Publications by authors named "Yingdong Ni"

58 Publications

Elevated thyroid hormones caused by high concentrate diets participate in hepatic metabolic disorders in dairy cows.

Anim Biosci 2022 Jan 5. Epub 2022 Jan 5.

Laboratory of Gastrointestinal Microbiology, Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.

Objective: High concentrate diets are widely used to satisfy high-yielding dairy cows; however, long-term feeding of high concentrate diets can cause subacute ruminal acidosis (SARA). The endocrine disturbance is one of the important reasons for metabolic disorders caused by SARA. However, there is no current report about thyroid hormones involved in liver metabolic disorders induced by a high concentrate diet.

Methods: In this study, 12 mid-lactating dairy cows were randomly assigned to HC group (60% concentrate of dry matter, n = 6) and LC group (40% concentrate of dry matter, n = 6). All cows were slaughtered on the 21st day, and the samples of blood and liver were collected to analyze the blood biochemistry, histological changes, thyroid hormones, and the expression of genes and proteins.

Results: Compared with LC group, HC group showed decreased serum triglyceride (TG), free fatty acid (FFA), total cholesterol (TC), low-density lipoprotein (LDL-C), increased hepatic glycogen, and glucose. For glucose metabolism, the gene and protein expression of glucose-6-phosphatase and phosphoenolpyruvate carboxykinase 1 in the liver were significantly up-regulated in HC group. For lipid metabolism, the expression of sterol regulatory element-binding protein 1, long-chain acyl-CoA synthetase 1, and fatty acid synthase in the liver was decreased in HC group, whereas carnitine palmitoyltransferase 1α and peroxisome proliferator activated receptor α were increased. Serum triiodothyronine, thyroxin, free triiodothyronine (FT3), and hepatic FT3 increased in HC group, accompanied by increased expression of thyroid hormone receptor (THR) in the liver.

Conclusion: Taken together, thyroid hormones may increase hepatic gluconeogenesis, β-oxidation and reduce fatty acid synthesis through the THR pathway to participate in the metabolic disorders caused by a high concentrate diet.
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http://dx.doi.org/10.5713/ab.21.0397DOI Listing
January 2022

Whole transcriptome analysis of RNA expression profiles reveals the potential regulating action of long noncoding RNA in lactating cows fed a high concentrate diet.

Anim Nutr 2021 Dec 12;7(4):1315-1328. Epub 2021 Oct 12.

Key Laboratory of Animal Physiology & Biochemistry, Nanjing Agricultural University, Nanjing 210095, China.

Subacute ruminal acidosis (SARA) is a common metabolic disease in the dairy farming industry which is usually caused by an excessive amount of high concentrate diet. SARA not only threatens animal welfare but also leads to economic losses in the farming industry. The liver plays an important role in the distribution of nutritional substances and metabolism; however, a high concentrate diet can cause hepatic metabolic disorders and liver injury. Recently, noncoding RNA has been considered as a critical regulator of hepatic disease, however, its role in the bovine liver is limited. In this study, 12 mid-lactating dairy cows were randomly assigned to a control (CON) group (40% concentrate of dry matter,  = 6) and a SARA group (60% concentrate of dry matter,  = 6). After 21 d of treatment, all cows were sacrificed, and liver tissue samples were collected. Three dairy cows were randomly selected from the CON and SARA groups respectively to perform whole transcriptome analysis. More than 20,000 messenger RNA (mRNA), 10,000 long noncoding RNA (lncRNA), 3,500 circular RNA (circRNA) and 1,000 micro RNA (miRNA) were identified. Furthermore, 43 mRNA, 121 lncRNA and 3 miRNA were differentially expressed, whereas no obvious differentially expressed circRNA were detected between the 2 groups. Gene Ontology (GO) annotation revealed that the differentially expressed genes were mainly enriched in oxidoreductase activity, stress, metabolism, the immune response, cell apoptosis, and cell proliferation. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that the deferentially expressed genes were highly enriched in the phosphatidylinositol 3 kinase ()serine/threonine kinase () signaling pathway ( < 0.05). According to KEGG pathway analysis, the differentially expressed lncRNA (DElncRNA) target genes were mainly related to proteasomes, peroxisomes, and the hypoxia-inducible factor-1 signaling pathway ( < 0.005). Further bioinformatics and integrative analyses revealed that the lncRNA were strongly correlated with mRNA; therefore, it is reasonable to speculate that lncRNA potentially play important roles in the liver dysfunction induced by SARA. Our study provides a valuable resource for future investigations on the mechanisms of SARA to facilitate an understanding of the importance of lncRNA, and offer functional RNA information.
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http://dx.doi.org/10.1016/j.aninu.2021.10.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8567331PMC
December 2021

α-Lipoic Acid Alleviates Hepatic Lipid Deposition by Inhibiting FASN Expression via miR-3548 in Rats.

Nutrients 2021 Jul 8;13(7). Epub 2021 Jul 8.

Key Laboratory of Animal Physiology and Biochemistry, Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China.

Excessive liver lipid deposition is a vital risk factor for the development of many diseases. Here, we fed Sprague-Dawley rats with a control or α-lipoic acid-supplemented diet (0.2%) for 5 weeks to elucidate the effects of α-lipoic acid on preventive ability, hepatic lipid metabolism-related gene expression, and the involved regulatory mechanisms. In the current study, α-lipoic acid supplementation lowered plasma triglyceride level and hepatic triglyceride content. Reduced hepatic lipid deposition was closely associated with inhibiting fatty acid-binding protein 1 and fatty acid synthase expression, as well as increasing phosphorylated hormone-sensitive lipase expression at the protein level in α-lipoic acid-exposed rats. Hepatic miRNA sequencing revealed increased expression of miR-3548 targeting the 3'untranslated region of Fasn mRNA, and the direct regulatory link between miRNA-3548 and FASN was verified by dual-luciferase reporter assay. Taken together, α-lipoic acid lowered hepatic lipid accumulation, which involved changes in miRNA-mediated lipogenic genes.
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http://dx.doi.org/10.3390/nu13072331DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8308747PMC
July 2021

Chronic Variable Stress Induces Hepatic Fe(II) Deposition by Up-Regulating ZIP14 Expression via miR-181 Family Pathway in Rats.

Biology (Basel) 2021 Jul 12;10(7). Epub 2021 Jul 12.

Key Laboratory of Animal Physiology and Biochemistry, Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China.

It is well-known that hepatic iron dysregulation, which is harmful to health, can be caused by stress. The aim of the study was to evaluate chronic variable stress (CVS) on liver damage, hepatic ferrous iron deposition and its molecular regulatory mechanism in rats. Sprague Dawley rats at seven weeks of age were randomly divided into two groups: a control group (Con) and a CVS group. CVS reduces body weight, but increases the liver-to-body weight ratio. The exposure of rats to CVS increased plasma aspartate aminotransferase (AST), alkaline phosphatase (ALP) and hepatic malondialdehyde (MDA) levels, but decreased glutathione peroxidase (GSH-Px) activity, resulting in liver damage. CVS lowered the total amount of hepatic iron content, but induced hepatic Fe(II) accumulation. CVS up-regulated the expression of transferrin receptor 1 (TFR1) and ZRT/IRT-like protein 14 (ZIP14), but down-regulated ferritin and miR-181 family members. In addition, miR-181 family expression was found to regulate ZIP14 expression in HEK-293T cells by the dual-luciferase reporter system. These results indicate that CVS results in liver damage and induces hepatic Fe(II) accumulation, which is closely associated with the up-regulation of ZIP14 expression via the miR-181 family pathway.
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http://dx.doi.org/10.3390/biology10070653DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8301360PMC
July 2021

Glucocorticoid receptors involved in melatonin inhibiting cell apoptosis and NLRP3 inflammasome activation caused by bacterial toxin pyocyanin in colon.

