Dietary supplementation with L-citrulline improves placental angiogenesis and embryonic survival in gilts

Methionine in embryonic development: metabolism, redox homeostasis, epigenetic modification and signaling pathway

Methionine, an essential sulfur-containing amino acid, plays a critical role in methyl metabolism, folate metabolism, polyamine synthesis, redox homeostasis maintenance, epigenetic modification and signaling pathway regulation, particularly during embryonic development. Animal and human studies have increasingly documented that methionine deficiency or excess can negatively impact metabolic processes, translation, epigenetics, and signaling pathways, with ultimate detrimental effects on pregnancy outcomes. However, the underlying mechanisms by which methionine precisely regulates epigenetic modifications and affects signaling pathways remain to be elucidated. In this review, we discuss methionine and the metabolism of its metabolites, the influence of folate-mediated carbon metabolism, redox reactions, DNA and RNA methylation, and histone modifications, as well as the mammalian rapamycin complex and silent information regulator 1-MYC signaling pathway. This review also summarizes our present understanding of the contribution of methionine to these processes, and current nutritional and pharmaceutical strategies for the prevention and treatment of developmental defects in embryos.

Dietary citrulline supplementation enhances milk production in lactating dairy goats

BACKGROUND

Lactational performance depends heavily on age, health, and nutrition. L-Citrulline (Cit) is an effective precursor of L-arginine (Arg), an amino acid that has important roles in synthesis of nitric oxide (NO) and polyamines. Ruminal microbes degrade extracellular Arg; however, extracellular L-citrulline (Cit) is not degraded by ruminal microbes due to lack of uptake and can be fed unencapsulated as a precursor for Arg. As NO is a vasodilator, an increase in blood flow and transport of molecules to mammary tissue may enhance lactational performance and milk composition. Increases in polyamine production may increase milk protein synthesis within mammary tissue, thus increasing milk protein content. This study determined, for the first time, effects of dietary Cit supplementation on milk production and milk composition of Alpine dairy goats.

METHODS

Does were synchronized to estrus and bred to Alpine bucks. Parturition was induced on d 149 of gestation and does were suckled overnight allowing kid(s) to obtain colostrum before being milked 24 h later (d 1 of lactation). Does were assigned to either control (CON, n = 24) or Cit (CIT, n = 23) diets. The isonitrogenous control diet consisted of 97.63% basal diet and 2.37% supplement (1.37% L-alanine and 1.00% soybean hydrogenated oil). The CIT supplemented diet consisted of 97.63% basal diet and 2.37% supplement (0.5% Cit, 0.5% L-glutamine, 1% soybean hydrogenated oil, 0.37% cornstarch). Diets were group fed ad-libitum by treatment group. Blood samples were collected on d 0 and 30 of lactation, milk volumes measured twice daily, and on d 10, 20, and 40 of lactation, milk samples were collected.

RESULTS

CIT-treated does had greater daily milk production (P < 0.05) and there was an effect of day of lactation on daily milk production (P < 0.0001). Sire had significant effect on daily milk production as well (P < 0.05). Milk compositional analyses revealed Cit supplementation increased solid-non-fat (SNF; P < 0.05) and protein (P < 0.05) content in milk.

CONCLUSIONS

Our novel results indicate that dietary supplementation of Cit fed ad-libitum in Alpine does increased daily milk yield, milk SNF content, and protein content. Supplemental Cit may be a proxy for Arg in goats to enhance lactational performance.

Increased proline intake during gestation alleviates obesity-related impaired fetal development and placental function in gilts

