Inulin supplementation induces expression of hypothalamic antioxidant defence genes in weaned piglets.

Fibre plays an important role in diluting dietary energy density. Fibre is also implicated in the regulation of appetite, perhaps through direct effects in the brain. However, there is little information on this effect in pigs. Therefore, this study was conducted to investigate the effect of fibre type in regulating the expression of genes involved in appetite control, inflammation and antioxidant defence in the hypothalamus of weaned piglets. A total of 64 Duroc × Landrace × Yorkshire barrows at 37 days old were blocked by body weight and allotted to two dietary treatments, supplementation with either 0.25% cellulose (Solka-Floc) or inulin (INU) for 28 days, after which animals were killed for analysis. Pigs fed INU had a tendency (p = 0.06) for reduced feed intake in the first week, although this effect disappeared in subsequent weeks. Pigs supplemented with INU had lower expression of dopamine (dopamine receptor D2), serotonin (5-hydroxytryptamine receptor 1B), free fatty acid (GPR43) and neuropeptide Y receptor Y2 receptors in the hypothalamus (p < 0.05). Expression of the tryptophan hydroxylase 2 gene in the hypothalamus also tended (p = 0.09) to be lower for pigs fed INU. The abundance of antioxidant defence genes, superoxide dismutase (SOD1) and catalase, were greater (p < 0.05) but that of a proinflammatory gene, interleukin 1ß, was lower (p < 0.05) in the hypothalamus of pigs fed INU. Therefore, consumption of INU causes downregulation of inflammation in the hypothalamus and regulation of the abundance of serotonin or dopamine receptors, and may also increase antioxidant defence through upregulation of SOD and catalase in weaned piglets.

Mechanism of endocytic regulation of intestinal tight junction remodeling during nutrient starvation in jejunal IPEC-J2 cells.

Intestinal epithelial cells are tightly bound by tight junction proteins (TJP) which are dynamic and sensitive to environmental stress. However, the role of the endocytic pathway in the regulation of TJP abundance and tight junction integrity during nutrient stress is poorly understood. Therefore, this study was conducted to investigate the regulation of TJP abundance during nutrient starvation and the role of the endocytic mechanism in this process. IPEC-J2 cells were subjected to nutrient starvation in Krebs-Ringer bicarbonate buffer (KRB) and abundance of TJP, an indication of tight junction remodeling, was characterized with RT-PCR, western blotting and immunofluorescence. Abundance of TJP was dynamically regulated by nutrient starvation. The protein levels of claudin-1, 3, and 4 were initially downregulated within the first 6 hours of starvation, and then, increased thereafter (P < .01). However, there was no change in occludin and ZO-1. Lysosome and proteasome inhibitors were used to determine the contribution of these protein degradation pathways to the TJP remodeling. Short-term starvation-induced degradation of claudin-1, 3, and 4 was found to be lysosome dependent. Specifically, the downregulation of claudin-3 and 4 was via a dynamin-dependent, but clathrin and caveolae independent, endocytic pathway and this downregulation was partly reversed by amino acids supplementation. Interestingly, the re-synthesis of TJP with prolonged starvation partly depended on proteasome function. Collectively, this study, for the first time, elucidated a major role for dynamin-dependent endocytosis of claudin-3 and 4 during nutrient stress in intestinal epithelial cells. Therefore, transient endocytosis inhibition may be a potential mechanism for preserving tight junction integrity and function in metabolic or pathological states such as inflammatory bowel disease that involves destruction of intestinal epithelial TJP.

Mechanisms of deoxynivalenol-induced endocytosis and degradation of tight junction proteins in jejunal IPEC-J2 cells involve selective activation of the MAPK pathways.

