Antioxidative activity of amino acids on tissue oxidative stress in human intestinal epithelial cell model

Effects of chili straw on rumen fermentation, meat quality, amino acid and fatty acid contents, and rumen bacteria diversity in sheep

Crop residues have shown promise as non-conventional feed sources to enhance animal health and growth. This study evaluated the effects of chili straw (CS) on rumen fermentation, meat quality, amino and fatty acid composition, and rumen microbial diversity in sheep. Fifty F1 Dorper×Hu lambs (29.58 ± 2.06 kg) were randomly assigned to five groups, fed pelleted feed with 0%, 5%, 10%, 15%, or 20% CS over a 63-day period, including a 7-day pre-test. Post-trial, rumen fluid was sampled to assess fermentation and microbial profiles, and slaughter performance and meat quality were evaluated. Key findings include: (1) No significant differences were observed in rumen pH, NH3-N, or acetic acid-to-propionic acid ratio across groups (P > 0.05). (2) Rumen microbial diversity indices did not vary significantly between groups (P > 0.05), though the relative abundance of Firmicutes and Proteobacteria increased, and Bacteroidota decreased in CS-fed groups, with specific genus-level changes. (3) Carcass weight decreased in the CS20% group (P < 0.01). (4) Cooking loss decreased in CS10%, 15%, and 20% groups (P < 0.05), and meat redness increased in CS15% and 20% groups (P < 0.01). (5) Saturated fatty acids decreased, while the PUFA/SFA ratio and amino acid profiles, including sulfur-containing amino acids (SAA), dibasic amino acids (DAA), essential amino acids (EAA), and total amino acids (TAA), increased with CS, with a significant rise in Gly content in the CS15% group (P < 0.05). In conclusion, incorporating CS into lamb diets can enhance meat quality without adversely affecting rumen fermentation, with recommended levels between 10% and 15%.

Effects of Oxidized Soybean Meal and Oxidized Soybean Oil on the Muscle Oxidative Stability, Flesh Quality, Amino Acid Profile, and Fatty Acid Profile of Megalobrama amblycephala

This study aimed to investigate the effects of oxidized soybean meal and oxidized soybean oil on the muscle oxidative stability, flesh quality, amino acid profile, and fatty acid profile of blunt snout bream Megalobrama amblycephala. Oxidized soybean meal and oxidized soybean oil were obtained from fresh soybean meal (FSM) and fresh soybean oil (FSO) by heating. In the experimental diet, the proportions of oxidized soybean meal (OSM) and oxidized soybean oil (OSO) were 30% and 4.19%, respectively. The feeding trial was conducted for 8 weeks. The findings revealed that both OSM and OSO reduced glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT), hardness, chewiness, and oxymyoglobin (OxyMb) and elevated the content of malondialdehyde (MDA), protein carbonyl (PC), and metmyoglobin (MetMb) in the muscle. OSM notably decreased the content of muscle essential amino acids (EAAs), nonessential amino acids (NEAAs), delicious amino acids (DAAs), and total amino acids (TAAs) compared with CON and OSO. Compared with CON and OSM, OSO significantly reduced the content of elaidic acid (C18:1n9t), linoelaidic acid (C18:2n6c), polyunsaturated fatty acids (PUFAs), ω-6 PUFAs, and the ratio of ω-6/ω-3, while stearic acid (C18:0), γ-linolenic acid (C18:3n6) and saturated fatty acids (SFAs) were significantly elevated. In conclusion, this study demonstrated that both OSM and OSO negatively impacted muscle antioxidant capacity and flesh quality. Moreover, OSM adversely affected the amino acid profile of the muscle, while OSO impaired the fatty acid profile.

Metabolomics analysis of human spermatozoa reveals impaired metabolic pathways in asthenozoospermia

BACKGROUND

Infertility is a major health issue, affecting 15% of reproductive-age couples with male factors contributing to 50% of cases. Asthenozoospermia (AS), or low sperm motility, is a common cause of male infertility with complex aetiology, involving genetic and metabolic alterations, inflammation and oxidative stress. However, the molecular mechanisms behind low motility are unclear. In this study, we used a metabolomics approach to identify metabolic biomarkers and pathways involved in sperm motility.

METHODS

We compared the metabolome and lipidome of spermatozoa of men with normozoospermia (n = 44) and AS (n = 22) using untargeted LC-MS and the metabolome of seminal fluid using 1H-NMR. Additionally, we evaluated the seminal fluid redox status to assess the oxidative stress in the ejaculate.

RESULTS

We identified 112 metabolites and 209 lipids in spermatozoa and 27 metabolites in the seminal fluid of normozoospermic and asthenozoospermic men. PCA analysis of the spermatozoa's metabolomics and lipidomics data showed a clear separation between groups. Spermatozoa of asthenozoospermic men presented lower levels of several amino acids, and increased levels of energetic substrates and lysophospholipids. However, the metabolome and redox status of the seminal fluid was not altered inAS.

CONCLUSIONS

Our results indicate impaired metabolic pathways associated with redox homeostasis and amino acid, energy and lipid metabolism in AS. Taken together, these findings suggest that the metabolome and lipidome of human spermatozoa are key factors influencing their motility and that oxidative stress exposure during spermatogenesis or sperm maturation may be in the aetiology of decreased motility in AS.

Development of an ultra-sensitive laser stimulated fluorescence system for simultaneous detection of amino acids

An ultra-sensitive, high-performance liquid chromatography-based laser-stimulated fluorescence detection system was developed and validated for the simultaneous detection of 20 derivatized amino acids. Dansyl chloride was used as a derivatizing agent, and key derivatization parameters, such as reaction time and temperature, were optimized to enhance sensitivity and reproducibility. The majority of amino acids showed a relative standard deviation of less than 5%, indicating the reliability of the approach. The method demonstrated excellent sensitivity for all 20 amino acids, with detection limits ranging from 4.32 to 85.34 femtomoles. It also exhibited good linearity, with regression (R 2) values greater than 0.98 for the amino acids. The system's performance was tested on human serum, and the eluted amino acids were identified. This method has great potential for analyzing amino acids in various body fluids and can be used in various clinical applications. It is ultra-sensitive, reliable, user-friendly, and cost-effective, offering a valuable tool for diagnosing and managing amino acid-related disorders.

