Multiomics Analysis Reveals Leucine Deprivation Promotes Bile Acid Synthesis by Upregulating Hepatic CYP7A1 and Intestinal Turicibacter sanguinis in Mice.

BACKGROUND: Leucine, a branched-chain amino acid, participates in the regulation of lipid metabolism and the composition of the intestinal microbiota. However, the related mechanism remains unclear. OBJECTIVES: Here, we aimed to reveal the potential mechanisms by which hepatic CYP7A1 (a rate-limiting enzyme for bile acid [BA] synthesis) and gut microbiota coregulate BA synthesis under leucine deprivation. METHODS: To this end, 8-wk-old C57BL/6J mice were fed with either regular diets or leucine-free diets for 1 wk. Then, we investigated whether secondary BAs were synthesized by Turicibacter sanguinis in 7-wk-old C57BL/6J germ-free mice gavaged with T. sanguinis for 2 wk by determining BA concentrations in the plasma, liver, and cecum contents using liquid chromatography-tandem mass spectrometry. RESULTS: The results showed that leucine deprivation resulted in a significant increase in total BA concentration in the plasma and an increase in the liver, but no difference in total BA was observed in the cecum contents before and after leucine deprivation. Furthermore, leucine deprivation significantly altered BA profiles such as taurocholic acid and ω-muricholic acid in the plasma, liver, and cecum contents. CYP7A1 expression was significantly upregulated in the liver under leucine deprivation. Leucine deprivation also regulated the composition of the gut microbiota; specifically, it significantly upregulated the relative abundance of T. sanguinis, thus enhancing the conversion of primary BAs into secondary BAs by intestinal T. sanguinis in mice. CONCLUSIONS: Overall, leucine deprivation regulated BA profiles in enterohepatic circulation by upregulating hepatic CYP7A1 expression and increasing intestinal T. sanguinis abundance. Our findings reveal the contribution of gut microbiota to BA metabolism under dietary leucine deprivation.

SGMFQP: An ontology-based Swine Gut Microbiota Federated Query Platform.

Gut microbiota plays a crucial role in modulating pig development and health, and gut microbiota characteristics are associated with differences in feed efficiency. To answer open questions in feed efficiency analysis, biologists seek to retrieve information across multiple heterogeneous data sources. However, this is error-prone and time-consuming work since the queries can involve a sequence of multiple sub-queries over several databases. We present an implementation of an ontology-based Swine Gut Microbiota Federated Query Platform (SGMFQP) that provides a convenient, automated, and efficient query service about swine feeding and gut microbiota. The system is constructed based on a domain-specific Swine Gut Microbiota Ontology (SGMO), which facilitates the construction of queries independent of the actual organization of the data in the individual sources. This process is supported by a template-based query interface. A Datalog+-based federated query engine transforms the queries into sub-queries tailored for each individual data source, and an automated workflow orchestration mechanism executes the queries in each source database and consolidates the results. The efficiency of the system is demonstrated on several swine feeding scenarios.

Mechanisms of Selective Autophagy.

Autophagy is a lysosome-dependent degradation process. During autophagy, cytoplasmic components are sequestered and catabolized to supply nutrition and energy under starvation conditions. Recent work has demonstrated that many cargos can be specifically recognized and then eliminated via the core mechanism of autophagy which is termed as selective autophagy. The cargo recognition program provides the basis for the specific degradation of selective autophagy; thus, the exploration of the interaction between the cargo and the receptor is the key for revealing the underlying mechanism. Also, receptor protein complexes are required in various selective autophagy subtypes which process and guide the cargo to the core mechanism. Ubiquitination and phosphorylation are the main methods to modulate the affinity of the receptor toward cargo. Although many key processes of selective autophagy subtypes have been discovered and intensively studied, the precise ways in which the mechanisms of cargo recognition function remain mostly elusive. A fuller mechanistic understanding of selective autophagy will be important for efforts to promote disease treatment and drug development.

Lactobacillus frumenti improves antioxidant capacity via nitric oxide synthase 1 in intestinal epithelial cells.

