Dietary L-arginine Research Articles

Comparing Nitric Oxide Generation Pathways using Dietary L-Arginine and Dietary Nitrate: A 15N tracer study in Wistar Rats

Mammals generate nitric oxide (NO) through two main pathways. In the direct production pathway, endogenous nitric oxide synthase (NOS) enzymes catalyze the reaction of L-arginine with oxygen, producing nitric oxide and citrulline. When oxygen accessibility is low, the reductive pathway supplies nitric oxide through the nitrate-nitrite-NO reduction cascade. Additional research is needed to understand whether the two NO generation pathways interact and what effects the two pathways have on the body and each other. We investigated how dietary supplementation of 15N-L-arginine (0.5 g/kg), 15N-nitrate (0.013 g/kg), or a combination of L-arginine and nitrate influences nitrate concentrations in plasma, skeletal muscle, and liver tissue from Wistar rats. We administered treatments via oral gavage. Two hours after treatment administration, we euthanized the rats and collected tissue samples. The nitrate concentrations were measured using chemiluminescence, and future mass spectrometry analysis for 15N/14N ratios will be performed. The calculated concentrations were compared between treatment groups using single factor analysis of variance. Firstly, we observed that nitrate administration significantly increased total nitrate levels in plasma, liver, and muscle tissues compared to the control group. Interestingly, L-arginine alone did not result in a significant rise in total nitrate concentrations. Notably, liver tissue from the L-arginine-treated group had slightly lower concentrations of nitrate than the control group. The combination of L-arginine and nitrate showed no statistically significant difference when compared with the nitrate-treated group in all three tissues. These results suggest that a bolus of L-arginine does not have a substantial short-term effect (within 2 hours after ingestion) on total nitrate concentrations in rat tissues. Future mass spectrometry analysis will indicate how the tissues handle acute ingestion of two different NO sources: L-arginine and nitrate. Further research must be performed for a more detailed understanding of the kinetics of arginine and nitrate, as well as for the effects of these dietary supplements on improving NO homeostasis. This work was supported by intramural NIDDK/NIH grant ZIA DK 025104-15 to Alan N. Schechter. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Effect of dietary L-arginine on growth performance and physiological responses of Nile tilapia, Oreochromis niloticus

Effect of dietary L-arginine on growth performance and physiological responses of Nile tilapia, Oreochromis niloticus

Estimation of genetic parameters for egg production traits in Japanese quail that selected for immune responses and fed different level of dietary L-arginine

This study was conducted in the fields of the Department of Animal Production - College of Agriculture at Kirkuk University for the period from 6/14/2021 to 7/30/2022. 750 quail chicks were supplied from the Poultry Research Station of the Agricultural Research Department in Abu Ghraib. The chicks were fed the starter ration until the age of 30 days, and then they were fed the production ration. At the age of 4 weeks, the chicks were vaccinated with the attenuated Newcastle vaccine, and the chicks were divided into six experimental treatments: the first treatment represented the negative control group that was not vaccinated and did not have the amino acid arginine added to it, the second treatment represented the positive control group whose chicks were vaccinated with the Newcastle vaccine with no arginine added to their diet As for the third and fourth treatments, they were vaccinated with the Newcastle vaccine with the addition of 5% arginine higher than the bird''s needs. The fifth and sixth treatments represented groups of birds vaccinated with the Newcastle vaccine, while feeding the birds with diets to which the amino acid arginine was added, 10% higher than the bird''s needs. A week after the initial immunization, the bird was vaccinated again with Newcastle vaccine, and the immune level was examined by the agglutination test to find out the level of the birds'' immune response, dividing them into two levels of high immune response and low immune response. This process was repeated for the next three generations. The characteristic of egg production at the age of 90 and 120 days, and the egg mass was recorded. The data were analyzed according to the general linear model method using the ready-made statistical program SAS. The genetic equivalent and the genetic and phenotypic correlations were estimated. The characteristics of egg production decreased until the age of 90 and 120 days, as well as the mass of eggs at the age of 120 days, compared to the base population (21.61 vs. 34.84), (22.01 vs. 26.53), (323.47 vs. 545.97), respectively. The egg mass was significantly affected by the level of immunity and the percentage of added arginine, where the highest value of the egg mass was for birds selected for the high immune level and to which arginine was added by 10% higher than the needs of the bird. Estimates of genotyped egg production at 90 and 120 days of age and egg mass at 120 days of age were (0.64, 0.65 and 0.21), respectively. The results showed weak genetic correlations (0.0263) between egg production at the age of 90 days and egg production at the age of 120 days, but the phenotypic correlations were high (0.6248) between egg production at the age of 90 days and egg production at the age of 120 days. The current study indicates that the selection of birds according to the immune response against Newcastle disease led to decrease in egg production and egg mass. Addition the Arginine amino acid did not increase production at the age of 90 and 120 days. While the addition of arginine 10% led to an increase in the egg mass.