Free Radic Biol Med 2021 01 12;162:478-489. Epub 2020 Nov 12.

Key Laboratory of Animal Physiology & Biochemistry, Nanjing Agricultural University, Nanjing, 210095, PR China. Electronic address:

The immunoinhibitory effect of glucocorticoid and immunoenhancing attributes of melatonin (MEL) are well known, however, the involvement of glucocorticoid receptor (GR) in melatonin modulation of bacterial toxins caused-inflammation has not been studied in colon. Pyocyanin (PCN), a toxin released by Pseudomonas aeruginosa, can destroy cells through generating superoxide products and inflammatory response. Here we report that PCN treatment elevated the generation of reactive oxygen species (ROS), which further lead to mitochondrial swelling and caspase cascades activation both in vivo and in vitro. However, MEL treatment alleviated the oxidative stress caused by PCN on cells through scavenging ROS and restoring the expression of antioxidant enzyme so that to effectively alleviate the apoptosis. Large amounts of ROS can activate the NLRP3 signaling pathway, so MEL inhibited PCN induced NLRP3 inflammasome activation and inflammatory cytokines (IL-1β, IL-8, and TNF-α) secretion. In order to further investigate the molecular mechanism, goblet cells were exposed to MEL and PCN in the presence of luzindole and RU486, inhibitors of MEL receptors and GR respectively. It was found that PCN significantly inhibited the expression level of GR, and MEL effectively alleviated the inhibition phenomenon. Moreover, we found that MEL mainly upregulated the expression of GR to achieve its anti-inflammatory and anti-apoptotic functions rather than through its own receptor (MT2) in colon goblet cells. Therefore, MEL can reverse the inhibitory effects of PCN on GR/p-GR expression to present its anti-oxidative and anti-apoptotic function.
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http://dx.doi.org/10.1016/j.freeradbiomed.2020.11.003DOI Listing
January 2021

Hepatic Inflammatory Response to Exogenous LPS Challenge is Exacerbated in Broilers with Fatty Liver Disease.

Animals (Basel) 2020 Mar 19;10(3). Epub 2020 Mar 19.

Key Laboratory of Animal Physiology & Biochemistry, Nanjing Agricultural University, Nanjing 210095, China.

This study aimed to examine hepatic function and inflammatory response in broilers with fatty livers, following acute lipopolysaccharide (LPS) challenge. One-day-old Lihua yellow broilers were fed a basal diet. Broilers were divided into four groups: control (CON), corticosterone treatment (CORT), LPS treatment (LPS), and LPS and CORT treatment (LPS&CORT). Results show that CORT induced an increase in plasma and liver triglycerides (TGs), which were accompanied by severe hepatic steatosis. The LPS group showed hepatocyte necrosis with inflammatory cell infiltration. Total liver damage score in the LPS&CORT group was significantly higher than that in the LPS group ( < 0.05). Activity levels of plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were similar in the CON and CORT groups, but higher in the LPS group. Gene expression upregulation of the proinflammatory cytokines (NF-κB, IL-1β, IL-6, IFN-γ, and iNOS) was also noted in the LPS group ( < 0.05). In particular, LPS injection exacerbated the gene expression of these proinflammatory cytokines, even when accompanied by CORT injections ( < 0.05). In summary, our results indicate that broilers suffering from fatty liver disease are more susceptible to the negative effects of LPS, showing inflammatory response activation and more severe damages to the liver.
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http://dx.doi.org/10.3390/ani10030514DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7143745PMC
March 2020

Repeated Restraint Stress Enhances Hepatic TFR2 Expression and Induces Hepatic Iron Accumulation in Rats.

Biol Trace Elem Res 2020 Aug 9;196(2):590-596. Epub 2019 Nov 9.

Key Laboratory of Animal Physiology and Biochemistry, College of Veterinary Medicine, Nanjing Agricultural University, No. 1 Weigang Road, Nanjing, 210095, Jiangsu, People's Republic of China.

Abnormal hepatic iron metabolism is detrimental to health. The objective of this study was to detect repeated restraint stress on liver iron metabolism in rats. Twenty-four male rats aged 7 weeks were randomly divided into 2 groups: control group (Con) and repeated restraint stress group (RS). Rats were subjected to 6 h of daily restraint stress for 14 consecutive days in the repeated restraint stress group. The results showed that repeated restraint stress exposure decreased growth performance including impaired final weight (P = 0.07), reducing average daily gain (P = 0.01), and average daily feed intake (P = 0.00) during the 14-day experimental period. Repeated restraint stress exposure did not affect hemoglobin content and plasma iron parameters except downregulated unsaturated iron-binding capacity (P = 0.04). Repeated restraint stress exposure inhibited liver development (P = 0.03) and induced liver iron accumulation (P = 0.05). In addition, repeated restraint stress downregulated the expression of transferrin (TF) and transferrin receptor 2 (TFR2) at the mRNA level (P < 0.01), but upregulated at the protein level (P = 0.03 for TF; P = 0.00 for TFR2). These results indicated that repeated restraint stress induces hepatic iron accumulation, which is closely related to higher expression of hepatic TFR2 protein in rats.
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http://dx.doi.org/10.1007/s12011-019-01956-4DOI Listing
August 2020

MiR-20b Down-Regulates Intestinal Ferroportin Expression In Vitro and In Vivo.

Cells 2019 09 24;8(10). Epub 2019 Sep 24.

Key Laboratory of Animal Physiology and Biochemistry, Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China.

Ferroportin (FPN) is the only known cellular iron exporter in mammalian. However, post-transcriptional regulation of intestinal FPN has not yet been completely understood. In this study, bioinformatics algorithms (TargetScan, PicTar, PITA, and miRanda) were applied to predict, screen and obtain microRNA-17 family members (miR-17, miR-20a, miR-20b, and miR-106a) targeting FPN, 'seed sequence' and responding binding sites on the 3'untranslated region (3'UTR) region of FPN. Dual-luciferase reporter assays revealed miRNA-17 family members' mimics decreased the luciferase activity, whereas their inhibitors increased the luciferase activity. Compared with the FPN 3'UTR wild type reporter, co-transfection of a miRNA-17 family members' over-expression plasmids and FPN 3'UTR mutant reporters enhanced the luciferase activity in HCT116 cells. Transfection with miR-20b overexpression plasmid significantly enhanced its expression, and it inhibited endogenous FPN protein expression in Caco-2 cells. Additionally, tail-vein injection of miR-20b resulted in increasing duodenal miR-20b expression, decreasing duodenal FPN protein expression, which was closely related to lower plasma iron level in mice. Taken together, these data suggest that the miR-20b is identified to regulate intestinal FPN expression in vitro and in vivo, which will provide a potential target for intestinal iron exportation.
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http://dx.doi.org/10.3390/cells8101135DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6829237PMC
September 2019

Chronic Dexamethasone exposure activates the TLR4-Mediated inflammation pathway and induces epithelial apoptosis in the goat colon.