Mycotoxin contamination in foods is a major risk factor for human and animal health due to its prevalence in cereals and their by-products. Deoxynivalenol (DON), mainly produced by Fusarium genera, is the most common mycotoxin detected in cereal products. Deoxynivalenol disrupts intestinal barrier function and decreases protein levels of tight junction proteins (TJP). However, the overall mechanism by which DON regulates specific TJP turnover and epithelial cell integrity remains unclear. Herein, we show that DON (2 µM) decreases the protein stability and accelerates the degradation of TJP in the lysosome. Interestingly, pretreatment of cells with dynasore (a dynamin-dependent endocytosis inhibitor) protected against DON-induced degradation of claudin-3 and 4. Immunofluorescence analysis also shows that the decreased membrane presence of claudin-4 and ZO-1 induced by DON is reversible with dynamin inhibition, whereas the pretreatment with cytochalasin D (an actin-dependent endocytosis inhibitor) reverses the degradation of claudin-1 and 4 induced by DON. We also show that the endocytosis and degradation of claudin-1 is regulated by p38 mitogen-activated protein kinase (MAPK), whereas the endocytosis of claudin-4 and ZO-1 is mediated by c-Jun-N-terminal kinase (JNK). Resveratrol, with JNK inhibitory activity, also prevents the endocytosis and degradation of claudin-4 and ZO-1 and protects against DON-induced decrease in transepithelial electrical resistance (TEER) and increase in FITC-dextran permeability. Collectively, this study, for the first time, shows that DON accelerates the endocytosis and degradation of TJP and this is regulated by the activation of p38 MAPK and JNK signaling pathways. Therefore, natural bioactive compounds with p38 MAPK and JNK inhibitory activities may be effective in preventing the DON-induced TJP disruption and preserve gut barrier function in vivo.

Consuming Diet Supplemented with Either Red Wheat Bran or Soy Extract Changes Glucose and Insulin Levels in Female Obese Zucker Rats.

Type 2 diabetes mellitus is characterized by the inability to regulate blood glucose levels due to insulin resistance, resulting in hyperglycemia and hyperinsulinemia. Research has shown that consuming soy and fiber may protect against type 2 diabetes mellitus. We performed a study to determine whether supplementing diet with soy extract (0.5% weight of diet) or fiber (as red wheat bran; 11.4% weight of diet) would decrease serum insulin and blood glucose levels in a pre-diabetic/metabolic syndrome animal model. In our study, female obese Zucker rats were fed either a control diet (n = 8) or control diet supplemented with either soy extract (n = 7) or red wheat bran (n = 8) for seven weeks. Compared to rats consuming control diet, rats fed treatment diets had significantly lower (p-value < 0.05) fasting serum insulin (control = 19.34±1.6; soy extract = 11.1±1.54; red wheat bran = 12.4±1.11) and homeostatic model assessment of insulin resistance values (control = 2.16±0.22; soy extract = 1.22±0.21; red wheat bran = 1.54±0.16). Non-fasted blood glucose was also significantly lower (p-value < 0.05) in rats fed treatment diets compared to rats consuming control diet at weeks four (control = 102.63±5.67; soy extract = 80.14±2.13; red wheat bran = 82.63±3.16), six (control = 129.5±10.83; soy extract = 89.14±2.48; red wheat bran = 98.13±3.54), and seven (control = 122.25±8.95; soy extract = 89.14±4.52; red wheat bran = 84.75±4.15). Daily intake of soy extract and red wheat bran may protect against type 2 diabetes mellitus by maintaining normal glucose homeostasis.

Time-series responses of swine plasma metabolites to ingestion of diets containing myo-inositol or phytase.

The effect of the ingestion of diets containing either myo-inositol or exogenous phytase on plasma metabolites was examined using 29 kg barrows. The diets were: control (maize, soya, rapeseed, rice bran), control plus 2 g/kg myo-inositol, control plus 1000 phytase units (FYT)/kg or 3000 FYT/kg exogenous phytase. Pigs were housed in a PigTurn device and blood was collected, from jugular catheters, via an automated system at -30, (30 min before feeding), 0, 15, 30, 45, 60, 90, 120, 150, 180, 240, 300 and 360 min post-feeding. The addition of 2 g/kg myo-inositol to the basal diet resulted in an increase in plasma myo-inositol concentration that was evident 45-60 min after diet introduction and persisted to 360 min post-feeding. Similarly, supplementation of the basal diet with either 1000 or 3000 FYT/kg exogenous phytase resulted in an increase in plasma myo-inositol concentration that was still rising 360 min post-feeding. Plasma P concentration was increased over time by the addition of 1000 and 3000 FYT/kg phytase, but not by the addition of myo-inositol. Other plasma metabolites examined were not affected by dietary treatment. It can be concluded that oral delivery of myo-inositol results in rapid increase in plasma myo-inositol concentrations that peak approximately 45-60 min after feeding. Use of supplemental phytase achieves similar increases in myo-inositol concentration in plasma but the appearance is more gradual. Furthermore, supplementation of pig diets with exogenous phytase results in rapid appearance of P in plasma that may be sustained over time relative to diets with no added phytase.

Docosahexaenoic acid increases accumulation of adipocyte triacylglycerol through up-regulation of lipogenic gene expression in pigs.