Oxidative damages have adverse effects on mammals. Growing studies have focused on exploring new antioxidants. Here, we report that Lactobacillus frumenti increases the total antioxidation capacity activities and decreases the total reactive oxygen species levels in porcine intestinal epithelial cells. Comparative proteomics revealed that expressions of peroxiredoxin 2, isocitrate dehydrogenase 1, NAD(P)H dehydrogenase quinone 1, antioxidant protein 1, and metallothionein-2A, which are associated with antioxidant defense system, were significantly increased with L. frumenti treatment. In germ-free mice, L. frumenti treatment also remarkably improves the intestinal antioxidant capacity. We further illustrated that nitric oxide production-mediated by nitric oxide synthase 1 activation is essential for L. frumenti-induced improvements in intestinal epithelial antioxidant capacity and barrier function. This study suggested that L. frumenti may be a potential probiotic used to prevent oxidative stress-induced aging and diseases in mammals.-Nie, Y., Hu, J., Hou, Q., Zheng, W., Zhang, X., Yang, T., Ma, L., Yan, X. Lactobacillus frumenti improves antioxidant capacity via nitric oxide synthase 1 in intestinal epithelial cells.

Dietary leucine supplementation alters energy metabolism and induces slow-to-fast transitions in longissimus dorsi muscle of weanling piglets.

Leucine plays an important role in promoting muscle protein synthesis and muscle remodelling. However, what percentage of leucine is appropriate in creep feed and what proteome profile alterations are caused by dietary leucine in the skeletal muscle of piglets remain elusive. In this case, we applied isobaric tags for relative and absolute quantitation to analyse the proteome profile of the longissimus dorsi muscles of weanling piglets fed a normal leucine diet (NL; 1·66 % leucine) and a high-leucine diet (HL; 2·1 % leucine). We identified 157 differentially expressed proteins between these two groups. Bioinformatics analysis of these proteins exhibited the suppression of oxidative phosphorylation and fatty acid ß-oxidation, as well as the activation of glycolysis, in the HL group. For further confirmation, we identified that SDHB, ATP5F1, ACADM and HADHB were significantly down-regulated (P<0·01, except ATP5F1, P<0·05), whereas the glycolytic enzyme pyruvate kinase was significantly up-regulated (P<0·05) in the HL group. We also show that enhanced muscle protein synthesis and the transition from slow-to-fast fibres are altered by leucine. Together, these results indicate that leucine may alter energy metabolism and promote slow-to-fast transitions in the skeletal muscle of weanling piglets.

Global Liver Proteome Analysis Using iTRAQ Reveals AMPK-mTOR-Autophagy Signaling Is Altered by Intrauterine Growth Restriction in Newborn Piglets.

Intrauterine growth restriction (IUGR) impairs fetal growth and development, perturbs nutrient metabolism, and increases the risk of developing diseases in postnatal life. However, the underlying mechanisms by which IUGR affects fetal liver development and metabolism remain incompletely understood. Here, we applied a high-throughput proteomics approach and biochemical analysis to investigate the impact of IUGR on the liver of newborn piglets. As a result, we identified 78 differentially expressed proteins in the three biological replicates, including 31 significantly up-regulated proteins and 47 significantly down-regulated proteins. Among them, a majority of differentially expressed proteins were related to nutrient metabolism and mitochondrial function. Additionally, many significantly down-regulated proteins participated in the mTOR signaling pathway and the phagosome maturation signaling pathway. Further analysis suggested that glucose concentration and hepatic glycogen storage were both reduced in IUGR newborn piglets, which may contribute to AMPK activation and mTORC1 inhibition. However, AMPK activation and mTORC1 inhibition failed to induce autophagy in the liver of IUGR neonatal pigs. A possible reason is that PP2Ac, a potential candidate in autophagy regulation, is significantly down-regulated in the liver of IUGR newborn piglets. These findings may provide implications for preventing and treating IUGR in human beings and domestic animals.

Quantitative proteomics analysis reveals glutamine deprivation activates fatty acid ß-oxidation pathway in HepG2 cells.

