Altered gut microbiome associated with metabolic-associated fatty liver disease in Chinese children.

BACKGROUND & AIM: Limited studies have investigated the association between gut microbiota and metabolic dysfunction-associated fatty liver disease (MAFLD) in children and adolescents. We aimed to identify differences in gut microbiota composition and diversity between children with MAFLD and healthy counterparts. METHODS: Data were collected from a nested case-control study (October to December, 2021) of the "Huantai Childhood Cardiovascular Health Cohort Study" in Huantai County, Zibo City, China. The study included 52 children aged 5-11 years with new-onset MAFLD and 52 healthy children matched by age and sex. Stool samples were collected and analyzed using 16S rRNA gene sequencing. Shannon index and Chao index were used to assess the α diversity of gut microbiota and Principal coordinates analysis (PCoA) was performed to evaluate ß diversity between the two groups. The differences in the relative abundance of gut microbiota between MAFLD group and control group were compared by the Wilcoxon rank-sum test after false discovery rate (FDR) correction. Additionally, the gut-microbial metabolic pathways were identified using the phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt). RESULTS: We found that children with MAFLD had significant different gut microbiota composition and reduced α diversity compared with the control group. PCoA showed that the two groups can be significantly distinguished based on the unweighted unifrac distance algorithm. Gut microbiota at the phylum level such as Verrucomicrobia and Desulfobacterial, genus level such as Blautia, Lachnospiraceae_NK4A136_group, Coprococcus, Erysipelotrichaceae_UCG-003, UCG-002 and Akkermansia, and species level such as Bifidobacterium_longum abundances were significantly decreased in children with MAFLD compared with that in children without MAFLD. Notably, the abundance of these bacteria were found to be associated with HDL-C, SBP, DBP, WC, BMI, etc. In addition, our analysis of gut-microbial metabolic pathways identified differences in carbohydrate transport and metabolism, as well as amino acid transport and metabolism between the two groups. CONCLUSION: Significant differences in gut microbiota composition are observed between children with and without MAFLD, which indicate that gut microbiota may be a potential contributor to the development of MAFLD in childhood.

CLA improves the lipo-nutritional quality of pork and regulates the gut microbiota in Heigai pigs.

Conjugated linoleic acid (CLA) is a potential nutritional strategy to regulate meat quality in pigs and produce high-quality pork. However, the effects of CLA on nutritional quality, lipid dynamics, microbiota, and their metabolites in the gut of pigs remain unclear. Our study explored the effects of CLA on lipo-nutritional quality based on a Heigai pig model and investigated the regulatory mechanism using an integrated analysis of multiple omics. A total of 58 Heigai finishing pigs (body weight: 85.58 ± 10.39 kg) were randomly divided into 2 treatments and fed diets containing 1% soyabean oil and 1% CLA for 40 days. 1% CLA significantly decreased the backfat thickness (P < 0.05) and increased the intramuscular fat (IMF) content (P < 0.05). The expression of lipid metabolism-related genes was significantly changed (P < 0.05) and lipidome analysis showed the alternations of lipid dynamics in the longissimus dorsi muscle (LDM). In addition, based on the microbiome and metabolomic analyses, the relative abundances of Parabacteroides, Bacteroides, and Lachnospiraceae_UCG-010 increased and CLA changed the metabolome profiles and the short-chain fatty acid (SCFA) composition in the gut, which were significantly increased (P < 0.05). Additionally, Pearson's correlation analysis indicated that differential microbial genera and SCFAs induced by CLA had tight correlations with the backfat thickness, IMF content and lipids in the LDM. CLA enhances the lipid accumulation and metabolism in muscle and these changes are associated with the production and functions of the differential bacteria and SCFAs in the gut of pigs.

Effects of alfalfa levels on carcass traits, meat quality, fatty acid composition, amino acid profile, and gut microflora composition of Heigai pigs.

Recent years have witnessed a dramatic increase in the demand for healthy and high-quality pork. Alfalfa, one of the most popular perennial forages, is considered a rich source of highly nutritional forage for livestock feed, as it contains over 90% insoluble dietary fiber. Nevertheless, there is a paucity of data confirming the effects of adding alfalfa on pork quality, amino acid composition, and intestinal microbiota composition. Therefore, the objective of this study was to investigate the effects of different dietary levels of alfalfa on carcass traits, meat quality, amino acid and fatty acid composition, and the intestinal microbiota of Heigai pigs. A total of 72 finishing Heigai pigs were randomly assigned to two groups (n = 36), with six replicate groups and six pigs per replication. The two experimental diets were formulated to include graded levels of alfalfa, 20% (AM20) and 30% (AM30). The results showed that adding 30% alfalfa meal did not affect the growth performance of Heigai pigs but significantly reduced backfat thickness (P < 0.05), pH (P < 0.05), increased the a* value, b* value, and flavor amino acid and essential amino acid contents in longissimus dorsi muscle (LDM). In addition, AM30 didn't affect colonic microbiota abundance but significantly reduced the relative abundances of three phyla, such as Verrucomicrobia, and 43 genera, such as Akkermansia, and significantly increased the relative abundances of 47 genera, such as Prevotella-2. Overall, these results advocate for a diet containing 30% alfalfa to improve meat quality by changing the intestinal microflora composition without affecting the growth performance of Heigai pigs, which provides compelling evidence for the use of alfalfa to relieve the pressure on corn and soybean meal demand and produce high-quality pork.

