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Eucommia ulmoides flavones (EUF) have been demonstrated to attenuate the inflammation and oxidative stress of piglets. This study aimed to test whether EUF could be used as an alternative antibiotic growth promoter to support growth performance and maintain intestinal health in weanling piglets. Weaned piglets (n = 480) were assigned into three groups and fed with a low-protein basal diet (NC), or supplementation with antibiotics (PC) or 0.01% EUF (EUF). Blood, intestinal contents, and intestine were collected on days 15 and 35 after weaning. The results showed the PC and EUF supplementations increased (p &lt, 0.05) body weight on day 35, average daily gain and gain: feed ratio from day 15 to day 35 and day 0 to day 35, whereas decreased (p &lt, 0.05) the diarrhea index of weanling piglets. EUF treatment increased (p &lt, 0.05) jejunal villus height: crypt depth ratio, jejunal and ileal villus height, and population of ileal lactic acid bacteria on day 15 but decreased (p &lt, 0.05) the population of ileal coliform bacteria on day 15 and day 35. These findings indicated the EUF, as the potential alternative to in-feed antibiotic growth promoter, could improve growth performance and intestinal morphology, and decrease colonization of coliform bacteria and diarrhea index in weanling piglets.

The antioxidant function and metabolic profiles in mice after dietary supplementation with methionine were investigated. The results showed that methionine supplementation enhanced liver GSH-Px activity and upregulated Gpx1 expression in the liver and SOD1 and Gpx4 expressions in the jejunum. Nrf2/Keap1 is involved in oxidative stress, and the western blotting data exhibited that dietary methionine markedly increased Keap1 abundance, while failed to influence the Nrf2 signal. Metabolomics investigation showed that methionine administration increased 2-hydroxypyridine, salicin, and asparagine and reduced D-Talose, maltose, aminoisobutyric acid, and inosine 5’-monophosphate in the liver, which are widely reported to involve in oxidative stress, lipid metabolism, and nucleotides generation. In conclusion, our study provides insights into antioxidant function and liver metabolic profiles in response to dietary supplementation with methionine.

The present study is conducted to determinate fatty acids (FA) composition in 3 adipose tissues. Subcutaneous and perirenal adipose tissues were prepared from 24 Ningxiang castrated boars and 24 castrated gilts fattened by a traditional diet for 56 d, respectively. The results showed that the FA profile in the 3 adipose tissues (dorsal subcutaneous adipose [DSA], abdominal subcutaneous adipose [ASA], and perirenal adipose [PA]) differed greatly. In boars, the proportions of oleic acid (c18:1n9c) (P

The synthetic dipeptides alanyl-glutamine (Ala-Gln) and glycyl-glutamine (Gly-Gln) are used as Gln substitution to provide energy source in the gastrointestinal tract due to their high solubility and stability. This study aimed to investigate the effects of Gln, Ala-Gln and Gly-Gln on mitochondrial respiration and protein turnover of enterocytes. Intestinal porcine epithelial cells (IPEC-J2) were cultured for 2 days in Dulbecco's modified Eagle's-F12 Ham medium (DMEM-F12) containing 2.5 mM Gln, Ala-Gln or Gly-Gln. Results from 5-ethynyl-2'-deoxyuridine incorporation and flow cytometry analysis indicated that there were no differences in proliferation between free Gln and Ala-Gln-treated cells, whereas Gly-Gln treatment inhibited the cell growth compared with Gln treatment. Significantly lower mRNA expressions of Sp1 and PepT1 were also observed in Gly-Gln-treated cells than that of Ala-Gln treatment. Ala-Gln treatment increased the basal respiration and ATP production, compared with free Gln and Gly-Gln treatments. There were no differences in protein turnover between free Gln and Ala-Gln-treated cells, but Gly-Gln treatment reduced protein synthesis and increased protein degradation. Ala-Gln treatment stimulated mTOR activation whereas Gly-Gln decreased mTOR phosphorylation and increased the UB protein expression compared with free Gln treatment. These results indicate that Ala-Gln has the very similar functional profile to free Gln in porcine enterocytes in vitro and can be substituted Gln as energy and protein sources in the gastrointestinal tract.