Biochem Biophys Res Commun 2019 10 19;518(1):7-13. Epub 2019 Aug 19.

Key Laboratory of Animal Physiology & Biochemistry, Nanjing Agricultural University, Nanjing, 210095, PR China. Electronic address:

Chronic stress has a profound effect on health in both animals and humans. Dexamethasone (Dex), a synthetic glucocorticoid, is used to induce chronic stress in many studies. The impact of chronic stress on epithelial cells of hindgut of ruminants is still unknown. In this study, we investigated the effect of chronic stress induced by long term injection of low dosage of Dex on the colonic epithelium of goats. The results showed that Dex exposure increased the number of TUNEL-positive cells, upregulated caspase-3 and caspase-8 enzyme activity, but decreased protein expression of cell proliferation markers proliferating cell nuclear antigen (PCNA) and Cyclin D2(CCND2). It also activated TLR-4 and NF-κB pathway and increased the transcription levels of vital inflammatory cytokines such as interleukin-10 (IL-10), interleukin-1β (IL-1β), and inducible nitric oxide synthase 2 (iNOS2). Chronic stress down-regulated the methylation level of total DNA, suggesting a mechanism for the transcriptional activation of genes, such as claudin-1, claudin-4, ZO-1, and cell cycle-related genes. Taken together, long-term injection of a low dosage of Dex caused damage to the colon epithelium accompanied with the inhibition of cell proliferation and the activation of cell apoptosis and inflammation. However, a general up-regulation of genes expression induced by Dex is due to a lower level of genomic DNA methylation.
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http://dx.doi.org/10.1016/j.bbrc.2019.07.071DOI Listing
October 2019

Identification and Functional Verification of MicroRNA-16 Family Targeting Intestinal Divalent Metal Transporter 1 (DMT1) and .

Front Physiol 2019 27;10:819. Epub 2019 Jun 27.

Key Laboratory of Animal Physiology and Biochemistry, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.

Divalent metal transporter 1 (DMT1) is a key transporter of iron uptake and delivering in human and animals. However, post-transcriptional regulation of DMT1 is poorly understood. In this study, bioinformatic algorithms (TargetScan, PITA, miRanda, and miRDB) were applied to predict, screen, analyze, and obtain microRNA-16 family members (miR-16, miR-195, miR-497, and miR-15b) targeting DMT1, seed sequence and their binding sites within DMT1 3' untranslated region (3' UTR) region. As demonstrated by dual-luciferase reporter assays, luciferase activity of DMT1 3' UTR reporter was impaired/enhanced when microRNA-16 family member over-expression plasmid/its inhibitor was transfected to HCT116 cells. Corroboratively, co-transfection of microRNA-16 family member over-expression plasmid and DMT1 3' UTR mutant reporter repressed the luciferase activity in HCT116 cells. In addition, over-expression microRNA-16 family member augmented its expression and diminished DMT1 protein expression in HCT116 cells. Interestingly, tail vein injection of miR-16 assay revealed reduced plasma iron levels, higher miR-16 expression, and lower DMT1 protein expression in the duodenum of mice. Taken together, we provide evidence that microRNA-16 family (miR-16, miR-195, miR-497, and miR-15b) is confirmed to repress intestinal DMT1 expression and , which will give valuable insight into post-transcriptional regulation of DMT1.
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http://dx.doi.org/10.3389/fphys.2019.00819DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6610423PMC
June 2019

Caspase-1-dependent mechanism mediating the harmful impacts of the quorum-sensing molecule N-(3-oxo-dodecanoyl)-l-homoserine lactone on the intestinal cells.

J Cell Physiol 2019 04 23;234(4):3621-3633. Epub 2018 Nov 23.

Key Laboratory of Animal Physiology & Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, Jiangsu, China.

N-(3-oxododecanoyl)-l-homoserine lactone (3-oxo-C12-HSL), a quorum-sensing (QS) molecule produced by Gram-negative bacteria in the gastrointestinal tract, adversly impacts host cells. Our previous study demonstrated that 3-oxo-C12-HSL induced a decrease in cell viability via cell apoptosis and eventually disrupted mucin synthesis from LS174T goblet cells. However, the molecular mechanism underlying cell apoptosis and whether pyroptosis was involved in this process are still unknown. In this study, we emphasized on the caspases signal pathway and sterile inflammation to reveal the harmful effects of 3-oxo-C12-HSL on LS174T goblet cells. Our data showed that 3-oxo-C12-HSL is a major inducer of oxidative stress indicated by a high level of intracellular reactive oxygen species (ROS). However, TQ416, an inhibitor of paraoxonase 2, can effectively block oxidative stress. A higher ROS level is the trigger for activating the caspase-1 and 3 cascade signal pathways. Blockade of ROS synthesis and caspase-1 and 3 cascades can obviously rescue the viability of LS174T cells after 3-oxo-C12-HSL treatment. We also found that paralleled with a higher level of ROS and caspases activation, an abnormal expression of proinflammatory cytokines was induced by 3-oxo-C12-HSL treatment; however, the blockage of TLRs-NF-κB pathway cannot restore cell viability and secretary function. These data collectively indicate that 3-oxo-C12-HSL exposure induces damages to cell viability and secretary function of LS174T goblet cells, which is mediated by oxidative stress, cell apoptosis, and sterile inflammation. Overall, the data in this study will provide a better understanding of the harmful impacts of some QS molecules on host cells and their underlying mechanism.
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http://dx.doi.org/10.1002/jcp.27132DOI Listing
April 2019

Long-Term High-Fat Diet Decreases Hepatic Iron Storage Associated with Suppressing TFR2 and ZIP14 Expression in Rats.

J Agric Food Chem 2018 Nov 24;66(44):11612-11621. Epub 2018 Oct 24.

MOE Joint International Research Laboratory of Animal Health & Food Safety , Nanjing Agricultural University , Nanjing , Jiangsu 210095 , People's Republic of China.

High-fat diet-induced obesity is known to disturb hepatic iron metabolism in a time-dependent manner. The mechanism of decreased hepatic iron deposits induced by long-term high-fat diet needs to be further investigated. In this study, 24 6-week-old male Sprague-Dawley rats were given a 16-week high-fat diet and hepatic iron metabolism was examined. High-fat diet feeding considerably decreased hepatic iron contents, enhanced transferrin expression, and reduced the expression of ferritin heavy chain, ferritin light chain, and hepatic iron uptake-related proteins (transferrin receptor 2, TFR2, and ZRT/IRT-like protein 14, ZIP14) in rats. Impaired expression of hepatic TFR2 coincided with DNA hypermethylation on the promoter and repressed expression of transcription factor hepatocyte nuclear factor 4α (HNF4α). miR-181 family expression was markedly increased and verified to regulate Zip14 expression by the dual-luciferase reporter system. Taken together, long-term high-fat diet decreases hepatic iron storage, which is closely linked to inhibition of liver iron transport through the TFR2 and ZIP14-dependent pathway.
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http://dx.doi.org/10.1021/acs.jafc.8b02974DOI Listing
November 2018

Chronic dexamethasone exposure retards growth without altering the digestive tract microbiota composition in goats.

BMC Microbiol 2018 09 10;18(1):112. Epub 2018 Sep 10.

Key Laboratory of Animal Physiology & Biochemistry, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.