Changes in Serum Fatty Acid Composition and Metabolome-Microbiome Responses of Heigai Pigs Induced by Dietary N-6/n-3 Polyunsaturated Fatty Acid Ratio.

Changing fatty acid composition is a potential nutritional strategy to shape microbial communities in pigs. However, the effect of different n-6/n-3 polyunsaturated fatty acid (PUFA) ratios on serum fatty acid composition, microbiota, and their metabolites in the intestine of pigs remains unclear. Our study investigated the changes in serum fatty acid composition and metabolome-microbiome responses induced by dietary n-6/n-3 PUFA ratio based on a Heigai-pig model. A total of 54 Heigai finishing pigs (body weight: 71.59 ± 2.16 kg) fed with 3 types of diets (n-6/n-3 PUFA ratios are 8:1, 5:1, and 3:1) were randomly divided into 3 treatments with 6 replications (3 pigs per replication) for 75 days. Results showed that dietary n-6/n-3 PUFA ratio significantly affected biochemical immune indexes including glucose (Glu), triglycerides (TG), total cholesterol (TChol), non-esterified fatty acid (NEFA), high-density lipoprotein (HDL), low-density lipoprotein (LDL), and total thyroxine (TT4), and medium- and long-chain fatty acid composition, especially n-3 PUFA and n-6/n-3 PUFA ratio in the serum. However, no significant effects were found in the SCFAs composition and overall composition of the gut microbiota community. In the low dietary n-6/n-3 PUFA ratio group, the relative abundance of Cellulosilyticum, Bacteroides, and Alloprevotella decreased, Slackia and Sporobacter increased. Based on the metabolomic analysis, dietary n-6/n-3 PUFA ratio altered the metabolome profiles in the colon. Moreover, Pearson's correlation analysis indicated that differential microbial genera and metabolites induced by different n-6/n-3 PUFA ratio had tight correlations and were correlated with the n-6 PUFA and n-3 PUFA content in longissimus dorsi muscle (LDM) and subcutaneous adipose tissue (SAT). Taken together, these results showed that lower dietary n-6/n-3 PUFA ratio improved serum fatty acid composition and metabolome-microbiome responses of Heigai pigs and may provide a new insight into regulating the metabolism of pigs and further better understanding the crosstalk with host and microbes in pigs.

Cold Exposure Induces Depot-Specific Alterations in Fatty Acid Composition and Transcriptional Profile in Adipose Tissues of Pigs.

Cold exposure promotes fat oxidation and modulates the energy metabolism in adipose tissue through multiple mechanisms. However, it is still unclear about heat-generating capacity and lipid mobilization of different fat depots without functional mitochondrial uncoupling protein 1 (UCP1). In this study, we kept finishing pigs (lack a functional UCP1 gene) under cold (5-7°C) or room temperature (22-25°C) and determined the effects of overnight cold exposure on fatty acid composition and transcriptional profiles of subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT). And the plasma metabolomes of porcine was also studied by LC-MS-based untargeted metabolomics. We found that the saturated fatty acids (SFAs) content was decreased in SAT upon cold exposure. While in VAT, the relative content of lauric acid (C12:0), myristic acid (C14:0) and lignoceric acid (C24:0) were decreased without affecting total SFA content. RNA-seq results showed SAT possess active organic acid metabolism and energy mobilization upon cold exposure. Compared with SAT, cold-induced transcriptional changes were far less broad in VAT, and the differentially expressed genes (DEGs) were mainly enriched in fat cell differentiation and cell proliferation. Moreover, we found that the contents of organic acids like creatine, acamprosate, DL-3-phenyllactic acid and taurine were increased in plasma upon overnight cold treatment, suggesting that cold exposure induced lipid and fatty acid metabolism in white adipose tissue (WAT) might be regulated by functions of organic acids. These results provide new insights into the effects of short-term cold exposure on lipid metabolism in adipose tissues without functional UCP1.

Cold Exposure Affects Lipid Metabolism, Fatty Acids Composition and Transcription in Pig Skeletal Muscle.

Cold exposure promotes glucose oxidation and modulates the lipid metabolism in adipose tissue, but it is still not fully clear whether cold exposure could affect meat quality and fatty acid metabolism in skeletal muscle of pig in vivo. Here, we kept finishing pigs under cold or room temperature overnight and determined the effects of cold exposure on meat quality, fatty acids composition and transcriptional changes in skeletal muscle of pigs. We found that cold exposure significantly reduced the meat colour24 h and pH24 h, without affecting carcass characteristics and other meat quality traits. Considerable changes were found in the proportions of individual fatty acids and the total content of saturated fatty acid, polyunsaturated fatty acids, monounsaturated fatty acid and n3-fatty acids. RNA-seq results showed upregulated fatty acid biosynthesis genes and downregulated mitochondrial beta-oxidation genes. The lipid metabolism in cold-treated longissimus dorsi muscle might be regulated by functions of the lipoprotein particle, the extracellular matrix, and the PPAR signaling pathways. Our study revealed the potential of cold exposure to regulate the lipid metabolism and fatty acid composition in skeletal muscle of farmed animals.

