Dietary L-arginine Supplementation Research Articles

L-arginine supplementation abrogates hypoxia-induced virulence of Staphylococcus aureus in a murine diabetic pressure wound model.

Diabetic foot ulcers (DFUs) are the most common complications of diabetes resulting from hyperglycemia leading to ischemic hypoxic tissue and nerve damage. Staphylococcus aureus is the most frequently isolated bacteria from DFUs and causes severe necrotic infections leading to amputations with a poor 5-year survival rate. However, very little is known about the mechanisms by which S. aureus dominantly colonizes and causes severe disease in DFUs. Herein, we utilized a pressure wound model in diabetic TALLYHO/JngJ mice to reproduce ischemic hypoxic tissue damage seen in DFUs and demonstrated that anaerobic fermentative growth of S. aureus significantly increased the virulence and the severity of disease by activating two-component regulatory systems leading to expression of virulence factors. Our in vitro studies showed that supplementation of nitrate as a terminal electron acceptor promotes anaerobic respiration and suppresses the expression of S. aureus virulence factors through inactivation of two-component regulatory systems, suggesting potential therapeutic benefits by promoting anaerobic nitrate respiration. Our in vivo studies revealed that dietary supplementation of L-arginine (L-Arg) significantly attenuated the severity of disease caused by S. aureus in the pressure wound model by providing nitrate. Collectively, these findings highlight the importance of anaerobic fermentative growth in S. aureus pathogenesis and the potential of dietary L-Arg supplementation as a therapeutic to prevent severe S. aureus infection in DFUs.IMPORTANCES. aureus is the most common cause of infection in DFUs, often resulting in lower-extremity amputation with a distressingly poor 5-year survival rate. Treatment for S. aureus infections has largely remained unchanged for decades and involves tissue debridement with antibiotic therapy. With high levels of conservative treatment failure, recurrence of ulcers, and antibiotic resistance, a new approach is necessary to prevent lower-extremity amputations. Nutritional aspects of DFU treatment have largely been overlooked as there has been contradictory clinical trial evidence, but very few in vitro and in vivo modelings of nutritional treatment studies have been performed. Here we demonstrate that dietary supplementation of L-Arg in a diabetic mouse model significantly reduced duration and severity of disease caused by S. aureus. These findings suggest that L-Arg supplementation could be useful as a potential preventive measure against severe S. aureus infections in DFUs.

Effects of dietary supplementation of tomato pomace (Solanum lycopersicum L.) and L-Arg on reproductive performance of aged male broiler breeders

This study aimed to investigate the effects of different dietary supplementation of tomato pomace (TP) and L-arginine (L-Arg) supplementation on sperm characteristics, reproductive performance, and semen biochemical components of aged commercial male broiler breeders. Thirty Ross 308 male broiler breeders (58 wk old) were provided and assigned to 5 dietary treatment groups, including control (CON), 5% TP (TPS-5), 10% TP (TPS-10), 15% TP (TPS-15), and L-Arg supplemented (10% above the recommendation, LAS-10). The results indicated that the semen volume increased in the TPS-15 group compared to that of the LAS-10 (and CON on wk 9) throughout the study (P < 0.05). The sperm concentration significantly increased in TPS-10 and TPS-15 groups in comparison to the other experimental groups. On wk 5 and 7, the sperm viability increased in all TPS groups compared to the CON and LAS-10, while on wk 9, it only increased in the TPS-10 group in comparison to the LAS-10 group (P < 0.05). The hypo-osmotic swelling test decreased in the LAS-10 group compared to the other experimental groups on wk 5 and all TPS groups on wk 7 and 9 (P < 0.05). The sperm total motility and forward progressive motility decreased in the LAS-10 group compared to the other experimental groups (P < 0.05). In contrast, unprogressive motility and immotile sperms were increased in the LAS-10 group compared to the other experimental groups (P < 0.05). In addition, the sperm penetration and fertility rate increased in TPS-10 and TPS-15 groups in comparison to CON and LAS-10 groups (P < 0.05). However, hatchability was reduced in the LAS-10 group (P < 0.05). The semen adenosine triphosphate increased in TPS-10, TPS-15, and LAS-10 groups compared to the CON (P < 0.05). Finally, the semen TAC and superoxidase dismutase decreased in the LAS-10 group (P < 0.05), while the glutathione peroxidase increased in the TPS-15 group (P < 0.05). In conclusion, 15% dietary TPS is recommended to improve the reproductive performance of aged commercial male broiler breeders.