Background: Dexamethasone (Dex), an artificially synthetic cortisol substitute, is commonly used as an anti-inflammatory drug, and is also employed to mimic the stress state experimentally. It is well known that chronic stress disturbs the gut microbiota community and digestive functions. However, no relevant studies have been conducted in ruminants.

Results: In this study, a low dosage of Dex (0.2 mg/kg body weight, Dex group, n = 5) was consecutively injected intramuscularly for 21 days to simulate chronic stress in growing goats. Goats were injected with saline (0.2 mg/kg body weight) as the control group (Con, n = 5). Dex-treated goats showed a higher number of white blood cells and blood glucose levels (p < 0.01), but lower dry matter intake (DMI) and body weight (p < 0.01) than those of saline-injected goats. Plasma cortisol concentration decreased significantly in response to the Dex injection compared to the control (p < 0.05). The Dex treatment did not change most ruminal volatile fatty acid (VFAs) concentrations before the morning feeding after 1-21 days of treatment (p > 0.05); however, ruminal VFA concentrations decreased dramatically 2, 4, 6, and 8 h after the morning feeding on day 21 of the Dex injections. In this study, chronic Dex exposure did not alter the community structure of microbes or methanogenes in the rumen, caecum, or colonic digesta. Only Prevotella increased on days 7 and 14 of Dex treatment, but decreased on day 21, and Methanosphaera was the only genus of methanogene that decreased.

Conclusions: Our results suggest that chronic Dex exposure retards growth by decreasing DMI, which may be mediated by higher levels of blood glucose and lower ruminal VFA production. Microbiota in the digestive tract was highly resistant to chronic Dex exposure.
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http://dx.doi.org/10.1186/s12866-018-1253-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6131888PMC
September 2018

Dexamethasone impacts zinc levels in goats by regulating zinc transportation in the colon and the metabolism in the liver.

Anim Sci J 2018 Sep 25;89(9):1296-1301. Epub 2018 Jun 25.

Key Laboratory of Animal Physiology & Biochemistry, Nanjing Agricultural University, Nanjing, China.

The aim of this study was to investigate the effects of dexamethasone (DEX) on zinc metabolism in goats. In this study, 10 goats were randomly divided into two groups. One group was injected with dexamethasone (Dex group) and the other group was injected with saline (Con group). Dex treatment significantly decreased hepatic zinc levels (p < .01) and increased Zn transporters 1 (ZNT-1) expression (p < .05). The concentration of zinc in the cecal and colonic contents was significantly increased (p < .05). However, zinc levels were increased only in the colon tissues (p < .05) but not in the cecal tissues (p > .05). A dramatic increase in Zrt-, Irt-related proteins 14 (ZIP-14) expression (p < .05) following Dex treatment was also observed and likely induced the elevated zinc levels in the colon, and a significant reduction in Zip-14 methylation (p < .05) may be responsible for the observed increase in Zip-14 expression. Together, these results indicate that Dex influences zinc homeostasis by increasing hepatic ZNT-1 and colonic ZIP-14 expression. Additionally, these results provide valuable information for the clinical application of Dex.
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http://dx.doi.org/10.1111/asj.13059DOI Listing
September 2018

N-(3-oxododecanoyl)-l-homoserine lactone modulates mitochondrial function and suppresses proliferation in intestinal goblet cells.

Life Sci 2018 May 27;201:81-88. Epub 2018 Mar 27.

Key Laboratory of Animal Physiology & Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, Jiangsu, China.

Aims: The quorum-sensing molecule N‑(3‑oxododecanoyl)‑l‑homoserine lactone (C12-HSL), produced by the Gram negative human pathogenic bacterium Pseudomonas aeruginosa, modulates mammalian cell behavior. Our previous findings suggested that C12-HSL rapidly decreases viability and induces apoptosis in LS174T goblet cells.

Main Methods: In this study, the effects of 100 μM C12-HSL on mitochondrial function and cell proliferation in LS174T cells treated for 4 h were evaluated by real-time PCR, enzyme-linked immunosorbent assay (ELISA) and flow cytometry.

Key Findings: The results showed that the activities of mitochondrial respiratory chain complexes IV and V were significantly increased (P < 0.05) in LS174T cells after C12-HSL treatment, with elevated intracellular ATP generation (P < 0.05). Flow cytometry analysis revealed significantly increased intracellular Ca levels (P < 0.05), as well as disrupted mitochondrial activity and cell cycle arrest upon C12-HSL treatment. Apoptosis and cell proliferation related genes showed markedly altered expression levels (P < 0.05) in LS174T cells after C12-HSL treatment. Moreover, the paraoxonase 2 (PON2) inhibitor TQ416 (1 μM) remarkably reversed the above C12-HSL associated effects in LS174T cells.

Significance: These findings indicated that C12-HSL alters mitochondrial energy production and function, and inhibits cell proliferation in LS174T cells, with PON2 involvement.
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http://dx.doi.org/10.1016/j.lfs.2018.03.049DOI Listing
May 2018

Effects of chronic dexamethasone administration on hyperglycemia and insulin release in goats.

J Anim Sci Biotechnol 2018 16;9:26. Epub 2018 Mar 16.

Key Laboratory of Animal Physiology & Biochemistry, Nanjing Agricultural University, Nanjing, 210095 People's Republic of China.

Background: Dexamethasone (Dex), a synthetic glucocorticoid, is among the most commonly used drugs worldwide in animals and humans as an anti-inflammatory and immunosuppressive agent. GC has profound effects on plasma glucose level and other metabolic conditions. However, the effect of prolonged use of Dex on glucose metabolism in ruminants is still unclear.

Results: Ten goats were randomly assigned to two groups: the control goats were injected with saline, and the Dex-treated goats were intramuscularly injected daily for 21 d with 0.2 mg/kg Dex. The results showed that plasma glucose and insulin concentrations were significantly increased after Dex administration ( < 0.05). Additionally, the content of hepatic glycogen was also markedly increased in Dex-treated goats ( < 0.01), while the content of glycogen in dorsal longissimus was unchanged by Dex ( > 0.05). The expression of several key genes, involved in blood glucose regulation, was detected by real-time PCR in the small intestine, skeletal muscle and liver. The expression of glucose transporter type 2 (), sodium-glucose transporter 1 () and sodium-potassium ATPase () in the small intestine were generally increased by Dex, and mRNA expression was significantly up-regulated ( < 0.05). In liver, the expression of genes involved in gluconeogenesis including glucose-6-phosphatase catalytic subunit (), cytosolic form of phosphoenolpyruvate carboxykinase () and pyruvate carboxylase (), were significantly down-regulated by Dex. However, the protein expression levels of PCK1 & PCK2 were significantly increased by Dex, suggesting a post-transcriptional regulation. In dorsal longissimus, the mRNA expression of genes associated with gluconeogenesis and the insulin signaling pathway were generally up-regulated by Dex, but the mRNA expression of two markers of muscle atrophy, namely F-box protein 32 () and muscle RING-finger protein 1 (), was not altered by Dex.

Conclusions: Taken together, these results indicate that chronic administration of a low dosage of Dex induces hyperglycemia mainly through gluconeogenesis activation in the goat liver.
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http://dx.doi.org/10.1186/s40104-018-0242-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5855938PMC
March 2018

Exploring differentially expressed genes related to metabolism by RNA-Seq in goat liver after dexamethasone treatment.

Gene 2018 Jun 18;659:175-182. Epub 2018 Mar 18.