Maternal proline (Pro) supplementation enhances fetal survival and placental development in mice. However, the effect of Pro on fetal and placental development in gilts remains to be investigated, particularly in the context of obesity-induced impaired pregnancy. Here, we investigated the effect of dietary Pro on fetal and placental development in obese gilts. Exp.1: On day 60 of gestation, 48 gilts with similar delivery times were selected and followed up until delivery to determine the relationship between maternal obesity, litter performance, and Pro abundance in term placentae. The results showed that impaired reproductive performance was associated with body condition parameters and inadequate placental Pro availability of gilts. Exp. 2: A total of 114 gilts were then used in a 2 × 3 factorial design to investigate the interaction between body condition (factor I: normal or obese gilts) and dietary Pro levels (factor II: low [0.89%, L-Pro], medium [1.39%, M-Pro], and high [1.89%, H-Pro]) on farrowing performance and placental angiogenesis. This resulted in six treatment combinations: normal-L-Pro, obese-L-Pro, normal-M-Pro, obese-M-Pro, normal-H-Pro, and obese-H-Pro. The effective number of replicates per group was 17, 21, 19, 21, 18, and 18, respectively (1 gilt per replicate). The results showed that increasing Pro intake increased piglet birth weight (P = 0.001), litter weight (P < 0.001), placental efficiency (P = 0.036) and placental vascular density (P < 0.001), and decreased the number of mummified fetuses (P = 0.001), the rate of low-birth-weight piglets (P = 0.005), and the rate of invalid piglets (P = 0.029). Interaction effects were observed between body condition and dietary Pro levels on piglet birth weight (P = 0.046), within-litter birth weight variation (P = 0.012), and placental vascular density (P = 0.007). Moreover, the beneficial effect of Pro on farrowing performance may be related to the improvement of sirtuin 1-superoxide dismutase 2-mitochondrial reactive oxygen species axis homeostasis and angiogenesis in the placenta. Our results suggest that gestation diets need to provide adequate Pro to meet the needs of fetal and placental development, particularly in obese gilts.

Maternal supplementation spermidine during gestation improves placental angiogenesis and reproductive performance of high prolific sows

Spermidine (SPD) is a widely recognized polyamine compound found in mammalian cells and plays a key role in various cellular processes. We propose that SPD may enhance placental vascular development in pregnant sows, leading to increased birth weight of piglets. Six hundred and nine sows at 60 days of gestation were randomly assigned into a basal diet (CON group), basal diet supplemented 10 mg/kg of SPD (SPD1 group), and basal diet supplemented 20 mg/kg of SPD (SPD2 group), respectively. Compared with the CON, SPD1 significantly increased the average number of healthy piglets per litter and the placental efficiency (P < .05), while the average number of mummified fetus per litter and the percentage of weak piglets significantly decreased (P < .05). In the plasma metabolomics, SPD content in plasma of sows (P = .075) and umbilical cord plasma of piglets (P = .078) had an increasing trend in response to SPD1. Furthermore, SPD1 increased the expression of the vascular endothelial cell marker protein, platelet endothelial cell adhesionmolecule-1 (PECAM-1/CD31) and the density of placental stromal vessels (P < .05). Moreover, as compared to CON, SPD2 significantly decreased the average number of mummified fetus per litter (P < .05), while the placental efficiency and the expression of amino acid transporter solute carrier (SLC) family 7, member7 (SLC7A7) and glucose transporters SLC2A2) and SLC5A4 in placental tissue significantly increased (P < .05). These results suggest that maternal supplementation of SPD during pregnancy increased healthy litter number, and promoted placental tissue development. Our findings provide evidence that maternal SPD has the potential to improve the production performance of sows.

Promotion of nitric oxide production: mechanisms, strategies, and possibilities

The discovery of nitric oxide (NO) and the role of endothelial cells (ECs) in its production has revolutionized medicine. NO can be produced by isoforms of NO synthases (NOS), including the neuronal (nNOS), inducible (iNOS), and endothelial isoforms (eNOS), and via the non-classical nitrate-nitrite-NO pathway. In particular, endothelium-derived NO, produced by eNOS, is essential for cardiovascular health. Endothelium-derived NO activates soluble guanylate cyclase (sGC) in vascular smooth muscle cells (VSMCs), elevating cyclic GMP (cGMP), causing vasodilation. Over the past four decades, the importance of this pathway in cardiovascular health has fueled the search for strategies to enhance NO bioavailability and/or preserve the outcomes of NO's actions. Currently approved approaches operate in three directions: 1) providing exogenous NO, 2) promoting sGC activity, and 3) preventing degradation of cGMP by inhibiting phosphodiesterase 5 activity. Despite clear benefits, these approaches face challenges such as the development of nitrate tolerance and endothelial dysfunction. This highlights the need for sustainable options that promote endogenous NO production. This review will focus on strategies to promote endogenous NO production. A detailed review of the mechanisms regulating eNOS activity will be first provided, followed by a review of strategies to promote endogenous NO production based on the levels of available preclinical and clinical evidence, and perspectives on future possibilities.

