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Cordyceps militaris (CM), a well-known parasitic fungus that grows on the larvae of Lepidoptera, has a variety of pharmacological activities. However, little is known about its safe dosage for animals, including pigs. To explore its effect on intestinal health and evaluate its safe dosage, 30 weaned pigs were randomly allotted to five groups and fed with a basal diet supplemented with different doses of CM for 42 days. The results showed that CM supplementation at 100 mg/kg increased the average daily weight gain (ADG) and significantly decreased the ratio of feed intake to gain (F:G) in the weaned pigs (p < 0.05). However, CM supplementation at a higher dose (1000 to 4000 mg/kg) had no effect on growth performance. CM supplementation at 100 mg/kg also increased the digestibility of gross energy and increased the ratio of villus height to crypt depth (V/C) in the duodenum and ileum (p < 0.05). Moreover, CM supplementation at 100 mg/kg increased the activities of catalase (CAT) and total antioxidant capacity (T-AOC), but decreased the concentration of malondialdehyde (MDA) in serum (p < 0.05). Importantly, histopathological studies of tissues (e.g., heart, liver, kidney, spleen, lungs, pancreas, thymus, mesenteric lymph nodes, stomach, and small intestine), organ indexes, major hematological parameters, and serum biochemical parameters were not affected upon CM supplementation. These results suggest that CM may have the potential to act as a safe and effective supplement to improve the growth performance and intestinal health of weaned pigs. [ABSTRACT FROM AUTHOR]

Simple Summary: Lipids are an ideal source of energy for piglets. Several studies have shown that dietary oil supplementation can improve the growth performance of weaned piglets. This experiment investigated the effects of different fat sources on the growth performance and intestinal health of weaned piglets, and compared with the conventional use of soybean oil, pigs treated with fish–palm–rice oil mixture (FPRO) and coconut–palm–rice oil mixture (CPRO) showed improvements in digestibility and intestinal epithelial function, and a reduction in the production of inflammatory cytokines. The results of this study can provide the theoretical basis for the rational selection of lipid sources in weaned piglets and other mammals. To investigate the effects of lipid sources on growth performance and intestinal health, 72 weaned pigs were randomly allocated to three treatments. Pigs were fed with a corn–soybean meal diet containing 2% soybean oil (SO), or fish–palm–rice oil mixture (FPRO), or coconut–palm–rice oil mixture (CPRO). The trial lasted for 28 days; blood and intestinal tissue samples were collected. The results showed that the crude fat digestibility of the FPRO group was higher than that of the SO and CPRO groups (p < 0.05). The FPRO group also had higher digestibility of dry matter, ash, and gross energy than the SO group (p < 0.05); compared to the SO group, the serum interlukin-6 (IL-6) concentration was decreased. Interestingly, the FPRO and CPRO groups had higher villus height than the SO group in the jejunum and ileum, respectively (p < 0.05). Moreover, the FPRO group had higher Lactobacillus abundance than the SO group in the colon and cecum (p < 0.05). Importantly, the expression levels of tight junction protein ZO-1, Claudin-1, and Occludin in the duodenal and ileal mucosa were higher in the FPRO group than in the SO and CPRO groups (p < 0.05). The expression levels of nutrient transporters such as the CAT-1, PepT1, FATP1, and SGLT1 were higher in the FPRO group than in the SO group (p < 0.05). The improved digestibility and intestinal epithelium functions, as well as the reduced inflammatory cytokines, in the FPRO and CPRO group suggest that a mixed lipid source such as the FPRO deserves further attention. [ABSTRACT FROM AUTHOR]