Key Laboratory of Animal Physiology & Biochemistry, Nanjing Agricultural University, Nanjing 210095, PR China.

Chronic stress severely threatens the welfare and health of animals and humans. In order to study the effects of chronic stress on metabolism, de novo transcriptome sequencing was used to generate the expressed sequence tag dataset for the goat, using nextgeneration sequencing technology. For this study, consecutive dexamethasone (Dex) injection was used in 10 healthy male goats (body weight 25 ± 1.0 kg) to mimic chronic stress. Ten male goats were randomly assigned into two groups, one group was injected intramuscularly with the same volume of saline as control (Con) group, and another (Dex) group was injected intramuscularly with 0.2 mg/kg Dex for 21 days. To elucidate the resulting changes in genes, transcriptome profiling of liver was conducted by analysing samples from three goats of each group using RNA-Seq. A total of 137 differentially expressed genes (DEGs) were identified between Con group and Dex group. GO classification showed rhythmic process and hormone secretion in term cellular, and chemoattractant activity in term molecular function had noticeable differences in the proportion between DEGs and all genes. By mapping the DEGs to the COG database, we found that general function prediction only, energy production and conversion, and amino acid transport and metabolism were the most frequently represented functional clusters. We mapped the unigenes to the KEGG pathway database and found most annotated genes were involved in the AMPK signalling pathway as well as pathways in cancer and insulin signalling pathway. Via KEGG enrichment analysis, we found the DEGs were significantly enriched in insulin signalling pathway, AMPK signalling pathway and adipocytokine signalling pathway. In addition, these pathways have close relationship with metabolism, which resulted in metabolic changes in which the identified DEGs may play important roles. These results provide valuable information for further research on the complex molecular mechanisms of dexamethasone in goats and will provide a foundation for future studies.
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http://dx.doi.org/10.1016/j.gene.2018.03.055DOI Listing
June 2018

Dietary betaine supplementation in hens modulates hypothalamic expression of cholesterol metabolic genes in F1 cockerels through modification of DNA methylation.

Comp Biochem Physiol B Biochem Mol Biol 2018 Mar 14;217:14-20. Epub 2017 Dec 14.

MOE Joint International Research Laboratory of Animal Health & Food Safety, Nanjing Agricultural University, Nanjing 210095, PR China; Key Laboratory of Animal Physiology & Biochemistry, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, PR China; Jiangsu Collaborative Innovation Centre of Meat Production and Processing, Quality and Safety Control, Nanjing 210095, PR China. Electronic address:

Betaine is widely used in animal nutrition to promote growth, development and methyl donor during methionine metabolism through nutritional reprogramming via regulation of gene expression. Prenatal betaine exposure is reported to modulate hypothalamic cholesterol metabolism in chickens, yet it remains unknown whether feeding hens with betaine-supplemented diet may affect hypothalamic cholesterol metabolism in F1 offspring. In this study, hens were fed with basal or betaine-supplemented (0.5%) for 30days, and the eggs were collected for incubation. The hatchlings were raised under the same condition up to 56days of age. Betaine-treated group showed significantly (P<0.05) higher plasma concentration of total cholesterol and HDL-cholesterol, together with increased hypothalamic content of total cholesterol and cholesterol ester. Concordantly, hypothalamic gene expression of SREBP2, HMGCR, and LDLR was significantly up regulated (P<0.05). Also, mRNA abundances of SREBP1, ACAT1 and APO-A1 were up-regulated, while that of CYP46A1 was significantly down-regulated (P<0.05). These changes coincided with a significant down-regulation of BDNF and CRH, and a significant up-regulation of NPY mRNA expression. Moreover, genes involved in methyl transfer cycle were also modulated. DNMT1 and BHMT were up-regulated (P<0.05) at both mRNA and protein levels, which was associated with significant modifications of CpG methylation on the promoter of SREBP-1, SREBP-2 and APO-A1 genes as detected by bisulfate sequencing. These results indicate that feeding betaine to hens modulates hypothalamic expression of genes involved in cholesterol metabolism and brain functions in F1 cockerels with modification of promoter DNA methylation.
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http://dx.doi.org/10.1016/j.cbpb.2017.12.001DOI Listing
March 2018

Chronic dexamethasone exposure markedly decreased the hepatic triglyceride accumulation in growing goats.

Gen Comp Endocrinol 2018 04 16;259:115-121. Epub 2017 Nov 16.

Key Laboratory of Animal Physiology & Biochemistry, Nanjing Agricultural University, Nanjing 210095, PR China.

Chronic stress seriously threatens welfare and health in animals and humans. Consecutive dexamethasone (Dex) injection was used to mimic chronic stress previously. In order to investigate the effect of chronic stress on hepatic lipids metabolism, in this study, 10 healthy male goats were randomly allocated into two groups, one received a consecutive injection of Dex via intramuscularly for 3 weeks (Dex group), the other received the same volume of saline as the control group (Con group). Hepatic health and triglyceride (TG) metabolism were analyzed and compared between two groups. The data showed that a significant decrease of TG in plasma and the liver was significantly decreased by Dex (P < .05), while the hepatic nonesterified fatty acid (NEFA) concentration was increased compared to the Con group (P < .05). Consistent with the decrease of TG level, the activity of hepatic lipoprotein lipase (LPL) and hepatic lipase (HL) enzymes activities were significantly enhanced by Dex. Real-time PCR results showed that the mRNA expression of sterol regulatory element binding transcription factor 1 (SREBP-1), acyl-CoA dehydrogenase long chain (ACADL) and acyl-CoA synthetase bubblegum family member 1 (ACSBG1) genes in liver was significantly up-regulated by chronic Dex injection (P < .05), whereas perilipin 2 (PLIN2) and adipose triglyceride lipase (ATGL) mRNA expression was significantly decreased by Dex (P < .05). In addition, no obvious damages were observed in the liver in both Con and Dex groups demonstrating by the sirius red staining, HE staining as well as several biochemical parameters related to the functional status of hepatocytes. Our data indicate that chronic Dex exposure decreases TG levels in the circulation and the liver through activating lipolysis and inhibiting lipogenesis without causing hepatic damages in the growing goats.
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http://dx.doi.org/10.1016/j.ygcen.2017.11.011DOI Listing
April 2018

Negative effects of long-term feeding of high-grain diets to lactating goats on milk fat production and composition by regulating gene expression and DNA methylation in the mammary gland.

J Anim Sci Biotechnol 2017 1;8:74. Epub 2017 Oct 1.

Key Laboratory of Animal Physiology & Biochemistry, Nanjing Agricultural University, Nanjing, 210095 People's Republic of China.

Background: It is well known that feeding a high concentrate (HC) diet to lactating ruminants likely induces subacute ruminal acidosis (SARA) and leads to a decrease in milk fat production. However, the effects of feeding a HC diet for long periods on milk fatty acids composition and the mechanism behind the decline of milk fat still remains poorly understood. The aim of this study was to investigate the impact of feeding a HC diet to lactating dairy goats on milk fat yield and fatty acids composition with an emphasis on the mechanisms underlying the milk fat depression. Seventeen mid-lactating dairy goats were randomly allocated to three groups. The control treatment was fed a low-concentrate diet (35% concentrate,  = 5, LC) and there were two high-concentrate treatments (65% concentrate, HC), one fed a high concentrate diet for a long period (19 wks,  = 7, HL); one fed a high concentrate diet for a short period of time (4 wk,  = 5, HS). Milk fat production and fatty acids profiles were measured. In order to investigate the mechanisms underlying the changes in milk fat production and composition, the gene expression involved in lipid metabolism and DNA methylation in the mammary gland were also analyzed.