Dietary L-arginine supplementation influences the muscle fiber characteristics and meat quality of Mongolian sheep through the NO/AMPK/PGC-1α pathway

L-arginine serves as a substrate for the production of nitric oxide (NO) in animals, and it can also impact muscle fiber characteristics and meat quality in these animals. The present study was designed to explore the effects of adding 1% L-arginine to a basal diet regimen on the muscle fiber characteristics and meat quality of Mongolian sheep. Dietary L-arginine supplementation reduced shear force in the longissimus thoracis (LT) and increased a* in biceps femoris (BF) muscles (p < 0.05). L-arginine supplementation also increased the proportion of type IIA muscle fiber in the LT (p < 0.05) and type I muscle fiber in the BF (p < 0.05) while reducing both the diameter and CSA of type IIB muscle fiber in both the LT and BF (CSA in LT, p < 0.01; all others, p < 0.05). L-arginine treatment was also associated with the upregulation of MyHC IIa (LT), MyHC I (BF), nNOS (LT & BF), AMPKα1 (BF), PGC-1α (LT & BF) (PGC-1α in BF, p < 0.01; all others, p < 0.05), together with an increase in nNOS content (LT, p < 0.01; BF, p < 0.05). Dietary L-arginine supplementation was associated with a significant increase in the post-slaughter tenderness of lamb meat, which is related to transitions in muscle fiber types. The gene expression and nNOS analysis results generated herein further indicate that this effect is mediated by the NO/AMPK/PGC-1α pathway. Further studies are thus warranted to provide further insight into the role that NO signaling plays in controlling the associations between L-arginine, muscle fiber characteristics, and meat quality.

Evaluation of dietary arginine supplementation to increase placental nutrient transporters in aged mares.

Nine pregnant mares (18.2 ± 0.7 yr; 493.82 ± 12.74 kg body weight [BW]) were used to test the hypothesis that dietary supplementation of l-arginine would enhance placental vascularity and nutrient transport throughout gestation in aged mares. Mares were balanced by age, BW, and stallion pairing, and assigned randomly to dietary treatments of either supplemental l-arginine (50 mg/kg BW; n = 7) or l-alanine (100 mg/kg BW; n = 6; isonitrogenous control). Mares were individually fed concentrate top-dressed with the respective amino acid treatment plus ad libitum access to Coastal Bermudagrass hay. Treatments began on day 14 of gestation and were terminated at parturition. Mare BW, body condition score (BCS), and rump fat were determined, and body fat percentage was calculated every 28 d and concentrate adjusted accordingly. Doppler blood flow measurements including resistance index (RI) and pulsatility index for uterine artery ipsilateral to the pregnant uterine horn were obtained beginning on day 21 and continued every 7 d until day 154 of gestation, and prior to parturition. Parturition was attended with foaling variables and placental measures recorded. Placental tissue from the pregnant horn was analyzed histologically to assess cell-specific localization of vascular endothelial growth factor (VEGF) and cationic amino acid transporter 1 (SLC7A1) proteins. Semiquantitative analyses were performed using 10 nonoverlapping images per sample fixed in a 10× field (Fiji ImageJ v1.2). Mare performance data were analyzed using PROC MIXED in SAS and foaling and placental data were analyzed using PROC GLM. Gestation length at parturition was not influenced (P > 0.05) by supplemental arginine. Compared with arginine-supplemented mares, control mares had a thicker rump fat layer (P < 0.01) and greater percent body fat (P = 0.03), and BCS (P < 0.01) at parturition. Arginine-supplemented mares had a lower RI than control mares prior to parturition (P < 0.01). Body length, height, and BW of foals at birth, as well as placental weight and volume, and immunohistochemical staining for VEGF and SLC7A1 at parturition, were not affected (P > 0.05) by maternal arginine supplementation. These results indicate that dietary arginine supplementation (50 mg/kg BW) is safe for gestating mares. A larger number of mares is required to extend knowledge of effects of supplemental arginine on embryonic/fetal survival and growth in mares.