The Effects of L-citrulline Supplementation on the Athletic Performance, Physiological and Biochemical Parameters, Antioxidant Capacity, and Blood Amino Acid and Polyamine Levels in Speed-Racing Yili Horses

The objective of this study was to evaluate the effects of pre-exercise L-citrulline supplementation on the athletic performance of Yili speed-racing horses during a high-intensity exercise. On the 20th day of the experiment, blood samples were collected at 3 h and 6 h post-supplementation to measure the amino acid and polyamine concentrations. On the 38th day of the experiment, the horses participated in a 2000 m speed race, and three distinct blood samples were gathered for assessing blood gases, hematological parameters, the plasma biochemistry, antioxidant parameters, and NO concentrations. The results indicate that the L-citrulline group showed a significant increase in the plasma citrulline and arginine concentrations. Conversely, the concentrations of alanine, serine, and threonine were significantly decreased. The glycine concentration decreased significantly, while there was a trend towards an increase in the glutamine concentration. Additionally, the levels of putrescine and spermidine in the plasma of the L-citrulline group were significantly increased. In terms of exercise performance, L-citrulline can improve the exercise performance of sport horses, significantly reduce the immediate post-race lactate levels in Yili horses, and accelerate the recovery of blood gas levels after an exercise. Furthermore, in the L-citrulline group of Yili horses, The levels of the total protein of plasma, superoxide dismutase, catalase, and lactate dehydrogenase were significantly increased both 2 h before and 2 h after the race. The total antioxidant capacity showed a highly significant increase, while the malondialdehyde content significantly decreased. In the immediate post-race period, the creatinine content in the L-citrulline group significantly increased. In conclusion, this study demonstrates that L-citrulline supplementation can influence the circulating concentrations of L-citrulline and arginine in Yili horses, enhance the antioxidant capacity, reduce lactate levels, and improve physiological and biochemical blood parameters, thereby having a beneficial effect on the exercise performance of athletic horses.

Maternal folic acid and vitamin B12 supplementation during medium to late gestation promotes fetal development via improving placental antioxidant capacity, angiogenesis and amino acid transport

BACKGROUND

Folic acid and vitamin B12 (FV), being B vitamins, not only facilitate the remethylation of homocysteine (Hcy) but also contribute to embryonic development. This study aimed to assess the impact of FV supplementation during late pregnancy on sows' reproductive performance, amino acid metabolism, placental angiogenesis, and related parameters. Twenty primiparous sows at day 60 of gestation were randomly allocated to two groups: a basal diet (CON) group and a group receiving a basal diet supplemented with folic acid at 20 ppm and vitamin B12 at 125 ppb.

RESULTS

The findings revealed that dietary FV supplementation significantly reduced the incidence of intrauterine growth retardation compared to the CON group (P < 0.05). Furthermore, it led to a decrease in the Hcy levels in umbilical cord serum (P < 0.05) and activation of the placental mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway (P < 0.05). Additionally, FV supplementation lowered placental malondialdehyde levels (P < 0.05) and increased the expression of placental thioredoxin (P = 0.05). Moreover, maternal FV supplementation notably elevated placental vascular density (P < 0.05) and the expression of sodium-coupled neutral amino acid transporter 2 (SNAT2) (P < 0.05), as well as amino acid concentrations in umbilical cord blood (P < 0.05).

CONCLUSION

Maternal FV supplementation during medium to late gestation reduced Hcy levels in umbilical cord blood and positively impacted fetal development. This improvement was closely associated with increased placental antioxidant capacity and vascular density, as well as activation of the placental mTORC1-SNAT2 signaling pathway. © 2023 Society of Chemical Industry.

Maternal Supplementation with Ornithine Promotes Placental Angiogenesis and Improves Intestinal Development of Suckling Piglets

The blood vessels of the placenta are crucial for fetal growth. Here, lower vessel density and ornithine (Orn) content were observed in placentae for low-birth-weight fetuses versus normal-birth-weight fetuses at day 75 of gestation. Furthermore, the Orn content in placentae decreased from day 75 to 110 of gestation. To investigate the role of Orn in placental angiogenesis, 48 gilts (Bama pig) were allocated into four groups. The gilts in the control group were fed a basal diet (CON group), while those in the experimental groups were fed a basal diet supplemented with 0.05% Orn (0.05% Orn group), 0.10% Orn (0.10% Orn group), and 0.15% Orn (0.15% Orn group), respectively. The results showed that 0.15% Orn and 0.10% Orn groups exhibited increased birth weight of piglets compared with the CON group. Moreover, the 0.15% Orn group was higher than the CON group in the blood vessel densities of placenta. Mechanistically, Orn facilitated placental angiogenesis by regulating vascular endothelial growth factor-A (VEGF-A). Furthermore, maternal supplementation with 0.15% Orn during gestation increased the jejunal and ileal villi height and the concentrations of colonic propionate and butyrate in suckling piglets. Collectively, these results showed that maternal supplementation with Orn promotes placental angiogenesis and improves intestinal development of suckling piglets.