Results: Milk production was increased by feeding the HC diet in the HS and HL groups compared with the LC diet ( < 0.01), while the percentage of milk fat was lower in the HL ( < 0.05) but not in the HS group. The total amount of saturated fatty acids (SFA) in the milk was not changed by feeding the HC diet, whereas the levels of unsaturated fatty acids (UFA) and monounsaturated fatty acids (MUFA) were markedly decreased in the HL group compared with the LC group ( < 0.05). Among these fatty acids, the concentrations of C15:0 ( < 0.01), C17:0 ( < 0.01), C17:1 ( < 0.01), C18:1n-9c ( < 0.05), C18:3n-3r ( < 0.01) and C20:0 ( < 0.01) were markedly lower in the HL group, and the concentrations of C20:0 ( < 0.05) and C18:3n-3r ( < 0.01) were lower in the HS group compared with the LC group. However, the concentrations of C18:2n-6c ( < 0.05) and C20:4n-6 ( < 0.05) in the milk fat were higher in the HS group. Real-time PCR results showed that the mRNA expression of the genes involved in milk fat production in the mammary gland was generally decreased in the HL and HS groups compared with the LC group. Among these genes, , & , , , , and were down-regulated in the mammary gland of the HL group ( < 0.05), and the expressions of , and mRNA were markedly decreased in the HS goats compared with the LC group ( < 0.05). In contrast to the gene expression, the level of DNA methylation in the promoter regions of the and genes was increased in the HL group compared with the LC group ( < 0.05). The levels of ACSL1 protein expression and FAS enzyme activity were also decreased in the mammary gland of the HL compared with the LC group ( < 0.05).

Conclusions: Long-term feeding of a HC diet to lactating goats induced milk fat depression and FAs profile shift with lower MUFAs but higher SFAs. A general down-regulation of the gene expression involved in the milk fat production and a higher DNA methylation in the mammary gland may contribute to the decrease in milk fat production in goats fed a HC diet for long time periods.
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http://dx.doi.org/10.1186/s40104-017-0204-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5623059PMC
October 2017

Microbiome-Metabolome Responses to a High-Grain Diet Associated with the Hind-Gut Health of Goats.

Front Microbiol 2017 14;8:1764. Epub 2017 Sep 14.

Key Laboratory of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agricultural UniversityNanjing, China.

Studies on the effect of a high-concentrate (HC) diet on the hindgut microbiota and metabolome of ruminants are rarely reported. We used 454 pyrosequencing of 16S rDNA genes and gas chromatography-mass spectrometry to evaluate the effects of long-term feeding (HL) or short-term (HS) feeding of an HC diet on changes in bacterial microbiota and their metabolites in the hindgut, with Guanzhong goat as a ruminant model. Results indicated that an HC diet decreased bacterial diversity and induced metabolic disorder in the hindgut. The levels of lactate, endotoxin (lipopolysaccharide, LPS), and volatile fatty acid concentrations were higher in the intestinal digesta of the HC goats than in those of the LC goats ( < 0.05). The level of beta-alanine decreased, whereas the levels of stigmasterol and quinic acid decreased in the cecal and colonic digesta of the HC goats. At the genus level, the abundance of and was significantly increased in both the colonic and cecal digesta of the HC goats. Several potential relationships between metabolites and several microbial species were revealed in this study. The mRNA expression of the genes functionally associated with nutrients transport, including , and were significantly downregulated in the colonic mucosa by the HC diet ( < 0.05). The expression levels of the genes related to the inflammatory response, including α, and β were markedly upregulated in the cecal mucosa by the HC diet ( < 0.05). Our results indicate that an HC diet induces microbiota dysbiosis, metabolic disorders, and mucosal damage in the hindgut of goats.
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http://dx.doi.org/10.3389/fmicb.2017.01764DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5603706PMC
September 2017

Feeding a High Concentration Diet Induces Unhealthy Alterations in the Composition and Metabolism of Ruminal Microbiota and Host Response in a Goat Model.

Front Microbiol 2017 2;8:138. Epub 2017 Feb 2.

Key Laboratory of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agricultural University Nanjing, China.

There is limited knowledge about the impact of long-term feeding a high-concentrate (HC) diet on rumen microbiota, metabolome, and host cell functions. In this study, a combination of mass spectrometry-based metabolomics techniques, 454 pyrosequencing of 16S rDNA genes, and RT-PCR was applied to evaluate the changes of ruminal microbiota composition, ruminal metabolites, and related genes expression in rumen epithelial cells of lactating goats received either a 35% concentrate diet or a 65% concentrate diet for 4 or 19 weeks, respectively. Results show that feeding a HC diet reduced the microbiota diversity and led to the disorders of metabolism in the rumen. The concentrations of lactate, phosphorus, NH3-N and endotoxin Lipopolysaccharide in ruminal fluids, and plasma histamine, lactate and urine N (UN) were increased significantly in goats fed with a HC diet. A significant increase of genes expression related to volatile fatty acids transport, cell apoptosis, and inflammatory responses were also observed in goats fed with a HC diet. Correlation analysis revealed some potential relationships between bacteria abundance and metabolites concentrations. Our findings indicate that a HC diet can induce ruminal microbiota dysbiosis and metabolic disorders, thus increasing risks to host health and potential harm to the environment.
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http://dx.doi.org/10.3389/fmicb.2017.00138DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5288341PMC
February 2017

Paraoxonase 2 modulates a proapoptotic function in LS174T cells in response to quorum sensing molecule N-(3-oxododecanoyl)-L-homoserine lactone.

Sci Rep 2016 07 1;6:28778. Epub 2016 Jul 1.

Key Laboratory of Animal Physiology &Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, Jiangsu, China.

A mucus layer coats the gastrointestinal tract and serves as the first line of intestinal defense against infection. N-acyl-homoserine lactone (AHL) quorum-sensing molecules produced by gram-negative bacteria in the gut can influence the homeostasis of intestinal epithelium. In this study, we investigated the effects of two representative long- and short-chain AHLs, N-3-(oxododecanoyl)-homoserine lactone (C12-HSL) and N-butyryl homoserine lactone (C4-HSL), on cell viability and mucus secretion in LS174T cells. C12-HSL but not C4-HSL significantly decreased cell viability by inducing mitochondrial dysfunction and activating cell apoptosis which led to a decrease in mucin expression. Pretreatment with lipid raft disruptor (Methyl-β-cyclodextrin, MβCD) and oxidative stress inhibitor (N-acetyl-L-cysteine, NAC) slightly rescued the viability of cells damaged by C12-HSL exposure, while the paraoxonase 2 (PON2) inhibitor (Triazolo[4,3-a]quinolone, TQ416) significantly affected recovering cells viability and mucin secretion. When LS174T cells were treated with C12-HSL and TQ416 simultaneously, TQ416 showed the maximal positive effect on cells viability. However, if cells were first treated with C12-HSL for 40 mins, and then TQ46 was added, the TQ416 had no effect on cell viability. These results suggest that the C12-HSL-acid process acts at an early step to activate apoptosis as part of C12-HSL's effect on intestinal mucus barrier function.
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http://dx.doi.org/10.1038/srep28778DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4929476PMC
July 2016

Activation of epithelial proliferation induced by Eimeria acervulina infection in the duodenum may be associated with cholesterol metabolism.

