell density, and cell density in the lamina propria were not significantly affected. However, density of blood vessels in R7 was reduced by 48% (p<0.05) and this alteration was mostly prevented by glutamine (p<0.02). In R15, density of blood vessels in the lamina propria was not significantly modified. However, epithelial thickness was reduced by 25% (p<0.05) in R15, and this effect was prevented by glutamine (p<0.01). In R15, epithelial cell density was increased by 35% (p<0.02), but glutamine did not protect against this radiation-induced increase. Cell density in the lamina propria was likewise unaffected in R15. Density of mast cells in the lamina propria was markedly reduced in R7 and R15. The density was still reduced in RG7, but a higher density in RG15 suggested a glutamine-mediated recovery. Alpha-actin positive cells in the lamina propria formed a suburothelial layer and were identified as myofibroblasts. Thickness of this layer was increased in R7, but was similar to controls in RG7, while changes in R15 and RG15 were less evident. In conclusion, pelvic radiation leads to significant acute and post-acute alterations in the composition and structural features of the vesical lamina propria and epithelium. Most of these changes, however, can be prevented by glutamine nutritional supplementation. These results emphasize, therefore, the potential use of this aminoacid as a radioprotective drug.

Effect of Dietary L-Arginine and L-Glutamine Supplementation on Enterococcus faecalis Infected Mice

Effect of Dietary L-Arginine and L-Glutamine Supplementation on Enterococcus faecalis Infected Mice

Response to dietary L-glutamine supplementation in weaned piglets: a serum metabolomic comparison and hepatic metabolic regulation analysis

Response to dietary L-glutamine supplementation in weaned piglets: a serum metabolomic comparison and hepatic metabolic regulation analysis

Response to dietary L-glutamine supplementation in weaned piglets: A serum metabolomic comparison and hepatic metabolic regulation analysis1

A novel metabolomic method based on gas chromatography-mass spectrometry was applied to investigate serum metabolites in response to dietary Gln supplementation in piglets. Sixteen, 21-d-old pigs were weaned and assigned randomly to 2 isonitrogenous diets: 1) Gln diet, which contained 1% L-Gln (as-fed basis), and 2) control diet, which contained L-Ala to make this diet isonitrogenous with the Gln diet. Serum samples were collected to characterize metabolites after a 30-d treatment. in addition, 4 liver samples per treatment were collected to examine enzyme activity and gene expression involved in metabolic regulation. Results indicated that 12 metabolites were altered (P < 0.05) by Gln treatment, including carbohydrates, AA, and fatty acids. A leave-one-out cross validation of random forest analysis indicated that Pro was most important among the 12 metabolites. Thus, these data demonstrate that the control and Gln-supplemented pigs differed (P < 0.05) in terms of metabolism of carbohydrates, Pro, Tyr, and glycerophospholipids. Principal component analysis yielded separate clusters of profiles between the Gln and control groups. Metabolic enzyme activities of Ala aminotransferase and hexokinase increased by 26.8% (P = 0.026) and 26.2% (P = 0.004) in the liver of Gln-supplemented pigs vs. control, respectively, whereas pyruvate kinase (PK) activity decreased by 29.1% (P = 0.001). The gene expression of PK in the liver decreased by 66.1% (P = 0.034) by Gln treatment for 30 d. No differences were observed for the mRNA abundance of mammalian target of rapamycin and PPARγ. On the basis of these data, Gln treatment affected carbohydrate, lipid, and AA metabolism in the whole body of the early weaned piglets. These findings provide insight into specific metabolic pathways and lay the groundwork for the complex metabolic alteration in response to dietary Gln supplementation of pigs.

Response to weaning and dietary l-glutamine supplementation: metabolomic analysis in piglets by gas chromatography/mass spectrometry