PS-B07-6: L-ARGININE SUPPLEMENTATION SUBSTANTIALLY ATTENUATES HYPERTENSION BUT NOT CARDIAC INJURY IN RATS WITH METABOLIC SYNDROME

Objective: L-arginine is not only a building block for protein but also a physiological substrate for the synthesis of nitric oxide (NO) and plays a regulatory role in signal transduction pathways in cells. Dietary L-arginine supplementation reduced fat mass both in Zucker diabetic fatty rats and in diet-induced obese rats. However, little is known about the effects of L-arginine on cardiac morphology and function in metabolic disorders. We have now examined the effects of L-arginine on cardiac pathology in DahlS.Z-Leprfa/Leprfa (DS/obese) rats, an animal model of metabolic syndrome (MetS). Design and method: DS/obese rats and their homozygous lean (DahlS.Z-Lepr+/Lepr+, or DS/lean) littermate controls were fed a purified control diet and were supplemented with 0.50% L-arginine-HCl or 0.85% L-alanine (isonitrogenous control) in drinking water from 13 to 17 weeks of age. Results: L-arginine supplementation did not affect body weight, visceral and subcutaneous fat mass, insulin resistance, or food and water intake in DS/obese rats, but substantially alleviated hypertension. However, left ventricular (LV) and cardiomyocyte hypertrophy and the upregulation of myocardial fetal-type gene expression, macrophage infiltration in the heart, and increased perivascular and interstitial fibrosis of the LV myocardium and the upregulation of fibrosis-related gene expression were not improved by such intervention. Additionally, L-arginine did not ameliorate impairments of Doppler- or micromanometer-derived indices of LV diastolic function. None of these parameters were influenced by L-arginine supplementation in DS/lean rats. Conclusions: L-arginine supplementation substantially ameliorated hypertension but did not attenuate LV remodeling or diastolic dysfunction in this model of MetS. These data suggest that in addition to its role as a precursor of NO, L-arginine may play a role as a functional amino acid that modulates growth and inflammation.

Dietary L-arginine supplementation increases the hepatic expression of AMP-activated protein kinase in rats.

The goal of this study was to elucidate the molecular mechanisms responsible for the anti-obesity effect of L-arginine supplementation in diet-induced obese rats. Male Sprague-Dawley rats were fed either a low-fat or high-fat diet for 15weeks. Thereafter, lean or obese rats were pair-fed their same respective diets and received drinking water containing either 1.51% L-arginine-HCl or 2.55% L-alanine (isonitrogenous control) for 12weeks. Gene and protein expression of key enzymes in the metabolism of energy substrates were determined using real-time polymerase-chain reaction and western blotting techniques. The mRNA levels of hepatic fatty acid synthase and stearoyl-CoA desaturase were reduced (P < 0.05) but those of hepatic AMP-activated protein kinase-α (AMPKα), peroxisome proliferator activator receptor γ coactivator-1α, and carnitine palmitoyltransferase I (CPT-I), as well as skeletal muscle CPT-I were increased (P < 0.05) by L-arginine treatment. The protein expression and activity of hepatic AMPKα markedly increased (P < 0.05) but the activity of hepatic acetyl-CoA carboxylase (ACC) decreased (P < 0.05) in response to dietary L-arginine supplementation. Collectively, our results indicate that liver is the major target for the action of dietary L-arginine supplementation on reducing white-fat mass in diet-induced obese rats by inhibiting fatty acid synthesis and increasing fatty acid oxidation via the AMPK-ACC signaling pathway. Additionally, increased CPT-I expression in skeletal muscle may also contribute to the enhanced oxidation of long-chain fatty acids in L-arginine-supplemented rats.

L-Arginine increases AMPK phosphorylation and the oxidation of energy substrates in hepatocytes, skeletal muscle cells, and adipocytes.