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.

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 or N-Carbamylglutamate Alleviates Colonic Barrier Injury, Oxidative Stress, and Inflammation by Modulation of Intestinal Microbiota in Intrauterine Growth-Retarded Suckling Lambs.

Our previous studies have revealed that dietary N-carbamylglutamate (NCG) and L-arginine (Arg) supplementation improves redox status and suppresses apoptosis in the colon of suckling Hu lambs with intrauterine growth retardation (IUGR). However, no studies have reported the function of Arg or NCG in the colonic microbial communities, barrier function, and inflammation in IUGR-suckling lambs. This work aimed to further investigate how dietary Arg or NCG influences the microbiota, barrier function, and inflammation in the colon of IUGR lambs. Forty-eight newborn Hu lambs of 7 d old were assigned to four treatment groups (n = 12 per group; six male, six female) as follows: CON (normal birth weight, 4.25 ± 0.14 kg), IUGR (3.01 ± 0.12 kg), IUGR + Arg (2.99 ± 0.13 kg), and IUGR + NCG (3.03 ± 0.11 kg). A total of 1% Arg or 0.1% NCG was supplemented in a basal diet of milk replacer, respectively. Lambs were fed the milk replacer for 21 d until 28 d after birth. Compared to the non-supplemented IUGR lambs, the transepithelial electrical resistance (TER) was higher, while fluorescein isothiocyanate dextran 4 kDa (FD4) was lower in the colon of the NCG- or Arg-supplemented IUGR lambs (p &lt; 0.05). The IUGR lambs exhibited higher (p &lt; 0.05) colonic interleukin (IL)-6, IL-1β, tumor necrosis factor (TNF)-α, reactive oxygen species (ROS), and malondialdehyde (MDA) levels than the CON lambs; the detrimental effects of IUGR on colonic proinflammatory cytokine concentrations and redox status were counteracted by dietary Arg or NCG supplementation. Both IUGR + Arg and IUGR + NCG lambs exhibited an elevated protein and mRNA expression of Occludin, Claudin-1, and zonula occludens-1 (ZO-1) compared to the IUGR lambs (p &lt; 0.05). Additionally, the lipopolysaccharide (LPS) concentration was decreased while the levels of acetate, butyrate, and propionate were increased in IUGR + Arg and IUGR + NCG lambs compared to the IUGR lambs (p &lt; 0.05). The relative abundance of Clostridium, Lactobacillus, and Streptococcus was lower in the colonic mucosa of the IUGR lambs than in the CON lambs (p &lt; 0.05) but was restored upon the dietary supplementation of Arg or NCG to the IUGR lambs (p &lt; 0.05). Both Arg and NCG can alleviate colonic barrier injury, oxidative stress (OS), and inflammation by the modulation of colonic microbiota in IUGR-suckling lambs. This work contributes to improving knowledge about the crosstalk among gut microbiota, immunity, OS, and barrier function and emphasizes the potential of Arg or NCG in health enhancement as feed additives in the early life nutrition of ruminants.

The Potency of Oral L-Arginine Suplementation Based on Chitosan-Coated Gold Nanoparticles (c-AuNPs) as Preeclampsia Prevention in Pregnant Women

Preeclampsia is a multi-systemic hypertensive disorder in pregnant women after two weeks of gestation and can cause complications in about 6-10% of all pregnancies. The incidence of preeclampsia in Indonesia is 128,273/year or about 5.3%. However, the handling of preeclampsia in Indonesia is still not optimal. This disease is difficult to detect and often appears suddenly, so prevention efforts need to be taken as an essential step in reducing morbidity and mortality due to this disease. Previous studies have shown that L-Arginine exhibits potential properties in preventing preeclampsia. This literature review aims to determine the potential for oral L-Arginine supplementation to prevent preeclampsia in pregnant women. Search for literature using search engines such as Google Scholar, Science Direct, ResearchGate, and NCBI. Inclusion and exclusion criteria are used to eliminate unrelated journals so 38 journals are obtained. L-Arginine has great potential as a preventive supplementation of preeclampsia by increasing the vascular NO synthesis where NO deficiency in pregnant women can induce changes in the uteroplacental structure. Supplementation of the dietary L-Arginine at a low dose of 3 g/day for three to four weeks is required in early pregnancy. The use of chitosan-coated gold nanoparticles (c-AuNPs) as encapsulation on a protein increases the bioavailability of oral supplementation and improves the patient's clinical state. Further research regarding the effectiveness of L-Arginine supplementation orally with c-AuNPs and the optimal dosage as a preeclampsia preventive supplement is needed.