Glutamine, a multifunctional amino acid, functions in nutrient metabolism, energy balance, apoptosis, and cell proliferation. Lipid is an important nutrient and controls a broad range of physiological processes. Previous studies have demonstrated that glutamine can affect lipolysis and lipogenesis, but the effect of glutamine on the detailed lipid metabolism remains incompletely understood. Here, we applied the quantitative proteomics approach to estimate the relative abundance of proteins in HepG2 cells treated by glutamine deprivation. The results showed that there were 212 differentially abundant proteins in response to glutamine deprivation, including 150 significantly increased proteins and 62 significantly decreased proteins. Interestingly, functional classification showed that 43 differentially abundant proteins were related to lipid metabolism. Further bioinformatics analysis and western blotting validation revealed that lipid accumulation may be affected by ß-oxidation of fatty acid induced by glutamine deprivation in HepG2 cells. Together, our results may provide the potential for regulating lipid metabolism by glutamine in animal production and human nutrition. The MS data have been deposited to the ProteomeXchange Consortium with identifier PXD003387.

Multi-Omics Analysis Reveals Sphingomyelin Accumulation, Glycerolipids Loss, and Disorders of Lipid Metabolism Regulated by Leucine Deprivation in the Liver of Mice.

SCOPE: Branched-chain amino acids, especially leucine, have been reported to play a role in regulating lipid metabolism. This study aims to examine the effects of leucine deprivation on hepatic lipid metabolism. METHODS AND RESULTS: C57BL/6 mice are fed with a chow diet (control group, n = 8) or a leucine-free diet (-Leu group, n = 8) for 7 days. Histology, lipidomics, targeted metabolomics, and transcriptomics are performed to analyze the liver tissue. Compared to control group, -Leu group exhibits a notably reduced liver weight, accompanied by hepatic injury, and disorders of lipid metabolism. The level of sphingomyelin (SM) is significantly increased in the liver of -Leu group, while the glycerolipids (GL) level is significantly decreased. The expression of sphingomyelin synthase 1 (SGMS1) is upregulated by leucine deprivation in a time-dependent manner, leading to hepatic SM accumulation. Moreover, leucine deprivation results in hepatic GL loss via suppressing fatty acid synthase (FASN) and acetyl-CoA carboxylase 1 (ACC1) expression. CONCLUSION: The findings demonstrate that leucine deprivation results in abnormal lipid metabolism in the liver, mainly manifested as SM accumulation and GL loss. These results provide insights into the role of leucine in regulating lipid metabolism.

Characterizing the gut phageome and phage-borne antimicrobial resistance genes in pigs.

BACKGROUND: Mammalian intestine harbors a mass of phages that play important roles in maintaining gut microbial ecosystem and host health. Pig has become a common model for biomedical research and provides a large amount of meat for human consumption. However, the knowledge of gut phages in pigs is still limited. RESULTS: Here, we investigated the gut phageome in 112 pigs from seven pig breeds using PhaBOX strategy based on the metagenomic data. A total of 174,897 non-redundant gut phage genomes were assembled from 112 metagenomes. A total of 33,487 gut phage genomes were classified and these phages mainly belonged to phage families such as Ackermannviridae, Straboviridae, Peduoviridae, Zierdtviridae, Drexlerviridae, and Herelleviridae. The gut phages in seven pig breeds exhibited distinct communities and the gut phage communities changed with the age of pig. These gut phages were predicted to infect a broad range of 212 genera of prokaryotes, such as Candidatus Hamiltonella, Mycoplasma, Colwellia, and Lactobacillus. The data indicated that broad KEGG and CAZy functions were also enriched in gut phages of pigs. The gut phages also carried the antimicrobial resistance genes (ARGs) and the most abundant antimicrobial resistance genotype was diaminopyrimidine resistance. CONCLUSIONS: Our research delineates a landscape for gut phages in seven pig breeds and reveals that gut phages serve as a key reservoir of ARGs in pigs. Video Abstract.

Lactobacillus-derived protoporphyrin IX and SCFAs regulate the fiber size via glucose metabolism in the skeletal muscle of chickens.

