N-carbamylglutamate Research Articles

N-Carbamylglutamate Improves Reproductive Performance and Alters Fecal Microbiota and Serum Metabolites of Primiparous Sows during Gestation after Fixed-Time Artificial Insemination.

Simple SummaryLarger litter size (born alive) and higher uniformity of piglets’ birth weight are the most desired characteristics in pig production. Application of N-carbamylglutamate (NCG) was shown to increase litter size and decrease the coefficient of variation of piglets’ birth weight from sows after conventional artificial insemination. In this study, we report that, in sows after fixed-time artificial insemination (FTAI), NCG improved the number of piglets born alive and the coefficient of variation of birth weight through direct effects (increased serum NCG levels) and indirect effects (altered intestinal microbiome and serum metabolites). These findings indicate that NCG can improve reproductive performance by improving both the number of piglets born alive and the uniformity of piglets’ birth weight in sows after FTAI.N-carbamylglutamate (NCG) supplementation during gestation improves reproductive performance in sows after conventional artificial insemination. However, whether NCG can improve reproductive performance and change fecal microbiota and serum metabolite levels during pregnancy in sows after fixed-time artificial insemination (FTAI) remains unclear. Two hundred multiparous sows were assigned a diet from mating until farrowing: control (corn–soybean meal) or NCG supplementation (0.05% NCG). At days 30, 70, and 110 of gestation and after farrowing, maternal microbial diversity and serum metabolites were studied. Supplementation of NCG increased the number of piglets born alive and the litter weight (all p < 0.05) and altered the fetal microbial community during gestation. Some genera were particularly abundant at different time points during gestation and after farrowing, but none were commonly abundant across all four time points. Metabolic analysis revealed that NCG supplementation significantly increased the serum concentrations of NCG, ferulic acid, cinnamoylglycine, 3-phenyllactic acid, and gamma-glutamylglutamic acid in the NCG group compared with levels in the control group. Our results reveal that NCG supplementation during gestation improves reproductive performance in sows after FTAI, exerting both direct (increased serum NCG levels) and indirect effects (altered intestinal microbiome and serum metabolites) on sow reproduction and, ultimately, improving placental and fetal development.

Influence of concentrate level with or without N- carbamylglutamate on rumen bacteria and fermentation characteristics of Shami goats

This study was conducted to evaluate the effect of three levels of concentrate 2%, 3%, 4% with or without N-carbamylglutamate (NCG) on rumen bacteria and fermentation characteristics in Shami goats. Twenty-four male goats aged 8-10 months with initial weight 32,685 ± 1.52kg divided into six treatments in a 2×3 factorial experiment/ Completely Randomized Design. Individual feeding was used for 70 days. Rumen fluid was sampled at 0, 3, 6h after feeding while jugular blood was sampled after 70 days before morning feeding. Results showed decreasing (P&lt;0.01) of rumen pH and increasing volatile fatty acids (P&lt;0.01) after 3h and 6h of feeding for 3% level of concentrate with NCG. Rumen ammonia increased (P&lt;0.01) after 3h of feeding with NCG. Total rumen bacteria increased insignificantly with superiority 3% level of feeding without NCG and 4% concentrate with NCG. A linear decrease (P&lt;0.01) of blood urea with increasing feeding level with NCG and GPT decreased (P&lt;0.05) with 3% concentrate. In conclusion, it is preferred to feed 3% concentrate and use NCG as additive with urea.

Integration of transcriptomic and metabolomic analysis of the mechanism of dietary N-carbamoylglutamate in promoting follicle development in yaks.

Yak is the main livestock in the highlands of China. The low reproductive rate of yaks is a serious constraint on their production and utility. N-carbamylglutamate (NCG) can increase arginine synthesis in mammals and has been shown to improve reproductive performance. Twelve multiparous and simutaneous anoestrous female yaks were randomly divided into two groups, one of which was fed the basal diet (Control, n = 6), and the other was fed the basal diet supplemented with NCG at 6 g/day/yak (NCG, n = 6). All yaks were slaughtered on the 32nd day (the time predicted for the selection of the last wave of dominant follicles), and their ovarian tissues were collected and follicles were classified. NCG supplementation increased the number of large ovarian follicles (diameter > 10 mm), as well as caused significant changes in the transcriptional and metabolic levels in yak ovaries which due to the differential expression of 889 genes and 94 metabolites. Integrated analysis of the transcriptomics and metabolomics data revealed that the differentially expressed genes and differential metabolites were primarily involved in the process of energy metabolism, amino acid metabolic pathways, carbohydrate metabolic pathways, and lipid metabolic pathways. The highlighted changes were associated with amino acid synthesis and metabolism, ovarian steroid hormone synthesis, the pentose phosphate pathway, and the tricarboxylic acid cycle, suggesting that NCG supplementation may promote estrogen synthesis and help regulate follicular development by altering the pathways associated with glucose catabolism. The results present important clues for understanding the mechanisms by which NCG supplementation promotes follicular development in yaks. The findings of this study provide a basis for the development and application of NCG in optimizing animal reproduction, including yak reproductive performance, which may help optimize livestock management and uplift the pastoral economy.