The present study was conducted to evaluate the effects of glucose, soya oil or glutamine on jejunal morphology, protein metabolism and protein expression of the mammalian target of rapamycin complex 1 (mTORC1) signalling pathway in jejunal villus or crypt compartment of piglets. Forty-two 21 d-weaned piglets were randomly allotted to one of the three isoenergetic diets formulated with glucose, soya oil or glutamine for 28 d. On day 14 or 28, the proteins in crypt enterocytes were analysed with isobaric tags for relative and absolute quantification and proteins involved in mTORC1 signalling pathway in villus or crypt compartment cells were determined by Western blotting. Our results showed no significant differences (P > 0·05) in jejunal morphology among the three treatments on day 14 or 28. The differentially expressed proteins mainly took part in a few network pathways, including antimicrobial or inflammatory response, cell death and survival, digestive system development and function and carbohydrate metabolism. On day 14 or 28, there were higher protein expression of eukaryotic initiation factor-4E binding protein-1 in jejunal crypt compartment of piglets supplemented with glucose or glutamine compared with soya oil. On day 28, higher protein expression of phosphor-mTOR in crypt compartment was observed in piglets supplemented with glucose compared with the soya oil. In conclusion, the isoenergetic glucose, soya oil or glutamine did not affect the jejunal morphology of piglets; however, they had different effects on the protein metabolism in crypt compartment. Compared with soya oil, glucose or glutamine may be better energy supplies for enterocytes in jejunal crypt compartment.

Eucommia ulmoides flavones (EUF) have been demonstrated to alleviate oxidative stress and intestinal damage in piglets, but their effect target is still poorly understood. NF-E2-related factor 2 (Nrf2) pathway plays a very important role in the defense mechanism. This study was designed to investigate the regulation of EUF on the Nrf2 pathway and inhibition of Nrf2 on oxidative stress in the intestine of piglets. An in vivo study was conducted in weaned piglets treated with basal diet, basal diet+diquat, and 100 mg/kg EUF diet+diquat for 14 d to determine Nrf2 and Keap1 protein expressions, as well as downstream antioxidant gene mRNA expression. An in vitro study was performed in a porcine jejunal epithelial cell line to investigate the effect of inhibiting Nrf2 on cell growth and intracellular oxidative stress parameters. The results showed that the supplementation of EUF decreased the oxidized glutathione (GSSG) concentration and the ratio of GSSG to glutathione (GSH) but increased the protein expressions of nuclear Nrf2 and Kelch-like ECH-associated protein 1 (Keap1) as well as mRNA expression of heme oxygenase 1 (HO-1), NAD(P)H:quinone oxidoreductase 1 (NQO-1), and glutamate cysteine ligase catalytic subunit (GCLC) in the small intestinal mucosa of diquat-challenged piglets. When Nrf2 was inhibited by using ML385, cell viability, cellular antioxidant activities, expressions of nuclear Nrf2 and Keap1 protein, and downstream antioxidant enzyme (HO-1, NQO-1, and GCLC) mRNA were decreased in paraquat-treated enterocytes. These results showed that the Nrf2 signaling pathway played an important role in EUF-regulating oxidative stress in the intestine of piglets.

Resveratrol (3,4′,5-trihy- droxystilbene), a natural phytoalexin polyphenol, exhibits anti-oxidant, anti-inflammatory, and anti-carcinogenic properties. This phytoalexin is well-absorbed and rapidly and extensively metabolized in the body. Inflammation is an adaptive response, which could be triggered by various danger signals, such as invasion by microorganisms or tissue injury. In this review, the anti-inflammatory activity and the mechanism of resveratrol modulates the inflammatory response are examined. Multiple experimental studies that illustrate regulatory mechanisms and the immunomodulatory function of resveratrol both in vivo and in vitro. The data acquired from those studies are discussed.

This study was conducted to explore the effect of chitosan supplementation on mouse intestinal microbiota and interleukin-17 (IL-17) expression. Chitosan supplementation reduced mouse body weight, associating with change of intestinal microbiota (i.e. lowering the ratio of Firmicutes: Bacteroidetes). In antibiotics treated mice, chitosan supplementation had little effect on mouse body weight. Chitosan supplementation decreased expression of IL-17 in mouse jejunum and inhibited the mTOR pathway. In antibiotics treated mice, chitosan also reduced expression of IL-17 in the jejunum. Activation of mTOR signalling in mouse increased expression of IL-17 in the jejunum in the context of chitosan supplementation. We conclude that chitosan supplementation reduces mouse body weight through the intestinal microbiota, and inhibits intestinal IL-17 expression through the mTOR signalling. The discovery of this study suggests the potentials of chitosan as a functional supplement in intestinal health.

