Effects of weaning on intestinal longitudinal muscle-myenteric plexus function in piglets.

Weaning piglets usually suffer from severe diarrhea (commonly known as postweaning diarrhea, PWD) along with intestinal motility disorder. Intestinal peristalsis is mainly regulated by the longitudinal muscle-myenteric plexus (LM-MP). To understand the relationship between intestinal LM-MP function and the development of PWD, we compared the intestinal electrical activity, and the transcriptional profile of the LM-MP between 21-day-old piglets (just weaned, n=7) and 24-day-old piglets (suffered the most severe weaning stress, n=7). The results showed that 24-day-old piglets exhibited different degrees of diarrhea. A significant increase in the slow-wave frequency in the ileum and colon was observed in 24-day-old piglets, while c-kit expression in the intestinal LM-MPs was significantly decreased, indicating that PWD caused by elevated slow-wave frequency may be associated with loss of c-kit. The real-time quantitative PCR (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA) showed that intestinal LM-MPs in 24-day-old piglets may undergo inflammation and oxidative stress. Significant increases in 8-hydroxy-2'-deoxyguanosine and decreases in thioredoxin suggest that weaning may lead to DNA damage in the LM-MP of 24-day-old piglets. In addition, activating transcription factor 3 was significantly upregulated, indicating nerve damage in the LM-MP of 24-day-old piglets. The transcriptomic results showed that most of the differentially expressed genes in the ileal LM-MP after weaning were downregulated and closely related to the cell cycle process. Subsequent RT-qPCR analysis showed that the relative expression of p21 was upregulated, while the expression of cyclin A2, cyclin B1, and proliferating cell nuclear antigen was downregulated in the ileal and colonic LM-MP of 24-day-old piglets, suggesting that weaning may inhibit cell proliferation and cause G1/S cell cycle arrest in ileal and colonic LM-MP. In conclusion, weaning may lead to cell cycle arrest by causing DNA damage in the LM-MP, impairing intestinal motility regulation, and ultimately leading to diarrhea in piglets.

Shikimic Acid Regulates the NF-κB/MAPK Signaling Pathway and Gut Microbiota to Ameliorate DSS-Induced Ulcerative Colitis.

Shikimic acid (SA) is a compound extracted from the plant anise and has anti-inflammatory effects. However, any impact on intestinal inflammation or mechanisms involved has not been investigated. The present study used a dextran sulfate sodium (DSS)-induced mouse colitis model to investigate the effects of SA on intestinal inflammation. Intragastric administration of SA slowed DSS-induced weight loss, reduced disease activity index (DAI) score, enhanced the intestinal barrier, reduced the destruction of the colonic structure, inhibited the phosphorylation of key proteins in MAPK and NF-κB signaling pathways, inhibited the expression of inflammatory factors TNF-α, IL-1ß, and MPO (P < 0.05), decreased IFN-γ expression (P < 0.05), and increased immunoglobulin IgG content (P < 0.05). After 50 mg/kg SA treatment, the content of Bacteroidetes increased and Proteobacteria decreased in the cecal feces of mice with colitis (P < 0.05) and the richness of gut species increased. In conclusion, SA could improve intestinal inflammation and enhance intestinal immunity, indicating its suitability as a therapeutic candidate.

The Effects of Phytase and Non-Starch Polysaccharide-Hydrolyzing Enzymes on Trace Element Deposition, Intestinal Morphology, and Cecal Microbiota of Growing-Finishing Pigs.