N-carbamylglutamate improves feed conversion efficiency, feed digestibility and immunity status in finishing Holstein bulls

N-carbamylglutamate (NCG), an alternative of arginine, has been applied to improve nitrogen utilization by promoting the synthesis of urea and nitric oxide in dairy cows. However, scarce data on the effects of NCG on bulls exist, especially on antioxidant and immunity status and rumen fermentation. This study was conducted to investigate the effects of NCG on growth performance, nutrient digestibility, antioxidant and immunity status, and rumen fermentation patterns in finishing Holstein bulls. Forty-five healthy Holstein bulls with initial body weight (BW) of 478 ± 13.7 kg were assigned to a randomized complete design with 3 treatments. The NCG supplementation was 0, 15, or 25 g/d per bull in the three different treatments. The experimental period was 122 d, after a-7 d adaptation period. Although the final BW and average daily gain were not affected by NCG supplementation, dry matter intake tended to decrease linearly, and feed to gain ratio decreased linearly with increasing NCG supplementation. The apparent total tract digestibility of dry matter, organic matter, non-fiber carbohydrate were not affected, whereas a linear increase was observed in acid detergent fiber and neutral detergent fiber digestibility, and a quadratic increase was observed in crude protein digestibility. The concentration of total protein and nitric oxide was greater in bulls fed 15 g/d and 25 g/d NCG than in control. The serum total anti-oxidant capacity increased quadratically with increasing NCG supplementation, and peaked at 15 g/d. The interleukin-2 concentration significantly increased in bulls fed 15 g/d NCG. The concentration of total volatile fatty acids was greater in bulls fed 15 g/d NCG compared to the other groups. In conclusion, NCG supplementation in finishing Holstein bulls may be beneficial for the improvement of feed efficiency, by increasing feed digestibility and improving antioxidant and immunity status. The most optimal dose appeared to be 15 g/d.

Effectiveness and safety evaluation of graded levels of N-carbamylglutamate in growing-finishing pigs.

The aim of this study was as follows: 1) to investigate the effects of graded levels of N-carbamylglutamate (NCG) on performance, blood biochemical indexes, carcass traits and related indicators in growing-finishing pigs, and 2) to determine the optimal supplemental level. The toxicity of high-dose (much higher than recommended levels) NCG was assessed by routine blood tests and blood biochemical and histopathologic examinations of the heart, liver, spleen, lung, kidney and stomach. One hundred and forty-four growing-finishing pigs (Duroc × Large White × Landrace, 32.24 ± 1.03 kg) were used in a 74-d experiment and each treatment was replicated 6 times with 4 pigs (2 barrows and 2 gilts) per replicate. The dietary treatments were a corn-soybean meal basal diet supplemented with 0% (control), 0.05%, 0.1%, 0.15%, 0.2% or 1% NCG. The first 5 groups were used to explore the optimal supplemental level of NCG, while the control, 0.1% and 1% NCG groups were used to explore the safety of high-dose NCG. Compared with the normal control group, the final body weight and average daily gain tended to be higher in the 0.1% group (P = 0.08), the lean percentage tended to be higher in the 0.05% group (P = 0.07), the levels of free amino acids in the blood significantly increased in the 0.1% group (P < 0.05), both 0.1% and 0.15% NCG supplementation increased the levels of nitric oxide (NO) in serum (P = 0.07) and muscle growth- and lipid metabolism-related gene expression (P < 0.05) and NCG supplementation improved C18:1N9C monounsaturated fatty acids (MUFA) in a dose-dependent manner (P = 0.08). In addition, routine blood tests, blood biochemical indexes and histopathological examination revealed no abnormalities. Overall, increasing the levels of NCG did not linearly improve the above indicators; the 0.1% dose showed the best effect, and a high dose (1%) did not pose a toxicity risk.

Microbiome-Metabolome Responses in Ruminal Content and Feces of Lactating Dairy Cows With N-Carbamylglutamate Supplementation Under Heat Stress.