Simple Summary: Microbially fermented feed can improve the nutritional value and quality of the feed. Liquid feeding can increase feed intake and reduce the morbidity and mortality of piglets. Therefore, in this study, the integrated technology of a diet fermented with bacterial enzymes and liquid feeding was used to study its effects on the growth performance and intestinal health of weaned piglets. Compared with the control group (standard dry feed, control group), the diet of the liquid feeding group (liquid feeding group with fermented diet) was able to increase palatability, improve nutrient digestibility, and modulate metabolism, resulting in higher feed efficiency and better growth performance. The results of this study provide a reference for the development and utilization of antibiotic-free feed for weaned piglets. Microbial fermentation has been widely used to preserve or improve the nutritional properties of food. Liquid feeding can increase feed intake and reduce the morbidity of piglets. The objective of this study was to evaluate the effects of a diet fermented with bacteria and enzymes and liquid feeding on growth performance, nutrient digestibility, digestive enzyme activity, microflora, and expressions of intestinal development-related genes in weaning pigs. A total of 198 piglets (Duroc × Landrace × Yorkshire) with body weights of 8.70 ± 0.45 kg were assigned to three groups with six replicates per treatment, and 11 weaned piglets per replicate according to the initial body weight and sex. The three dietary treatments (all nonpelleted diets) were a standard dry feed as the control (CON), a control diet supplemented with antibiotics (AB), and a liquid feeding with a fermented diet (LFD). The liquid feeding diet, having the same composition and proportion of each ingredient as the control diet, was prepared by storing the dietary cereals (corn, soybeans, etc.) and water (1:0.5, wt/wt) in a closed tank at 26–30 °C with enzymes and bacteria, and then adding the remaining dietary ingredients immediately before feeding. The whole trial lasted 42 days. On days 11 to 14 and 39 to 42, fresh faecal samples were collected to evaluate the apparent total tract digestibility of nutrients. Performance, digestibility, serum physiochemical parameters, intestinal barrier function, microbiota, and microbial metabolites were measured. The experimental data were subjected to analysis of variance using the GLM procedure of SAS for a complete randomized block design, with a "pen" as the experimental unit. The results showed that the AB increased (p < 0.05) average daily gain and reduced (p < 0.05) feed conversion (F/G) over the course of 1–14 days compared to the control. The liquid feeding group significantly increased (p < 0.05) average daily gain, average daily feed intake, and final body weight compared to the other two dietary groups. The digestibility of crude protein, ether extract, ash, gross energy, Ca, and P also improved in the liquid feeding group. Moreover, the liquid feeding group significantly decreased (p < 0.05) serum urea nitrogen and D-lactate concentrations, as well as the activity of diamine oxidase, and increased (p < 0.05) serum total protein and glucose concentrations on day 14. Furthermore, the liquid feeding group significantly increased (p < 0.05) mRNA expressions of zonula occludens-2 (ZO-2) in the jejunum and zonula occludens-1 (ZO-1), ZO-2, occludin, and claudin-1 in the ileum. In addition, microbiota measurement suggested an increase in Lactobacillus content and a decrease in Escherichia coli with higher (p < 0.05) concentrations of acetic acid, propionic acid, butyric acid, and total volatile fatty acids in the caecal and colonic digesta of piglets in the liquid feeding group. In conclusion, the diet in the liquid feeding group was able to increase palatability, improve nutrient digestibility, and modulate metabolism, which resulted in higher feed efficiency and better growth performance in the piglets. [ABSTRACT FROM AUTHOR]

To explore the protective effect of dietary β-glucan (BGL) supplementation on intestinal epithelium exposure to enterotoxigenic Escherichia coli (ETEC), thirty-two weaned pigs were assigned to four groups. Pigs were fed with a basal diet or basal diet containing 500 mg/kg BGL, and were orally infused with ETEC or culture medium. Results showed BGL supplementation had no influence on growth performance in weaned pigs. However, BGL supplementation increased the absorption of D-xylose, and significantly decreased the serum concentrations of D-lactate and diamine oxidase (DAO) in the ETEC-challenged pigs (p < 0.05). Interestingly, BGL significantly increased the abundance of the zonula occludens-1-(ZO-1) in the jejunal epithelium upon ETEC challenge (p < 0.05). BGL supplementation also increased the number of S-phase cells and the number of sIgA-positive cells, but significantly decreased the number of total apoptotic cells in the jejunal epithelium upon ETEC challenge (p < 0.05). Moreover, BGL significantly increased the duodenal catalase (CAT) activity and the ileal total superoxide dismutase (T-SOD) activity in the ETEC-challenged pigs (p < 0.05). Importantly, BGL significantly decreased the expression levels of critical inflammation related proteins such as the tumor necrosis factor-α (TNF-α), interlukin-6 (IL-6), myeloid differentiation factor 88 (MyD88), and nuclear factor-κB (NF-κB) in the jejunal and ileal mucosa upon ETEC challenge (p < 0.05). BGL also elevated the propanoic acid content and the abundance of Lactobacillus and Bacillus in the colon upon ETEC challenge (p < 0.05). These results suggested BGL could alleviate the ETEC-induced intestinal epithelium injury, which may be associated with suppressed inflammation and improved intestinal immunity and antioxidant capacity, as well as the improved intestinal macrobiotic. [ABSTRACT FROM AUTHOR]