Previous work has shown that dietary L-arginine (Arg) supplementation reduced white fat mass in obese rats. The present study was conducted with cell models to define direct effects of Arg on energy-substrate oxidation in hepatocytes, skeletal muscle cells, and adipocytes. BNL CL.2 mouse hepatocytes, C2C12 mouse myotubes, and 3T3-L1 mouse adipocytes were treated with different extracellular concentrations of Arg (0, 15, 50, 100 and 400µM) or 400µM Arg + 0.5mM NG-nitro-L-arginine methyl ester (L-NAME; an NOS inhibitor) for 48h. Increasing Arg concentrations in culture medium dose-dependently enhanced (P < 0.05) the oxidation of glucose and oleic acid to CO2 in all three cell types, lactate release from C2C12 cells, and the incorporation of oleic acid into esterified lipids in BNL CL.2 and 3T3-L1 cells. Arg at 400µM also stimulated (P < 0.05) the phosphorylation of AMP-activated protein kinase (AMPK) in all three cell types and increased (P < 0.05) NO production in C2C12 and BNL CL.2 cells. The inhibition of NOS by L-NAME moderately reduced (P < 0.05) glucose and oleic acid oxidation, lactate release, and the phosphorylation of AMPK and acetyl-CoA carboxylase (ACC) in BNL CL.2 cells, but had no effect (P > 0.05) on these variables inC2C12 or 3T3-L1 cells. Collectively, these results indicate that Arg increased AMPK activity and energy-substrate oxidation in BNL CL.2, C2C12, and 3T3-L1 cells through both NO-dependent and NO-independent mechanisms.

Arginine supplementation in the feed of gestating sows

The high prolificacy achieved by the genetic improvement of sows has resulted in decreased birth weights and uniformity of litters, as well as increased prenatal and preweaning mortality. Amino acids, such as arginine, are essential for the proper development of the placenta and the swine fetus. Their role include regulating angiogenesis, vascular development, and therefore potentially placental vascularization, providing a greater supply of nutrients and oxygen from the sow to the fetuses. The objective of the trial was to evaluate the effects of dietary l-arginine supplementation on the reproductive and productive performance of gestating sows from days 30 to 60 and days 80 to 114 of gestation. Forty-eight pluriparous sows with two to six parities were divided into two different treatments with a total of 24 replicates per treatment. The treatments consisted of a control diet without l-arginine supplementation (CON) and a diet with top-dressed supplementation of 1.0% l-arginine (ARG). Blood samples were collected from the sows on days 30, 60, 90, and 114 of gestation to determine the plasma concentrations of albumin, creatinine, and urea. Sows were weighed 24 h after farrowing and at weaning to calculate body weight loss during lactation. Piglets were individually weighed at birth before the first feeding and at weaning. Supplementation of the diet with l-arginine during gestation affected (p = 0.025) the plasma concentrations of triglycerides at 60 days, but it did not impact the albumin, creatinine, and urea's concentrations at 30, 60, 90, and 114 days of gestation. However, the concentrations of creatinine differed (p = 0.006) for gestational periods. The average weight of piglets born alive was greater (p = 0.0485) for ARG compared to CON and the other performance and reproductive characteristics did not differ. The percentage of piglets born weighing over 1.81 kg was greater (p < 0.05) for sows fed ARG than in CON fed sows. l-arginine supplementation in the feed of gestating sows increased the average weight of piglets born alive and the percentage of piglets with a birth weight above 1.81 kg, reduced the concentration of triglycerides at 60 days of gestation, and the gestational period had effect about the creatinine concentrations.

Response of guinea fowls to dietary L-arginine supplementation

Abstract This experiment aimed at evaluating the influence of supplementing L-arginine in the diets fed to guinea fowls on growth response, haematological profile, serum biochemical indices and internal organs. A total of 300 one-day-old guinea fowl keets were allotted in a completely randomised design to three dietary treatments of basal diets (starter and grower) supplemented with 0, 0.5 and 1.0 g arginine/kg. Each treatment group was replicated four times consisting of 25 keets per replicate. At the starter phase, final weight, weight gain and feed conversion ratio (p &lt; 0.05) improved as arginine level increased in the diet. However, feed intake was higher (p &lt; 0.05) in the group fed 1.0 g/kg arginine supplemented diet when compared to other treatment groups. Final weight at the grower phase increased linearly (p &lt; 0.05) with arginine supplementation without corresponding effect on weight gain in birds fed different arginine levels. Red blood cell counts, white blood cell counts and lymphocytes (p &lt; 0.05) increased in the blood of guinea fowls fed diets supplemented with arginine. Creatinine and uric acid (p &lt; 0.05) were reduced in guinea fowls fed arginine supplemented diets at the starter and grower phases, respectively. Liver weight linearly increased (p &lt; 0.05) with arginine in the diets of the guinea fowls. This study indicates that supplementing guinea fowl diet with arginine at 1.0 g/kg at the starter phase and 0.5 g/kg at the finisher phase improved their growth and feed conversion ratio. Birds fed arginine supplemented diets had higher lymphocyte and reduced heterophil counts which may suggest a better immune response.