The objective of the present study was to investigate the effects of N-carbamylglutamate (NCG) supplementation on metabolic profile and microbiota in ruminal content and feces of lactating dairy cows under heat stress (HS). Forty-eight lactating Holstein cows (154 ± 13.6 days in milk) were assigned randomly to four treatments (n = 12), to receive 0, 15, 20, or 25 g/day of commercial NCG (proportion: 97.7%) for the period of 60 days. The recorded ambient temperature–humidity index (THI) suggested that the cows were exposed to HS for almost the entire experimental period (average THI: 80.6). Samples of ruminal content and feces were collected at the end of the trial (day 60) to determine the biological effects of NCG supplementation on metabolome and microbiota using mass spectrometry-based metabolomics and 16S rRNA gene sequencing techniques, respectively. Results showed that NCG supplementation enhanced the levels of ruminal microbial protein, total volatile fatty acids (VFAs), and the molar proportion of propionate in the rumen, but lowered the ruminal pH, ammonia nitrogen (NH3-N), and the ratio of acetate to propionate. NCG at doses of 20 and 25 g/day reduced the community richness and diversity of ruminal microbiota with the decrease of Shannon and Simpson diversity. Compositions of ruminal and fecal microbiotas were altered by NCG, and the PICRUSt results revealed that metabolic pathways of the bacteria, such as amino acid metabolism, energy metabolism, and pyruvate metabolism, were enriched in NCG groups. Distinct changes in the metabolomic profile of ruminal fluid were observed between the control and NCG groups. Changes of 26 metabolites mainly involved in arginine metabolism, glutamate metabolism, and nitrogen metabolism were observed associated with NCG supplementation. These results provided new insights into the effects of NCG on metabolomic profile and microbiota in ruminal content and feces, and the optimal dose of NCG supplemented to dairy cows was 20 g/hd/day, which contributed to understanding the effects of NCG on HS in lactating dairy cows.

Effects of dietary supplementation of N-carbamylglutamate on the haematology parameters, secondary sexual characteristicsand testicular gene expression in roosters.

A total of 288 11-week-age roosters were used to evaluate the effects of dietary supplementation of N-carbamylglutamate (NCG) on reproductive traits and testicular gene expression. The experimental periods were 12 weeks. All birds were randomly assigned to 4 treatments with 6 replicates per treatment and 12 birds per replicate. Dietary conditions were based on a basal diet and supplemented with 0%, 0.08%, 0.12%, or 0.16% NCG to form C, N1, N2and N3 groupsrespectively. Dietary supplementation of NCG had positive effects on the seminiferous tubule parameters, serum gonadotropin-releasing hormone and testosterone levelsand the secondary sexual characteristics. Transcriptomics analysis was performed on the testicular tissues between C and N3 groups at the 16-week-age. Genes were mainly enriched in nine pathways, such as cytochrome P450 exogenous metabolism, drug metabolism, steroid hormone synthesisand glutathione metabolism, in which the ZP4 gene, cytochrome P450 family member 11A1and other genes involved in the maintenance of gonadal function, steroid hormone biosynthesis and metabolism, and soforth, exist differences in expression levels. In summary, dietary supplementation of NCG had positive effects on the reproductive traits of roosters. NCG supplementation improved the development of reproductive traits of roosters by regulating the genes expression in testicular tissues and thus improved the synthesis of reproductive hormones in vivo.

Effects of arginine and/or N-carbamylglutamate supplementation on growth, biochemical composition and expression of growth-regulating factors of hybrid sturgeon (Acipenser schrenckii ♀ ×A. baerii ♂) juveniles fed an arginine-deficient diet

A 2 × 3 factorial experiment was carried out to determine the roles of arginine (Arg) and/or N-carbamylglutamate (NCG) supplemented in diet on growth, biochemical composition as well as mRNA expression levels of growth hormone/insulin-like growth factor-I (GH/IGF-I) in the hybrid sturgeon (Acipenser schrenckii ♀×A. baerii ♂) juveniles raised by the Arg-deficient diet. 30 fish pre tank was fed with each diet (Arg levels: 0% and 1%; NCG levels: 0%, 0.05% and 0.1%) for 8 weeks with three replications for each group. Fish supplemented with 0.1% NCG showed significantly increased final body weight, weight gain rate and protein efficiency ratio, whereas decreased feed conversion ratio compared with those supplemented with 0% NCG (P < 0.05). Dietary Arg or NCG reduced the body moisture but elevated the body crude lipid (P < 0.05). Body crude protein content was significantly increased by the addition of 0.05% NCG (P < 0.05). The Arg concentration of the carcass was significantly affected by dietary Arg and NCG levels (P < 0.05). Dietary NCG supplementation significantly increased the NO concentrations (P < 0.05). The hepatic nitric oxide synthase (NOS) activity in fish supplemented with 0.1% NCG significantly increased relative to that in those supplemented with 0% NCG (P < 0.05). Dietary NCG supplementation markedly increased IGF-I mRNA expression level(P < 0.05). Besides, GH mRNA expression level in 0.1% NCG groups evidently increased relative to those in 0% NCG groups. These results indicated that dietary supplementation with 1% Arg and/or 0.1% NCG could improve growth performance and increase Arg concentration and the GH/IGF-1 gene expression of hybrid sturgeon fed an Arg-deficient diet.

Effects of dietary supplementation with N-carbamylglutamate on maternal endometrium and fetal development during early pregnancy in Inner Mongolia white cashmere goats.