This study investigated the effects of supplementing phytase and non-starch polysaccharide-degrading enzymes (NSPases) to corn-soybean meal-based diet on the growth performance, trace element deposition, and intestinal health of growing-finishing pigs. Fifty pigs were randomly assigned into the control (basal diet), phytase (basal diet + 100 g/t of phytase), ß-mannanase (basal diet + 40 g/t of ß-mannanase), ß-glucanase (basal diet + 100 g/t of ß-glucanase), and xylanase (basal diet + 100 g/t of xylanase) groups. The results show that the supplementation of phytase and NSPases had no impacts (p > 0.05) on the growth performance of pigs. Compared with the control group, pigs fed with xylanase had higher (p < 0.05) Zn concentrations in the ileum and muscle and those fed with phytase had higher (p < 0.05) Zn concentrations in the ileum. Phytase and xylanase supplementation decreased (p < 0.05) fecal Zn concentrations in pigs compared with the control group (p < 0.05). In addition, phytase, ß-mannanase, ß-glucanase, and xylanase supplementation up-regulated (p < 0.05) the FPN1 expression, whereas xylanase up-regulated (p < 0.05) the Znt1 expression in the duodenum of pigs compared with the control group. Moreover, phytase, ß-glucanase, and xylanase supplementation up-regulated (p < 0.05) the jejunal Znt1 expression compared with the control group. The intestinal morphology results show that the phytase, ß-mannanase, and xylanase groups had increased villus heights (VHs), an increased villus height-crypt depth ratio (VH:CD), and decreased crypt depths (CDs) in the duodenum, whereas phytase, ß-mannanase, ß-glucanase, and xylanase groups had decreased VH and VH:CD, and increased CD in the jejunum compared with the control group (p < 0.05). Pigs fed with exogenous enzymes had decreased bacterial diversity in the cecum. The dietary supplementation of NSPases increased the relative abundance of Firmicutes and decreased spirochaetes (p < 0.05). Compared with the control group, dietary NSPase treatment decreased (p < 0.05) the opportunistic pathogens, such as Treponema_2 and Eubacterium_ruminantium. Moreover, the relative abundances of Lachnospiraceae_XPB1014 and Lachnospiraceae were enriched in the ß-glucanase and ß-mannanase groups (p < 0.05), respectively. In conclusion, phytase and xylanase supplementation may promote zinc deposition in pigs. Additionally, the supplementation of NSPases may improve the gut health of pigs by modulating the intestinal morphology and microbiota.

Dietary supplementation with a microencapsulated complex of thymol, carvacrol, and cinnamaldehyde improves intestinal barrier function in weaning piglets.

BACKGROUND: The authors previously prepared a microencapsulated complex of thymol, carvacrol, and cinnamaldehyde (MEEO). This study aimed to evaluate the effect of MEEO on the intestinal mucosal barrier and homeostasis in weaning piglets. A comparison of the effect of MEEO versus chlortetracycline (CTC) was performed in this study. RESULTS: Piglets were divided into three groups - control (Con), MEEO, and CTC groups - and raised for 28 days. The results showed that MEEO significantly elevated the ratio of the villus height and the crypt depth in the jejunum and decreased the crypt depth in the ileum compared with the other groups (P < 0.05); it also upregulated the messenger ribonucleic acid (mRNA) expression of tight junction protein in the small intestine. Compared with the Con group, MEEO increased the concentration of secretory immunoglobulin A (sIgA), cathelicidin antimicrobial peptides (CAMP), and interleukin 10 (IL-10), while decreasing the interleukin 1 beta (IL-1ß) concentration in both jejunal and ileal mucosa (P < 0.05). The mRNA expression of jejunal mucosal MUC1 and ileal mucosal MUC2 was increased in the MEEO group compared with the other groups (P < 0.05). Intestinal microbial analysis showed that dietary treatment had little impact on the ileal microbial structure. A significant rise in the genus Lactobacillus was, however, found in the MEEO group. There is a positive correlation between the Lactobacillus and sIgA, and between the Lactobacillus and CAMP, indicating that an improvement in the mucosal barrier function by the addition of MEEO may be associated with the proliferation of Lactobacillus. CONCLUSION: Dietary supplementation with MEEO improves intestinal barrier function in weaning piglets, the effect of which was superior to CTC. © 2022 Society of Chemical Industry.

Characterization of NDM-5-producing Enterobacteriaceae isolates from retail grass carp ( Ctenopharyngodon idella) and evidence of bla NDM-5-bearing IncHI2 plasmid transfer between ducks and fish.

We aimed to characterize NDM-5-producing Enterobacteriaceae from aquatic products in Guangzhou, China. A total of 196 intestinal samples of grass carp collected in 2019 were screened for carbapenemase genes. Characterization of bla NDM-5 positive isolates and plasmids was determined by antimicrobial susceptibility testing, conjugation experiments, Illumina HiSeq, and Nanopore sequencing. One Citrobacter freundii and six Escherichia coli strains recovered from seven intestinal samples were verified as bla NDM-5 carriers (3.57%, 7/196). The bla NDM-5 genes were located on the IncX3 ( n=5), IncHI2 ( n=1), or IncHI2-IncF ( n=1) plasmids. All bla NDM-5-bearing plasmids were transferred by conjugation at frequencies of ~10 -4-10 -6. Based on sequence analysis, the IncHI2 plasmid pHNBYF33-1 was similar to other bla NDM-5-carrying IncHI2 plasmids deposited in GenBank from Guangdong ducks. In all IncHI2 plasmids, bla NDM-5 was embedded in a novel transposon, Tn 7051 (IS 3000-ΔIS Aba125-IS 5-ΔIS Aba125- bla NDM-5- ble MBL- trpF- tat-∆ dct-IS 26-∆ umuD-∆IS Kox3-IS 3000), which was identical to the genetic structure surrounding bla NDM-5 found in some IncX3 plasmids. The IncHI2-IncF hybrid plasmid pHNTH9F11-1 was formed by homologous recombination of the bla NDM-5-carrying IncHI2 plasmid and a heavy-metal-resistant IncF plasmid through ∆Tn 1721. To the best of our knowledge, this is the first report on the characterization of bla NDM-5-bearing plasmids in fish in China. The IncHI2 plasmid pHNBYF33-1 may be transmitted from ducks, considering the common duck-fish freshwater aquaculture system in Guangdong. Tn 7051 is likely responsible for the transfer of bla NDM-5 from IncX3 to IncHI2 plasmids in Enterobacteriaceae, resulting in the expansion of transmission vectors of bla NDM-5.