Analysis of Gizzerosine in Foodstuffs by HPLC Involving Pre-column Derivatization with o-Phthaldialdehyde

Gizzerosine [2-amino-9-(4-imidazolyl)-7-azanonanoic acid] is a toxic amino acid formed from histamine and lysine at high temperatures, and may be present in foodstuffs (e.g., fishmeal and meat-bone meal) for animals including cats and dogs. Here we developed a simple, rapid, sensitive, specific, and automated method for the analysis of gizzerosine in foodstuffs by high-performance liquid chromatography (HPLC) involving pre-column derivatization with o-phthaldialdehyde (OPA) in the presence of N-acetylcysteine (instead of the usual 2-mercaptoethanol or ethanethiol reagent). OPA reacted immediately (within 1 min) with gizzerosine in an autosampler at room temperatures (e.g., 20-25 °C), and their derivative was directly injected into the HPLC column. The highly fluorescent gizzerosine-OPA derivative was well separated from the OPA derivatives of all natural amino acids known to be present in physiological fluids (e.g., plasma), proteins and foodstuffs, and was detected at an excitation wavelength of 340 nm and an emission wavelength of 450 nm. The total time for chromatographic separation (including column regeneration) was 20 min per sample rather than 40 min and longer in previous HPLC methods. The detection limit for gizzerosine was at least 6 pmol/ml in an assay solution (HPLC vial) or at least 0.09 pmol per injection into the HPLC column. The analysis of gizzerosine was linear between 1 and 100 pmol per injection. When gizzerosine was extracted from foodstuffs, its detection limit was at least 875 pmol/g foodstuff or at least 0.21 mg/kg foodstuff. Our routine HPLC technique does not require any cleanup of samples or the OPA derivatization products (including the OPA-gizzerosine adduct), and is applicable for the analysis of gizzerosine in both foodstuffs and animal tissues.

Assessing Metabolic Differences Associated with Exposure to Polybrominated Biphenyl and Polychlorinated Biphenyls in the Michigan PBB Registry

BACKGROUND

Polybrominated biphenyls (PBB) and polychlorinated biphenyls (PCB) are persistent organic pollutants with potential endocrine-disrupting effects linked to adverse health outcomes.

OBJECTIVES

In this study, we utilize high-resolution metabolomics (HRM) to identify internal exposure and biological responses underlying PCB and multigenerational PBB exposure for participants enrolled in the Michigan PBB Registry.

METHODS

HRM profiling was conducted on plasma samples collected from 2013 to 2014 from a subset of participants enrolled in the Michigan PBB Registry, including 369 directly exposed individuals (F0) who were alive when PBB mixtures were accidentally introduced into the food chain and 129 participants exposed to PBB in utero or through breastfeeding, if applicable (F1). Metabolome-wide association studies were performed for PBB-153 separately for each generation and Σ PCB (PCB-118, PCB-138, PCB-153, and PCB-180) in the two generations combined, as both had direct PCB exposure. Metabolite and metabolic pathway alterations were evaluated following a well-established untargeted HRM workflow.

RESULTS

Mean levels were 1.75  ng / mL [standard deviation (SD): 13.9] for PBB-153 and 1.04  ng / mL (SD: 0.788) for Σ PCB . Sixty-two and 26 metabolic features were significantly associated with PBB-153 in F0 and F1 [false discovery rate (FDR) p < 0.2 ], respectively. There were 2,861 features associated with Σ PCB (FDR p < 0.2 ). Metabolic pathway enrichment analysis using a bioinformatics tool revealed perturbations associated with Σ PCB in numerous oxidative stress and inflammation pathways (e.g., carnitine shuttle, glycosphingolipid, and vitamin B9 metabolism). Metabolic perturbations associated with PBB-153 in F0 were related to oxidative stress (e.g., pentose phosphate and vitamin C metabolism) and in F1 were related to energy production (e.g., pyrimidine, amino sugars, and lysine metabolism). Using authentic chemical standards, we confirmed the chemical identity of 29 metabolites associated with Σ PCB levels (level 1 evidence).

CONCLUSIONS

Our results demonstrate that serum PBB-153 is associated with alterations in inflammation and oxidative stress-related pathways, which differed when stratified by generation. We also found that Σ PCB was associated with the downregulation of important neurotransmitters, serotonin, and 4-aminobutanoate. These findings provide novel insights for future investigations of molecular mechanisms underlying PBB and PCB exposure on health. https://doi.org/10.1289/EHP12657.