This study investigated the effects of dietary supplementation with N-carbamylglutamate (NCG) on maternal endometrium and fetal development during early pregnancy of Inner Mongolia white cashmere goats. Forty-eight pregnant Inner Mongolia white cashmere goats (average age 3 years old, average lactation parity 2, and average body weight 43.81 ± 2.66 kg) were randomly allocated to three groups: a basal diet (control group, n = 16), a basal diet plus 0.30-g NCG/d (NCG1 group, n = 16), and a basal diet plus 0.40-g NCG/d (NCG2 group, n = 16). All of the does were housed in individual pens and the NCG treatment was conducted from Days 0 to 90 of pregnancy. At Days 17 and 90 of pregnancy, six representative pregnant does in each group were slaughtered. The current study results demonstrated that maternal NCG administration during early pregnancy effectively increased the arginine family of amino acids and the glucogenic amino acids concentrations and promoted the mRNA expression of osteopontin (OPN), αv and β3 integrins, and endometrial development of Inner Mongolia white cashmere goats. The supplementation improved the fetal brown adipose tissue (BAT) stores and the mRNA expression of UCP-1 and BMP7, thereby helping to the fetal early development.

Dietary N-carbamylglutamate or L-arginine improves fetal intestinal amino acid profiles during intrauterine growth restriction in undernourished ewes.

Our previous studies demonstrated that prenatal in utero growth restriction impairs postnatal intestinal function. Thus, improving postpartal intestinal absorption capacity and growth by manipulating the maternal diet prepartum is of importance. This work was conducted to determine whether supplementation of N-carbamylglutamate (NCG) or rumen-protected L-arginine (RP-Arg) increased fetal intestinal amino acid (AA) profiles in intrauterine growth retardation (IUGR) fetuses. On d 35 of gestation, Hu ewes (n = 32) carrying twin fetuses were randomized into 4 groups (8 ewes and 16 fetuses in each group), where diets were as follows: 100% of nutrient requirements recommended by National Research Council (NRC, 2007) (CON); 50% of nutrient requirements recommended by NRC (2007) (RES); RES + RP-Arg (20 g/d), (RES + ARG); and RES + NCG (5 g/d), (RES + NCG). On d 110 of gestation, both fetal and maternal tissues were collected and weighed. Compared with RES, solute carrier family 1, member 5 (SLC1A5) was upregulated (P < 0.05) within fetal jejunum, duodenum and ileum when supplementing NCG and RP-Arg. Relative to RES, RP-Arg or NCG supplementation to RES resulted in upregulation (P < 0.05) of peptide transporter 1 protein abundance within the fetal ileum. NCG or RP-Arg supplementation to RES also upregulated phosphorylated mechanistic target of rapamycin (pmTOR)-to-mTOR ratio in the fetal ileum induced by IUGR (P < 0.05). As a result, during IUGR, supplementation of Arg or NCG affected intestinal AA profiles in the fetus in part through controlling mTOR signal transduction as well as AA and peptide transport. Future studies should be conducted to understand the role (if any) of the placenta on the improvement of growth and AA profiles independent of the fetal intestine. This would help demonstrate the relative contribution of intestinal uptake in fetal life.

Effects of Inclusion of N-Carbamylglutamate in the Non-Protein Diet on Growth and Slaughter Performance, Meat Quality, Nitrogen Metabolism and Antioxidant of Holstein Bulls.

Simple SummaryUsing dietary non-protein nitrogen is an effective way to decrease the dependence on protein resources in cattle production. N-carbamylglutamate (NCG) is a structural analogue of N-acetylglutamate (NAG), which is a precursor of endogenous Arg synthesis. NCG improves urea cycling and enhances the endogenous synthesis of Arg, nitric oxide synthase and NO. The present study showed that beef benefited from being fed NCG product in the urea diet by enhancing its growth and slaughter performance, meat quality, nitrogen metabolism and plasma amino acids.The objectives of this experiment were to investigate the effects of N-carbamylglutamate (NCG) on growth and slaughter performance, meat quality, nitrogen utilization, plasma antioxidant and amino acids of Holstein bulls. In this case, 24 Holstein bulls (490 ± 29.0 kg of body weights and 540 ± 6.1 d of age) were blocked by body weights and age and randomly assigned to 1 of 4 groups: (1) CON group: bulls were fed the control diet, (2) CON + NCG group: bulls were fed the control diet with 40 mg/kg BW NCG, (3) Urea group: bulls were fed the urea diet, and (4) Urea + NCG group: bulls were fed the urea diet with 40 mg/kg BW NCG. Feeding NCG significantly improved ADG, FCR, DM and CP digestibility, carcass weight, slaughter weight, DOP, eye muscle area, shear force (p = 0.001) and reduced L* of color, drip loss and cooking loss. Concurrently, feeding the urea diet induced a decreased ADG, carcass weight and slaughter weight, DOP, eye muscle area and shear force. NCG decreased contents of fecal N and urinary N, plasma urea in bulls and ammonia but increased N retention and utilization, plasma NO, plasma Arg, Leu, Ile and Tyr. On the other hand, feeding the urea diet increased urinary N, plasma urea and ammonia. Thus the study efficiently demonstrates that beef benefited from being fed a NCG product in the urea diet by enhancing its growth and slaughter performance, meat quality, nitrogen metabolism and plasma amino acids.