The gut microbiota contributes to skeletal muscle energy metabolism and is an indirect factor affecting meat quality. However, the role of specific gut microbes in energy metabolism and fiber size of skeletal muscle in chickens remains largely unknown. In this study, we first performed cecal microbiota transplantation from Chinese indigenous Jingyuan chickens (JY) to Arbor Acres chickens (AA), to determine the effects of microbiota on skeletal muscle fiber and energy metabolism. Then, we used metagenomics, gas chromatography, and metabolomics analysis to identify functional microbes. Finally, we validated the role of these functional microbes in regulating the fiber size via glucose metabolism in the skeletal muscle of chickens through feeding experiments. The results showed that the skeletal muscle characteristics of AA after microbiota transplantation tended to be consistent with that of JY, as the fiber diameter was significantly increased, and glucose metabolism level was significantly enhanced in the pectoralis muscle. L. plantarum, L. ingluviei, L. salivarius, and their mixture could increase the production of the microbial metabolites protoporphyrin IX and short-chain fatty acids, therefore increasing the expression levels of genes related to the oxidative fiber type (MyHC SM and MyHC FRM), mitochondrial function (Tfam and CoxVa), and glucose metabolism (PFK, PK, PDH, IDH, and SDH), thereby increasing the fiber diameter and density. These three Lactobacillus species could be promising probiotics to improve the meat quality of chicken.IMPORTANCEThis study revealed that the L. plantarum, L. ingluviei, and L. salivarius could enhance the production of protoporphyrin IX and short-chain fatty acids in the cecum of chickens, improving glucose metabolism, and finally cause the increase in fiber diameter and density of skeletal muscle. These three microbes could be potential probiotic candidates to regulate glucose metabolism in skeletal muscle to improve the meat quality of chicken in broiler production.

Characterizing core microbiota and regulatory functions of the pig gut microbiome.

Domestic pigs (Sus scrofa) are the leading terrestrial animals used for meat production. The gut microbiota significantly affect host nutrition, metabolism, and immunity. Hence, characterization of the gut microbial structure and function will improve our understanding of gut microbial resources and the mechanisms underlying host-microbe interactions. Here, we investigated the gut microbiomes of seven pig breeds using metagenomics and 16S rRNA gene amplicon sequencing. We established an expanded gut microbial reference catalog comprising 17 020 160 genes and identified 4910 metagenome-assembled genomes. We also analyzed the gut resistome to provide an overview of the profiles of the antimicrobial resistance genes in pigs. By analyzing the relative abundances of microbes, we identified three core-predominant gut microbes (Phascolarctobacterium succinatutens, Prevotella copri, and Oscillibacter valericigenes) in pigs used in this study. Oral administration of the three core-predominant gut microbes significantly increased the organ indexes (including the heart, spleen, and thymus), but decreased the gastrointestinal lengths in germ-free mice. The three core microbes significantly enhanced intestinal epithelial barrier function and altered the intestinal mucosal morphology, as was evident from the increase in crypt depths in the duodenum and ileum. Furthermore, the three core microbes significantly affected several metabolic pathways (such as "steroid hormone biosynthesis," "primary bile acid biosynthesis," "phenylalanine, tyrosine and tryptophan biosynthesis," and "phenylalanine metabolism") in germ-free mice. These findings provide a panoramic view of the pig gut microbiome and insights into the functional contributions of the core-predominant gut microbes to the host.

Knowledge graph-derived feed efficiency analysis via pig gut microbiota.