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.

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.

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.

Research Note: Effects of dietary L-arginine on the production performance and gene expression of reproductive hormones in laying hens fed low crude protein diets

The present study was designed to investigate whether L-arginine (Arg) supplementation would influence the production performance and reproductive traits of laying hens fed low crude protein (LCP) diets. Hy-Line brown laying hens were randomly assigned to dietary treatments of control, LCP, and LCP supplemented with 0.05, 0.10, 0.15, or 0.20% Arg for 7 wk. The results showed no significant variations on the production performance, and relative organ indexes of hens. However, significant transcriptional and structural changes were evident along the HPG axis of hens. Arg supplementation linearly upregulated (P < 0.05) the gonadotropin-releasing hormone 1 (GnRH1), and gonadotropin inhibitory hormone in the hypothalamus. The pituitary growth hormone, GnRH receptor, and follicle-stimulating hormone (FSHβ) were also increased (P < 0.05). In the ovary, GnRH1, and estrogen receptor β were linearly increased by Arg, and the ovarian morphology revealed that LCP induced structural alterations which were minimally recovered by Arg supplementation. Serum insulin-like growth factor 1 (IGF-1) and nitric oxide (NO) were increased (P < 0.05) at higher levels of Arg supplementation. Therefore, supplementing high Arg (0.20%) to LCP hens influenced the ovarian morphology and modulated the gene expression of reproductive hormones in the hypothalamic-pituitary-gonadal axis of laying hens via actions that may be related to NO and IGF-1 activity.

The Potential of L-Arginine in Prevention and Treatment of Disturbed Carbohydrate and Lipid Metabolism-A Review.

L-arginine, an endogenous amino acid, is a safe substance that can be found in food. The compound is involved in synthesis of various products responsible for regulatory functions in the body. Particularly noteworthy is, among others, nitric oxide, a signaling molecule regulating carbohydrate and lipid metabolism. The increasing experimental and clinical data indicate that L-arginine supplementation may be helpful in managing disturbed metabolism in obesity, regulate arterial blood pressure or alleviate type 2 diabetes symptoms, but the mechanisms underlying these effects have not been sufficiently elucidated. This review aims to present the up-to-date information regarding the current uses and health-promoting potential of L-arginine, its effects on nitric oxide, carbohydrate and lipid metabolisms, based on the results of in vivo, in vitro studies, and clinical human trials. Available literature suggests that L-arginine may have beneficial effects on human health. However, some studies found that higher dietary L-arginine is associated with worsening of an existing disease or may be potential risk factor for development of some diseases. The mechanisms of regulatory effects of L-arginine on carbohydrate and lipid metabolism have not been fully understood and are currently under investigation.

Microarray analysis reveals an important role for dietary L-arginine in regulating global gene expression in porcine placentae during early gestation.

Increasing the dietary provision of L-arginine to pregnant swine beginning at Day 14 of gestation enhances embryonic survival, but the underlying mechanisms are largely unknown. This study determined the effects of dietary supplementation with 0.8% L-arginine to gilts between Days 14 and 25 of gestation on the global expression of genes in their placentae. Between Days 14 and 24 of gestation, gilts were fed 2 kg of a corn- and soybean meal-based diet (containing 12.0% crude protein and 0.70% Arg) supplemented with 0.8% L-arginine or without L-arginine (0.0%; with 1.64% L-alanine as the isonitrogenous control). On Day 25 of gestation, 30 min after the consumption of their top dressing containing 8 g L-arginine or 16.4 g L-alanine, gilts underwent hysterectomy to obtain placentae, which were snap-frozen in liquid nitrogen. Total RNAs were extracted from the frozen tissues and used for microarray analysis based on the 44-K Agilent porcine gene platform. L-Arginine supplementation affected placental expression of 575 genes, with 146 genes being up-regulated and 429 genes being down-regulated. These differentially expressed genes play important roles in nutrient metabolism, polyamine production, protein synthesis, proteolysis, angiogenesis, immune development, anti-oxidative responses, and adhesion force between the chorioallantoic membrane and the endometrial epithelium, as well as functions of insulin, transforming growth factor beta, and Notch signaling pathways. Dietary supplementation with L-arginine plays an important role in regulating placental gene expression in gilts. Our findings help to elucidate mechanisms responsible for the beneficial effect of L-arginine in improving placental growth and embryonic/fetal survival in swine.

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.

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.