Context Heat stress is one of the problems commonly found in broiler industry in tropic and subtropic regions that results in impairment of intestinal integrity, leading to inflammation and poor performance. Aims This study aimed to investigate the effect of dietary resveratrol supplementation on growth performance, intestinal morphology and barrier integrity, and inflammation response of yellow-feather broilers under heat stress. Methods In total, 288 birds (28-day-old) were randomly allotted to three treatment groups, with six replicates. A thermo-neutral group (24 ± 2°C) received a basal diet and two heat-stressed groups (37 ± 2°C for 8 h/day and 24 ± 2°C for the remaining time) were fed the basal diet (HT) or basal diet supplemented with 500 mg/kg resveratrol for 14 consecutive days. Key results Compared with the thermo-neutral group, birds in the HT group had a decreased (P < 0.05) average daily feed intake, average daily gain, villus height, villus height to crypt depth ratio, mRNA concentrations of mucin-2, secreted immunoglobulin A (sIgA), claudin-1,zona occludens-1 and serum concentrations of interferon γ, and increased (P < 0.05) feed to gain ratio, crypt depth, mRNA levels of expression of heat-shock protein (HSP) 70, HSP90, nuclear factor kappa B, mucin-4, claudin-2 and serum concentrations of endotoxin, interleukin (IL)-1β, IL-4, IL-6 and tumour necrosis factor (TNF)-α on Day 3 and Day 14, except for claudin-1 on Day 14 and TNF-α on Day 3 (P > 0.05). Compared with HT group, birds in HT supplemented with resveratrol group decreased (P < 0.05) crypt depth (in jejunum on Day 3, ileum on Day 14), mRNA levels of expression of HSP70, HSP90, nuclear factor kappa B, mucin-4, claudin-2 and serum concentrations of endotoxin, IL-1β, IL-4, IL-6 and TNF-α, and increased (P < 0.05) average daily feed intake (+11%), average daily gain (+22%) and villus height, villus height to crypt depth ratio, mRNA levels of expression of mucin-2, sIgA, claudin-1,zona occludens-1 and serum concentrations of interferon γ, although with few fluctuations between Day 3 and Day 14. Conclusions Dietary supplementation of resveratrol was effective in partially alleviating the adverse effects of heat stress on growth performance and intestinal barrier function in yellow-feather broilers, by restoring the impaired villus-crypt structure, altering the mRNA expression of intestinal HSPs, mucins, sIgA and tight junction-related gene, and inhibiting secretion of pro-inflammation cytokines. Implications Dietary resveratrol supplementation is a considerable nutritional strategy to anti-stress in animal production.

Peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) has gained popularity as a very attractive target for diabetic therapies due to its role in lipid and glucose metabolism. Pharmacological activation of PGC-1α is thought to elicit health benefits. However, this notion has been questioned by increasing evidence, which suggests that insulin resistant is exacerbated when PGC-1α expression is far beyond normal physiological limits and is prevented under the condition of PGC-1α deficiency. This narrative review suggests that PGC-1α, as a master metabolic regulator, exerts roles in insulin sensitivity in a tissue-specific manner and in a physical activity/age-dependent fashion. When using PGC-1α as a target for therapeutic strategies against insulin resistance and T2DM, we should take these factors into consideration. Level of evidence: Level V, narrative review.

This study was to investigate the effect of soyabean isoflavones (SIF) on onset of puberty, serum hormone concentration, and gene expression in hypothalamus, pituitary and ovary of female Bama miniature pigs. Fifty five, 35-days old pigs were randomly assigned into 5 treatment groups consisting of 11 pigs per treatment. Results showed that dietary supplementation of varying dosage (0, 250, 500, and 1,250 mg/kg) of SIF induced puberty delay of the pigs with the age of puberty of pigs fed basal diet supplemented with 1,250 mg/kg SIF was significantly higher (p