Feed efficiency (FE) is essential for pig production, has been reported to be partially explained by gut microbiota. Despite an extensive body of research literature to this topic, studies regarding the regulation of feed efficiency by gut microbiota remain fragmented and mostly confined to disorganized or semi-structured unrestricted texts. Meanwhile, structured databases for microbiota analysis are available, yet they often lack a comprehensive understanding of the associated biological processes. Therefore, we have devised an approach to construct a comprehensive knowledge graph by combining unstructured textual intelligence with structured database information and applied it to investigate the relationship between pig gut microbes and FE. Firstly, we created the pgmReading knowledge base and the domain ontology of pig gut microbiota by annotating, extracting, and integrating semantic information from 157 scientific publications. Secondly, we created the pgmPubtator by utilizing PubTator to expand the semantic information related to microbiota. Thirdly, we created the pgmDatabase by mapping and combining the ADDAGMA, gutMGene, and KEGG databases based on the ontology. These three knowledge bases were integrated to form the Pig Gut Microbial Knowledge Graph (PGMKG). Additionally, we created five biological query cases to validate the performance of PGMKG. These cases not only allow us to identify microbes with the most significant impact on FE but also provide insights into the metabolites produced by these microbes and the associated metabolic pathways. This study introduces PGMKG, mapping key microbes in pig feed efficiency and guiding microbiota-targeted optimization.

YWHAE/14-3-3ε crotonylation regulates leucine deprivation-induced autophagy.

Macroautophagy/autophagy is an important process responsible for protein turnover and cell survival in amino acid-deprived conditions, especially for leucine (Leu). With the dramatic advances in mass spectrometry, many new post-translational modifications (PTMs) have been identified. However, whether these PTMs regulate autophagy remains unclear. Here we found global lysine crotonylation levels are significantly upregulated during Leu deprivation-induced autophagy. A comprehensive crotonylome profiling showed that YWHA/14-3-3 proteins are significantly enriched in the Leu regulated-crotonylome. The inhibition of YWHAE/14-3-3ε crotonylation by mutating two crotonylated sites to arginine, K73R K78R, significantly attenuates autophagy induced by Leu deprivation. Molecular dynamics suggest that YWHAE K73 and K78 crotonylations decrease protein conformation and thermodynamic stability. Moreover, we found crotonylation of YWHAE releases PPM1B to dephosphorylate ULK1 and consequently activate autophagy. Decrotonylation of YWHAE is mediated by HDAC7 whose activity is inhibited significantly by Leu deprivation. Taken together, our finding reveals a critical role of YWHAE crotonylation in Leu deprivation-induced autophagy.

Effects of Aeriscardovia aeriphila on growth performance, antioxidant functions, immune responses, and gut microbiota in broiler chickens. / Aeriscardovia aeriphilaå¯¹è‚‰é¸¡ç”Ÿé•¿æ€§èƒ½ã€æŠ—æ°§åŒ–åŠŸèƒ½ã€å ç–«åº”ç­”å’Œè‚ é“èŒç¾¤çš„å½±å“.

Aeriscardovia aeriphila, also known as Bifidobacterium aerophilum, was first isolated from the caecal contents of pigs and the faeces of cotton-top tamarin. Bifidobacterium species play important roles in preventing intestinal infections, decreasing cholesterol levels, and stimulating the immune system. In this study, we isolated a strain of bacteria from the duodenal contents of broiler chickens, which was identified as A. aeriphila, and then evaluated the effects of A. aeriphila on growth performance, antioxidant functions, immune functions, and gut microbiota in commercial broiler chickens. Chickens were orally gavaged with A. aeriphila (1×109 CFU/mL) for 21 d. The results showed that A. aeriphila treatment significantly increased the average daily gain and reduced the feed conversion ratio (P<0.001). The levels of serum growth hormone (GH) and insulin-like growth factor 1 (IGF-1) were significantly increased following A. aeriphila treatment (P<0.05). Blood urea nitrogen and aspartate aminotransferase levels were decreased, whereas glucose and creatinine levels increased as a result of A. aeriphila treatment. Furthermore, the levels of serum antioxidant enzymes, including catalase (P<0.01), superoxide dismutase (P<0.001), and glutathione peroxidase (P<0.05), and total antioxidant capacity (P<0.05) were enhanced following A. aeriphila treatment. A. aeriphila treatment significantly increased the levels of serum immunoglobulin A (IgA) (P<0.05), IgG (P<0.01), IgM (P<0.05), interleukin-1 (IL-1) (P<0.05), IL-4 (P<0.05), and IL-10 (P<0.05). The broiler chickens in the A. aeriphila group had higher secretory IgA (SIgA) levels in the duodenum (P<0.01), jejunum (P<0.001), and cecum (P<0.001) than those in the control group. The messenger RNA (mRNA) relative expression levels of IL-10 (P<0.05) and IL-4 (P<0.001) in the intestinal mucosa of chickens were increased, while nuclear factor-|κB (NF|-|κB) (P<0.001) expression was decreased in the A. aeriphila group compared to the control group. Phylum-level analysis revealed Firmicutes as the main phylum, followed by Bacteroidetes, in both groups. The data also found that Phascolarctobacterium and Barnesiella were increased in A. aeriphila-treated group. In conclusion, oral administration of A. aeriphila could improve the growth performance, serum antioxidant capacity, immune modulation, and gut health of broilers. Our findings may provide important information for the application of A. aeriphila in poultry production.

