Integrated Metabolomics and Metagenomics Unveiled Biomarkers of Antioxidant Potential in Fermented Brewer's Grains.

About one-third of the global food supply is wasted. Brewers' spent grain (BSG), being produced in enormous amounts by the brewery industry, possesses an eminence nutritional profile, yet its recycling is often neglected for multiple reasons. We employed integrated metagenomics and metabolomics techniques to assess the effects of enzyme treatments and Lactobacillus fermentation on the antioxidant capacity of BSG. The biotreated BSG revealed improved antioxidant capability, as evidenced by significantly increased (p < 0.05) radical scavenging activity and flavonoid and polyphenol content. Untargeted metabolomics revealed that Lactobacillus fermentation led to the prominent synthesis (p < 0.05) of 15 novel antioxidant peptides, as well as significantly higher (p < 0.05) enrichment of isoflavonoid and phenylpropanoid biosynthesis pathways. The correlation analysis demonstrated that Lactiplantibacillus plantarum exhibited strong correlation (p < 0.05) with aucubin and carbohydrate-active enzymes, namely, glycoside hydrolases 25, glycosyl transferases 5, and carbohydrate esterases 9. The fermented BSG has potential applications in the food industry as a culture medium, a functional food component for human consumption, and a bioactive feed ingredient for animals.

Magnolol-driven microbiota modulation elicits changes in tryptophan metabolism resulting in reduced skatole formation in pigs.

Skatole of gut origin has garnered significant attention as a malodorous pollutant due to its escalating emissions, recalcitrance to biodegradation and harm to animal and human health. Magnolol is a health-promoting polyphenol with potential to considerably mitigate the skatole production in the intestines. To investigate the impact of magnolol and its underlying mechanism on the skatole formation, in vivo and in vitro experiments were conducted in pigs. Our results revealed that skatole concentrations in the cecum, colon, and faeces decreased by 58.24% (P = 0.088), 44.98% (P < 0.05) and 43.52% (P < 0.05), respectively, following magnolol supplementation. Magnolol supplementation significantly decreased the abundance of Lachnospira, Faecalibacterium, Paramuribaculum, Faecalimonas, Desulfovibrio, Bariatricus, and Mogibacterium within the colon (P < 0.05). Moreover, a strong positive correlation (P < 0.05) between skatole concentration and Desulfovibrio abundance was observed. Subsequent in silico studies showed that magnolol could dock well with indolepyruvate decarboxylase (IPDC) within Desulfovibrio. Further in vitro investigation unveiled that magnolol addition led to less indole-3-pyruvate diverted towards the oxidative skatole pathway by the potential docking of magnolol towards IPDC, thereby diminishing the conversion of substrate into skatole. Our findings offer novel targets and strategies for mitigating skatole emission from the source.

Mulberry leaf extract improves intestinal barrier function and displays beneficial effects on colonic microbiota and microbial metabolism in weaned piglets.

BACKGROUND: Mulberry leaf extract (MLE) extracted from mulberry leaves is rich in a variety of bioactive ingredients and can be used as feed additives of weaned piglets. The present study was conducted to evaluate the effects of dietary MLE supplementation on intestinal barrier function, colon microbial numbers and microbial metabolites of weaned piglets. RESULTS: MLE supplementation increased the villus height and the villus height/crypt depth ratio in jejunum and ileum (P < 0.05), increased the mRNA expression of ZO-1, Claudin-1 and MUC-2 in the ileal mucosa (P < 0.05), and decreased the serum level of lipopolysaccharide (P < 0.01). Meanwhile, MLE reduced the mRNA expression of tumor necrosis factor-α and interleukin-1ß (P < 0.05) and increased secretory immunoglobulin A level in the ileal mucosa (P < 0.05). In addition, MLE increased the numbers of beneficial bacteria Bifidobacterium and Lactobacillus (P < 0.05) and decreased the number of potential pathogenic bacteria Escherichia coli (P < 0.05) in the colon. Correspondingly, MLE supplementation reduced the pH value of colonic digesta (P < 0.05) and altered the microbial fermentation pattern of the colon by increasing the concentrations of microbial metabolites derived from carbohydrates fermentation such as lactate, acetate, butyrate and total short-chain fatty acids (P < 0.05), and decreasing the concentrations of microbial metabolites derived from amino acid fermentation such as p-cresol, skatole, spermine, histamine and tryptamine (P < 0.05). CONCLUSION: MLE supplementation improved intestinal barrier function and displayed beneficial effects on colon microbes and microbial metabolism in weaned piglets. © 2022 Society of Chemical Industry.

Guanidine acetic acid supplementation altered plasma and tissue free amino acid profiles in finishing pigs.