Effects of L-Leu-L-Leu peptide on growth, proliferation, and apoptosis in broiler intestinal epithelial cells

Small peptides are nutrients and bioactive molecules that have dual regulatory effects on nutrition and physiology. They are of great significance for maintaining the intestinal health and production performance of broilers. We here cultured the primary small intestinal epithelial cells (IEC) of chicken in a medium containing L-Leu (Leu) and L-Leu-L-Leu (Leu-Leu) for 24 h. The untreated cells were considered as the control group. The growth, proliferation, and apoptosis of IEC were examined. By combining RNA-seq and label-free sequencing technology, candidate genes, proteins, and pathways related to the growth, proliferation, and apoptosis of IEC were screened. Immunofluorescence detection revealed that the purity of the isolated primary IEC was >90%. The Leu-Leu group significantly promoted IEC growth and proliferation and significantly inhibited IEC apoptosis, and the effect was better than those of the Leu and control groups. Using transcriptome sequencing, four candidate genes, CCL20, IL8L1, IL8, and IL6, were screened in the Leu group, and one candidate gene, IL8, was screened in the Leu-Leu group. Two candidate genes, IL6 and RGN, were screened in the Leu-Leu group compared with the Leu group. Nonquantitative proteomic marker sequencing results revealed that through the screening of candidate proteins and pathways, found one growth-related candidate protein PGM3 and three proliferation-related candidate proteins RPS17, RPS11, and RPL23, and two apoptosis-related candidate proteins GPX4 and PDPK1 were found in the Leu-Leu group compared with Leu group. In short, Leu-Leu could promote IEC growth and proliferation and inhibit IEC apoptosis. On combining transcriptome and proteome sequencing technologies, multiple immune- and energy-related regulatory signal pathways were found to be related to IEC growth, proliferation, and apoptosis. Three candidate genes of IL8, IL6, and RGN were identified, and six candidate proteins of PGM3, RPS17, RPS11, RPL23, GPX4, and PDPK1 were involved in IEC growth, proliferation, and apoptosis. The results provide valuable data for preliminarily elucidating small peptide-mediated IEC regulation pathways, improving the small peptide nutrition theoretical system, and establishing small peptide nutrition regulation technology.

Effects of Branched-Chain Amino Acids on the Inflammatory Response Induced by LPS in Caco-2 Cells

Branched-chain amino acids (BCAA) are essential for maintaining intestinal mucosal integrity. However, only a few studies have explored the role of BCAA in the modulation of intestinal inflammation. In this study, we investigated in vitro effects of BCAA on the inflammatory response induced by lipopolysaccharide (LPS) (1 µg/mL) in Caco-2 cells. Caco-2 cells were assigned to six groups: control without BCAA (CTL0), normal BCAA (CTL; 0.8 mM leucine, 0.8 mM isoleucine, and 0.8 mM valine); leucine (LEU; 2 mM leucine), isoleucine (ISO; 2 mM isoleucine), valine (VAL; 2 mM valine), and high BCAA (LIV; 2 mM leucine, 2 mM isoleucine, and 2 mM valine). BCAA was added to the culture medium 24 h before LPS stimulation. Our results indicated that BCAA supplementation did not impair cell viability. The amino acids leucine and isoleucine attenuated the synthesis of IL-8 and JNK and NF-kB phosphorylation induced by LPS. Furthermore, neither BCAA supplementation nor LPS treatment modulated the activity of glutathione peroxidase or the intracellular reduced glutathione/oxidized glutathione ratio. Therefore, leucine and isoleucine exert anti-inflammatory effects in Caco-2 cells exposed to LPS by modulating JNK and NF-kB phosphorylation and IL-8 production. Further in vivo studies are required to validate these findings and gather valuable information for potential therapeutic or dietary interventions.

Glycomacropeptide (GMP) rescued the oxidative and inflammatory activity of free L-AAs in human Caco-2 cells: New insights that support GMP as a valid and health-promoting product for the dietary management of phenylketonuria (PKU) patients

Phenylketonuria represents the most prevalent inborn error of amino acid metabolism. In early diagnosed patients adequate and continued dietary treatment results in a good neurologic outcome. However, due to the natural protein and phenylalanine-restricted diet, oxidative stress represents a concern in phenylketonuric patients. Clear evidences suggest that the pathophysiology of PKU is also dependent by mitochondrial impairment and oxidative stress. In this context due to the tight connection between oxidative and inflammatory stress and noncommunicable diseases (NCDs) development, it is reasonable to hypothesize that PKU patients may present a higher risk to develop NCDs during their life. Currently available protein substitutes on the market include free amino acids (L-AAs), prolonged-release protein substitute and formula containing glycomacropeptide (GMP). Our results suggest that free L-AAs significanlty worsens the intestinal hydrogen peroxide (H2O2) and lipopolysaccharides (LPS)-induced oxidative and inflammatory status in Caco-2 cells, which are significantly restored towards physiological condition by GMP alone and when present in a 1:1 mixture with free L-AAs, providing new preclinical piece of information which can shed a shadow on the mechanism of action of these products on PKU patients and their future management.

Transcriptome sequencing and metabolite analysis reveal the single and combined effects of microplastics and di-(2-ethylhexyl) phthalate on Peneaus vannamei

Due to the rising usage of plastics, plastic debris are present throughout marine ecosystems and detrimentally affects marine biota. Additionally, plastics likely result in elusive toxicity effects due to addition of plasticizers. The aim of the present study was to reveal the potential effects and mechanism of microplastics (MPs), di-(2-ethylhexyl) phthalate (DEHP) and copollution of MPs and DEHP (MPs-DEHP) on Peneaus vannamei (P. vannamei) juveniles regarding oxidative stress, transcriptomics and metabolomics. MPs, DEHP and MPs-DEHP significantly induced the activities of superoxide dismutase (SOD) and catalase (CAT); MPs and DEHP have an antagonistic effect for malondialdehyde (MDA); suggesting that disorders of the antioxidant defence systems. 13, 133 and 58 differentially expressed genes and 21, 82 and 39 differentially expressed metabolites were responsible for the distinction of MPs, DEHP and MPs-DEHP groups, respectively. The combination of transcriptomic and metabolomic analyses showed that MPs, DEHP and MPs-DEHP exposure disturbed amino acid and lipid metabolism, and further induced inflammatory responses and dysfunction of purine metabolism. Furthermore, the presence of MPs might alleviate the biotoxicity of DEHP in P. vannamei. These findings provide new insights into the single and combined toxicological effects of MPs and additives for marine biota.

Effects of Dietary Isoleucine Supplementation on the Production Performance, Health Status and Cecal Microbiota of Arbor Acre Broiler Chickens

A total of 24,000 healthy 1-day-old Arbor Acres broilers with similar initial weights were used in this study and fed a basal diet supplemented with 0, 400 and 800 mg/kg isoleucine (Ile), denoted CON, ILE400 and ILE800, respectively. Results revealed that the final body weight, average daily weight gain, and eviscerated carcass rate, of broiler chickens in the ILE400 group were significantly higher than in other groups (p < 0.05). In addition, the ILE400 and ILE800 groups had a lower feed conversion rate and a higher survival rate and breast muscle rate (p < 0.05), while the abdominal fat rate was significantly lower than the CON group (p < 0.05). There were significantly lower serum concentrations of UREA, glucose (GLU) and total cholesterol (TCHO) in the ILE400 and ILE800 groups than in the CON group (p < 0.05); glutathione peroxidase (GSH-Px) activity was significantly higher in the ILE400 group than in the other groups, and tumor necrosis factor-alpha (TNF-α) concentration was considerably lower than in other groups (p < 0.05). Moreover, interleukin (IL)-10 concentration in the ILE800 group was significantly higher than in the other groups (p < 0.05). The ILE400 group significantly down-regulated the mRNA expressions of fatty-acid synthase (FASN) and solid alcohol regulatory element binding protein 1c (SREBP1c), and significantly up-regulated the mRNA expressions of adipose triglyceride lipase (ATGL), hormone-sensitive lipase (HSL), lipoprotein lipase (LPL) and sirtuin1 (Sirt1) (p < 0.05). The ILE400 group had significantly higher intestinal villus height than the CON and ILE800 groups, while the ILE800 group had significantly lower intestinal villus height/crypt depth (p < 0.05). Furthermore, high-throughput sequencing showed that the Shannon index, and Verrucomicrobiota, Colidextribacter and Bacteroides abundances were significantly higher in the ILE400 group than in the CON group (p < 0.05). Interestingly, the ILE800 group reduced the Simpson index, phylum Firmicutes and Bacteroidota abundances (including genera Colidextribacter, Butyricicoccus, [Ruminococcus]_torques_group, Bacteroides, Alistipes, Barnesiella and Butyricimonas), and increased Proteobacteria and Cyanobacteria (including genera Dyella, Devosia, unidentified_Chloroplast and Hyphomicrobium) (p < 0.05). Overall, our study showed that adding 400 mg/kg Ile to the diet (diets total Ile levels at 1.01%, 0.90% and 0.87% during the starter, grower and finisher phases, respectively) increased production performance and improved the health status in broiler chickens.