Noncoding sequence variants define a novel regulatory element in the first intron of the N-acetylglutamate synthase gene.

N-acetylglutamate synthase deficiency is an autosomal recessive urea cycle disorder caused either by decreased expression of the NAGS gene or defective NAGS enzyme resulting in decreased production of N-acetylglutamate (NAG), an allosteric activator of carbamylphosphate synthetase 1 (CPS1). NAGSD is the only urea cycle disorder that can be effectively treated with a single drug, N-carbamylglutamate (NCG), a stable NAG analog, which activates CPS1 to restore ureagenesis. We describe three patients with NAGSD due to four novel noncoding sequence variants in the NAGS regulatory regions. All three patients had hyperammonemia that resolved upon treatment with NCG. Sequence variants NM_153006.2:c.427-222G>A and NM_153006.2:c.427-218A>C reside in the 547 bp-long first intron of NAGS and define a novel NAGS regulatory element that binds retinoic X receptor α. Sequence variants NC_000017.10:g.42078967A>T (NM_153006.2:c.-3065A>T) and NC_000017.10:g.42078934C>T (NM_153006.2:c.-3098C>T) reside in the NAGS enhancer, within known HNF1 and predicted glucocorticoid receptor binding sites, respectively. Reporter gene assays in HepG2 and HuH-7 cells demonstrated that all four substitutions could result in reduced expression of NAGS. These findings show that analyzing noncoding regions of NAGS and other urea cycle genes can reveal molecular causes of disease and identify novel regulators of ureagenesis.

Dietary rumen-protected L-arginine or N-carbamylglutamate attenuated fetal hepatic inflammation in undernourished ewes suffering from intrauterine growth restriction.

This study aimed to explore whether dietary rumen-protected L-arginine (RP-Arg) or N-carbamylglutamate (NCG) supplementation to feed-restricted pregnant ewes counteracts fetal hepatic inflammation and innate immune dysfunction associated with intrauterine growth retardation (IUGR) in ovine fetuses. On d 35 of pregnancy, twin-bearing Hu ewes (n = 32) were randomly assigned to 4 treatment groups (8 ewes and 16 fetuses per group) and fed diets containing 100% of the NRC requirements (CON), 50% of the NRC requirements (RES), RES + RP-Arg (20 g/d) (RESA), or RES + NCG (5 g/d) (RESN). At 08:00 on d 110 of gestation, fetal blood and liver tissue samples were collected. The levels of triglyceride, free fatty acid, cholesterol and β-hydroxybutyrate in the fetal blood of RESA and RESN groups were lower (P < 0.05) than those of the RES group, but were higher (P < 0.05) than those of the CON group. The interleukin (IL)-6 and IL-1 levels in fetal blood and liver tissue as well as the myeloid differentiation primary response 88 (MyD88), transforming growth factor β (TGFβ), and nuclear factor kappa B (NF-κB) mRNA levels in the fetal liver were decreased (P < 0.05) by the NCG or RP-Arg supplementation compared to the RES treatment. Similarly, the toll-like receptor (TLR)-4, MyD88, TGFβ, and p-c-Jun N-terminal kinase (JNK) protein levels in the fetal liver were reduced (P < 0.05) in the NCG and RP-Arg -supplemented groups compared to the RES group. These results showed that dietary supplementation of RP-Arg or NCG to underfed pregnant ewes could protect against IUGR fetal hepatic inflammation via improving lipid metabolism, down-regulating the TLR-4 and the inflammatory JNK and NF-κB signaling pathways, and decreasing cytokine production in ovine fetal blood and liver tissue.

N-Carbamylglutamate Promotes Follicular Development by Modulating Cholesterol Metabolism in Yak Ovaries

This study aimed to investigate the effects of N-carbamylglutamate (NCG) supplementation on the follicular development of yaks to identify potential mechanisms essential for fertility in yaks. Twelve multiparous anoestrous female yaks were randomly assigned to two groups—Control (fed with a basal diet, n = 6) and NCG (basal diet supplemented with 6.0 g day−1 NCG, n = 6). Yaks in the NCG group had higher numbers of large follicles (&gt;5 mm in diameter) than those in the Control group. An RNA-sequencing analysis of yak ovaries revealed a total of 765 genes were differentially expressed between experimental groups, of which 181 genes were upregulated and 584 genes were downregulated following NCG supplementation. The results of a transcriptome functional analysis, qRT-PCR validation, and immunohistochemistry revealed that NCG supplementation increased angiogenesis and de novo synthesis of cholesterol in yak ovaries. NCG was also found to upregulate the gene expression of steroidogenic enzymes. Based on this, it was concluded that NCG supplementation promotes the follicular development of yaks mainly by affecting cholesterol metabolism to initiate steroidogenesis in ovaries. The results provide evidence for understanding the mechanisms responsible for NCG promoting follicular development of female yaks, which may contribute to the development and application of NCG in animal reproduction.