Inclusion of dietary L-arginine supplementation during late gestation and lactation on litter performance in sow

Sureshkumar, S., Park, J.H. and Kim, I.H. 2022. Inclusion of dietary L-arginine supplementation during late gestation and lactation on litter performance in sow. Animal Nutrition and Feed Technology, 22:177-185.

Amelioration of Alzheimer's Disease by Gut-Pancreas-Liver-Brain Interaction in an App Knock-In Mouse Model.

In this study, we observed disease progression, changes in the gut microbiota, and interactions among the brain, liver, pancreas, and intestine in a mouse model of Alzheimer’s disease (AD), in addition to attempting to inhibit disease progression through the dietary supplementation of L-arginine and limonoids. Wild-type mice (WC) and AD mice were fed a normal diet (AC), a diet supplemented with L-arginine and limonoids (ALA), or a diet containing only limonoids (AL) for 12–64 weeks. The normal diet-fed WC and AC mice showed a decrease in the diversity of the gut microbiota, with an increase in the Firmicutes/Bacteroidetes ratio, and bacterial translocation. Considerable bacterial translocation to the pancreas and intense inflammation of the pancreas, liver, brain, and intestinal tissues were observed in the AC mice from alterations in the gut microbiota. The ALA diet or AL diet-fed mice showed increased diversity of the bacterial flora and suppressed oxidative stress and inflammatory responses in hepatocytes and pancreatic cells, bacterial translocation, and neurodegeneration of the brain. These findings suggest that L-arginine and limonoids help in maintaining the homeostasis of the gut microbiota, pancreas, liver, brain, and gut in AD mice.

Dietary L-arginine supplementation during days 14-25 of gestation enhances aquaporin expression in the placentae and endometria of gestating gilts.

This study tested the hypothesis that dietaryL-arginine (Arg) supplementation to pregnant gilts enhanced theexpression of water channel proteins [aquaporins (AQPs)] in their placentae and endometria. Gilts were fed twice daily 1kg of a corn and soybean meal-based diet supplemented with 0.0%, 0.4%, or 0.8% Arg between Days 14 and 25 of gestation. On Days 25 and 60 of gestation, gilts were hysterectomized to obtain placentae and endometria. On Day 25 of gestation, supplementation with 0.4% Arg increased (P < 0.05) the abundance of placental AQP9 protein, whereas supplementation with 0.8% Arg increased (P < 0.05) placental AQP1 and AQP9 proteins, compared with controls. On Day 60 of gestation, supplementation with 0.4% Arg increased (P < 0.05) endometrial AQP1 protein, whereas supplementation with 0.8% Arg increased (P < 0.05) endometrial AQP5 and AQP9 proteins. Supplementation with 0.8% Arg increased the endometrial expression of AQP1, AQP5, and AQP9 proteins located in the luminal epithelium and glandular epithelium of endometria, and placental transport of 3H2O. Collectively, these results indicate that dietary Arg supplementation stimulates theexpression of selective AQPs in porcine placenta and endometria, thereby enhancing water transport from mother to fetus and expanding the chorioallantoic membranes during the period of placentation.

Dietary L-arginine supplementation of tilapia (Oreochromis niloticus) alters the microbial population and activates intestinal fatty acid oxidation.