Effects of Aeriscardovia aeriphila on growth performance, antioxidant functions, immune responses, and gut microbiota in broiler chickens. / Aeriscardovia aeriphilaå¯¹è‚‰é¸¡ç”Ÿé•¿æ€§èƒ½ã€æŠ—æ°§åŒ–åŠŸèƒ½ã€å ç–«åº”ç­”å’Œè‚ é“èŒç¾¤çš„å½±å“.

Aeriscardovia aeriphila, also known as Bifidobacterium aerophilum, was first isolated from the caecal contents of pigs and the faeces of cotton-top tamarin. Bifidobacterium species play important roles in preventing intestinal infections, decreasing cholesterol levels, and stimulating the immune system. In this study, we isolated a strain of bacteria from the duodenal contents of broiler chickens, which was identified as A. aeriphila, and then evaluated the effects of A. aeriphila on growth performance, antioxidant functions, immune functions, and gut microbiota in commercial broiler chickens. Chickens were orally gavaged with A. aeriphila (1×109 CFU/mL) for 21 d. The results showed that A. aeriphila treatment significantly increased the average daily gain and reduced the feed conversion ratio (P<0.001). The levels of serum growth hormone (GH) and insulin-like growth factor 1 (IGF-1) were significantly increased following A. aeriphila treatment (P<0.05). Blood urea nitrogen and aspartate aminotransferase levels were decreased, whereas glucose and creatinine levels increased as a result of A. aeriphila treatment. Furthermore, the levels of serum antioxidant enzymes, including catalase (P<0.01), superoxide dismutase (P<0.001), and glutathione peroxidase (P<0.05), and total antioxidant capacity (P<0.05) were enhanced following A. aeriphila treatment. A. aeriphila treatment significantly increased the levels of serum immunoglobulin A (IgA) (P<0.05), IgG (P<0.01), IgM (P<0.05), interleukin-1 (IL-1) (P<0.05), IL-4 (P<0.05), and IL-10 (P<0.05). The broiler chickens in the A. aeriphila group had higher secretory IgA (SIgA) levels in the duodenum (P<0.01), jejunum (P<0.001), and cecum (P<0.001) than those in the control group. The messenger RNA (mRNA) relative expression levels of IL-10 (P<0.05) and IL-4 (P<0.001) in the intestinal mucosa of chickens were increased, while nuclear factor-|κB (NF|-|κB) (P<0.001) expression was decreased in the A. aeriphila group compared to the control group. Phylum-level analysis revealed Firmicutes as the main phylum, followed by Bacteroidetes, in both groups. The data also found that Phascolarctobacterium and Barnesiella were increased in A. aeriphila-treated group. In conclusion, oral administration of A. aeriphila could improve the growth performance, serum antioxidant capacity, immune modulation, and gut health of broilers. Our findings may provide important information for the application of A. aeriphila in poultry production.

Lactobacillus gasseri LA39 promotes hepatic primary bile acid biosynthesis and intestinal secondary bile acid biotransformation. / æ ¼æ°ä¹³é ¸æ†èŒLA39ä¿ƒè¿›äº†è‚è„åˆçº§èƒ†æ±é ¸çš„ç”Ÿç‰©åˆæˆå’Œè‚ é“æ¬¡çº§èƒ†æ±é ¸çš„ç”Ÿç‰©è½¬åŒ–.