Cells Adapt to Resist Fluoride through Metabolic Deactivation and Intracellular Acidification

Fluoride is highly abundant in the environment. Many organisms have adapted specific defense mechanisms against high concentrations of fluoride, including the expression of proteins capable of removing fluoride from cells. However, these fluoride transporters have not been identified in all organisms, and even organisms that express fluoride transporters vary in tolerance capabilities across species, individuals, and even tissue types. This suggests that alternative factors influence fluoride tolerance. We screened for adaptation against fluoride toxicity through an unbiased mutagenesis assay conducted on Saccharomyces cerevisiae lacking the fluoride exporter FEX, the primary mechanism of fluoride resistance. Over 80 independent fluoride-hardened strains were generated, with anywhere from 100- to 1200-fold increased fluoride tolerance compared to the original strain. The whole genome of each mutant strain was sequenced and compared to the wild type. The fluoride-hardened strains utilized a combination of phenotypes that individually conferred fluoride tolerance. These included intracellular acidification, cellular dormancy, nutrient storage, and a communal behavior reminiscent of flocculation. Of particular importance to fluoride resistance was intracellular acidification, which served to reverse the accumulation of fluoride and lead to its excretion from the cell as HF without the activity of a fluoride-specific protein transporter. This transport mechanism was also observed in wild-type yeast through a manual mutation to lower their cytoplasmic pH. The results demonstrate that the yeast developed a protein-free adaptation for removing an intracellular toxicant.

Enzyme-Treated Caviar Prevents UVB Irradiation-Induced Skin Photoaging

For this research article, we investigated the protective effects of enzyme-treated caviar powder extract (CV) in ultraviolet B (UVB)-irradiated hairless mice and keratinocytes by confirming moisturizing-related factors and elasticity-related factors. UVB irradiation induced wrinkle formation, dehydration, oxidative stress, and inflammation in the dorsal skin of mice; however, these were suppressed in the CV-supplemented groups in UVB-irradiated hairless mice. Furthermore, in UVB-irradiated keratinocytes, CV treatment increased the antioxidant enzyme activities and the levels of sphingomyelin and hyaluronic acid and decreased the production of pro-inflammatory cytokines and the expression of IkB-α and p65 phosphorylation. These findings indicate that CV can directly protect keratinocytes against UVB irradiation-induced oxidative stress and inflammation. Therefore, we suggest that CV can protect against UVB-induced skin photoaging. Therefore, we suggest that caviar is effective for skin health by preventing UVB-induced skin photoaging.

Maternal Amino Acid Mixtures Supplementation during Late Gestation and Lactation Improved Growth Performance of Piglets through Improving Colostrum Composition and Antioxidant Capacity

During late gestation and lactation, oxidative stress in sows can affect their health and reproductive performance. Supplemental amino acid contributes to the antioxidant capacity of pigs. This study was conducted to evaluate the effects of different combinations of Gln, Leu and γ-GABA (amino acid mixtures, AAMs) during late gestation and lactation on the performance of the sows and their offspring. Fifty large white × landrace sows were randomly assigned to 5 groups (n = 10), including a control group and four AAMs groups (AAMs1, Gln + Leu; AAMs2 (Gln + GABA; AAMs3, Leu + GABA; AAMs4, Gln + Leu + GABA). AAMs supplementation improved the antioxidant capacity of sows, including significantly enhanced total antioxidant capacity in AAMs2, 3 and 4 groups and reduced malonaldehyde concentration in AAMs1, 3 and 4 groups. Additionally, all AAMs significantly increased lactoprotein, total solid and IgA levels of colostrum in sows during lactation. Average body weight of piglets on day 21 after birth in all AAMs groups were significantly increased. Furthermore, the significantly increased total antioxidant capacity was observed in the piglets of every AAMs group. In conclusion, supplementing AAMs during late gestation and lactation improved the antioxidant capacity of sows and colostrum composition, thereby enhancing antioxidant status and the growth performance of piglets. This study provides the possibility of maternal amino acid mixtures to improve the productivity of the swine industry.

Leucine protects bovine intestinal epithelial cells from hydrogen peroxide-induced apoptosis by alleviating oxidative damage

BACKGROUND

The present study aimed to investigate whether leucine (Leu) alleviates oxidative injury in bovine intestinal epithelial cells (BIECs) induced by hydrogen peroxide (H₂ O₂ ), as well as the underlying molecular mechanisms.

RESULTS

BIECs were treated with H₂ O₂ (1 mmol L^-1 ) and/or Leu (0, 0.9, 1.8 or 3.6 mmol L^-1 ) for 2 h. Leu increased cell viability (P < 0.05) and decreased the release of lactate dehydrogenase (P < 0.05) in BIECs challenged by H₂ O₂ . Then, the cells were treated with H₂ O₂ (1 mmol L^-1 ) and/or Leu (1.8 mmol L^-1 ) for 2 h. Compared with the H₂ O₂ group, cells treated with Leu and Leu + H₂ O₂ exhibited increased (P < 0.05) mRNA and protein expression of superoxide dismutase 2 (SOD2), catalase (CAT), glutathione peroxidase 1 (GPx1), heme oxygenase 1 (HO-1) and nuclear factor erythroid 2-related factor 2 (Nrf2). BIECs treatment with Leu significantly reduced (P < 0.05) apoptosis induced by H₂ O₂ . BIECs were transfected with Nrf2 small interfering RNA (siRNA) for 48 h and/or treated with H₂ O₂ (1 mmol L^-1 ) and/or Leu (1.8 mmol L^-1 ) for another 2 h. Transfection with Nrf2 siRNA abrogated the protective effect of Leu against H₂ O₂ -induced apoptosis and the mRNA and protein expression of SOD2 (P < 0.05).

CONCLUSION

These results indicate that Leu promotes the relative expression of antioxidant enzymes (SOD2, CAT and GPx1) and phase II detoxification enzymes (HO-1) by upregulating nuclear Nrf2 and activating the Nrf2 signaling pathway, thus enhancing the antioxidant capacity of cells. © 2022 Society of Chemical Industry.