Effect of Dietary Supplementation with L-Arginine and Vitamin C on Egg Production Performance for Matrouh Strain Hens

The present work was aimed to study the effect of dietary L-arginine level, vitamin C, and their interaction between them on some productive performance of Matrouh laying hens during the summer season. A 4X3 factorial treatment arrangement was carried out including four levels of dietary L-Arg (0.0, 0.4, 0.8, and 1.2 g/kg diet) and three VC concentrations (0, 150, and 300 mg/kg diet). A total number of 108 Matrouh hens (Egyptian local strain) aged 64 weeks were randomly distributed into twelve treatment groups (three replicate each). The results obtained showed a significant (p < 0.05) effect in live body weight due to dietary L-Arg and VC supplementation at 72 weeks of age only. Significant (p < 0.05) differences were observed in feed intake and feed conversion ratio due to dietary L-Arg levels during all periods of estimation. Dietary L-Arg levels had significant (P<0.05) effects on the rate of egg prodction during the periods from 68-71 and 64-75 weeks of birds age. Significant (p < 0.05) differences were observed in egg weight due to dietary L-Arg and VC levels during all periods of estimation except at 72-75 weeks of age. Dietary L-Arg levels had significant (P<0.05) effect on egg mass during the periods from 68-71,72-75 and 64-75 weeks of bird’s age. The VC supplementation didn't have any significant effects on feed conversion ratio, egg production rate, egg weight, and egg mass. The interaction effects between dietary L-Arg and VC levels had a major influence (p < 0.05) on body weight, feed consumption, feed conversion ratio, egg production rate, egg weight and egg mass. In conclusion, it could be concluded that Matrouh laying hens supplemented diet with L-Arg at a level of 1.2 g or VC at a level of 300 mg/kg diet, seemed to be adequate to achieve the favorite results and is recommended.

Effect of Dietary Supplementation with L-Arginine and Vitamin C on Reproduction Performance and Economical Efficiency for Matrouh Strain Hens under Egyptian Summer Conditions

The present work was aimed to study the effect of dietary L-arginine level, vitamin C, and their interaction between them on some reproductive performance and economical efficiency of Matrouh laying hens during the summer season. A 4X3 factorial treatment arrangement was carried out including four levels of dietary L-Arg (0.0, 0.4, 0.8, and 1.2 g/kg diet) and three VC concentrations (0, 150, and 300 mg/kg diet). A total number of 108 Matrouh hens and 36 cocks (Egyptian local strain) aged 64 weeks were randomly distributed into twelve treatment groups (three replicate each). The results obtained showed non-significant (p < 0.05) effect in fertility percentages due to dietary L-Arg or VC supplementation through all the experimental periods. The interaction effects between dietary L-Arg and VC levels had a major influence (p < 0.05) on fertility percentage. Dietary L-Arg levels had significant (P<0.05) effects on the hatchability percentages of total eggs set and fertile egg during all periods of estimation. The VC supplementation didn't have any significant effects on fertility and hatchability of fertile eggs percentage. The interaction effects between dietary L-Arg and VC levels had a major influence (p < 0.05) on the hatchability percentages of total eggs set during all the interval periods. In conclusion, it could be concluded that Matrouh laying hens supplemented diet with L-Arg at a level of 0.4 g and VC at a level of 150 mg/kg diet, seemed to be adequate to achieve the favorite results and is recommended.

Effect of L-Arginine Supplementation in Ossimi Rams’ Diets on Biometry of Testes and Epididymis, Immune-Histochemical Expression and Characteristics of Epididymal Spermatozoa

This experiment was conducted to evaluate the impact of dietary L-arginine supplementation on some epididymal spermatozoa characteristics, differential White blood cells count, some reproductive organs'metrics. Fifteen adult Ossimi rams averaging 44.9± 0.57 kg were utilized, divided into three comparable groups (5 rams each) , were fed a basal ration supplemented with L- arginine at concentration of 0.0 (G1) or 0.5(G2) or 1.0%(G3) of body weight/day for two months. At the end of the study rams were slaughtered for conducting biometric studies on tests and epididymis and testicular Immunohistochemical NOS analysis. Epididymis Semen was collected and evaluated for motility, viability, abnormality and acrosome integrity.L-arginine Supplementation at 0.5(G2) or 1.0%(G3) significantly (P<0.05) improved epididymal spermatozoa characteristics, as % of motility, livability, acrosome integrity while, % of dead and abnormal spermatozoa decreased in supplemented groups as compared with G1. This improving was greatest in G2 than that happened in G3. Measurements of testes and epididymis increased in G2 and G3 compared with G1 . In addition, there was a significant increase of immunoexpression of testicular Nitric oxide synthase (NOS) in rams received L-arginine at 1% or 0.5% of body weight/day as compared to G1, and this expression was clearly found within the spermatid layer and few sertoli cells in both treated groups, while in G1, it was limited to spermatid layer only. . It could be concluded that dietary L- arginine supplementation to Ossimi ram ration has positive effects on epididymal spermatozoa characteristics, Sexual organs anthropometries and immunohistochemical expression of testicular NOS.