BACKGROUND: As a nutritive feed additive, guanidine acetic acid (GAA) participates in the metabolism of energy and proteins. This study aimed to investigate the effects of GAA on growth performance, organ index, plasma and tissue free amino acid profiles, and related metabolites in finishing pigs. A total of 72 crossbred pigs (body weight 86.59 ± 1.16 kg) were randomly assigned to 1 of 4 dietary treatments (GAA0, GAA500, GAA1000, and GAA1500). They were fed the basal diets supplemented with 0, 500, 1000, or 1500 mg/kg GAA for 42 days, respectively. The growth performance and organ weight were evaluated, and the contents of crude protein, free amino acids, and metabolites in plasma and tissues were determined. Spearman correlation between plasma and tissue free amino acids and related metabolites was also analyzed. RESULTS: Growth performance in pigs was not altered by GAA (P > 0.05). The absolute and relative weight of kidneys increased (quadratic, P < 0.05). As dietary GAA concentration was increased, the contents of plasma glycine, serine, leucine, ornithine, and ratio of ornithine/arginine decreased (linear or quadratic, P < 0.05), but the contents of plasma isoleucine and taurine and the ratios of alanine/branched-chain amino acids and proline/ornithine increased quadratically (P < 0.05). The hepatic γ-amino-n-butyric acid content increased linearly and quadratically (P < 0.001), while the carnosine content decreased (quadratic, P = 0.004). The contents of renal arginine, proline, cystine, glutamate, and total amino acids (TAA) decreased quadratically (P < 0.05), but the contents of glycine (quadratic, P = 0.015) and γ-amino-n-butyric acid (linear, P = 0.008) increased. The pancreatic tryptophan content (quadratic, P = 0.024) increased, while the contents of pancreatic proline (linear, P = 0.005) and hydroxyproline (quadratic, P = 0.032) decreased in response to GAA supplementation. The contents of cardiac essential amino acids (EAA), nonessential amino acids (NEAA), and TAA in GAA1000 were higher than those in GAA1500 (P < 0.05). Supplementing with GAA linearly increased the contents of methionine, threonine, valine, isoleucine, leucine, phenylalanine, tryptophan, lysine, histidine, arginine, serine, alanine, glutamine, asparagine, tyrosine, proline, taurine, cystathionine, α-aminoadipic acid, ß-aminoisobutyric acid, EAA, NEAA, and TAA in the spleen (P < 0.05). A strong Spearman correlation existed between plasma and tissue free amino acids and related metabolites. CONCLUSION: GAA supplementation did not altered pig growth performance, but it altered plasma and tissue free amino acid profiles and the contents of related metabolites in pigs in a tissue-dependent manner.

Functional Characterization and Whole-Genome Analysis of an Aflatoxin-Degrading Rhodococcus pyridinivorans Strain.

Aflatoxin B1 (AFB1) is one of the most toxic, naturally occurring carcinogen compounds and is produced by specific strains of fungi. Crop contamination with AFB1 can cause huge economic losses and serious health problems. Many studies have examined the microbiological degradation of AFB1, especially the use of efficient AFB1-degrading microorganisms, to control AFB1 contamination. Here, we reported the identification of a new Rhodococcus pyridinivorans strain (4-4) that can efficiently degrade AFB1 (degradation rate 84.9%). The extracellular component of this strain showed the strongest capacity to degrade AFB1 (degradation rate 83.7%). The effects of proteinase K, SDS, temperature, pH, incubation time, and AFB1 concentration on the AFB1 degradation ability of the extracellular component were investigated. We sequenced the complete genome of this strain, encoding 5246 protein-coding genes and 169 RNA genes on a circular chromosome and two plasmids. Comparative genomic analysis revealed high homology with other Rhodococcus strains with high AFB1-degradation ability. Further proteomic analyses of this strain identified a total of 723 proteins in the extracellular component, including multiple potential AFB1-degrading enzymes, along with enzymes that are reported to response to AFB1 treatment. Overall, the results demonstrate that R. pyridinivorans 4-4 would be an excellent candidate for the biodegradation and detoxification of AFB1 contamination.

Exogenous Glutathione Protects IPEC-J2 Cells against Oxidative Stress through a Mitochondrial Mechanism.

The accumulation of reactive oxygen species (ROS) triggers oxidative stress in cells by oxidizing and modifying various cellular components, preventing them from performing their inherent functions, ultimately leading to apoptosis and autophagy. Glutathione (GSH) is a ubiquitous intracellular peptide with multiple functions. In this study, a hydrogen peroxide (H2O2)-induced oxidative damage model in IPEC-J2 cells was used to investigate the cellular protection mechanism of exogenous GSH against oxidative stress. The results showed that GSH supplement improved the cell viability reduced by H2O2-induced oxidative damage model in IPEC-J2 cells in a dose-dependent manner. Moreover, supplement with GSH also attenuated the H2O2-induced MMP loss, and effectively decreased the H2O2-induced mitochondrial dysfunction by increasing the content of mtDNA and upregulating the expression TFAM. Exogenous GSH treatment significantly decreased the ROS and MDA levels, improved SOD activity in H2O2-treated cells and reduced H2O2-induced early apoptosis in IPEC-J2 cells. This study showed that exogenous GSH can protect IPEC-J2 cells against apoptosis induced by oxidative stress through mitochondrial mechanisms.

Effects of dietary citrus extract on growth performance, carcass characteristics and meat quality of pigs.