Implications of endocrine-disrupting chemicals on polycystic ovarian syndrome: A comprehensive review

Polycystic ovarian syndrome (PCOS) is a complex multifactorial disorder of unknown pathogenesis in which genetic and environmental factors contribute synergistically to its phenotypic expressions. Endocrine-disrupting chemicals (EDCs), a group of widespread pollutants freely available in the environment and consumer products, can interfere with normal endocrine signals. Extensive evidence has shown that EDCs, environmental contributors to PCOS, can frequently induce ovarian and metabolic abnormalities at low doses. The current research on environmental EDCs suggests that there may be link between EDC exposure and PCOS, which calls for more human bio-monitoring of EDCs using highly sophisticated analytical techniques for the identification and quantification and to discover the underlying pathophysiology of the disease. This review briefly elaborated on the general etiology of PCOS and listed various epidemiological and experimental data from human and animal studies correlating EDCs and PCOS. This review also provides insights into various analytical tools and sample preparation techniques for biomonitoring studies for PCOS risk assessment. Furthermore, we highlight the role of metabolomics in disease-specific biomarker discovery and its use in clinical practice. It also suggests the way forward to integrate biomonitoring studies and metabolomics to underpin the role of EDCs in PCOS pathophysiology.

Dietary alfalfa powder supplementation improves growth and development, body health, and meat quality of Tibetan sheep

The application of alfalfa powder (AP) in Tibetan sheep to explore its healthy effects and meat quality improvement potential has not been reported. Our study found that AP improved the growth performance, serum metabolism, and antioxidation of Tibetan sheep. The edible quality, sensory quality, and nutritional quality of longissimus dorsi (LD) were analyzed. We observed lower drip loss and hue angle of meat after AP supplementation. AP also increased the cooked meat percentage, pH_24h, a*_24h, chroma_24h, and the contents of protein and fat. The targeted metabolomics profiling revealed that the contents of essential amino acids and flavor amino acids in mutton increased by AP treatments. AP also promoted the deposition of MUFA and PUFA. Therefore, as a promising botanical supplement, AP has a positive effect on the growth, development, and body health of Tibetan sheep, and is also conductive to providing healthy and nutritious high-quality livestock products.

The effect of combined oral contraceptives containing drospirenone and ethinylestradiol on serum levels of amino acids and acylcarnitines

INTRODUCTION

Metabolome variations have long been associated with normal hormonal fluctuations, and similar effects, related to the use of early generation synthetic hormones as a means of contraception, have also been identified.

OBJECTIVE

We investigated the serum amino acid and acylcarnitine profiles induced by the use of combined oral contraceptives (COCs) consisting of Ethinylestradiol (EE) and a 4th generation progestin, Drospirenone (DRSP).

METHOD

Gas chromatography mass spectrometry and liquid chromatography with tandem mass spectrometry was used to identify and quantify the serum amino acids and acyl carnitine levels in 24 controls, 25 DRSP/20EE users and 26 DRSP/30EE users.

RESULTS

Of the 26 amino acid compounds measured, 13 showed significant variations in abundance between the control and COC user groups. Although none of the 21 acylcarnitine compounds detected were statistically significant with regards to group variations, a trend, related the EE concentration, was observed. The detected metabolome disparities corresponded to that identified for earlier generation COCs, all pointing toward increased oxidative stress levels in the user groups.

CONCLUSION

These findings suggest that the clinical complications associated with these COCs could, to some extent, be alleviated by the simultaneous use of antioxidants. The study also highlights the role that targeted metabolomics could play in the elucidation of the underlying mechanisms of drug-induced severe effects.

A review on recent advances of egg byproducts: Preparation, functional properties, biological activities and food applications

The rapid development of egg industries produced vast byproducts that have not been effectively used. In this paper, the comprehensive utilization of egg byproducts was reviewed. Protein extraction and enzymatic hydrolysis were the main used ways for recycle of egg byproducts. The fact that eggshell membrane could accelerate would healing and improve facial skin of healthy people for 12 weeks was found. However, salted egg white had poor functional properties owing to high salt and ultrafiltration was an effective technology to remove 92.93% of salt. Moreover, Defatted yolk protein had the great potential to be used as food additives and functional foods. Other egg byproducts such as egg inhibitor and eggshells also were discussed. The novel applications of egg byproducts in the food field included food additives, feeds, food packaging materials and nutraceuticals based on current knowledge, but the proportion needed to be improved. This paper would provide a new insight for comprehensive utilization of egg byproducts.

Chronological Metabolic Response to Intensive Phase TB Therapy in Patients with Cured and Failed Treatment Outcomes

Despite the arguable success of the standardized tuberculosis (TB) treatment regime, a significant number of patients still present with treatment failure. To improve on current TB treatment strategies, we sought to gain a better understanding of the hosts' response to TB therapy. A targeted metabolomics approach was used to compare the urinary acylcarnitine and amino acid profiles of eventually cured TB patients with those of patients presenting with a failed treatment outcome, comparing these patient groups at the time of diagnosis and at weeks 1, 2, and 4 of treatment. Among the significant metabolites identified were histidine, isoleucine, leucine, methionine, valine, proline, tyrosine, alanine, serine, and γ-aminobutyric acid. In general, metabolite fluctuations in time followed a similar pattern for both groups for most compounds but with a delayed onset or shift of the pattern in the successfully treated patient group. These time-trends detected in both groups could potentially be ascribed to a vitamin B6 deficiency and fluctuations in the oxidative stress levels and urea cycle intermediates, linked to the drug-induced inhibition and stimulation of various enzymes. The earlier onset of observed trends in the failed patients is proposed to relate to genotypic and phenotypic variations in drug metabolizing enzymes, subsequently leading to a poor treatment efficiency either due to the rise of adverse drug reactions or to insufficient concentrations of the active drug metabolites. This study emphasizes the need for a more personalized TB treatment approach, by including enzyme phenotyping and the monitoring of oxidative stress and vitamin B6 levels, for example.

The therapeutic potential of diet on immune-related diseases: based on the regulation on tryptophan metabolism

Tryptophan (TRP), as an essential amino acid, plays crucial roles in maintaining immune homeostasis due to its complex metabolism pathway, including the microbial metabolism, 5-hydroxytryptamine and kynurenine pathways (KP). Metabolites from these pathways can act antioxidant and endogenous ligand of aryl hydrocarbon receptor (including microbiota metabolites: indole, indole aldehyde, indole acetic acid, indole acrylic acid, indole lactate, indole pyruvate acid, indole propionic acid, skatole, tryptamine, and indoxyl sulfate; and KP metabolites: kynurenine, kynurenic acid, 3-hydroxyanthranilic acid, xanthurenic acid, and cinnabarinic acid) for regulating immune response. In immune-related diseases, the production of pro-inflammatory cytokine activates indoleamine-2,3-dioxygenase, a rate-limiting enzyme of KP, leading to abnormal TRP metabolism in vivo. Many recent studies found that TRP metabolism could be regulated by diet, and the diet regulation on TRP metabolism could therapy related diseases. Accordingly, this review provides a critical overview of the relationships among diet, TRP metabolism and immunity with the aim to seek a treatment opportunity for immune-related diseases.