The effects of dietary supplementation with lysine-yielding Bacillus subtilis on gut morphology, cecal microflora, and expression of intestinal cytokine mRNA of Linwu ducks (a Chinese local domesticated duck) were investigated after a 63-d feeding trial. Two hundred forty 1-d-old female ducklings were randomly assigned to 1 of 4 dietary treatments, and there were 60 birds per treatment replicated 6 times with 10 birds each. The experimental diets consisted of a basal diet containing no antibiotic or growth promoters, the basal diet supplemented with 150 mg Aureomycin per kg feed, and 2 others supplemented with 5.0 × 108 and 5.0 × 1010 cfu B. subtilis/kg feed, respectively. Birds fed the diets supplemented with B. subtilis had increased (P < 0.001) villi height in the jejunum and ileum and reduced (P < 0.001) crypt depth in the jejunum compared with birds fed the control diet. Greatest (P < 0.01) villus height:crypt depth ratio was obtained with the jejunum and ileum of birds fed the diet supplemented with 5.0 × 1010 cfu B. subtilis/kg feed. Dietary supplementation with B. subtilis resulted in increased (P < 0.05) cecal counts of Megasphaera elsdenii. Greater cecal Lactobacillus counts were obtained in ducks fed the diets supplemented with Aureomycin and B. subtilis. Ducks fed the diets supplemented with B. subtilis showed suppressed (P < 0.001) expression of interleukin (IL)-1β, IL-2, and IL-10 in their jejunum. When compared with the control, the expression of interferon (IFN)-γ in the jejunum of ducks fed the diet supplemented with 5.0 × 108 cfu B. subtilis/kg feed was significantly increased (P < 0.05). Dietary supplementation with B. subtilis or Aureomycin reduced (P < 0.001) ileal expression of IL-10. When compared with the control, the expression of IL-2 and IL-8 in the ileum of ducks fed the diet supplemented with 5.0 × 1010 cfu B. subtilis/kg feed showed a significant decrease (P < 0.05). In conclusion, dietary supplementation with lysine-yielding B. subtilis improved gut morphology, increased the population of beneficial gut microflora, and stimulated increased intestinal immune response of Linwu ducks.

Polyamines are necessary for normal integrity and the restitution after injury of the gastrointestinal epithelium. The objective of this study was to investigate the effects of oral administration of putrescine and proline during the suckling period on epithelial restitution after early weaning in piglets. Eighteen neonatal piglets (Duroc × Landrace × Large Yorkshire) from 3 litters (6 piglets per litter) were assigned to 3 groups, representing oral administration with an equal volume of saline (control), putrescine (5 mg/kg BW), and proline (25 mg/kg BW) twice daily from d 1 to weaning at 14 d of age. Plasma and intestinal samples were obtained 3 d after weaning. The results showed that oral administration of putrescine or proline increased the final BW and ADG of piglets compared with the control (P < 0.05). Proline treatment decreased plasma D-lactate concentration but increased the villus height in the jejunum and ileum, as well as the percentage of proliferating cell nuclear antigen (PCNA) positive cells and alkaline phosphatase (AKP) activity in the jejunal mucosa (P < 0.05). The protein expressions for zonula occludens (ZO-1), occludin, and claudin-3 (P < 0.05) but not mRNA were increased in the jejunum of putrescine- and proline-treated piglets compared with those of control piglets. The voltage-gated K+ channel (Kv) 1.1 protein expression in the jejunum of piglets administrated with putrescine and the Kv1.5 mRNA and Kv1.1 protein levels in the ileum of piglets administrated with proline were greater than those in control piglets (P < 0.05). These findings indicate that polyamine or its precursor could improve mucosal proliferation, intestinal morphology, as well as tight junction and potassium channel protein expressions in early-weaned piglets, with implications for epithelial restitution and barrier function after stress injury.

PCV2 is highly pathogenic, however, its effect on the serum amino acids profile is unknown. This study was conducted to explore the profile of amino acids in the serum in porcine circovirus type 2 (PCV2) infected mice. The serum levels of amino acids were detected with isotope dilution liquid chromatography-mass spectrometry methods at 3, 7, 10 and 14 days post infection (DPI). Meanwhile, the expression of seven amino acids transporters (SLC6A14, SLC6A20, SLC7A5, SLC7A6, SLC7A7, SLC7A8, SLC7A9) in the jejunum was analyzed by reverse transcription polymerase chain reaction (RT-PCR) at 3 and 7 DPI. Serum PCV2 load was also analyzed by quantitative PCR at 3, 7, 10 and 14 DPI. Serum levels of most amino acids, such as Pro, Orn, and Met, significantly (P < 0.05) increased at 3 DPI. However, most amino acids, including Asp, Sar, Arg, Hyl, Pro, Lys, Val, Ile and Leu, significantly (P < 0.05) decreased at 7 DPI. There was no significant difference for most amino acids at 10 and 14 DPI. PCV2 infection significantly (P < 0.05) decreased expression of SLC7A5 and SLC7A6 at 7 DPI. In conclusion, PCV2 infection affects the profile of amino acids in the serum and the expression of amino acids transporters in the intestine.