BACKGROUND: Changing dietary fatty acid composition in modern diet influences the prevalence of obesity. Increasing evidences suggest favorable effects of n-3 PUFA for protecting against obesity and the metabolic syndrome. However, the regulation of n-3 PUFA in adipose is still unclear. Thus, this study addressed metabolism of different dietary fats in the adipose tissue of porcine model. METHODS: Eight-week-old cross-bred pigs were randomly assigned to three groups and fed a 2% fat diet for 30 days from either soybean oil (SBO), docosahexaenoic acid (DHA) or beef tallow. An in vitro experiment was conducted in which linoleic acid (LA), DHA or oleic acid (OA) were added to represent the major fatty acid in the SBO-, DHA- or BT- diets, respectively. Adipocytes size and lipid metabolism related genes were analyzed. RESULTS: Plasma triacylglycerol (TAG) was lower in DHA- than in BT-fed pigs, and the product of lipolysis, glycerol was highest in BT-fed pigs. In addition, expression of the lipolytic genes, adipose triglyceride lipase and hormone sensitive lipase was higher in BT-fed pigs and with OA treatment in vitro. DHA promoted protein kinase A activity in pigs without affecting lipolytic genes. Adipocyte cell sizes, TAG content and expression of lipogenic-related genes including, adipose differentiated related protein (ADRP) and diacylglycerol acyltransferase 1 (DGAT1) were elevated by DHA in vivo and in vitro, indicating DHA promoted adipogenesis to trap TAG in adipose tissue. Fatty acid ß-oxidation genes were increased in the DHA-fed pigs. CONCLUSION: This effect was partly explained by the effect of DHA to promote adipogenesis to trap TAG in adipocytes and also increase expression of genes involved in adipocyte fatty acid oxidation. Therefore, our results suggest a direct effect of DHA on adipocyte metabolism, resulting in TAG turnover and fatty acid dissipation to facilitate plasma lipid uptake from the circulation.

Effect of threonine deficiency on intestinal integrity and immune response to feed withdrawal combined with coccidial vaccine challenge in broiler chicks.

For this study, threonine (Thr) deficiency was hypothesised to exacerbate the intestinal damage induced by feed withdrawal with coccidial infection because of its high obligatory requirement by the gut; two dietary Thr treatments (0·49 and 0·90 %) were applied to chicks from 0 to 21 d of age. At 13 d of age, feed was withdrawn for 24 h from one-half of birds of each dietary treatment with subsequent gavage of a 25× dose of coccidial vaccine. Overall, there were four treatments with eight replicate cages per treatment. Under combined challenge, birds fed the Thr-deficient diet had 38 % lower 13-21-d body weight gain (P≤0·05) compared with birds fed the Thr-control diet. At 21 d, the challenged group fed low Thr had higher number of oocysts (+40 %, P=0·03) and lower crypt depth (-31 %, P0·05). Overall, Thr deficiency worsened the detrimental effects of combined feed withdrawal and coccidial infection on growth performance and oocyst shedding by impairing intestinal morphology, barrier function, lymphocyte profiles and their cytokine expressions.

Cytotoxicity of various chemicals and mycotoxins in fresh primary duck embryonic fibroblasts: a comparison to HepG2 cells.

To screen cost-effectively the overall toxicity of a sample, particularly in the case of food and feed ingredient quality control, a sensitive bioassay is necessary. With the wide variety of cytotoxicity assays, performance comparison between assays using different cells has become of interest. Fresh primary duck embryonic fibroblasts (DEF) were hypothesized to be a sensitive tool for in vitro cytotoxicity screening; cell viability of DEF in response to various cytotoxins was determined and compared with response of HepG2 cells. The IC50 values by the alamar blue assay in the DEF cells had a high correlation (R(2) = 0.96) with those obtained in HepG2 cells. Within the same toxin, primary DEF yielded significantly lower IC50 values than that obtained from HepG2 cells using the MTT and alamar blue assay. Additionally, primary DEF responded to all mycotoxins tested using the alamar blue assay, while HepG2 was less sensitive, particularly at short exposure times. The estimated IC50 for aflatoxin B1 , fumonisins B1 and deoxynivalenol in DEF after 72 h incubation were 3.69, 4.19 and 1.26 µg ml(-1) , respectively. Results from the current study suggest that primary DEF are more sensitive to cytotoxins and mycotoxins compared to HepG2, and thus may have great potential as an effective tool for cytotoxicity assessment. The question remains whether in vitro IC50 values can accurately predict in vivo toxicity; however, the current study accentuates the need for further attention to identify sensitive cell models for in vitro cytotoxicity screening and subsequent exploration of species-specific prediction models for in vivo toxicity. Copyright © 2016 John Wiley & Sons, Ltd.