A growing body of evidence has linked the gut microbiota to liver metabolism. The manipulation of intestinal microflora has been considered as a promising avenue to promote liver health. However, the effects of Lactobacillus gasseri LA39, a potential probiotic, on liver metabolism remain unclear. Accumulating studies have investigated the proteomic profile for mining the host biological events affected by microbes, and used the germ-free (GF) mouse model to evaluate host-microbe interaction. Here, we explored the effects of L. gasseri LA39 gavage on the protein expression profiles of the liver of GF mice. Our results showed that a total of 128 proteins were upregulated, whereas a total of 123 proteins were downregulated by treatment with L. gasseri LA39. Further bioinformatics analyses suggested that the primary bile acid (BA) biosynthesis pathway in the liver was activated by L. gasseri LA39. Three differentially expressed proteins (cytochrome P450 family 27 subfamily A member 1 (CYP27A1), cytochrome P450 family 7 subfamily B member 1 (CYP7B1), and cytochrome P450 family 8 subfamily B member 1 (CYP8B1)) involved in the primary BA biosynthesis pathway were further validated by western blot assay. In addition, targeted metabolomic analyses demonstrated that serum and fecal ß|-muricholic acid (a primary BA), dehydrolithocholic acid (a secondary BA), and glycolithocholic acid-3-sulfate (a secondary BA) were significantly increased by L. gasseri LA39. Thus, our data revealed that L. gasseri LA39 activates the hepatic primary BA biosynthesis and promotes the intestinal secondary BA biotransformation. Based on these findings, we suggest that L. gasseri LA39 confers an important function in the gut‒liver axis through regulating BA metabolism.

Butyrate Improves Porcine Endometrial Epithelial Cell Receptivity via Enhancing Acetylation of Histone H3K9.

SCOPE: Uterine receptivity is a major restriction of embryo implantation and survival, and the endometrial luminal epithelium serves as the transient gateway for uterine receptivity and embryo implantation. Butyrate is reported to promote the success of embryo implantation, but the effects and mechanism of butyrate on uterine receptivity are still unknown. METHODS AND RESULTS: Porcine endometrial epithelial cells (PEECs) are used as a model, and the cellular receptivity changes, metabolism, and gene expression profiles influenced by butyrate are analyzed. The study finds that butyrate improves receptive changes in PEECs, including inhibiting proliferation, exhibiting more pinocytosis on the cell surface, and increasing adhesiveness to porcine trophoblast cells. In addition, butyrate increases prostaglandin synthesis and markedly impacts purine metabolism, pyrimidine metabolism, and the FoxO signaling pathway. siRNA to inhibit the expression of FoxO1 and chromatin immunoprecipitation-sequencing (ChIP-seq) of H3K9ac are used to demonstrate that the H3K9ac/FoxO1/PCNA pathway can contribute to the effects of cell proliferation inhibition and uterine receptivity improvement induced by butyrate. CONCLUSION: The findings reveal that butyrate improves endometrial epithelial cell receptivity by enhancing the acetylation of histone H3K9, which shows nutritional regulation and therapeutic potential for poor uterine receptivity and difficulty in embryo implantation.

Gut microbiota-derived 3-phenylpropionic acid promotes intestinal epithelial barrier function via AhR signaling.