Invited Review: Maintain or Improve Piglet Gut Health around Weanling: The Fundamental Effects of Dietary Amino Acids

Gut health has significant implications for swine nutrient utilization and overall health. The basic gut morphology and its luminal microbiota play determinant roles for maintaining gut health and functions. Amino acids (AA), a group of essential nutrients for pigs, are not only obligatory for maintaining gut mucosal mass and integrity, but also for supporting the growth of luminal microbiota. This review summarized the up-to-date knowledge concerning the effects of dietary AA supplementation on the gut health of weanling piglets. For instance, threonine, arginine, glutamine, methionine and cysteine are beneficial to gut mucosal immunity and barrier function. Glutamine, arginine, threonine, methionine and cysteine can also assist with relieving the post-weaning stress of young piglets by improving gut immunological functions, antioxidant capacity, and/or anti-inflammatory ability. Glutamine, glutamate, glycine and cysteine can assist to reconstruct the gut structure after its damage and reverse its dysfunction. Furthermore, methionine, lysine, threonine, and glutamate play key roles in affecting bacteria growth in the lumen. Overall, the previous studies with different AA showed both similar and different effects on the gut health, but how to take advantages of all these effects for field application is not clear. It is uncertain whether these AA effects are synergetic or antagonistic. The interactions between the effects of non-nutrient feed additives and the fundamental effects of AA warrant further investigation. Considering the global push to minimize the antibiotics and ZnO usage in swine production, a primary effort at present may be made to explore the specific effects of individual AA, and then the concert effects of multiple AA, on the profile and functions of gut microbiota in young pigs.

The glutathione peroxidase family of Theobroma cacao: Involvement in the oxidative stress during witches' broom disease

The glutathione peroxidases (GPXs) are enzymes which are part of the cell antioxidant system inhibiting the ROS-induced damages of membranes and proteins. In cacao (Theobroma cacao L.) genome, five GPX genes were identified. Cysteine insertion codons (UGU) were found in TcPHGPX, TcGPX2, TcGPX4, TcGPX6 and tryptophan insertion codon (UGG) in TcGPX8. Multiple alignments revealed conserved domains between TcGPXs and other plants and human GPXs. Homology modeling was performed using the Populus trichocarpa GPX5 structure as template, and the molecular modeling showed that TcGPXs have affinity with selenometionine in their active site. In silico analysis of the TcGPXs promoter region revealed the presence of conserved cis-elements related to biotic stresses and hormone responsiveness. The expression analysis of TcGPXs in cacao plantlet meristems infected by M. perniciosa showed that TcGPXs are most expressed in susceptible variety than in resistant one, mainly in disease stages in which oxidative stress and programmed cell death occurred. This data, associated with phylogenetic and location analysis suggested that TcGPXs may play a role in protecting cells from oxidative stress as a try of disease progression reduction. To our knowledge, this is the first study of the overall GPX family from T. cacao.

Elucidation of gastrointestinal dysfunction in response to irradiation using metabolomics

Gastrointestinal toxicity is frequently observed secondary to accidental or therapeutic radiation exposure. However, the variation in the intestinal metabolites after abdominal radiation exposure remains ambiguous. In the present study, C57BL/6 mice were exposed to 0, 2, and 20 Gy irradiation dose. The Head and chest of each mouse were covered with a lead shield before x-ray irradiation. 24 h post-irradiation treatment, intestinal tissue of each mouse was excised and prepared for metabolites measurement using gas chromatography-mass spectrometry (GC-MS). Our comprehensive analysis of metabolites in the intestinal tissues detected 44 metabolites after irradiation, including amino acids, carbohydrates, organic acids, and sugars. Amino acid levels in the intestinal tissue gradually rose, dependent on the radiation dose, perhaps as an indication of oxidative stress. Our findings raise the possibility that amino acid metabolism may be a potential target for the development of treatments to alleviate or mitigate the harmful effects of oxidative stress-related gastrointestinal toxicity due to radiation exposure.

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Gastrointestinal damage frequently results from radiation exposure.

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We analyzed the metabolic profile after local irradiation to the intestine.

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Amino acid levels in the intestinal tissue rose dependent on the radiation dose.

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Amino acid metabolism may be a good target for future therapies.

Sulforaphane prevents chromium-induced lung injury in rats via activation of the Akt/GSK-3β/Fyn pathway

Chromium (Cr) is an internationally recognized carcinogenic hazard that causes serious pulmonary toxicity. However, Cr-induced pulmonary toxicity lacks effective treatment to date. Sulforaphane (SFN), a well-known organosulfur compound, has gained increasing attention because of its unique biological function. This study investigates if SFN could decrease K₂Cr₂O₇-induced pulmonary toxicity and a potential mechanism involved using a rat 35-day Cr-induced pulmonary toxicity model and the mouse alveolar type II epithelial cell line (MLE-12). The results showed that SFN prevented Cr-induced oxidative stress, histopathological lesions, inflammation, apoptosis, and changes in protein kinase B (Akt) and glycogen synthase kinase 3 beta (GSK-3β) levels in vivo and in vitro. However, SFN can not play the protective effect against K₂Cr₂O₇-induced cell injury after treating by an Akt-specific inhibitor (MK-2206 2HCl) in MLE-12 cells. Furthermore, SFN increased the expression of nuclear factor-E2-related factor-2 (Nrf2) phase II detoxification enzymes. Collectively, this study demonstrates that SFN prevents K₂Cr₂O₇-induced lung toxicity in rats through enhancing Nrf2-mediated exogenous antioxidant defenses via activation of the Akt/GSK-3β/Fyn signaling pathway. SFN may be a novel natural substance to cure Cr-induced lung toxicity.

l-ornithine activates Ca2+ signaling to exert its protective function on human proximal tubular cells

Oxidative stress and reactive oxygen species (ROS) generation can be influenced by G-protein coupled receptor (GPCR)-mediated regulation of intracellular Ca2+ ([Ca2+]i) signaling. ROS production are much higher in proximal tubular (PT) cells; in addition, the lack of antioxidants enhances the vulnerability to oxidative damage. Despite such predispositions, PT cells show resiliency, and therefore must possess some inherent mechanism to protect from oxidative damage. While the mechanism in unknown, we tested the effect of l-ornithine, since it is abundantly present in PT luminal fluid and can activate Ca2+-sensing receptor (CaSR), a GPCR, expressed in the PT luminal membrane. We used human kidney 2 (HK2) cells, a PT cell line, and performed Ca2+ imaging and electrophysiological experiments to show that l-ornithine has a concentration-dependent effect on CaSR activation. We further demonstrate that the operation of CaSR activated Ca2+ signaling in HK-2 cells mediated by the transient receptor potential canonical (TRPC) dependent receptor-operated Ca2+ entry (ROCE) using pharmacological and siRNA inhibitors. Since PT cells are vulnerable to ROS, we simulated such deleterious effects using genetically encoded peroxide-induced ROS production (HyperRed indicator) to show that the l-ornithine-induced ROCE mediated [Ca2+]i signaling protects from ROS production. Furthermore, we performed cell viability, necrosis and apoptosis assays, and mitochondrial oxidative gene expression to establish that presence of l-ornithine rescued the ROS-induced damage in HK-2 cells. Moreover, l-ornithine-activation of CaSR can reverse ROS production and apoptosis via mitogen-activated protein kinase p38 activation. Such nephroprotective role of l-ornithine can be useful as the translational option for reversing kidney diseases involving PT cell damage due to oxidative stress or crystal nephropathies.