Role of n-3 Polyunsaturated Fatty Acids in Ameliorating the Obesity-Induced Metabolic Syndrome in Animal Models and Humans.

The incidence of obesity and its comorbidities, such as insulin resistance and type II diabetes, are increasing dramatically, perhaps caused by the change in the fatty acid composition of common human diets. Adipose tissue plays a role as the major energy reservoir in the body. An excess of adipose mass accumulation caused by chronic positive energy balance results in obesity. The n-3 polyunsaturated fatty acids (n-3 PUFA), DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid) exert numerous beneficial effects to maintain physiological homeostasis. In the current review, the physiology of n-3 PUFA effects in the body is delineated from studies conducted in both human and animal experiments. Although mechanistic studies in human are limited, numerous studies conducted in animals and models in vitro provide potential molecular mechanisms of the effects of these fatty acids. Three aspects of n-3 PUFA in adipocyte regulation are discussed: (1) lipid metabolism, including adipocyte differentiation, lipolysis and lipogenesis; (2) energy expenditure, such as mitochondrial and peroxisomal fatty acid ß-oxidation; and (3) inflammation, including adipokines and specialized pro-resolving lipid mediators. Additionally, the mechanisms by which n-3 PUFA regulate gene expression are highlighted. The beneficial effects of n-3 PUFA may help to reduce the incidence of obesity and its comorbidities.

Inhibition of MMP-13 prevents diet-induced obesity in mice and suppresses adipogenesis in 3T3-L1 preadipocytes.

Adipose tissue remodeling by the matrix metalloproteases (MMPs) is critical for tissue hypertrophy and obesity. MMP-13 is an important protein that is highly expressed in adipose tissue but whose potential role in adipose tissue expansion is poorly characterized. We investigated the effect of pharmacological inhibition of MMP-13 with a selective inhibitor, CP-544439, on adipose tissue mass in mice on a high fat diet, and determined the effect of the inhibitor during in vitro adipocyte differentiation of 3T3-L1 cells. CP-544439 was administered for 6 weeks to mice on a high fat diet. Body adiposity and glucose tolerance was determined. Differentiating 3T3-L1 adipocytes were also treated with the inhibitor for a maximum of 8 days and adipogenesis assessed. Treatment of mice with the inhibitor resulted in reduction in body adiposity and improvement in glucose clearance. Histological examination of epididymal adipose showed reduced adipocyte hypertrophy accompanied by increased staining for collagen in the inhibitor treated mice. Treatment of differentiating 3T3-L1 cells with the inhibitor resulted in reduced adipocyte differentiation. Knockdown of MMP-13 using small interfering RNA in differentiating 3T3-L1 cells reduced adipocyte differentiation indicated by reduced expression of PPARγ. These results suggest that MMP-13 may play a major role in adipose development and its inhibition could be a potential strategy to prevent obesity.

Impact of excess gestational and post-weaning energy intake on vascular function of swine offspring.

BACKGROUND: The development of long-term vascular disease can be linked to the intrauterine environment, and maternal nutrition during gestation plays a critical role in the future vascular health of offspring. The purpose of this investigation was to test the hypothesis that a high-energy (HE) gestational diet, HE post-weaning diet, or their combination will lead to endothelial dysfunction in offspring. METHODS: Duroc × Landrace gilts (n = 16) were assigned to either a HE (10,144 Kcal/day, n = 8) or normal energy (NE: 6721 Kcal/day, n = 8) diet throughout pregnancy. Piglets were placed on either a NE or HE diet during the growth phase. At 3 months of age femoral arteries were harvested from offspring (n = 47). Endothelial-dependent and -independent vasorelaxation was measured utilizing wire-myography and increasing concentrations of bradykinin (BK) and sodium nitroprusside (SNP), respectively. RESULTS: BK and SNP induced vasorelaxation were significantly reduced in the femoral arteries of gestational HE offspring. However, no effect for the post-weaning diet on BK and SNP induced vasorelaxation was seen. This investigation demonstrates that a HE diet prenatally diminishes both BK and SNP induced vasorelaxation in swine. CONCLUSIONS: These findings suggest that a HE gestational diet can play a critical role in the development of offspring's vascular function, predisposing them to endothelial dysfunction. This dysfunction may lead to atherosclerotic disease development later in life.