Transmissible gastroenteritis virus (TGEV), a coronavirus that causes severe diarrhea due to oxidative stress in the piglet intestine, is a major cause of economic loss in the livestock industry. However, limited interventions have been shown to be effective in the treatment of TGEV. Here, we demonstrate the therapeutic activity of eugenol in TGEV-induced intestinal oxidative stress and apoptosis. Our data show that eugenol supplementation protects intestine and IPEC-J2 cells from TGEV-induced damage. Mechanistically, eugenol reduces TGEV-induced oxidative stress in intestinal epithelial cells by reducing reactive oxygen species levels. Interestingly, eugenol also inhibits TGEV-induced intestinal cell apoptosis in vitro and in vivo. In conclusion, our data suggest that eugenol prevents TGEV-induced intestinal oxidative stress by reducing ROS-mediated damage to antioxidant signaling pathways. Therefore, eugenol may be a promising therapeutic strategy for TGEV infection. [ABSTRACT FROM AUTHOR]

Background: To examine the effect of β-glucan (BGL) supplementation on growth performance and intestinal epithelium functions in weaned pigs upon Enterotoxigenic Escherichia coli (ETEC) challenge. Methods: Thirty-two weaned pigs (Duroc × Landrace × Yorkshire) were assigned into four groups. Pigs fed with a basal diet or basal diet containing 500 mg/kg BGL were orally infused with ETEC or culture medium. Results: Results showed BGL tended to increase the average daily gain (ADG) in ETEC-challenged pigs (0.05 < p < 0.1). Dietary BGL supplementation had no significant influence on nutrient digestibility (p > 0.05). However, BGL improved the serum concentrations of immunoglobulin (Ig) A and IgG, and was beneficial to relieve the increasement of the concentrations of inflammatory cytokines such as the TNF-α and IL-6 upon ETEC-challenge (p < 0.05). Interestingly, BGL significantly increased the duodenal, jejunal and ileal villus height, and increased the jejunal ratio of villus height to crypt depth (V/C) upon ETEC challenge (p < 0.05). BGL also increased the activities of mucosal, sucrase and maltase in the ETEC-challenged pigs (p < 0.05). Moreover, BGL elevated the abundance of Lactobacillus and the concentration of propanoic acid in colon in the ETEC-challenged pigs (p < 0.05). Importantly, BGL elevated the expression levels of zonula occludins-1 (ZO-1) and mucin-2 (MUC-2) in the small intestinal mucosa upon ETEC challenge (p < 0.05). BGL also upregulated the expressions of functional genes such as the claudin-1, cationic amino acid transporter-1 (CAT-1), LAT-1, L amino acid transporter-1 (LAT1), fatty acid transport proteins (FATP1), FATP4, and sodium/glucose cotransporter-1 (SGLT-1) in the duodenum, and the occludin-1 and CAT-1 in the jejunum upon ETEC challenge (p < 0.05). Conclusions: These results suggested that BGL can attenuate intestinal damage in weaned pigs upon ETEC challenge, which was connected with the suppressed secretion of inflammatory cytokines and enhanced serum immunoglobulins, as well as improved intestinal epithelium functions and microbiota. [ABSTRACT FROM AUTHOR]

Manno-oligosaccharide (MOS) is a prebiotic derived from natural plants or yeasts. Here, we explored the response of intestinal microbiota and epithelial functions after ingestion of MOS in a porcine model. Sixteen pigs were randomly assigned into two treatments and fed with basal or MOS-containing (0.3% MOS) diet for 21 days. Results showed that MOS supplementation increased the cecal acetate content and ileal 16S rRNA gene copies (p < 0.05). Importantly, MOS decreased the abundance of phylum Proteobacteria in cecal digesta (p < 0.05). Moreover, MOS elevated the expression level of SCL5A8 and GPR109A but decreased the expression levels of HDAC1 and TNF-α in the ileal and cecal mucosa (p < 0.05). MOS upregulated the expression levels of tight-junction protein (ZO-1, claudin-1, and occludin) and IGF-1 in the ileum and cecum (p < 0.05). This study presents the alteration of intestinal microbiota composition and intestinal barrier function after MOS administration, and facilitates our understanding of the mechanisms behind the dietary MOS-modulated intestinal microbiota and health. [ABSTRACT FROM AUTHOR]