This study investigated the effects of citrus extract on growth, carcass and meat quality of Duroc × Landrace × Large White pigs. One hundred and eight pigs (54 barrows, 54 females) were assigned to one of three dietary treatments for 138 days. The dietary treatments were (1) basic diet; (2) basic diet supplemented with 75 mg/kg chlortetracycline; and (3) basic diet supplemented with citrus extract (0.25 ml/kg during 56-112 days of age and 0.20 ml/kg during 113-194 days of age). No significant differences among treatments were found for growth performance, carcass characteristics, meat quality and free amino acids (p > 0.05). Feeding citrus extract tended to increase intramuscular fat (p = 0.052). Citrus extract and chlortetracycline increased C15:0 concentration (p = 0.016) and superoxide dismutase activity (p = 0.004). The pigs that received chlortetracycline exhibited the lowest (p = 0.033) muscle malondialdehyde concentration. Overall, citrus extract ameliorated some meat quality indicators without adverse effects on pig growth or carcass performance.

Solid-state fermentation by Aspergillus niger and Trichoderma koningii improves the quality of tea dregs for use as feed additives.

This study evaluated the ability of Aspergillus niger and Trichoderma koningii to improve the quality of tea dregs (TDs) through solid-state fermentation as well as the value of the fermented tea dregs (FTDs) produced for use as bio-feed additives. After fermentation, FTDs differed in color and structure. Fermentation with A. niger and T. koningii increased the contents of crude protein, crude fiber, neutral detergent fiber, and acid detergent fiber of TDs. Compared to the unfermented group, the contents of reducing sugar, total flavonoids, total polyphenols, and theasaponins were increased in A. niger FTDs, while in T. koningii FTDs caffeine was completely degraded, the theasaponins were lower, and the contents of reducing sugar and caffeine higher. Regarding free amino acids, A. niger FTDs had the highest content of total amino acids, total essential amino acids, total non-essential amino acids, total aromatic amino acids, total branched-chain amino acids, and total non-protein amino acids, and all types of essential amino acids, followed by T. koningii FTDs and the control TDs. Fungal fermentation had similar effects on the content of various hydrolytic amino acids as those on above free amino acids, and increased the content of bitter and umami components. The composition of essential amino acids of TDs or FTDs was similar to that of the standard model, except for sulfur-containing amino acids and isoleucine. Solid-state fermentation with A. niger and T. koningii effectively improved the nutritional value of TDs, increased the contents of functional substances, and improved the flavor of TDs. This study demonstrated a feasible approach to utilize TDs that not only increases animal feed resources, but also reduces the production of resource waste and pollution.

Effect of amino acids and their derivatives on meat quality of finishing pigs.

Amino acids provide key nutritional value, and significantly contribute to taste and flavor of meat. Here, we review the role of free amino acids in the muscle fibers in meat quality and sensory signals. We furthermore discuss how dietary supplementation of free amino acids and their derivatives (e.g. tryptophan, threonine, arginine, lysine, leucine, glutamate, threonine, sarcosine, betaines, and cysteamine) can influence these attributes. The available data shows that the quality of the meat is subject to the amino acids that are provided in the animal feed.

Functional Characterization of a Novel Marine Microbial Esterase and its Utilization in the Enantioselective Preparation of (R)-Methyl 2-Chloropropionate.

Chiral 2-chloropropanoic acids and their ester derivatives are crucial intermediates in the synthesis of many chemicals, especially herbicides. The enzymatic synthesis of chiral 2-chloropropanoic acids and their ester derivatives by esterases was not easily achieved, because the structural difference between the two enantiomers was too small to be recognized by esterases. Herein, we report the expression and functional characterization of one novel low temperature-resistant esterase EST12-7 identified from the genome of Pseudonocardia antitumoralis SCSIO 01299 isolated from the sediments of the South China Sea. Biocatalyst EST12-7 could hydrolyze racemic methyl 2-chloropropinate and generate optically pure (R)-methyl 2-chloropropinate with high enantiomeric excess (>99 %) and conversion (>49 %) after process optimization. Notably, the addition of different surfactants and using surfactants of different concentrations in the kinetic resolution catalyzed by EST12-7 could greatly affect the enantiomeric excess and conversion rate of product (R)-methyl 2-chloropropinate.

A new flavanocoumarin from the root of Flemingia philippinensis.

One new flavanocoumarin, flemicoumarin A (1) was isolated from the EtOAc-soluble partition of the root of Flemingia philippinensis, along with three known compounds, namely 4,2'-epoxy-4',5-dihydroxy-7,5'-dimethoxy-3-phenylcoumarin (2), kaempferol 6-C-glucoside (3) and dracocephaloside (4). The structure of compound 1 was elucidated on the basis of its 1D, 2D NMR, CD and MS data. The structures of the known compounds were identified by comparison of their spectroscopic data with those reported in the literature. Compounds 1-4 exhibited inactivity against MCF-7, A549 and Hep-G2 human cancer cell lines in vitro by MTT colorimetric assay.