Currently, little is known about the function of L-arginine in the homeostasis of intestinal lipid metabolism. This study was conducted to test the hypothesis that dietary L-arginine supplementation may alter intestinal microbiota and lipid metabolism in tilapia. Tilapia were fed a basal diet (containing 16.9g L-arginine per kilogram diets) or the basal diet supplemented with 1% or 2% L-arginine for 8 wks. In the present study, we found that dietary supplementation with 1% or 2% L-arginine induced a shift in the community structure of gut microbiota, as showed by increased (p < 0.05) α-diversity, altered (p < 0.05) β-diversity and function profile. This finding coincided with decreased lipid accretion in the intestine of tilapia, which was associated with an enhancement in mRNA levels for peroxisome proliferator-activated receptor α (Pparα), acyl-coenzyme a oxidase 1 (Acox1), and peroxisome proliferator-activated receptor γ coactivator-1α (Pgc-1α). Using intestinal epithelial cell culture, we demonstrated that the lipid-lowering effect of L-arginine was mainly mediated by activating the AMP-activated protein kinase (AMPK) signaling pathway, carnitine palmitoyltransferase 1 (CPT1), and PPARα, as well as mRNA levels for Acox1 and Acox2. Collectively, our results suggest that dietary L-arginine supplementation of tilapia changed the intestinal microbiota and activated intestinal fatty acid oxidation. However, future studies are warranted to determine the relationship between microbiota and lipid metabolism in the intestine.

Detrimental Effects of Chronic L-Arginine Rich Food on Aging Kidney.

The impaired L-arginine/nitric oxide pathway is a well-recognized mechanism for cardiovascular and renal diseases with aging. Therefore, supplementation of L-arginine is widely proposed to boost health or as adjunct therapy for the patients. However, clinical data, show adverse effects and even enhanced mortality in patients receiving long-term L-arginine supplementation. The effects of long-term L-arginine supplementation on kidney aging and the underlying mechanisms remain elusive. Moreover, high protein and high amino acid diet has been thought detrimental for kidney. We therefore investigated effects of chronic dietary L-arginine supplementation on kidney aging. In both young (4 months) and old (18–24 months) mice, animals either receive standard chow containing 0.65% L-arginine or diet supplemented with L-arginine to 2.46% for 16 weeks. Inflammation and fibrosis markers and albuminuria are then analyzed. Age-associated increases in tnf-α, il-1β, and il-6, vcam-1, icam-1, mcp1, inos, and macrophage infiltration, collagen expression, and S6K1 activation are observed, which is not favorably affected, but rather further enhanced, by L-arginine supplementation. Importantly, L-arginine supplementation further enhances age-associated albuminuria and mortality particularly in females, accompanied by elevated renal arginase-II (Arg-II) levels. The enhanced albuminuria by L-arginine supplementation in aging is not protected in Arg-II−/− mice. In contrast, L-arginine supplementation increases ROS and decreases nitric oxide production in old mouse aortas, which is reduced in Arg-II−/− mice. The results do not support benefits of long-term L-arginine supplementation. It rather accelerates functional decline of kidney and vasculature in aging. Thus, the long-term dietary L-arginine supplementation should be avoided particularly in elderly population.

PSVIII-8 Effects of dietary L-arginine on growth performance, nutrient digestibility, and meat quality in finishing pigs

Abstract Arginine plays an important role in regulating arginine-nitric oxide synthase pathway, regulating lipid metabolism, and upregulating the mRNA levels of genes involved in fat synthesis in muscle in animals, and can therefore improve feed utilization for protein accretion. The objective of this study was to investigate the effects of supplementation of different concentrations of L-arginine on growth performance, nutrient digestibility, and meat quality in finishing pigs. A total of 120 crossbred [(Landrace × Yorkshire) × Duroc] pigs with an average initial body weight (BW) of 53.80 ± 1.86 kg were used in this 10-week feeding trial. The pigs were randomly allotted to 1 of 3 dietary treatments (5 pigs/pen and 8 replicates/treatment) in a randomized complete block design according to their sex (2 gilts and 3 barrows) and BW. Dietary treatments included: 1) CON, corn-soybean meal based basal diet (containing 13.81 MJ/kg metabolic energy and 0.95% lysine for entire experimental period); 2) LA0.5, CON + 0.5 g/kg L-arginine; 3) LA1.0, CON + 1.0 g/kg L-arginine. Individual body weight was measured initially and at the end of 5th and 10th week, feed consumption was recorded on pen basis during the experiment to determine growth performance. Meat samples were randomly taken from each pen (2 pigs per pen, 1 gilt and 1 barrow; 16 pigs per treatment) for determination of meat quality. All data were analysed using linear and quadratic contrast (SAS Institute Inc., Cary, NC, USA). The result showed that L-arginine did not affect pig growth performance and nutrient digestibility. However, dietary L-arginine supplementation linearly increased (P&amp;lt; 0.05) muscle marbling score, while linearly decreasing (P&amp;lt; 0.05) cooking loss and drip loss of pork muscle (Table 1). Results of present study demonstrated that 1.0 g/kg L-arginine would be beneficial in improving the meat quality in finishing pigs.