Corn and soybean meal are the two main components in formula feed of farm animals, leading to a serious food competition between humans and livestock. An alternative may be to encourage the utilization of unconventional feedstuff in animal diet. In the current study, we evaluated the utilization of fermented alfalfa meal (FAM) in weaned pigs. Twenty weaned piglets (separately caged) were randomly divided into two groups. Pigs in the control group (CON) were fed corn-soybean meal diet, and part of corn and soya protein concentrate in the diet of another group was replaced by 8% FAM. After 40 days of feeding, the average feed intake of FAM pigs was increased (P > 0.05), and the villus height (VH) of jejunum and duodenum, crypt depth (CD), and VH/CD in FAM pigs was improved compared to the CON group (P < 0.05). The increase (P < 0.05) of goblet cells in the jejunum of FAM pigs was positively correlated with the expression of MUC-2 gene (R = 0.9150). The expression of genes related to immunity (IRAK4 , NF -κ B , and IL-10) and intestinal barrier (Occludin and MUC-2) in the jejunum, as well as the expression of ZO-1 and MUC-2 in the colon of these pigs, also showed increase (P < 0.05) compared to CON pigs, which was accompanied by the decrease (P < 0.05) of LPS concentration in the serum. The elevated proportion of CD3+ and CD8+ T-lymphocyte subsets in spleen (P < 0.05) confirmed the improvement of systemic immune function in FAM pigs. In addition, FAM pigs have a higher β-diversity of microbial community (P < 0.05) and promoted enrichment of probiotics such as Lactobacillus that positively was correlated with acetate concentration in the colon over CON pigs. In summary, partially replacement of expanded corn and soya protein concentrate with FAM (8%) may benefit the intestinal barrier and immune function of weaned pigs without affecting their growth. Our findings also provide evidence of the feasibility of FAM as a dietary component in pigs to reduce the consumption of grain. [ABSTRACT FROM AUTHOR]

To explore the effect of manno-oligosaccharide (MOS) on intestinal health in weaned pigs upon enterotoxigenic Escherichia coli K88 (ETEC) challenge, thirty-two male weaned pigs were randomly assigned into four groups. Pigs fed with a basal diet or basal diet containing MOS (0·6 g/kg) were orally infused with ETEC or culture medium. Results showed that MOS significantly elevated the digestibility of crude protein and gross energy in both ETEC-challenged and non-challenged pigs (P < 0·05). MOS also elevated serum concentrations of IgA and IgM (P < 0·05), but decreased serum concentrations of TNF-α, IL-1β and IL-6 (P < 0·05) in ETEC-challenged pigs. Interestingly, MOS increased villus height and the ratio of villus height:crypt depth in duodenum and ileum (P < 0·05). MOS also increased duodenal sucrase and ileal lactase activity in ETEC-challenged pigs (P < 0·05). MOS decreased the abundance of E. coli, but increased the abundance of Lactobacillus, Bifidobacterium and Bacillus in caecum (P < 0·05). Importantly, MOS not only elevated the expression levels of zonula occludens-1 (ZO-1), claudin-1 and GLUT-2 in duodenum (P < 0·05) but also elevated the expression levels of ZO-1, GLUT-2 and L-type amino acid transporter-1 in ileum (P < 0·05) upon ETEC challenge. These results suggested that MOS can alleviate inflammation and intestinal injury in weaned pigs upon ETEC challenge, which was associated with suppressed secretion of inflammatory cytokines and elevated serum Ig, as well as improved intestinal epithelium functions and microbiota. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to determine the standardized ileal digestible lysine (SID Lys) requirement for weaned pigs fed with low crude protein (CP) diet. In Experiment 1, 144 pigs were fed a normal CP (20%) diet with 12.3 g/kg SID Lys and five low CP (18.5%) diets providing SID Lys levels of 9.8, 11.1, 12.3, 13.5, and 14.8 g/kg, respectively, for 28 days. Reducing dietary CP from 20% to 18.5% enhanced (p < 0.05) the growth performance. The average daily gain (ADG) and gain to feed ratio (G:F) increased (linear and quadratic; p < 0.05), serum urea nitrogen (SUN) decreased (linear and quadratic; p < 0.05) as SID Lys increased. The SID Lys levels required to maximize ADG and optimize G:F were 12.8 and 13.1 g/kg using a curvilinear plateau model, and to minimize SUN was 13.4 g/kg using a two‐slope broken‐line model, which averaged 13.1 g/kg SID Lys. In Experiment 2, 18 pigs were used in a 12‐day N balance trial and received the same diets of Experiment 1. Total N excretion was decreased when dietary CP reduced and further decreased when SID Lys increased. Collectively, 1.5% dietary CP reduction improved the growth performance and decreased the N excretion; the optimal SID Lys requirement was at 13.1 g/kg of 8–20 kg pigs fed with 18.5% CP diet. [ABSTRACT FROM AUTHOR]