Biological Activities of Egg Yolk Lipids: A Review

As one of six dietary nutrients, lipid derived from different food matrices has been extensively studied and has an appropriate application in food, medicine, and cosmetic industry. Egg is a richly nutritive food, of which proteins and lipids possess excellent functional characteristics and biological activities. In recent years, egg yolk lipid has been successively separated and investigated, such as egg yolk oil, phospholipids, and fatty acids, which have anti-inflammatory activity, antioxidant activity, cardiovascular protection, and memory improvement, involving the regulation of cell function and physiological homeostatic balance. In this paper, the biological activities and underlying benefit of egg yolk lipids and fat-soluble components have been highlighted and summarized. Meanwhile, the quantitative data of egg yolk lipids needed to achieve any of the described biological effects and recommended concentrations relevant for dietary intake are reviewed. Finally, current challenges and crucial issues of high-efficiency utilization of egg yolk lipids are also discussed.

Proteomic Analysis of Saccharomyces cerevisiae Response to Oxidative Stress Mediated by Cocoa Polyphenols Extract

The present study addressed the protective effects against oxidative stress (OS) of a cocoa powder extract (CPEX) on the protein expression profile of S. cerevisiae. A proteomic analysis was performed after culture preincubation with CPEX either without stress (−OS) or under stress conditions (+OS) (5 mM of H₂O₂). LC-MS/MS identified 33 differentially expressed proteins (–OS: 14, +OS: 19) that were included By Gene Ontology analysis in biological processes: biosynthesis of amino acids, carbohydrate metabolism and reactive oxygen species metabolic process. In a gene-knockout strains study, eight proteins were identified as putative candidates for being involved in the protective mechanism of cocoa polyphenols against OS induced by H₂O₂. CPEX was able to exert its antioxidant activity in yeast mainly through the regulation of: (a) amino acids metabolism proteins by modulating the production of molecules with known antioxidant roles; (b) stress-responsive protein Yhb1, but we were unable to fully understand its down-regulation; (c) protein Prb1, which can act by clipping Histone H3 N-terminal tails that are related to cellular resistance to DNA damaging agents.

Metabolites of stable fly reduce diarrhea in mice by modulating the immune system, antioxidants, and composition of gut microbiota

Escherichia coli (E. coli) O₁-induced diarrhea is associated with intestinal microbial imbalance, however, the results of using oral antibiotics still remain poor. To overcome such problem, our study investigates the role of metabolites from stable flies (MSF) in the occurrence of diarrhea. The amino acid composition and molecular weight analysis of MSF by RP-HPLC and GPC, respectively. Besides the normal control group, SPF mice in other group were inoculated with E. coli O1 received treatment as follows over a period of 7 days saline solution (E. coli control), ciprofloxacin (0.13 g/kg; positive control) and MSF (2, 4 and 8 mg/kg) dosage. Throughout the experiment, defecation and body weights were examined and recorded. On the eighth day, after administering anesthesia, blood, tissue of small intestine samples were obtained for immunological and anti-oxidant. Small intestinal tissues and cecum contents samples were used for histopathological and 16S rDNA sequencing analysis. Our showed that MSF was rich in isoleucine, and its molecular weight less than 400 Da is 60.03%. MSF (4 and 8 mg/kg) and ciprofloxacin, significantly decreased IL-6, IL-8 and TNF-α levels, whereas, increased IL-2, IL-4, IL-10, INF-γ, IgA and IgG levels in mice having diarrhea. These treatments also reversed intestinal flora imbalance as indicated by the increased in Firmicutes-to-Bacteroidetes ratio and Clostridium levels (P < 0.05) and improved 5-HT, CAT and SOD levels. MSF favored diarrhea management as compared to ciprofloxacin, suggesting that MSF can be used in the management of E. coli O₁-induced diarrhea, in normal gut microbiota and normal intestinal antioxidant function.

Novel fluorescent probe with a bridged Si–O–Si bond for the reversible detection of hypochlorous acid and biothiol amino acids in live cells and zebrafish

Herein, we report the design of a novel fluorescent probe consisting of a naphthalimide fluorophore and a silicone small molecule for the reversible detection of hypochlorous acid and biothiol amino acids.

Antioxidative Efficacy of a Pistacia Lentiscus Supplement and Its Effect on the Plasma Amino Acid Profile in Inflammatory Bowel Disease: A Randomised, Double-Blind, Placebo-Controlled Trial

Oxidative stress is present in patients with Inflammatory Bowel Disease (IBD), and natural supplements with antioxidant properties have been investigated as a non-pharmacological approach. The objective of the present study was to assess the effects of a natural Pistacia lentiscus (PL) supplement on oxidative stress biomarkers and to characterise the plasma-free amino acid (AA) profiles of patients with active IBD (Crohn's disease (CD) N = 40, ulcerative colitis (UC) N = 20). The activity was determined according to 5 ≤ Harvey Bradshaw Index ≤ 16 or 2 ≤ Partial Mayo Score ≤ 6. This is a randomised, double-blind, placebo-controlled clinical trial. IBD patients (N = 60) were randomly allocated to PL (2.8 g/day) or to placebo for 3 months being under no treatment (N = 21) or under stable medical treatment (mesalamine N = 24, azathioprine N = 14, and corticosteroids N = 23) that was either single medication (N = 22) or combined medication (N = 17). Plasma oxidised, low-density lipoprotein (oxLDL), total serum oxidisability, and serum uric acid were evaluated at baseline and follow-up. OxLDL/LDL and oxLDL/High-Density Lipoprotein (HDL) ratios were calculated. The plasma-free AA profile was determined by applying a gas chromatography/mass spectrometry analysis. oxLDL (p = 0.031), oxLDL/HDL (p = 0.020), and oxLDL/LDL (p = 0.005) decreased significantly in the intervention group. The mean change differed significantly in CD between groups for oxLDL/LDL (p = 0.01), and, in the total sample, both oxLDL/LDL (p = 0.015) and oxLDL/HDL (p = 0.044) differed significantly. Several changes were reported in AA levels. PL ameliorated a decrease in plasma-free AAs seen in patients with UC taking placebo. In conclusion, this intervention resulted in favourable changes in oxidative stress biomarkers in active IBD.

A Michael addition–cyclization-based switch-on fluorescent chemodosimeter for cysteine and its application in live cell imaging

We designed and synthesized a fast response fluorescent probe, BTAC (benzothiazol-azacoumarin), for detection of cysteine (Cys).

1H NMR-Based Metabonomic Study of Functional Dyspepsia in Stressed Rats Treated with Chinese Medicine Weikangning

1H NMR-based metabolic profiling combined with multivariate data analysis was used to explore the metabolic phenotype of functional dyspepsia (FD) in stressed rats and evaluate the intervention effects of the Chinese medicine Weikangning (WKN). After a 7-day period of model establishment, a 14-day drug administration schedule was conducted in a WKN-treated group of rats, with the model and normal control groups serving as negative controls. Based on 1H NMR spectra of urine and serum from rats, PCA, PLS-DA, and OPLS-DA were performed to identify changing metabolic profiles. According to the key metabolites determined by OPLS-DA, alterations in energy metabolism, stress-related metabolism, and gut microbiota were found in FD model rats after stress stimulation, and these alterations were restored to normal after WKN administration. This study may provide new insights into the relationship between FD and psychological stress and assist in research into the metabolic mechanisms involved in Chinese medicine.