Oncotarget 2016 May;7(19):27627-40

Key Laboratory of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China.

Cell proliferation in the intestine is commonly occurred during infection and inflammation to replace damaged enterocytes, and cholesterol as an essential constituent of cell membrane, is required for cell proliferation and growth. Here we found that coccidium-challenged (CC) chickens showed severe damages in intestinal structure, a significant increase of cell proliferation, and an activation of genes expression involved in the innate immune response. Compared to control (CON), CC chickens showed a marked decrease of cholesterol (Tch) level in the circulating system, but a significant increase in local duodenum epithelium. Increase of LDLR protein combined with a significant decrease of CYP27A1 protein expression in duodenum epithelium may contribute to intestinal cholesterol accumulation in CC chickens. Moreover, we found miRNAs targeting to CYP27A1 gene participating in post-transcriptional regulation. Hence, these results provide a new insight for the intervention of epithelial proliferation and cholesterol metabolism in the gastrointestinal tracts.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5053676PMC
http://dx.doi.org/10.18632/oncotarget.8490DOI Listing
May 2016

Comparative proteomic analysis of the effects of high-concentrate diet on the hepatic metabolism and inflammatory response in lactating dairy goats.

J Anim Sci Biotechnol 2016 6;7. Epub 2016 Feb 6.

Key Laboratory of Animal Physiology & Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, Jiangsu China.

Background: To understand the impact of feeding a high-concentrate diet to mid-lactating goats for a long time on liver metabolism and inflammatory response, two dimensional polyacrylamide gel electrophoresis (2-DE) and real-time PCR method were employed to detect proteins differentially expressed in liver and their mRNAs expression in goats fed high concentrate diet (HC) or low concentrate diet (LC). Twelve lactating dairy goats were randomly assigned to either a HC diet group (65 % concentrate of dry matter; n = 6) or a LC diet group (35 % concentrate of dry matter; n = 6) for 10 wk.

Results: Twenty differentially expressed spots (≥2.0-fold changes) in the hepatic tissues were excised and successfully identified using MALDI TOF/TOF. Of these, 8 proteins were up-regulated, while the rest 12 proteins were down-regulated in HC goats compared to LC. Differential expressed proteins including alpha enolase 1 (ENO1), glutamate dehydrogenase 1 (GLUD1), glutathione S-transferase A1 (GSTA1), ATP synthase subunit 5β (ATP5β), superoxide dismutase [Cu-Zn] (SOD1), cytochrom c oxidase subunit Via (COX6A1) and heat shock protein 60 (HSP60) were further verified by real-time PCR and/or western blot at mRNA or protein expression level. Consistent with the 2-DE results, a significant decrease of β-actin protein expression and SOD enzyme activity was observed in liver of HC goats (P < 0.05), while ENO1 protein expression was significantly up-regulated in HC compared to LC goats (P < 0.05) . However, western blot analysis did not show a significant difference of hepatic HSP60 protein between HC and LC group, which did not match the decrease of HSP60 content detected by 2-DE analysis. Real-time PCR showed that glutathione S-transferase P1 (GSTP1) and SOD1 mRNA expression was significantly decreased in liver of HC goats, while cytochrom c oxidase (COX3) and ATPase 8 (ATP8) mRNAs expression were markedly increased compared to LC (P < 0.05). Gene Ontology (GO) analysis revealed that HC diet resulted in altered expression of proteins related to catalytic and mitochondrial metabolism in the liver, and may increase the stress response with up-regulating the expression of differentiation 14 (CD14) cluster and serum amyloid A (SAA) as well as C-reactive protein (CRP) in the liver.

Conclusions: These results suggest that feeding high concentrate diet to lactating goats for 10 wk leads to the activation of the inflammatory response, and decreases the anti-oxidant capacity, and subsequently impairs the mitochondrial function in the liver.
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http://dx.doi.org/10.1186/s40104-016-0065-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4744397PMC
February 2016

Downregulation of prostaglandin E2 is involved in hindgut mucosal damage in lactating goats fed a high-concentrate diet.

Exp Physiol 2016 Feb 20;101(2):272-81. Epub 2015 Dec 20.

Key Laboratory of Animal Physiology & Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, Jiangsu, China.

New Findings: What is the central question of this study? A high-concentrate (HC) diet results in damage to the hindgut mucosa. The aim of the study was to investigate the status of epithelial proliferation in the hindgut mucosa of goats with subacute ruminal acidosis and, simultaneously, to evaluate prostaglandin E2 synthesis and the downstream signalling pathways. What is the main finding and its importance? The downregulation of local prostaglandin E2 synthesis and its downstream signalling pathway are involved in the process of inhibiting epithelial proliferation in the hindgut epithelium of HC-fed goats. Our results provide new insight into the relationship between abnormal fermentation in the hindgut and damage to the intestinal mucosal barrier. Our previous data demonstrated that feeding a high-concentrate (HC) diet to lactating goats for a long time causes severe damage to the hindgut mucosa and parallels the activation of cell apoptosis and local oxidative stress. In the present study, changes in production of prostaglandin E2 (PGE2 ) and its signalling pathway were evaluated in the process of epithelial barrier disruption in the hindgut. Twelve goats in mid-lactation were randomly assigned to either a HC diet group or a low-concentrate (LC) diet group for 10 weeks. Cell proliferation markers, cyclooxygenase-2 activity, PGE2 content and the relative signalling pathway, including CREB and AKT, were analysed by enzyme-linked immunosorbent assay and Western blot, respectively. The mRNA and protein expressions of MKI67 and CCND2 (two proliferation markers) were significantly decreased in the caecal mucosa of HC- compared with LC-fed goats (P < 0.05). The protein content of interleukin-10 and β-defensin in the caecal mucosa was also downregulated in HC-fed goats (P < 0.05). The HC-fed goats showed a tendency to a decrease in cyclooxygenase-2 enzyme activity (P = 0.081) and a significant decrease of local PGE2 content and EP4 (PGE2 receptor) protein expression in caecal mucosa (P < 0.05). Moreover, the protein abundance of p-CREB (P = 0.069) and p-AKT (P < 0.05) and the mRNA expression of epidermal growth factor receptor (P < 0.05) were downregulated in caecal mucosa of HC- compared with LC-fed goats. These results indicate that a reduction in epithelial cell proliferation was partly responsible for the damage to the epithelial barrier, which might be associated with the downregulation of PGE2 synthesis and its downstream signalling pathway.
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http://dx.doi.org/10.1113/EP085256DOI Listing
February 2016

Exogenous administration of chronic corticosterone affects hepatic cholesterol metabolism in broiler chickens showing long or short tonic immobility.

Comp Biochem Physiol A Mol Integr Physiol 2016 Jan 8;191:53-58. Epub 2015 Oct 8.

Key Laboratory of Animal Physiology & Biochemistry, Nanjing Agricultural University, Nanjing 210095, PR China.