PSVIII-7 Dietary L-arginine supplementation enhances growth performance, intestinal antioxidant capacity, immunity and modulate gut microbiota in yellow feathered chickens

Abstract This study investigated the effects of dietary Arginine (Arg) on performance, intestinal antioxidant capacity, immunity, and gut microbiota in Chinese yellow-feathered chickens. One thousand and two hundred 1-day-old female Qingyuan partridge chickens were randomly assigned to 5 groups with 6 replicates of 40 birds each. Chickens were fed diets with 5 total Arg levels (8.5, 9.7, 10.9, 12.1 and 13.3 g/kg) without antibiotics for 30 D. Average daily feed intake, average daily gain, and feed conversion ratio were improved with dietary Arg levels (P &amp;lt; 0.05). Dietary Arg level had a linear (P &amp;lt; 0.05) or quadratic (P &amp;lt; 0.05) effect on the gene expression of glutathione peroxidase 1, hame oxygenase 1, nuclear factor erythroid 2, linearly and quadraticly increased activities of GSH-Px and total antioxidant capacity in the jejunum and ileum. In addition, relative expression of interleukin-1β and toll-like receptor 4 decreased linearly (P &amp;lt; 0.05) and quadratically (P &amp;lt; 0.05) in the ileum with increasing dietary Arg levels; secretory immunoglobulin A contents were increased. In addition, sequencing data of 16S rRNA indicated that dietary Arg increased the abundances of Firmicutes phylum, Romboutsia and Candidatus Arthromitus genus, while decreased that of Clostridium sensu stricto 1. A diet containing 12.1 g Arg/kg could promote growth performance, intestinal antioxidation, innate immunity and modulate gut microbiota in yellow feathered chickens.

Dietary L-arginine supplementation enhances growth performance, intestinal antioxidative capacity, immunity and modulates gut microbiota in yellow-feathered chickens

This study investigated the effects of dietary Arginine (Arg) on performance, intestinal antioxidative capacity, immunity, and gut microbiota in Chinese yellow-feathered chickens. One thousand two hundred 1-day-old female Qingyuan partridge chickens were randomly assigned to 5 groups with 6 replicates of 40 birds each. Chickens were fed diets with 5 levels of total Arg (8.5, 9.7, 10.9, 12.1, and 13.3 g/kg) without antibiotics for 30 d. The ADFI, ADG, and feed conversion ratio were improved with dietary Arg levels (P < 0.05). The proportions of CD3+ and CD4+/CD8+ lymphocytes responded in a linear (P < 0.05) manner and those of CD4+ in a linear or quadratic (P < 0.05) manner as dietary Arg levels increased. Dietary Arg level had a linear (P < 0.05) or quadratic (P < 0.05) effect on the gene expression of glutathione peroxidase 1, heme oxygenase 1, nuclear factor erythroid 2–related factor 2, and the activities of glutathione peroxidase and total antioxidative capacity in the jejunum and ileum. The relative expression of IL-1β, myeloid differentiation primary response 88, and Toll-like receptor 4 decreased linearly (P < 0.05) in the ileum with increasing dietary Arg levels; secretory IgA contents were increased. In addition, sequencing data of 16S rRNA indicated that dietary Arg increased the relative abundance of Firmicutes phylum, Romboutsia and Candidatus Arthromitus genera, while decreased that of Clostridium sensu stricto 1. A diet containing 12.1 g Arg/kg promoted growth performance, intestinal antioxidation, and innate immunity and modulated gut microbiota in yellow-feathered chickens.