A novel metabolomic method based on gas chromatography/mass spectrometry (GC-MS) was applied to determine the metabolites in the serum of piglets in response to weaning and dietary L-glutamine (Gln) supplementation. Thirty-six 21-d-old piglets were randomly assigned into three groups. One group continued to suckle from the sows (suckling group), whereas the other two groups were weaned and their diets were supplemented with 1% (w/w) Gln or isonitrogenous L-alanine, respectively, representing Gln group or control group. Serum samples were collected to characterize metabolites after a 7-d treatment. Results showed that twenty metabolites were down-regulated significantly (P<0.05) in control piglets compared with suckling ones. These data demonstrated that early weaning causes a wide range of metabolic changes across arginine and proline metabolism, aminosugar and nucleotide metabolism, galactose metabolism, glycerophospholipid metabolism, biosynthesis of unsaturated fatty acid, and fatty acid metabolism. Dietary Gln supplementation increased the levels of creatinine, D-xylose, 2-hydroxybutyric acid, palmitelaidic acid, and α-L-galactofuranose (P<0.05) in early weaned piglets, and were involved in the arginine and proline metabolism, carbohydrate metabolism, and fatty acid metabolism. A leave-one-out cross-validation of random forest analysis indicated that creatinine was the most important metabolite among the three groups. Notably, the concentration of creatinine in control piglets was decreased (P=0.00001) compared to the suckling piglets, and increased (P=0.0003) in Gln-supplemented piglets. A correlation network for weaned and suckling piglets revealed that early weaning changed the metabolic pathways, leading to the abnormality of carbohydrate metabolism, amino acid metabolism, and lipid metabolism, which could be partially improved by dietary Gln supplementation. These findings provide fresh insight into the complex metabolic changes in response to early weaning and dietary Gln supplementation in piglets.

Glutamine Supplementation in Recovery From Eccentric Exercise Attenuates Strength Loss and Muscle Soreness

The purpose of this study was to examine the effect of glutamine supplementation on indices of recovery following eccentric exercise. In a randomized single-blind placebo-controlled design, 15 physically active males (mean age, 21 ± 1.5 years; mean height, 1.81 ± 0.07 m; mean body mass, 78.4 ± 9.2 kg) were assigned to a control or glutamine intervention group. Each participant performed 100 drop jumps from 0.6m followed by ingestion of 0.3 g · kg−1 body mass of maltodextrin mixed with 750 mL of distilled water and lemon flavoring (Control) or with an additional 0.3 g · kg−1 L-glutamine (Glutamine) at 0, 24, 48, and 72 hours post-exercise. Knee-extensor concentric peak torque at angular velocities of 0.52 and 3.14 rad · s−1, perceived muscle soreness, and plasma creatine kinase activity were measured at 0, 1, 24, 48, 72, and 96 hours post-exercise. L-glutamine supplementation resulted in a greater preservation of peak torque over the 96-hour measurement period at both 0.52 rad · s−1 (Control, 75 ± 16%; Glutamine, 85 ± 15% of pre-exercise values, p = 0.03) and 3.14 rad · s−1 (Control, 79 ± 16%; Glutamine, 90 ± 12%, p = 0.01). Muscle soreness was significantly lower over 96 hours with L-glutamine supplementation (Control, 4.6 ± 2.5 units; Glutamine, 3.6 ± 2.5 units, p = 0.03). L-glutamine supplementation did not affect the magnitude or temporal nature of the creatine kinase response. As a therapeutic intervention, glutamine supplementation was effective in attenuating strength loss and muscle soreness following eccentric exercise-induced muscle damage.

Dietary l-glutamine supplementation improves pregnancy outcome in mice infected with type-2 porcine circovirus

Porcine circovirus type 2 (PCV2) causes reproductive failure in swine. As glutamine can enhance immune function in animals, this study was conducted with mice to test the hypothesis that dietary glutamine supplementation will improve pregnancy outcome in PCV2-infected dams. Beginning on day 0 of gestation, mice were fed a standard diet supplemented with 1.0% L-glutamine or 1.22% L-alanine (isonitrogenous control). All mice were infected with PCV2 (2000 TCID50) on day 10 of gestation. On day 17 of gestation, six mice from each group were euthanized to obtain maternal tissues and fetuses for hematology and histopathology tests. The remaining mice continued to receive their respective diets supplemented with 1.0% L-glutamine or 1.22% L-alanine through lactation. The PCV2 virus was present in maternal samples (serum and lung) of most mice in the control group but was not detected in the glutamine-supplemented mice. Dietary glutamine supplementation reduced abortion, decreased fetal deaths, and enhanced neonatal survival. The glutamine treatment also reduced concentrations of interleukin-6, while increasing concentrations of tumor necrosis factor-α and C-reactive protein, in the maternal serum of mice. Furthermore, glutamine supplementation attenuated microscopic lesions in maternal tissues (lung, spleen, and liver). Collectively, these results indicate that dietary glutamine supplementation is beneficial for ameliorating reproductive failure in virus-infected mice. The findings support the notion that gestating dams require adequate amounts of dietary glutamine for the optimal survival and growth of embryos, fetuses, and neonates, and have important implications for nutritional support of mammals (including swine and humans) during gestation and lactation.