Impact of maternal live yeast supplementation to sows on intestinal inflammatory cytokine expression and tight junction proteins in suckling and weanling piglets.

Recent studies have highlighted the importance of maternal nutrition during gestation and lactation in modulating the gastrointestinal development and health of offspring. Therefore, the objective of this study was to determine the effects of live yeast (LY) supplementation to sows during late gestation and throughout lactation on markers of gut health of piglets prior to weaning and immediately postweaning. On day 77 of gestation, forty sows were allotted based on parity and expected farrowing dates to two dietary treatments: without (CON) or with (LY) supplementation at 0.05% and 0.1% of diet during gestation and lactation, respectively. On postnatal days (PND) 0, 10, 18, and postweaning days (PWD) 7 and 14, one piglet from each of 10 sows per treatment were selected for intestinal tissue collection (n = 10). Real-time PCR and western blotting analyses were used to determine the mucosal expression of immune and antioxidant-regulatory genes and tight junction markers of gut health in the duodenum, jejunum, and ileum. Inflammatory and tight junction markers on PND 0 were not affected by maternal dietary treatment. On PND 18, maternal LY supplementation increased (P < 0.05) mRNA expression of interleukin (IL)-6 and tended (P = 0.08) to increase expression of IL-10 in the ileal muocsa. Maternal LY supplementation also increased (P < 0.05) expression of IL-1ß in the ileal mucosa on PWD 14. Likewise, expression of superoxide dismutase (SOD) 1 was increased (P < 0.05) by LY on PND 10, 18, and PWD 14, with a tendency (P = 0.09) for a greater mRNA abundance of catalase on PND 14 in the ileal mucosa. Compared to CON piglets, LY piglets had a higher (P < 0.05) protein abundance of E-cadherin in the jejunal mucosa on PND 0, PWD 7, and PWD 14. Levels of occludin and claudin-4 were also higher (P < 0.05) in the jejunum of LY piglets on PWD 14. No differences were found in jejunal histomorphological measurements between treatments. In conclusion, this study shows that maternal LY supplementation affects key markers of gut health and development in the offspring that may impact the future growth potential and health of newborn piglets.

Increasing evidence supports the benefits of improving sow nutrition during gestation and lactation to promote gastrointestinal development and overall health of piglets. The objective of this research was to investigate the effects of maternal live yeast (LY) supplementation to sows during late gestation and lactation periods on the intestinal health of suckling and weaned piglets. Sows were fed LY during gestation and lactation and piglets were killed for sampling at different time points to track the temporal effect of maternal LY supplementation on changes in markers of intestinal health and development on postnatal days 0, 10, and 18, and postweaning days 7 and 14. Results showed that maternal LY supplementation affected several markers of health and development in the offspring, especially the expression of tight junction proteins, inflammatory cytokines, and antioxidant enzymes. These results indicate that nutritional intervention during gestation and lactation could serve as an effective strategy for raising piglets with better health and growth performance.

Regulation of adipocyte differentiation and gene expression-crosstalk between TGFß and wnt signaling pathways.

Obesity results in reduced differentiation potential of adipocytes leading to adipose tissue insulin resistance. Elevated proinflammatory cytokines from adipose tissue in obesity, such as TNFα have been implicated in the reduced adipocyte differentiation. Other mediators of reduced adipocyte differentiation include TGFß and wnt proteins. Although some overlap exists in the signaling cascades of the wnt and TGFß pathways it is unknown if TGFß or wnt proteins reciprocally induce the expression of each other to maximize their biological effects in adipocytes. Therefore, we investigated the possible involvement of TGFß signaling in wnt induced gene expression and vice versa in 3T3-L1 adipocyte. Effect of TGFß and Wnt pathways on differentiation was studied in preadipocytes induced to differentiate in the presence of Wnt3a or TGFß1 and their inhibitors (FZ8-CRD and SB431542, respectively). Regulation of intracellular signaling and gene expression was also studied in mature adipocytes. Our results show that both TGFß1 and Wnt3a lead to increased accumulation of ß-catenin, phosphorylation of AKT and p44/42 MAPK. However, differences were found in the pattern of gene expression induced by the two proteins suggesting that distinct, but complex, signaling pathways are activated by TGFß and wnt proteins to independently regulate adipocyte function.

Role of heat shock protein 70 in regulation of anti-inflammatory response to curcumin in 3T3-L1 adipocytes.