The mycotoxin deoxynivalenol (DON) is a food contaminant that leads to reduced feed intake and reduced BW gain, as well as organ impairment. On the other hand, antimicrobial peptides have been shown to have positive effects on growth performance, nutrient digestibility, and immune function. The purpose of this study was to investigate the protective effects of composite antimicrobial peptides (CAP) on piglets challenged with DON. After a 7-d adaptation period, 28 individually housed piglets (Duroc × Landrace × Large Yorkshire) weaned at 28 d of age were randomly assigned to receive 1 of 4 treatments (7 pigs/treatment): negative control, basal diet (NC), basal diet + 0.4% CAP (CAP), basal diet + 4 mg/kg DON (DON), and basal diet + 4 ppm DON + 0.4% CAP (DON + CAP). On d 15 and 30 after the initiation of treatment, blood samples were collected for the determination of blood profile. Piglets were monitored for 30 d to assess performance and then were slaughtered to obtain organs for the determination of the relative weight of organs. The results showed that dietary supplementation with DON decreased (P 0.05) on other relative weights of viscera, except the relative weight of the gallbladder, but the diamine oxidase activity in the liver decreased in DON-treated piglets (P 0.05) between the DON + CAP treatment and the other treatments. The DON treatment decreased the numbers of red blood cells and platelets, as well as the serum catalase concentrations, and decreased the serum concentrations of H2O2, maleic dialdehyde, and nitric oxide (P < 0.05). The numbers of platelets and thrombocytocrit, as well as the serum concentrations of catalase, were greater, whereas the maleic dialdehyde concentrations were decreased, in both the CAP and DON + CAP treatments compared with the other treatments (P < 0.05). Compared with the control treatment, DON decreased peripheral lymphocyte proliferation on d 15, whereas supplementation with CAP increased it on d 15 and 30 (P < 0.05). These findings indicate that CAP could improve feed efficiency, immune function, and antioxidation capacity and alleviate organ damage, and thus, it has a protective effect in piglets challenged with DON.

Chitosan oligosaccharide (COS) is a degradation product of chitosan with antioxidative, anti-inflammatory, and antibacterial effects. This study was conducted to investigate the effects of dietary COS on the intestinal inflammatory response and the calcium-sensing receptor (CaSR) and nuclear transcription factor kappa B (NF-κB) signaling pathways that may be involved using a lipopolysaccharide (LPS)-challenged piglet model. A total of 40 weaned piglets were used in a 2 × 2 factorial design; the main factors were dietary treatment (basal or 300 μg/kg COS) and inflammatory challenge (LPS or saline). On the morning of days 14 and 21 after the initiation of treatment, the piglets were injected intraperitoneally with Escherichia coli LPS at 60 and 80 μg/kg body weight or the same amount of sterilized saline, respectively. Blood and small intestine samples were collected on day 14 or 21, respectively. The results showed that piglets challenged with LPS have a significant decrease in average daily gain and gain:feed and histopathological injury in the jejunum and ileum, whereas dietary supplementation with COS significantly alleviated intestinal injury induced by LPS. Piglets fed the COS diet had lower serum concentrations of tumor necrosis factor alpha (TNF-α), interleukin (IL) 6, and IL-8 as well as lower intestinal abundances of pro-inflammatory cytokine mRNA but higher anti-inflammatory cytokine mRNA compared with piglets fed the basal diet among LPS-challenged piglets (p < 0.05). Dietary COS increased intestinal CaSR and PLCβ2 protein expressions in both saline- and LPS-treated piglets, but decreased p-NF-κB p65, IKKα/β, and IκB protein expressions in LPS-challenged piglets (p < 0.05). These findings indicate that COS has the potential to reduce the intestinal inflammatory response, which is concomitant with the activation of CaSR and the inhibition of NF-κB signaling pathways under an inflammatory stimulus.

Chitosan oligosaccharide (COS) has a blood glucose lowering effect in diabetic rats and is widely used as a dietary supplement. However, the effect of COS on the offspring of supplemented mothers is unknown. This experiment investigates the effect of supplementing sows during gestation and lactation on the levels of plasma glucose on suckling piglets. From day 85 of gestation to day 14 of lactation, 40 pregnant sows were divided into two treatment groups and fed either a control diet or a control diet containing 30mgCOS/kg. One 14 day old piglet per pen was selected to collect plasma and tissue (8pens/diet). Performance, hepatic gluconeogenesis genes and proteins expression, amino acids contents in sow milk, hepatic glycogen and free fatty acid were determined. Results showed that supplementation of the maternal diet with COS improved daily gain and weaning weight (P