Serum metabolomics of Indian women with polycystic ovary syndrome using 1H NMR coupled with a pattern recognition approach

Polycystic ovary syndrome (PCOS) is one of the most commonly occurring metabolic and endocrinological disorders affecting women of reproductive age. Metabolomics is an emerging field that holds promise in understanding disease pathophysiology. Recently, a few metabolomics based studies have been attempted in PCOS patients; however, none of them have included patients from the Indian population. The main objective of this study was to investigate the serum metabolomic profile of Indian women with PCOS and compare them with controls. Proton nuclear magnetic resonance (¹H NMR) was used to first identify the differentially expressed metabolites among women with PCOS from the Eastern region of India during the discovery phase and further validated in a separate cohort of PCOS and control subjects. Multivariate analysis of the binned spectra indicated 16 dysregulated bins in the sera of these women with PCOS. Out of these 16 bins, 13 identified bins corresponded to 12 metabolites including 8 amino acids and 4 energy metabolites. Amongst the amino acids, alanine, valine, leucine and threonine and amongst the energy metabolites, lactate and acetate were observed to be significantly up-regulated in women with PCOS when compared with controls. The remaining 4 amino acids, l-glutamine, proline, glutamate and histidine were down-regulated along with 2 energy metabolites: glucose and 3-hydroxybutyric acid. Our findings showed dysregulations in the expression of different metabolites in the serum of women with PCOS suggesting the involvement of multiple pathways including amino acid metabolism, carbohydrate/lipid metabolism, purine and pyrimidine metabolism and protein synthesis.

Individual Amino Acid Supplementation Can Improve Energy Metabolism and Decrease ROS Production in Neuronal Cells Overexpressing Alpha-Synuclein

Parkinson's disease (PD) is a neurodegenerative disorder characterized by alpha-synuclein accumulation and loss of dopaminergic neurons in the substantia nigra (SN) region of the brain. Increased levels of alpha-synuclein have been shown to result in loss of mitochondrial electron transport chain complex I activity leading to increased reactive oxygen species (ROS) production. WT alpha-synuclein was stably overexpressed in human BE(2)-M17 neuroblastoma cells resulting in increased levels of an alpha-synuclein multimer, but no increase in alpha-synuclein monomer levels. Oxygen consumption was decreased by alpha-synuclein overexpression, but ATP levels did not decrease and ROS levels did not increase. Treatment with ferrous sulfate, a ROS generator, resulted in decreased oxygen consumption in both control and alpha-synuclein overexpressing cells. However, this treatment only decreased ATP levels and increased ROS production in the cells overexpressing alpha-synuclein. Similarly, paraquat, another ROS generator, decreased ATP levels in the alpha-synuclein overexpressing cells, but not in the control cells, further demonstrating how alpha-synuclein sensitized the cells to oxidative insult. Proteomic analysis yielded molecular insights into the cellular adaptations to alpha-synuclein overexpression, such as the increased abundance of many mitochondrial proteins. Many amino acids and citric acid cycle intermediates and their ester forms were individually supplemented to the cells with L-serine, L-proline, L-aspartate, or L-glutamine decreasing ROS production in oxidatively stressed alpha-synuclein overexpressing cells, while diethyl oxaloacetate or L-valine supplementation increased ATP levels. These results suggest that dietary supplementation with individual metabolites could yield bioenergetic improvements in PD patients to delay loss of dopaminergic neurons.

Protective effects of leucine on redox status and mitochondrial-related gene abundance in the jejunum of intrauterine growth-retarded piglets during early weaning period

The aim of this study was to investigate the effects of dietary supplementation with 0.35% l-leucine on redox status and gene abundance relating to mitochondrial biogenesis and function in the jejunum of intrauterine growth-retarded (IUGR) piglets during early weaning period. According to a 2 × 2 factorial arrangement, 16 IUGR and 16 normal body weight (NBW) piglets were fed a basal diet without l-leucine supplementation or a basal diet plus 0.35% l-leucine supplementation from the age of 14 to 35 d. The results showed that compared with NBW piglets, IUGR piglets had a lower (p < 0.05) jejunal DNA concentration, a reduced (p < 0.05) manganese superoxide dismutase (MnSOD) and total antioxidant capability (T-AOC) activities and mitochondrial DNA content in the jejunum. Leucine supplementation increased (p < 0.05) MnSOD and T-AOC activities and decreased (p < 0.05) the malondialdehyde content in the jejunum of IUGR piglets. The mRNA gene abundance of nuclear respiratory factor-1 (NRF1), mitochondrial transcription factor A (TFAM), ATP synthase (ATPs), cytochrome c oxidase V (CcOX V), cytochrome c and glucokinase in the jejunum of IUGR piglets was reduced (p < 0.05) compared with NBW piglets. However, NRF1, peroxisome proliferation-activated receptor gamma coactivator-1 alpha, TFAM, ATPs and CcOX I mRNA gene abundance in the jejunum of IUGR piglets were increased (p < 0.05) by diets supplemented with leucine. These data indicate that leucine supplementation has therapeutic potential for attenuating intestinal oxidative stress and mitochondrial dysfunction in IUGR piglets during the early period of life via increasing enzyme activities and up-regulating mRNA gene abundance.

Alterations in the levels of plasma amino acids in polycystic ovary syndrome--A pilot study

Background & objectives:

Plasma amino acid levels are known to be altered in conditions like sepsis and burns which are situations of metabolic stress. Polycystic ovary syndrome (PCOS), a condition which affects a woman throughout her life, is said to be associated with metabolic stress. This study was undertaken to assess if there were significant alterations in the levels of plasma amino acids in women with PCOS.

Methods:

Sixty five women with PCOS along with the similar number of age matched normal controls were included in this study. Levels of 14 amino acids were determined using reverse phase high performance liquid chromatography.

Results:

The levels of methionine, cystine, isoleucine, phenylalanine, valine, tyrosine, proline, glycine, lysine and histidine were found to be significantly (P<0.001) lower in cases than in controls. Arginine and alanine levels were found to be significantly (P<0.001) higher in cases compared with controls.

Interpretation & conclusions:

Our findings showed significant derangement in the levels of plasma amino acids in women with PCOS which might be due to the oxidative and metabolic stress associated with it. Further studies need to be done to confirm the findings.

Co- and Post-Treatment with Lysine Protects Primary Fish Enterocytes against Cu-Induced Oxidative Damage

The aim of the work was primarily to explore the protective activity pathways of lysine against oxidative damage in fish in vivo and in enterocytes in vitro. First, grass carp were fed diets containing six graded levels of lysine (7.1-19.6 g kg-1 diet) for 56 days. Second, the enterocytes were treated with different concentrations of lysine (0-300 mg/L in media) prior to (pre-treatment), along with (co-treatment) or following (post-treatment) with 6 mg/L of Cu for 24 h. The results indicated that lysine improved grass carp growth performance. Meanwhile, lysine ameliorated lipid and protein oxidation by elevating the gene expression and activity of antioxidant enzymes (superoxide dismutase (SOD), glutathioneperoxidase (GPx), glutathione-S-transferase (GST) and reductase (GR)), and nuclear factor erythroid 2-related factor 2 (Nrf2) mRNA levels in fish intestine. The in vitro studies showed that co- and post-treatment with lysine conferred significant protection against Cu-induced oxidative damage in fish primary enterocytes as measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) OD values, along with alkaline phosphatase (ALP) and lactate dehydrogenase activities, and the depletion of protein carbonyl (PC), malondialdehyde (MDA) and 8-hydroxydeoxyguanosine contents. Moreover, lysine co-treatment decreased the activities and mRNA level of cellular SOD, GPx, GST and GR compared with the Cu-only exposed group. Gene expression of the signalling molecule Nrf2 showed the same pattern as that of SOD activity, whereas Kelch-like ECH-associated protein 1b (Keap1b) followed the opposite trend, indicating that co-treatment with lysine induced antioxidant enzymes that protected against oxidative stress through Nrf2 pathway. In addition, post-treatment with lysine increased proteasomal activity and blocked the Cu-stimulated increase in mRNA levels of GST and associated catalase (CAT) and GST activities (P<0.01 and P<0.001). GR activity and gene expression, and glutathione (GSH) content followed an opposite trend to GST activity (P<0.05). Thus, post-treatment of lysine elevated protein and DNA repair abilities and ameliorated the cellular redox state of enterocytes. The overall results suggest that lysine plays a significant role in the protection of fish intestine in vivo and in vitro through the induction of key antioxidant protection.