BACKGROUND/OBJECTIVES: Curcumin is a well-known phytochemical with anti-inflammatory effects. Heat shock protein (HSP) 70, an intracellular chaperone, inhibits proinflammatory signaling activation. Although curcumin has been shown to induce HSP70 expression in various cell types, whether HSP70 mediates the anti-inflammatory effects of curcumin in mature adipocytes remains unclear. MATERIALS/METHODS: To assess the role of HSP70 in regulating the anti-inflammatory response to curcumin in adipocytes, fully differentiated 3T3-L1 adipocytes were treated with curcumin, lipopolysaccharide (LPS), and/or the HSP70 inhibitor pifithrin-µ (PFT-µ). The expression levels of HSP70 and proinflammatory cytokines were then measured. RESULTS: Curcumin upregulated HSP70 expression at both protein and mRNA levels and attenuated LPS-induced Il6, Ptx3, and Ccl2 mRNA upregulation. PFT-µ tended to exacerbate the LPS-induced upregulation of Il6, Ptx3, Ccl2, and Tnfa mRNA expression. However, on curcumin pretreatment, the tendency of PFT-µ to upregulate LPS-induced proinflammatory cytokine expression decreased or disappeared. CONCLUSION: These results indicate that HSP70 is involved in the regulation of inflammatory responses but may not be crucial for the anti-inflammatory effects of curcumin in 3T3-L1 adipocytes.

PPARγ activation inhibits endocytosis of claudin-4 and protects against deoxynivalenol-induced intestinal barrier dysfunction in IPEC-J2 cells and weaned piglets.

The role of peroxisome proliferator activated receptor gamma (PPARγ) in the regulation of adipocyte differentiation has been well characterized. Besides adipose tissue, PPARγ is also highly expressed in the intestine. However, the functional role of PPARγ in the regulation of intestinal function still remains poorly understood. In the present study, we sought to understand the role of PPARγ activation on regulation of intestinal barrier function in intestinal porcine epithelial cells (IPEC-J2) and weaned piglets exposed to the mycotoxin, deoxynivalenol (DON). PPARγ activation by rosiglitazone and troglitazone, two pharmacological PPARγ ligands, increased the protein expression of tight junction proteins (TJP), claudin-3 and 4. PPARγ inhibition increased endocytosis of claudin-4 which was reversed by its activation with troglitazone. DON exposure decreased the protein expression of TJP, and also significantly suppressed PPARγ transcriptional activity. Interestingly, PPARγ activation reversed the reduction of claudin-3 and 4 caused by DON in vitro and in vivo. PPARγ activation also partially restored the transepithelial electrical resistance (TEER) and reduced the permeability of fluorescein isothiocyanate-dextran (FITC-dextran) that have been negatively impacted by DON. These effects were lost in the presence of a specific PPARγ antagonist or in PPARγ knockout cells, confirming the importance of PPARγ in the regulation of intestinal barrier function and integrity. Likewise, in weaned pigs exposed to DON, the PPARγ agonist pioglitazone mitigated the impaired villus-crypt morphology caused by DON. Therefore, pharmacological and natural bioactive compounds with PPARγ stimulatory activities could be effective in preventing DON-induced gut barrier dysfunction.

Quercetin attenuates deoxynivalenol-induced intestinal barrier dysfunction by activation of Nrf2 signaling pathway in IPEC-J2 cells and weaned piglets.

The presence of deoxynivalenol (DON), one of the most frequently occurring mycotoxin, in food and feed has been considered a risk factor to both human and animal health. Molecular mechanisms that regulate DON effects in tissues are still poorly understood. However, recent evidence suggests that nuclear factor erythroid 2-like 2 (Nrf2) may be a major target during mycotoxin-induced intestinal barrier dysfunction. Although quercetin, a plant-derived flavonoid, is known to induce the activation of Nrf2 signaling pathway, its potential to mitigate effects of DON and the implication of Nrf2 in its physiological effects is poorly understood. Therefore, this study was conducted to investigate the protective effects of quercetin in alleviating the DON-induced barrier loss and intestinal injuries in IPEC-J2 cells and weaned piglets and determine the potential role of Nrf2. Quercetin treatment dose-dependently increased mRNA expression of Nrf2 target gene, NQO-1, and concomitantly increased the expression of claudin-4 at both mRNA and protein levels. Quercetin supplementation also reversed the reduction of claudin-4 caused by DON exposure in vivo and in vitro. The decreased membrane presence of claudin-4 and ZO-1 induced by DON was also blocked by quercetin. Furthermore, quercetin attenuated the endocytosis and degradation of claudin-4 caused by DON exposure. The effects of quercetin also included the restoration of transepithelial electrical resistance (TEER) and reduction of FITC-dextran permeability that have been perturbed by DON. However, the protective effects of quercetin against DON exposure were abolished by a specific Nrf2 inhibitor (brusatol), confirming the importance of Nrf2 in the regulation of TJP expression and barrier function by quercetin. In vivo study in weaned pigs showed that DON exposure impaired villus-crypt morphology as indicated by diffuse apical villus necrosis, villus atrophy and fusion. Notably, intestinal injuries caused by DON administration were partly mitigated by quercetin supplementation. Collectively, this study shows that quercetin could be used to prevent the DON-induced gut barrier dysfunction in humans and animals and the protective effects of quercetin against DON-induced intestinal barrier disruption is partly through Nrf2-dependent signaling pathway.