Dietary N-carbamylglutamate or l-arginine supplementation improves hepatic energy status and mitochondrial function and inhibits the AMP-activated protein kinase-peroxisome proliferator-activated receptor γ coactivator-1α-transcription factor A pathway in intrauterine-growth-retarded suckling lambs.

The objective of this study was to investigate the effects of dietary administration of l-arginine (Arg) or N-carbamylglutamate (NCG) on hepatic energy status and mitochondrial functions in suckling Hu lambs with intrauterine growth retardation (IUGR). Forty-eight newborn Hu lambs of 7 d old were allocated into 4 treatment groups of 12 lambs each, in triplicate with 4 lambs per replicate (2 males and 2 females) as follows: CON (lambs of normal birth weight, 4.25 ± 0.14 kg), IUGR (3.01 ± 0.12 kg), IUGR + 1% Arg (2.99 ± 0.13 kg), or IUGR + 0.1% NCG (3.03 ± 0.11 kg). The experiment lasted for 21 d, until d 28 after birth, and all lambs were fed milk replacer as a basal diet. Compared with IUGR lambs, NCG or Arg administration increased (P < 0.05) the adenosine triphosphate (ATP) level and the activities of complexes I/III/IV, isocitrate dehydrogenase and citrate synthase in the liver. Compared with CON lambs, the relative mRNA levels of adenosine monophosphate-activated protein kinase α1 (AMPKα1), peroxisome proliferator-activated receptor γ coactivator-1α (PGC1α) and transcription factor A (TFAM) were increased (P < 0.05) in the liver of IUGR lambs, but were decreased (P < 0.05) in the liver of NCG- or Arg-treated lambs compared with those in the IUGR lambs. Compared with IUGR lambs, NCG or Arg administration decreased (P < 0.05) the total AMPKα (tAMPKα)-to-phosphorylated AMPKα (pAMPKα) ratio and the protein expression of PGC1α and TFAM. The results suggested that dietary Arg or NCG supplements improved hepatic energy status and mitochondrial function and inhibited the AMPK-PGC1α-TFAM pathway in IUGR suckling lambs.

Dietary supplementation of N-carbamylglutamate promotes growth performance by modulating the homeostasis of gut microbiota in tilapia (Oreochromis niloticus)

N-carbamylglutamate (NCG) supplementation promotes the synthesis of arginine, improves physiological parameters and modulates gut function in fish. However, its beneficial effect on the fish gut microbiota remains unclear. Thus, we investigated the beneficial effect of NCG on homeostasis of gut microbiota in tilapia. Tilapia were fed with diets supplemented with different levels of dietary NCG (Ctrl, NCGI and NCGII) for 8 weeks. The weight gain and the specific growth rate were significantly higher (p < 0.05) in NCG-supplemented groups compared to the group Ctrl. Moreover, the V3-V4 region of 16S rDNA was sequenced, and the bioinformatic analysis suggested that dietary NCG supplementation had a limited impact on the α-diversity of gut microbiota, while Non-metric multidimensional scaling analysis (NMDS) showed that dietary NCG leads to a clear separation on gut microbiota among the three groups. Furthermore, NCG supplementation reshaped the tilapia gut microbiota community, according to co-occurrence analysis and metabolic pathways prediction via PICRUSt analysis, leading to an enrichment of nutritional metabolism related functions, such as amino acid and lipid metabolisms (p < 0.05). Subsequently, the redundancy analysis (RDA) demonstrated that the structural changes of gut microbiota were determined by NCG concentration. In addition, the linear discriminant analysis effect size (LEfSe) analysis revealed 65 differentially abundant taxonomic clades were dominant in tilapia supplemented with NCG. The cross-validation and Random Forest model identified 12 key bacterial taxa in response to the NCG supplementation. Among them, four key bacterial taxa played a fundamental role in nitrogen-fixing, which may indicate that NCG increases the amino acid biosynthesis of gut microbiota and contributes to the growth promotion of tilapia.