Hen Egg as an Antioxidant Food Commodity: A Review

Intake of antioxidants through diet is known to be important in reducing oxidative damage in cells and improving human health. Although eggs are known for their exceptional, nutritional quality, they are not generally considered as antioxidant foods. This review aims to establish the importance of eggs as an antioxidant food by summarizing the current knowledge on egg-derived antioxidants. Eggs have various natural occurring compounds including the proteins ovalbumin, ovotransferrin and lysozyme in egg white, as well as phosvitin, carotenoids and free aromatic amino acids in egg yolk. Some lipophilic antioxidants such as vitamin E, carotenoids, selenium, iodine and others can be transferred from feed into egg yolk to produce antioxidant-enriched eggs. The bioactivity of egg antioxidants can be affected by food processing, storage and gastrointestinal digestion. Generally thermal processing methods can promote loss of antioxidant properties in eggs due to oxidation and degradation, whereas gastrointestinal digestion enhances the antioxidant properties, due to the formation of new antioxidants (free amino acids and peptides). In summary, in addition to its well-known nutritional contribution to our diet, this review emphasizes the role of eggs as an important antioxidant food.

Isolation and characterisation of in vitro and cellular free radical scavenging peptides from corn peptide fractions

Corn gluten meal, a corn processing industry by-product, is a good source for the preparation of bioactive peptides due to its special amino acid composition. In the present study, the in vitro and cellular free radical scavenging activities of corn peptide fractions (CPFs) were investigated. Results indicated that CPF1 (molecular weight less than 1 kDa) and CPF2 (molecular weight between 1 and 3 kDa) exhibited good hydroxyl radical, superoxide anion radical and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonicacid) diammonium salt (ABTS) radical scavenging activity and oxygen radical absorbance capacity (ORAC). Meanwhile, the in vitro radical scavenging activity of CPF1 was slightly higher than that of CPF2. Both CPF1 and CPF2 also exhibited significant cytoprotective effects and intracellular reactive oxygen species scavenging activity in Caco-2 cells exposed to hydrogen peroxide (H2O2). The amino acid composition analysis revealed that the CPF were rich in hydrophobic amino acids, which comprised of more than 45% of total amino acids. An antioxidant peptide sequence of Tyr-Phe-Cys-Leu-Thr (YFCLT) was identified from CPF1 using matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry (MALDI TOF/TOF MS). The YFCLT exhibited excellent ABTS radical scavenging activity with a 50% effective concentration (EC50) value of 37.63 µM, which was much lower than that of Trolox. In conclusion, corn gluten meal might be a good source to prepare antioxidant peptides.

γ-Glutamyl cysteine and γ-glutamyl valine inhibit TNF-α signaling in intestinal epithelial cells and reduce inflammation in a mouse model of colitis via allosteric activation of the calcium-sensing receptor

BACKGROUND

The extracellular calcium-sensing receptor (CaSR) is distributed throughout the gastrointestinal tract, and its activation has been shown to promote intestinal homeostasis, suggesting that CaSR may be a promising target for novel therapies to prevent chronic intestinal inflammation such as inflammatory bowel disease (IBD). The γ-glutamyl dipeptides γ-glutamyl cysteine (γ-EC) and γ-glutamyl valine (γ-EV) are dietary flavor enhancing compounds, and have been shown to activate CaSR via allosteric ligand binding. The aim of this study was to examine the anti-inflammatory effects of γ-EC and γ-EV in vitro in intestinal epithelial cells and in a mouse model of intestinal inflammation.

RESULTS

In vitro, treatment of Caco-2 cells with γ-EC and γ-EV resulted in the CaSR-mediated reduction of TNF-α-stimulated pro-inflammatory cytokines and chemokines including IL-8, IL-6, and IL-1β, and inhibited phosphorylation of JNK and IκBα, while increasing expression of IL-10. In vivo, using a mouse model of dextran sodium sulfate (DSS)-induced colitis, γ-EC and γ-EV treatment ameliorated DSS-induced clinical signs, weight loss, colon shortening and histological damage. Moreover, γ-EC and γ-EV reduced the expression of TNF-α, IL-6, INF-γ, IL-1β, and IL-17, and increased the expression of IL-10 in the colon, in a CaSR-dependent manner. The CaSR-mediated anti-inflammatory effects of γ-EC were abrogated in β-arrestin2 knock-down Caco-2 cells, and involvement of β-arrestin2 was found to inhibit TNF-α-dependent signaling via cross-talk with the TNF-α receptor (TNFR).

CONCLUSIONS

Thus CaSR activation by γ-EC and γ-EV can aid in maintaining intestinal homeostasis and reducing inflammation in chronic inflammatory conditions such as IBD.

Effect of dietary isoleucine on the immunity, antioxidant status, tight junctions and microflora in the intestine of juvenile Jian carp (Cyprinus carpio var. Jian)

This study was conducted to investigate the effects of dietary isoleucine (Ile) on the immune response, antioxidant status, tight junctions, and microbial population in the intestine of juvenile Jian carp (Cyprinus carpio var. Jian). A total of 1200 juvenile Jian carp with average initial weight 6.9 ± 0.03 g were fed semi-purified isonitrogenous diets containing 4.2 (unsupplemented control group), 7.0, 9.5, 11.9, 13.9 and 16.9 g Ile kg(-1) diet for 60 days. Results indicated that Ile supplementation decreased malondialdehyde (MDA) and protein carbonyl content, and the amounts of Escherichia coli and Aeromonas in the intestine (P < 0.05), and increased the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione reductase (GR), glutathione content and the amounts of Lactobacillus and Bacillus in the intestine (P < 0.05). Furthermore, real time polymerase chain reaction revealed that relative mRNA expression of copper/zinc superoxide dismutase (Cu-ZnSOD), manganese superoxide dismutase (MnSOD), CAT, NF-E2-related factor 2 (Nrf2), p38 mitogen-activated protein kinases (p38MAPK) in the intestine were increased with increasing of dietary Ile up to a certain point (P < 0.05). Conversely, the relative mRNA expression of occludin, claudin-3, claudin-7, TNF-α, IL-10, Kelch-like-ECH- associated protein 1 (Keap1), extracellular signal-regulated kinase 1 (ERK1) in the intestine showed a downward trend (P < 0.05). In conclusion, dietary Ile improves intestinal immune function, antioxidant capacity and microbial population, and regulates gene expression of antioxidant enzyme, tight junctions, Nrf2, Keap1, p38 and ERK1 in the intestine of Jian carp.