Dietary L-arginine supplementation reduces lipid accretion by regulating fatty acid metabolism in Nile tilapia (Oreochromis niloticus)

BackgroundExcessive white fat accumulation in humans and other animals is associated with the development of multiple metabolic diseases. It is unknown whether dietary L-arginine supplementation reduces lipid deposition in high fat diet-fed Nile tilapia (Oreochromis niloticus).ResultsIn the present study, we found that dietary supplementation with 1% or 2% arginine decreased the deposition and concentration of fats in the liver; the concentrations of triglycerides, low-density lipoprotein, total cholesterol, and high-density lipoprotein in the serum; and the diameter of adipocytes in intraperitoneal adipose tissue. Compared with the un-supplementation control group, the hepatic activities of alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase, and hepatic concentration of malondialdehyde were reduced but these for catalase and superoxide dismutase were enhanced by dietary supplementation with 2% arginine. Arginine supplementation reduced the total amounts of monounsaturated fatty acids, while increasing the total amounts of n-3 and n-6 polyunsaturated fatty acids in the liver. These effects of arginine were associated with reductions in mRNA levels for genes related to lipogenesis (sterol regulatory element-binding protein-1, acetyl-CoA carboxylase α, stearoyl-CoA desaturase, and fatty acid synthase) but increases in mRNA levels for genes involved in fatty acid β-oxidation (carnitine palmitoyltransferase 1α and peroxisome proliferator-activated receptor α). In addition, hepatic mRNA levels for Δ4 fatty acyl desaturase 2 and elongase 5 of very long-chain fatty acids were enhanced by arginine supplementation.ConclusionThese results revealed that dietary L-arginine supplementation to tilapia reduced high fat diet-induced fat deposition and fatty acid composition in the liver by regulating the expression of genes for lipid metabolism.

L-Arginine supplementation of gilts during early gestation modulates energy sensitive pathways in pig conceptuses.

Dietary l-arginine (ARG) supplementation has been studied as a nutritional strategy to improve reproductive performance of pregnant sows, since arginine is a conditionally essential amino acid. However, reports addressing the molecular mechanisms that mediate supplementation effects on embryos and fetuses development are still scarce. Therefore, we aimed to evaluate the effects of 1.0% ARG supplementation of commercial pregnant gilts on genes and proteins from energy metabolism and antioxidant defense pathways in embryos and fetuses. We also analyzed the global transcriptome profile of 25- and 35-day-old conceptuses. At Day 25, we observed a lower abundance of phospho-AMP-activated protein kinase (phospho-AMPK) protein and downregulation of oxidative phosphorylation system genes in ARG embryos. On the other hand, ARG fetuses showed greater expression of MLST8 and lower expression of MTOR genes, in addition to lower abundance of phospho-AMPK and phospho-mammalian target of rapamycin (phospho-mTOR) proteins. Transcriptome analysis at Day 35 did not present differentially expressed genes. For the antioxidant defense pathway, no differences were found between CON and ARG conceptuses, only trends. In general, supplementation of gilts with 1.0% ARG during early gestation affects energy sensitive pathways in 25- and 35-day conceptuses; however, no effects of supplementation were found on the antioxidative defense pathway in 25-day embryos.

Dietary Supplementation of L-Arginine and N-Carbamylglutamate Attenuated the Hepatic Inflammatory Response and Apoptosis in Suckling Lambs with Intrauterine Growth Retardation.

L-arginine (Arg) is a semiessential amino acid with several physiological functions. N-Carbamylglutamate (NCG) can promote the synthesis of endogenous Arg in mammals. However, the roles of Arg or NCG on hepatic inflammation and apoptosis in suckling lambs suffering from intrauterine growth restriction (IUGR) are still unclear. The current work is aimed at examining the effects of dietary Arg and NCG on inflammatory and hepatocyte apoptosis in IUGR suckling lambs. On day 7 after birth, 48 newborn Hu lambs were selected from a cohort of 432 twin lambs. Normal-birthweight and IUGR Hu lambs were allocated randomly (n = 12/group) to control (CON), IUGR, IUGR+1% Arg, or IUGR+0.1% NCG groups. Lambs were fed for 21 days from 7 to 28 days old. Compared with CON lambs, relative protein 53 (P53), apoptosis antigen 1 (Fas), Bcl-2-associated X protein (Bax), caspase-3, cytochrome C, tumor necrosis factor alpha (TNF-α), nuclear factor kappa-B (NF-κB) p65, and NF-κB pp65 protein levels were higher (P < 0.05) in liver from IUGR lambs, whereas those in liver from IUGR lambs under Arg or NCG treatment were lower than those in IUGR lambs. These findings indicated that supplementing Arg or NCG reduced the contents of proinflammatory cytokines at the same time when the apoptosis-related pathway was being suppressed, thus suppressing the IUGR-induced apoptosis of hepatic cells.