EPA and DHA inhibit endocytosis of claudin-4 and protect against deoxynivalenol-induced intestinal barrier dysfunction through PPARγ dependent and independent pathways in jejunal IPEC-J2 cells.

Peroxisome proliferator activated receptor gamma (PPARγ) activation has been shown to protect against intestinal injury induced by different stimuli. PPARγ is known to regulate tight junction proteins (TJP) in epithelial cells. Both eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are natural PPARγ agonists, but the implication of PPARγ in their physiological effects on the gut is poorly understood. Therefore, this study was conducted to investigate the mechanism of EPA and DHA effects on intestinal epithelial cell barrier function in IPEC-J2 cells exposed to deoxynivalenol (DON), a known food mycotoxin that is toxic to both humans and animals. Exposure of cells to EPA and DHA significantly increased mRNA expression of a PPARγ target gene, AP2, and concomitantly increased the protein expression of claudin-4. Treatment with EPA and DHA also reversed the endocytosis and degradation of claudin-4 caused by DON exposure. EPA and DHA also restored the membrane presence of claudin-4 and ZO-1 that was disrupted by DON. However, the protective effects of EPA and DHA against DON exposure was abolished by a specific PPARγ antagonist (T0070907), confirming the importance of PPARγ in regulating TJP expression by the fatty acids. Effect of PPARγ activation by EPA and DHA also included the restoration of transepithelial electrical resistance (TEER) and reduction of fluorescein isothiocyanate-labeled dextran (FITC-dextran) permeability that have been perturbed by DON. However, the effectiveness of EPA and DHA in opposing DON-induced decrease in TEER and the increase in FITC-dextran permeability was not affected by PPARγ inhibition, potentially suggesting the involvement of other PPARγ-independent mechanisms in the observed benefits from EPA and DHA. Collectively, this study shows that the protective effects of EPA and DHA against DON-induced intestinal barrier disruption are through both PPARγ-dependent and-independent pathways. Therefore, EPA and DHA containing ingredients could be used to prevent the DON-induced gut barrier dysfunction in humans and animals.

Effects of supplemental myo-inositol on growth performance and apparent total tract digestibility of weanling piglets fed reduced protein high-phytate diets and intestinal epithelial cell proliferation and function.

Myo-inositol is a breakdown product of phytate produced in the gut through the action of phytase. Although the effect of phytase-released phosphorus (P) on growth performance of animals has been well characterized, there is still little understanding of the effect of myo-inositol. The first objective of this study was to determine the effects of added myo-inositol to a phytate-rich low-protein diet on growth performance and apparent total tract digestibility (ATTD) in growing piglets. The second objective was to determine whether myo-inositol could directly affect intestinal epithelial cell proliferation and function for which we used intestinal porcine epithelial cells (IPEC-J2). A total of 128 weanling piglets were allotted to four dietary treatments consisting of eight replicates per treatment and four piglets per replicate in a randomized complete block design for 4 wk. The four experimental diets comprised the positive control [PC; 20% crude protein (CP)], negative control (NC; 17% CP), negative control plus 2.0g/kg myo-inositol (NC+INO; 17% CP), and negative control plus 3000FTU/kg phytase (NC+PHY; 17% CP). Average daily feed intake (ADFI), average daily gain (ADG), and gain-feed ratio (G: F) were recorded. Phytase supplementation in the protein-deficient NC diet increased the G:F ratio (P < 0.05) without myo-inositol effects on growth performance. Phosphorus digestibility in the phytase-supplemented group increased compared to the PC, NC, and NC+INO groups, whereas plasma myo-inositol concentration was significantly higher (P < 0.05) in the NC+INO group. Due to the lack of myo-inositol effect on growth performance, an additional in vitro study was conducted to determine the direct effect of myo-inositol on the intestinal epithelium that might not be reflected in growth performance. Myo-inositol increased the mRNA abundance of selected nutrient transporters in a concentration-dependent manner (P < 0.05). Myo-inositol also enhanced barrier integrity in the IPEC-J2 monolayer by increasing the transepithelial electrical resistance (TEER) with reduced paracellular permeability of FITC-dextran (P < 0.05). In conclusion, despite the lack of myo-inositol effect on animal performance, the in vitro data indicate that myo-inositol may directly regulate gut barrier integrity. Addition of myo-inositol to pig diets at levels that enhance intestinal epithelial cell function may result in effects on growth performance and gut health of pigs.