The aim of this study was to investigate whether supplementation with chitosan (COS) could reduce diarrhea and to explore how COS alleviates intestinal inflammation in weaned pigs. Thirty pigs (Duroc×Landrace×Yorkshire, initial BW of 5.65±0.27) weaned at age 21 d were challenged with enterotoxigenic Escherichia coli during a preliminary trial period, and then divided into three treatment groups. Pigs in individual pens were fed a corn-soybean meal diet, that contained either 0 (control), 50 mg/kg chlortetracycline, or 300 mg/kg COS for 21 days. The post-weaning diarrhea frequency, calprotectin levels and TLR4 protein expression were decreased (P

This study was conducted to investigate how chitosan (COS) affects intestinal mucosal barrier function and to further explain mechanisms of COS on growth performance. Thirty piglets, weaned at 21 days of age, were challenged with enterotoxigenic Escherichia coli during preliminary trial period. Three groups of Piglets in individual pens were fed a corn-soybean meal diet containing no addition, 50 mg/kg chlortetracycline, or 300 mg/kg COS for 21 days. Jejunal morphology and histology were analyzed under light microscope. The concentrations of occludin proteins were determined by western blot. Immunohistochemistry assays were used to determine secretory immunoglobulin (sIgA) level. Real-time PCR was used to detect Toll-like receptor 4 (TLR4) and Claudin-1 in jejunal mucosa. Feeding COS or chlortetracycline reduced (P0.05) feed conversion ratio. Villus length, villus length/crypt depth, and goblet cells, were increased (P0.05), but villus width and crypt depth were decreased (P0.05) in both COS and chlortetracycline groups. Intraepithelial lymphocytes were higher (P0.05) in the COS group than both chlortetracycline and control groups. Occludin protein expression was increased (P0.01) in the COS group, but was decreased (P0.05) in the chlortetracycline group. Expression of sIgA protein was higher (P0.05) in the COS group than both control and chlortetracycline groups, however TLR4 mRNA expression was decreased (P0.05) in both COS and chlortetracycline groups. There was no difference in expression of claudin-1 among the three groups. In conclusion, chitosan and the antibiotic have similar effects in promoting piglet growth and reducing intestinal inflammation, but different effects on intestinal mucosal barrier function. This indicates that chitosan can replace chlortetracycline as a feed additive for piglets.

This study was conducted to determine the effect of dietary supplementation of a low dose of chito-oligosaccharide (COS) on intestinal morphology, immune response, antioxidant capacity, and barrier function in weaned piglets. A total of 120 weaned pigs (21 d of age; 7.86 ± 0.22 kg average BW) were randomly assigned (6 pens/diet; 10 pigs/pen) to 2 dietary treatments consisting of a basal diet (negative control) or the basal diet supplemented with COS (30 mg/kg) for a 14-d period. Six randomly selected piglets from each treatment were killed for blood and tissue sampling. No significant differences were observed in ADG, ADFI, and G:F between treatment and the control group. Piglets fed the COS-supplemented diet had greater ( < 0.05) stomach pH than those fed the control diet on d 14 postweaning. Dietary supplementation with COS reduced villus height ( < 0.05) and villus height:crypt depth ( < 0.05) in the ileum. Dietary COS supplementation tended to reduce villus height in the duodenum ( = 0.065) and jejunum ( = 0.058). There was no effect on crypt depth in the intestinal segments of treatment group. Piglets fed the COS-supplemented diet increased ( < 0.05) the number of intraepithelial lymphocytes in duodenum or jejunum and goblet cells of ileum. However, COS decreased ( < 0.05) the number of intraepithelial lymphocytes in ileum of weaned piglets. The concentrations of IL-10 (duodenum, jejunum, and ileum) and secretory immunoglobulin (SIgA; duodenum and ileum) were higher in piglets fed the COS-supplemented diet compared with control ( < 0.05). Dietary COS supplementation reduced ( < 0.05) the concentration of total antioxidant capacity and superoxide dismutase of the jejunum or ileum. The mRNA expression of occludin in the ileum and ZO-1 in jejunum and ileum had a significant change in piglets fed the COS-supplemented diet compared with the control group ( < 0.05). In conclusion, these results indicated that dietary COS supplementation at 30 mg/kg had no effects on promoting growth performance and tended to reduce villus height in the duodenum or jejunum of weaned piglets. The results further showed that supplemental COS at this level may cause an immune and oxidative stress response in small intestine and have compromised the intestinal barrier integrity in weaned piglets. The research will provide guidance on the low dosage of COS supplementation on weaning pigs.