• MOS is a natural prebiotic that can alleviate ETEC-induced diarrhea. • MOS alleviates ETEC-induced intestinal epithelium disruption. • MOS elevated antioxidant capacity in the intestinal mucosa. • MOS decreases the expression levels of apoptosis-related genes. To explored the protective effect of manno -oligosaccharides (MOS) on intestinal epithelium exposure to Enterotoxigenic Escherichia coli (ETEC), thirty-two pigs were assigned into four treatments and fed with basal or MOS-containing (0.3% MOS) diet. Pigs were challenged by ETEC or culture medium. Results show that MOS not only reduced diarrhea incidence and fecal E. coli abundance but decreased serum D-lactate and DAO concentrations upon ETEC-challenge (P < 0.05). Interestingly, MOS attenuated ETEC-induced intestinal injury, as indicated by improved mucosa morphology and tight-junction protein distribution and decreased cell apoptosis. MOS also increased sIgA, GSH-Px, and SOD contents in jejunum (P < 0.05). Importantly, MOS down-regulated genes involved in inflammatory responses (TNF-α, IL-1β, TLR4, and NF-κB) and apoptosis (Caspase 3, Caspase 9, and Bax), but up-regulated expressions of antioxidant genes (HO-1 and Nrf2) (P < 0.05). These results suggested that MOS can alleviate ETEC-induced intestinal injury, which was associated with suppressed inflammation and improved antioxidant capacity and intestinal epithelial functions. [ABSTRACT FROM AUTHOR]

Simple Summary: Information about the optimal carbohydrate combination for pigs is scarce. This present study explored the effects of different combinations of starch, non-starch polysaccharides, and mannan-oligosaccharide on the growth performance, nutrient digestibility, and microbial communities in weaned pigs, which contributed a novel way of evaluating the carbohydrate quality of the diet for pigs. The present experiment was conducted to dissect the effects of different carbohydrate combinations on the growth performance, nutrient digestibility, and microbial communities in weaned pigs. The combination was optimized by constructing L9(34) orthogonal design. Three factors include starch (amylose to amylopectin (AM/AP) ratio 2:1, 1:1, 1:2), non-starch polysaccharides (NSP) (1%, 2%, 3%, a mixture of inulin with cellulose by 1:1), and mannan-oligosaccharide (MOS) (400, 800, 1200 mg/kg) were investigated and nine combinations were implemented under different levels of these factors. One hundred and sixty-two weaned pigs were randomly assigned to nine dietary treatments with six replicates per treatment and three pigs per replicate. Results exhibited that different combinations of starch, NSP, and MOS affected the gain to feed (G:F) (p < 0.05), diarrhea incidence (p < 0.10), nutrient digestibility (p < 0.05), microbial communities, and short-chain fatty acid (SCFA) concentrations (p < 0.05). In the present study, taking into account three-way ANOVA, range, and direct analysis, we found that the optimal carbohydrate combination was starch AM/AP 1:1, NSP 3%, MOS 400 mg/kg for weaned pigs. Moreover, feeding this combination diet could promote the growth performance and nutrient digestibility, increase the butyrate-producing bacteria, and to some extent improve lipid metabolism. This study provided a novel way to evaluate the carbohydrate quality in swine production. [ABSTRACT FROM AUTHOR]