Tonic immobility (TI) is an innate characteristic of animals related to fear or stress response. Animals can be classified into long TI (LTI) and short TI (STI) phenotypes based on TI test duration. In this study, effect of TI phenotype, chronic corticosterone administration (CORT), and their interaction on cholesterol metabolism in liver was evaluated in broilers. LTI broilers showed higher level of cholesterol in liver compared to STI chickens (p<0.05), and CORT significantly increased hepatic cholesterol content (p<0.01). Real-time PCR results showed that both TI and CORT potentially altered ABCA1 and CYP7A1 gene expressions (0.05
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http://dx.doi.org/10.1016/j.cbpa.2015.09.020DOI Listing
January 2016

Activation of cellular apoptosis in the caecal epithelium is associated with increased oxidative reactions in lactating goats after feeding a high-concentrate diet.

Exp Physiol 2015 Mar 12;100(3):278-87. Epub 2015 Feb 12.

Key Laboratory of Animal Physiology & Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, Jiangsu, China.

New Findings: What is the central question of this study? What are the ultrastructural changes of the caecal mucosa and the status of epithelial cellular apoptosis and oxidative reactions in lactating goats after prolonged feeding with a high-concentrate diet? What is the main finding and its importance? High-concentrate diet results in ultrastructural damage to the caprine caecal epithelium. Increased oxidative and decreased antioxidative reactions are involved in the process of activating epithelial apoptosis in the caecal epithelium of goats fed a high-concentrate diet. Our results provide new insight into the relationship between abnormal fermentation in the hindgut and damage to the intestinal mucosal barrier. The effect of feeding a high-concentrate diet (HC) to lactating ruminants on their hindgut epithelial structure remains unknown. In this study, 12 lactating goats were randomly assigned to either HC (65% of dry matter as concentrate; n = 6) or a low-concentrate diet (LC; 35% of dry matter as concentrate; n = 6). After 10 weeks, the epithelial ultrastructure and cell apoptotic status in the caecal mucosa were determined by transmission electron microscopy and TUNEL, respectively. The results showed that the level of free lipopolysaccharide (P < 0.05), total volatile fatty acid concentrations (P < 0.1) and starch content (P < 0.05) in the caecal digesta were significantly increased in HC- compared with LC-fed goats. The HC-fed goats exhibited obvious epithelial cellular damage, with widened tight junction spaces, nuclear breakdown and mitochondrial swelling. Compared with their LC-fed counterparts, HC-fed goats showed greater apoptosis in the caecal epithelium, as evidenced by more TUNEL-positive apoptotic cells. Western blot analysis showed that there was no significant difference in activated caspase-3, Bax protein expression in caecal epithelial mucosa between HC- and LC-fed goats (P > 0.05). However, the level of malondialdehyde content in the caecal epithelium from HC-fed goats was markedly higher than that in LC-fed goats (P < 0.05), whereas the level of glutathione peroxidase and the superoxide dismutase activity were significantly decreased. Gene expressions of cytokines, including interleukin-1β, interleukin-6, interleukin-10, tumour necrosis factor-α and interferon-γ, as well as myeloperoxidase activity in the caecal mucosa did not show any significant difference between HC- and LC-fed goats. These results indicate that feeding a high-concentrate diet to lactating goats for a prolonged period results in abnormal fermentation and structural disruption in the hindgut, which is accompanied by greater cellular apoptosis and an enhanced oxidative stress response.
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http://dx.doi.org/10.1113/expphysiol.2014.083352DOI Listing
March 2015

Fatmass and obesity associated (FTO) gene regulates gluconeogenesis in chicken embryo fibroblast cells.

Comp Biochem Physiol A Mol Integr Physiol 2015 Jan;179:149-56

Fat mass and obesity-associated (FTO) gene was found to be associated with energy homeostasis in mammals, yet the function of chicken FTO is less clear. In this study, chicken embryo fibroblast cells (DF-1) were transiently transfected to over-express (FTO(+)) or to knockdown (FTO−) the chicken FTO gene and were used for the functional analysis. FTO expression was significantly augmented in FTO(+) cells while depressed in FTO(−) cells (P < 0.05). FTO(+) cells had significantly lower glucose yet higher lactic acid (LD) concentrations (P < 0.05) in the culture media, which was associated with significantly up-regulated (P < 0.05) mRNA expression of the rate-limiting gluconeogenic enzymes, glucose-6-phosphatase (G6PC) and the phosphoenolpyruvate carboxykinase-mitochondrial (PEPCK-m). The protein content and enzyme activity of G6PC were also significantly higher (P < 0.05) in FTO(+) cells. Moreover, CCAAT/enhancer-binding protein-beta (C/EBP-beta) and cAMP responsive element binding protein 1 (CREB1), which were found to transcriptionally regulate the expression of G6PC, were increased at the level of both mRNA (P < 0.05) and protein (P < 0.05) in FTO(+)cells. ChIP analysis revealed significantly higher (P < 0.05) binding of C/EBP-beta and phospho-CREB1 to G6PC gene promoter in FTO(+) cells. In addition, the interaction of FTO and C/EBP-beta was significantly enhanced (P < 0.05) in FTO+ cells. Opposite changes in G6PC expression and regulation were observed in FTO(−) cells. Our results indicate that chicken FTO regulates gluconeogenesis in DF-1 cells through enhanced transcriptional regulation of G6PC gene by C/EBP-beta and phospho-CREB1.
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http://dx.doi.org/10.1016/j.cbpa.2014.10.003DOI Listing
January 2015

High concentrate diet induced mucosal injuries by enhancing epithelial apoptosis and inflammatory response in the hindgut of goats.

PLoS One 2014 30;9(10):e111596. Epub 2014 Oct 30.

Key Laboratory of Animal Physiology & Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, Jiangsu, China.

Purpose: It is widely accepted that lipopolysaccharide and volatile fatty acids (VFA) accumulate in the digestive tract of ruminants fed diets containing high portions of grain. Compared to the ruminal epithelium, the hindgut epithelium is composed of a monolayer structure that is more "leaky" for lipopolysaccharide and susceptible to organic acid-induced damage. The aim of this study was to investigate changes in epithelial structure, apoptosis and inflammatory response in the hindgut of goats fed a high-concentrate diet for 6 weeks.

Experimental Design: Eight local Chinese goats with rumen cannulas were randomly assigned to two groups: one group was fed a high-concentrate diet (65% concentrate of dry matter, HC) and the other group was fed a low-concentrate diet (35% concentrate of dry matter, LC) for 6 wks. Ruminal fluid, plasma, and hindgut mucosa tissues were collected. Histological techniques, real-time PCR and western blotting were used to evaluate the tissues structure, cell apoptosis and local inflammation in the hindguts.

Results: Feeding HC diet for 6 wks resulted in a significant decrease of ruminal pH (p<0.01), and ruminal lipopolysaccharide concentrations were significantly increased in HC goats (p<0.05). Obvious damage was observed to mucosal epithelium of the hindgut and the intercellular tight junctions in HC, but not in LC, goats. The expression of MyD88 and caspase-8 mRNA was increased in colonic epithelium of HC goats compared to LC (p<0.05), and the expression of TLR-4 and caspase-3 showed a tendency to increase. In the cecum, interleukin-1β mRNA expression was decreased (p<0.05), and caspase-3 showed a potential increase (p = 0.07) in HC goats. The level of NF-κB protein was increased in colonic epithelium of HC goats. Caspase-3 activity was elevated in both colon and cecum, whereas caspase-8 activity was statistically increased only in colon.

Conclusions: Feeding a high-concentrate diet to goats for 6 wks led to hindgut mucosal injuries via activating epithelial cells apoptosis and local inflammatory response.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0111596PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4214727PMC
December 2015
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