Long-term N-carbamylglutamate treatment of hyperammonemia in patients with classic organic acidemias

BackgroundClassic organic acidurias (OAs) usually characterized by recurrent episodes of acidemia, ketonuria, and hyperammonemia leading to coma and even death if left untreated. Acute hyperammonemia episodes can be treated effectively with N-carbamylglutamate (NCG). The effect of the long-term efficacy of N-carbamylglutamate is little known. Material-MethodsThis retrospective study was conducted at Istanbul University-Cerrahpasa, Cerrahpasa Medical Faculty, Pediatric Nutrition and Metabolism Clinic between January 2012 to January 2018. Patients with classic OAs were enrolled in the study. Patients' ammonia levels, hospitalization needs, hyperammonemia episodes, and management of hyperammonemia were recorded. NCG usage for more than consecutively 15 days was considered as a long-term treatment. ResultsTwenty-one patients, consisting of eleven patients with methylmalonic acidemia (MMA) and ten patients with propionic acidemia (PA) were eligible for the study. N-carbamylglutamate was used as ammonia scavenger for a total of 484 months with a median period of 23 months (min-max: 3–51 months) in all patients. A significant decrease in plasma ammonia levels was detected during long term NCG treatment (55.31 ± 13.762 μmol/L) in comparison with pre NCG treatment period (69.64 ± 17.828 μmol/L) (p = 0.021). Hospitalization required hyperammonemia episodes decreased with NCG treatment (p = 0.013). In addition, hyperammonemia episodes were also successfully treated with NCG (p = 0.000). Mean initial and final ammonia levels at the time of hyperammonemia episodes were 142 ± 46.495 μmol/L and 42.739 ± 12.120 μmol/L, respectively. The average NCG dosage was 85 mg/kg/day (range 12.5–250 mg/kg/day). No apparent side effects were observed. ConclusionN-Carbamylglutamate may be deemed an effective and safe treatment modality in the chronic management of hyperammonemia in patients with PA and MMA.

Effects of Dietary N-carbamylglutamate on Growth Performance, Apparent Digestibility, Nitrogen Metabolism and Plasma Metabolites of Fattening Holstein Bulls.

Simple SummaryIt is critical to find an effective and safe feed additive to improve the utilization of nitrogen by ruminants. N-carbamylglutamate (NCG), a structural analogue of N-acetylglutamate, may have the potential to improve the utilization of nitrogen by bulls. Therefore, the effects of adding different levels of NCG on the growth performance, nutrient digestibility, nitrogen metabolism and plasma metabolites of fattening Holstein bulls were investigated in this study. The addition of NCG increased concentrations of plasma Arg, Ile, Val, total essential amino acid and total nonessential amino acid, which in turn resulted in higher N utilization and CP digestibility for growth and, therefore, higher average daily gain in NCG-fed bulls.N-carbamylglutamate (NCG), a structural analog of N-acetylglutamate, improves nitrogen utilization in dairy cows. However, the effects of NCG on bulls are unknown. The purpose of the current research was to investigate the effects of adding different amounts of NCG on growth performance, nutrient digestibility, nitrogen metabolism and plasma metabolites of fattening Holstein bulls. Twenty-four Holstein bulls with similar body weights (BW, 408 ± 21.9 kg) and ages (450 ± 6.1 d; all mean ± SD) were selected for the feeding trial. After 2 weeks of adaptation, bulls were blocked by BW and age and subsequently randomly assigned to 1 of 4 groups: (1) CON group (control diet), (2) L group (supplementation with 20 mg/kg BW NCG), (3) M group (supplementation with 40 mg/kg BW NCG), or (4) H group (supplementation with 80 mg/kg BW NCG). The addition of NCG linearly and quadratically increased the average daily gain (CON vs. L vs. M vs. H = 1.03 vs. 1.19 vs. 1.40 vs. 1.26 kg/d) (p < 0.05), feed conversion ratio (CON vs. L vs. M vs. H = 11.92 vs. 9.22 vs. 7.76 vs. 8.62) (p < 0.05), crude protein digestibility (CON vs. L vs. M vs. H = 64.3 vs. 63.8 vs. 67.7 vs. 65.8%) (0.05 < p < 0.10), N retention (p < 0.05) and N utilization (p < 0.05) of bulls, whereas the contents of fecal N (0.05 < p < 0.10) and urinary N (0.05 < p < 0.10) in NCG-fed bulls linearly decreased compared with those in CON bulls. Bulls fed NCG showed a quadratic increased plasma nitric oxide (p < 0.05) concentration. Furthermore, Arg (p < 0.05), Ile (p < 0.05), Val (p < 0.05), Ala (p < 0.05), Glu (p < 0.05), Ser (p < 0.05), total essential amino acid (p < 0.05) and total nonessential amino acid (p < 0.05) concentrations linearly and quadratically increased with increasing doses of NCG. In contrast, plasma urea (p < 0.05) and ammonia (p < 0.05) concentration linearly and quadratically decreased with increasing doses of NCG. Overall, the addition of NCG increased plasma Arg, Ile, Val, TEAA and TNEAA concentration, which in turn resulted in a higher N utilization and, therefore, higher average daily gain in NCG-fed bulls, providing baseline data for the widespread application of NCG in beef cattle production.