Enterotoxigenic Escherichia coli (ETEC) infection destroys the intestinal barrier integrity, in turn, disrupting intestinal homoeostasis. Low-molecular-weight chitosan (LMWC) is a water-soluble chitosan derivative with versatile biological properties. Herein, we examined whether LMWC could relieve ETEC-induced intestinal barrier damage in weaned pigs. Twenty-four weaned pigs were allotted to three treatments: (1) non-infected control; (2) ETEC-infected control; and (3) ETEC infection + LMWC supplementation (100 mg/kg). On day 12, pigs in the infected groups were administered 100 mL of ETEC at 2.6 × 109 colony-forming units/mL to induce intestinal barrier injury. Three days later, serum samples were obtained from all pigs, which were then slaughtered to collect intestinal samples. We evidenced that LMWC not only increased (P < 0.05) the occludin protein abundance but also decreased (P < 0.05) the interleukin-6, tumour necrosis factor-α and mast cell tryptase contents, and the apoptotic epithelial cell percentages, in the small intestine of ETEC-infected pigs. Furthermore, LMWC down-regulated (P < 0.05) the small intestinal expression levels of critical inflammatory- and apoptotic-related genes, such as Toll-like receptor 4 (TLR4) and tumour necrosis factor receptor 1 (TNFR1), as well as the intra-nuclear nuclear factor-κB (NF-κB) p65 protein abundance, in the ETEC-infected pigs. Our study indicated a protective effect of LMWC on ETEC-triggered intestinal barrier disruption in weaned pigs, which involves the repression of intestinal inflammatory responses via blocking the TLR4/NF-κB signalling pathway and the depression of epithelial cell death via TNFR1-dependent apoptosis. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the effect of a coated protease on apparent (AID) and standardized (SID) ileal digestibility of crude protein (CP) and amino acids (AA) in weaned piglets. Eighteen barrows with initial body weight (BW) of 13.5 ± 0.2 kg were randomly allotted to 3 diets (control, protease diet, and nitrogen-free diet) with 6 piglets per diet after fitting with a T-cannula in the distal ileum. Control and protease diets were corn–soybean meal based diet supplemented with or without 200 mg/kg of coated protease. The nitrogen-free diet was used to measure basal endogenous losses of AA. The experiment lasted for 7 days, and ileal digesta were collected on days 6 and 7. Results showed that the coefficients of AID and SID of CP and total AA were increased by protease supplementation ( P < 0.05). For indispensable AA, the coefficients of AID of Ile, Lys, Met and Thr, and the coefficients of SID of Ile, Lys, Met, Thr and Trp were increased by protease ( P < 0.05). For dispensable AA, both the coefficients of AID and SID of Ala, Asp, Cys, Gly and Ser were increased by protease ( P < 0.05). In conclusion, dietary supplementation with coated protease increases coefficients of AID and SID of CP and most AAs in weaned piglets. [ABSTRACT FROM AUTHOR]

• Dietary xylanase improves growth performance of weaned piglets. • Different levels of xylanase increases nutrient digestibilities in vitro. • Dietary xylanase improves intestinal physical barrier and immune barrier functions in piglets. Supplementation of xylanase is an effective way to relieve anti-nutritional effects of dietary non-starch polysaccharides. Besides, the hydrolysis product xylo-oligosaccharides could affect intestinal microecology as prebiotics in pigs. However, whether there are other effects of xylanase on pig intestinal health is unclear. Two experiments were conducted in the present study to investigate the effects of xylanase on growth performance, nutrients digestibility and intestinal barrier function in piglets, and to explore whether the prebiotic effect of xylanase was related to the antioxidant function of NSP hydrolysates using an in vitro digestive system. In experiment 1, a total of 54 weaned pigs [Duroc × (Landrace × Yorkshire)] with an average body weight of 7.76 ± 0.10 kg were randomly assigned to one of three diets (corn-soybean meal diets with xylan content of 3.33%) supplemented with 0, 30, 60 mg/kg (0, 24000, 48000 BXU/kg) xylanase, respectively. The trial lasted for 28 days to investigate the effects of xylanase on growth performance, nutrient digestibility and intestinal health of piglets. In experiment 2, an in vitro study was conducted to simulate the digestion process of corn-soybean meal diets (the basal diet was same as that in experiment 1) in pig stomach and small intestine. Xylanase was supplemented in 0, 30, 60, 90 mg/kg (0, 24000, 48000, 72000 BXU/kg), respectively, to investigate the nutrient digestibility and system anti-oxidant ability (n = 6). In experiment 1, average daily gain (ADG) of piglets and viscosity of stomach digesta were quadratically decreased (P < 0.05), while the feed/gain ratio (F/G) was linearly decreased by xylanase (P < 0.05). The diarrhea rate (P = 0.066) and diarrhea index (P < 0.05) were quadratically affected by xylanase. Gene expression of zonula occludens-1 (ZO-1) and B-cell lymphoma/leukaemia-2 (Bcl-2) were linearly up-regulated by xylanase (P < 0.05). Also, xylanase linearly increased the contents of secretory immunoglobulin A (SIgA) in the jejunum of piglets (P < 0.05). In experiment 2, xylanase quadratically increased the in vitro dry matter digestibility (IVDMD) (P < 0.05), and linearly increased the glucose release rate of diets (P < 0.05). Dietary xylanase improves intestinal physical barrier and immune barrier functions in piglets, and increases nutrient digestibilities in vitro. [ABSTRACT FROM AUTHOR]