The Effect of Rearing Conditions on Carcass Traits, Meat Quality and the Compositions of Fatty Acid and Amino Acid of LTL in Heigai Pigs.

The present study evaluates the influence of captivity and grazing rearing conditions on the carcass traits, meat quality and fatty acid profiles of Heigai pigs. Ten Heigai pigs with market weight were randomly selected from both the indoor feeding farm and outdoor grazing farm groups (FF and GF; five pigs per group) for measuring production performance. The results showed that the shear force of longissimus thoracis et lumborum (LTL) in the GF group tended to increase (p = 0.06), and triglyceride and cholesterol contents in LTL and psoas major muscle (PMM) of the GF group significantly increased and decreased, respectively (p < 0.05). The proportion of saturated fatty acids (SFA) was significantly increased (p < 0.05) in the GF group. Meanwhile, the ratios of unsaturated fatty acid (UFA), polyunsaturated fatty acid (PUFA), monounsaturated fatty acid (MUFA) and the content of flavor amino acid of the LTL in the GF group were significantly decreased (p < 0.05). The GF upregulated the expression of MyHC-IIb and lipogenic genes, such as GLUT4 and LPL (p < 0.05), in LTL and PMM, but downregulated the expression of MyHC-I, MyHC-IIa, PPARγ and leptin (p < 0.05). In conclusion, these results suggested that the different rearing conditions can alter the meat qualities by mediating the muscle fiber type and lipid metabolism of Heigai pigs.

Low Dietary n-6/n-3 PUFA Ratio Regulates Meat Quality, Reduces Triglyceride Content, and Improves Fatty Acid Composition of Meat in Heigai Pigs.

The objective of this study was to investigate the effects of dietary supplementation with different n-6/n-3 polyunsaturated fatty acid (PUFA) ratios on growth performance, meat quality, and fatty acid profile in Heigai pigs. A total of 54 Heigai finishing pigs (body weight: 71.59 ± 2.16 kg) were randomly divided into three treatments with six replications (three pigs per replication) and fed diets containing different n-6/n-3 PUFA ratios: 8:1, 5:1, and 3:1. Pigs fed the dietary n-6/n-3 PUFA ratio of 8:1 had the highest feed to gain ratio (p < 0.01), carcass weight (p < 0.05), redness a* (p < 0.01), and yellowness b* (p < 0.01). Fatty acid compositions in longissimus dorsi muscle (LDM) and subcutaneous adipose tissue (SAT) were significantly changed (p < 0.01). Notably, the meat from the pigs fed with the low dietary n-6/n-3 PUFA ratio had higher n-3 PUFA contents (p < 0.01) and lower n-6/n-3 PUFA ratio (p < 0.01). The triglyceride and total cholesterol contents were significantly decreased in SAT from the pigs fed with dietary n-6/n-3 PUFA ratios of 5:1 (p < 0.05) and 3:1 (p < 0.01). Reducing n-6/n-3 PUFA ratio upregulated the expression of HSL (p < 0.05), CPT1 (p < 0.01), and FABP4 (p < 0.01) but downregulated ATGL (p < 0.01) expression. These results demonstrate that the lower n-6/n-3 PUFA ratio regulates meat quality and enhances the deposition of n-3 PUFA in Heigai pigs.

Upregulation of activator protein-4 in human colorectal cancer with metastasis.

The aim of this study is to investigate the expression of AP-4, VEGF, and MMP-9 genes in human colorectal cancer. The expression pattern of activator protein-4 in 160 colorectal cancer compared with 32 colorectal adenomas and 32 normal colorectal tissues is demonstrated by tissue microarray-immunohistochemistry and real-time reverse transcriptase-polymerase chain reaction. Apoptosis status using terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling by comparing activator protein-4 positive versus activator protein-4 negative colorectal cancer is also assessed. The messenger RNA levels of vascular endothelial growth factor and matrix metalloproteinase-9 expression in activator protein-4 positive and negative colorectal cancer were measured using real-time reverse transcriptase- polymerase chain reaction. The activator protein-4 expression in normal colorectal tissue, adenoma, and adenocarcinoma were 4 of 32, 8 of 32, and 78 of 160, respectively. It is shown that the activator protein-4 expression was significantly correlated with the progression of colorectal cancer (P < .01) and differentiation and lymph node metastasis (P < .01). Our results also presented that the activator protein-4 expression was associated with the expression of matrix metalloproteinase-9 and vascular endothelial growth factor in the advanced colorectal cancer.