BACKGROUND: The intestinal epithelial barrier confers protection against the intestinal invasion by pathogens and exposure to food antigens and toxins. Growing studies have linked the gut microbiota to the intestinal epithelial barrier function. The mining of the gut microbes that facilitate the function of intestinal epithelial barrier is urgently needed. RESULTS: Here, we studied a landscape of the gut microbiome of seven pig breeds using metagenomics and 16S rDNA gene amplicon sequencing. The results indicated an obvious difference in the gut microbiome between Congjiang miniature (CM) pigs (a native Chinese breed) and commercial Duroc × [Landrace × Yorkshire] (DLY) pigs. CM finishing pigs had stronger intestinal epithelial barrier function than the DLY finishing pigs. Fecal microbiota transplantation from CM and DLY finishing pigs to germ-free (GF) mice transferred the intestinal epithelial barrier characteristics. By comparing the gut microbiome of the recipient GF mice, we identified and validated Bacteroides fragilis as a microbial species that contributes to the intestinal epithelial barrier. B. fragilis-derived 3-phenylpropionic acid metabolite had an important function on the enhancement of intestinal epithelial barrier. Furthermore, 3-phenylpropionic acid facilitated the intestinal epithelial barrier by activating aryl hydrocarbon receptor (AhR) signaling. CONCLUSIONS: These findings suggest that manipulation of B. fragilis and 3-phenylpropionic acid is a promising strategy for improving intestinal epithelial barrier. Video Abstract.

Identification of gut microbes associated with feed efficiency by daily-phase feeding strategy in growing-finishing pigs.

Feed efficiency is one of the most important issues for sustainable pig production. Daily-phase feeding (DPF) is a form of precision feeding that could improve feed efficiency in pigs. Gut microbiota can regulate host nutrient digestion, absorption, and metabolism. However, which key microbes may play a vital role in improving the feed efficiency during DPF remains unclear. In the present study, we used a DPF program compared to a three-phase feeding (TPF) program in growing-finishing pigs to investigate the effects of gut microbiota on feed efficiency. A total of 204 Landrace × Yorkshire pigs (75 d) were randomly assigned into 2 treatments. Each treatment was replicated 8 times with 13 to 15 pigs per replicate pen. Pigs in the TPF group were fed with a commercial feeding program that supplied fixed feed for phases I, II, and III, starting at 81, 101, and 132 d of age, respectively, and pigs in the DPF group were fed a blend of adjacent phase feed from 81 to 155 d at a gradual daily ratio and phase III feed from 155 to 180 d of age. Daily feed intake and body weight were recorded by a computerized device in the feeders. Feces and blood samples were collected from 1 pig per replicate at 155 and 180 d of age. The results showed that the DPF program remarkably improved the feed efficiency at 155 d (P < 0.001) and 180 d of age (P < 0.001), with a significant reduction of the intake of crude protein (P < 0.01), net energy (P < 0.001), crude fiber (P < 0.001), ether extract (P < 0.01), and ash (P < 0.001). The daily-phase feeding program increased the abundance of Prevotella copri (P < 0.05) and Paraprevotella clara (P < 0.05), while it decreased the abundance of Ocilibacter (P < 0.05) at 155 d of age. The results of correlation analysis indicated that the differentially abundant microbiota communities were closely associated with 20 metabolites which enriched amino acid and phenylalanine metabolism. Our results suggest that 2 key microbes may contribute to feed efficiency during daily-phase feeding strategies in pigs.

Point-of-care testing for lysine concentration in swine serum via blue-emissive carbon dot-entrapped microfluidic chip.

Lysine is one of the essential amino acids and plays a vital role in the growth, development and health of pigs. Blood lysine concentration is a direct indication of lysine status; however, current methods can not satisfy the demands for rapid and on-site lysine concentration measurement of swine serum. Here, we developed blue-emissive nitrogen-doped carbon dots as a fluorescence probe for the determination of lysine with high fluorescence quantum yield, stability, sensitivity and specificity. The carbon dots were entrapped within hydrogel microstructures to fabricate microfluidic chips for rapid assay for lysine quantification. We further developed an imaging attachment to integrate the microfluidic chip and a smartphone into a portable point-of-care testing platform. This platform requires only 3 µL sample and has a linear detection range of 25 to 300 µmol/L with a limit of detection less than 16 µmol/L, which covers the normal range of lysine concentration in swine serum. We tested lysine concentration in swine serum using this platform with high accuracy, low sample consumption, and within 3 min. Together, these results may provide a rapid and portable platform for dynamic monitoring of swine lysine status and contribute to precise feed formula modulation with low-protein diet strategy.