Effects of dietary N-carbamylglutamate supplementation on milk production performance, nutrient digestibility and blood metabolomics of lactating Holstein cows under heat stress

Heat stress is a serious threat to dairy cow health worldwide. N-carbamylglutamate (NCG), a novel feed additive, has been applied in dairy cow industry. However, the effects and mechanisms of NCG on dairy cows under heat stress are still unknown. A total of 48 Holstein dairy cows with similar days in milk (154 ± 13.6 d), parity (1-3), and body condition score were randomly divided into 4 groups of 12 animals each. Under heat stress, the cows were fed a TMR diet supplemented with 0 (control), 15, 20, 25 g of NCG/d per cow for 60 days. Milk production performance was recorded and serum parameters were examined. Meanwhile, metabolomics study of plasma based on liquid chromatography-mass spectrometry was also applied to investigate metabolites and pathways in response to NCG supplementation. Milk yield was increased but milk urea nitrogen was reduced by the NCG treatment. Addition of 15 g of NCG/d increased the milk protein percentage compared with the control. No effect of NCG was observed on dry matter intake, lactose percentage, milk fat percentage and somatic cell count. Serum glucose concentrations in cows fed with 15, 20, 25 g of NCG/d were 5.34 ± 0.312, 5.78 ± 0.473 and 5.54 ± 0.711 mmol/L, which were greater than those in the control (4.87 ± 0.367 mmol/L, P < 0.05). Meanwhile, the concentrations of blood urea nitrogen and blood ammonia were decreased with the addition of NCG. Results for antioxidant capacity and immune function showed beneficial effects of NCG, such as the increases in total antioxidant capacity, superoxide dismutase, glutathione peroxidase, IgG, IgM and IgA. Clear separations of plasma metabolic profiles between control and NCG groups were observed in the score plots. Sixteen different metabolites involved in metabolisms of amino acids, ketone bodies, butanoate and energy, as well as gut microbiome-derived metabolism were regulated by NCG supplementation. In conclusion, supplementation with NCG has the potential to enhance production performance, antioxidant capacity and immune function, and improved the metabolic profile of dairy cows under heat stress.

Combination of non-protein nitrogen and N‑carbamylglutamate supplementation improves growth performance, nutrient digestibility and carcass characteristics in finishing pigs fed low protein diets

This study was conducted to determine whether supplemental non-protein nitrogen (NPN) and/or N-carbamylglutamate (NCG) in the low protein diet enhance the growth performance, nutrient digestibility and carcass characteristics of finishing pigs. A total of 150 (Duroc boar× (Landrace boar × Yorkshire) sow) finishing pigs (initially body weight 74.3 ± 3.8 kg) were blocked by weight and sex, and allotted to one 5 treatments with 6 replicate pens (3 barrows and 2 gilts per pen). Diets were normal protein diet (NP, crude protein (CP) 136.4 g/kg), low protein diet (LP, CP 111.4 g/kg), LP supplemented with 0.8 g/kg NCG (LNCG, CP 111.8 g/kg), LP supplemented with 7.1 g/kg NPN (LNPN, CP 119.8 g/kg), and LP supplemented with 7.1 g/kg NPN and 0.8 g/kg NCG (LNN, CP 120.3 g/kg) and fed to pigs for 40 days. At the end of the experiment, 30 pigs (one barrow per pen) were slaughtered to evaluate carcass traits and meat quality. Compared to the LP group, the combination of NPN and NCG supplementation significantly increased (P < 0.05) the average daily gain (ADG) of finishing pigs. The coefficient of apparent total tract digestibility (CATTD) of gross energy (GE), crude protein (CP) and acid detergent fiber (ADF) in LP group were lower (P < 0.05) than that in the NP group, while LNN group significantly increased (P < 0.05) the CATTD of GE, CP, ether extraction (EE), neutral detergent fiber (aNDF) and ADF when compared with LP group. Similarly, the concentrations of arginine, isoleucine, threonine, glycine, serine, tyrosine, and citrulline in the serum of pigs fed LNN diet were higher (P < 0.05) than that in those pigs fed LP diet. The carcass traits and meat quality did not differ between the NP group and the LP group, but the combination of NPN and NCG supplementation in LP diet significantly increased (P < 0.05) the concentrations of intramuscular fat. Compared to NP group, LP group increased (P < 0.05) the concentration of C16:0 and decreased (P < 0.05) the concentrations of C20:4, C22:6 and polyunsaturated fatty acid (PUFA) in the M. longissimus lumborum of finishing pigs, and LNN group further decreased (P < 0.05) the concentrations of C18:2 and PUFA when compared with the LP group. This study indicates that dietary supplementation with both NPN and NCG has important complementary advantages in improving the growth performance and meat quality of finishing pigs fed low protein diet balanced with amino acids.