After weaning, piglets undergo various kinds of stress that limit feed intake and nutrient digestibility. Much of the effects are strongest at the still-developing gastrointestinal tract where active feed digestion and nutrient uptake takes place. To sustain intestinal development and function during this stage of life, several nutrient additives are included in diets to promote intestinal function and nutrient uptake. The objective of this study was to assess the effects of phytase and myo-inositol on growth performance and apparent total tract digestibility (ATTD) in growing piglets and determine whether they had any effects on integrity in a cell culture model. In the animal study, phytase supplementation in the protein-reduced diets enhanced the rate of feed conversion, whereas the effect of myo-inositol on growth was not pronounced. Also, plasma concentration increased with myo-inositol addition. Under cell culture condition, myo-inositol enhanced the machinery for nutrients uptake and protein formation of the cells in a fashion that is dependent on its concentration. This study provides information on the potential role of myo-inositol on growth performance of growing piglets.

Gastrointestinal dynamics, immune response, and nutrient digestibility of weanling pigs fed diets supplemented with enzymatically treated yeast1.

The objective of this trial was to investigate the effect of enzymatically treated yeast (ETY) on the growth performance, nutrient digestibility, immune response, and gut health of weanling pigs. A total of 192 weanling pigs (6.0 ± 1.04 kg) were allocated to 4 corn and soybean-based diets with increasing concentrations of ETY (0, 1, 2, or 4 g/kg) for a 43-d trial. There were 8 replicate pens (4 replicate pens per sex) and 6 pigs per replicate. The experiment was set up as a randomized complete block design with body weight used as a blocking factor. Pigs had ad libitum access to water and diets for the duration of the study. There was no effect of ETY supplementation on the growth performance indices of weanling pigs. At day 14, there was a quadratic decrease (P < 0.05) in the apparent total tract digestibility (ATTD) of acid detergent fiber (ADF). At day 28, there was a linear increase (P < 0.05) in the ATTD of neutral detergent fiber and a quadratic decrease (P < 0.05) in the ATTD of ADF. On day 14, there was a linear increase (P < 0.05) in serum catalase activity with ETY supplementation. There was a linear increase (P < 0.01) in the gene expression of glutathione peroxidase-4 in the ileal mucosa of pigs. Increasing dietary ETY supplementation linearly decreased (P < 0.05) the gene expression of ileal peptide transporter 1. There was a tendency for a quadratic effect (P = 0.07) in the ileal villus height to crypt depth ratio with ETY supplementation. In addition, there was a tendency for a linear increase (P = 0.06) in ileal digesta butyrate with ETY supplementation. In conclusion, the current study demonstrated that dietary ETY supplementation could partly ameliorate the deleterious effects of post-weaning stress by enhancing the antioxidative status of weanling pigs. However, prolonged supplementation of ETY may be needed to see its effect on growth performance.

The post-weaning stage is fraught with challenges that could affect piglet lifetime growth, development, and gut health. Various factors predispose pigs to stress after weaning. These factors include the separation of piglets from the sow, temperature changes, crowding stress, exposure to new animals, and dietary and environmental antigens. With the increased search for antibiotic alternatives in weanling pigs, identifying potential health-promoting feed additives is exigent. Enzymatically treated yeast (ETY) is rich in bioactive components, including immune-stimulating glucans, mannans, and peptides. These may confer beneficial effects on pigs during the post-weaning period. In this study, ETY was supplemented in graded levels in the diet of weanling pigs. Our results showed that dietary ETY supplementation influenced gut health by promoting a better antioxidant status in weanling pigs.