Superiority of Microencapsulated Essential Oils Compared With Common Essential Oils and Antibiotics: Effects on the Intestinal Health and Gut Microbiota of Weaning Piglet.

Essential oils (EOs) have long been considered an alternative to antibiotics in the breeding industry. However, they are unstable and often present unpleasant odors, which hampers their application. Microencapsulation can protect the active gradients from oxidation and allow them to diffuse slowly in the gastrointestinal tract. The purpose of this study was to investigate the effect of microencapsulation technology on the biological function of EOs and the possibility of using microencapsulate EOs (MEEOs) as an alternative to antibiotics in weaning piglets. First, we prepared MEEOs and common EOs both containing 2% thymol, 5% carvacrol and 3% cinnamaldehyde (w/w/w). Then, a total of 48 weaning piglets were randomly allotted to six dietary treatments: (1) basal diet; (2) 75 mg/kg chlortetracycline; (3) 100 mg/kg common EOs; (4) 500 mg/kg common EOs; (5) 100 mg/kg MEEOs; and (6) 500 mg/kg MEEO. The trial lasted 28 days. The results showed that piglets in the 100 mg/kg MEEOs group had the lowest diarrhea index during days 15-28 (P < 0.05). In addition, 100 mg/kg MEEOs significantly alleviated intestinal oxidative stress and inflammation (P < 0.05), whereas 500 mg/kg common EOs caused intestinal oxidative stress (P < 0.05) and may lead to intestinal damage through activation of inflammatory cytokine response. MEEOs (100 mg/kg) significantly reduced the ratio of the relative abundance of potential pathogenic and beneficial bacteria in the cecum and colon (P < 0.05), thus contributing to the maintenance of intestinal health. On the other hand, chlortetracycline caused an increase in the ratio of the relative abundance of potential pathogenic and beneficial bacteria in the colon (P < 0.05), which could potentially have adverse effects on the intestine. The addition of a high dose of MEEOs may have adverse effects on the intestine and may lead to diarrhea by increasing the level of colonic acetic acid (P < 0.05). Collectively, the results suggest that microencapsulation technology significantly promotes the positive effect of EOs on the intestinal health of weaning piglets and reduces the adverse effect of EOs, and 100 mg/kg MEEOs are recommended as a health promoter in piglets during the weaning period.

Zinc Supplementation Forms Influenced Zinc Absorption and Accumulation in Piglets.

The study aimed at determining the effect of different zinc (Zn) supplementation forms on Zn accumulation, activities of Zn-containing enzymes, gene expression of metallothionein (MT), and Zn transporters in piglets. Eighteen piglets were randomly divided into three groups: (a) a basal diet supplemented with 150 mg/kg Zn from Zn methionine (Zn-Met) in the feed (Zn-Met group), (b) a basal diet supplemented with 150 mg/kg Zn from Zn sulfate (ZnSO4) in the feed (ZnSO4, feed group), and (c) a basal diet supplemented with the same dose of Zn as in ZnSO4,feed group but in water (ZnSO4, water group). The results showed that Zn-Met added in feed and ZnSO4 dissolved in drinking water significantly improved (p < 0.05) the Zn concentration in liver and jejunum and the apparent digestibility of Zn in comparison with the ZnSO4 added in feed. In addition, dietary Zn supplementation as Zn-Met significantly increased (p < 0.05) the activity of alkaline phosphatase (AKP) in the jejunum of piglets in comparison with the ZnSO4, feed group. Furthermore, the Zn-Met and ZnSO4, water groups showed an improved total superoxide dismutase activity (T-SOD) in the ileum as compared to the ZnSO4, feed group. Meanwhile, the qPCR and western blot results showed that Zn-Met and ZnSO4 dissolved in drinking water increased the expression of MT in the jejunum in comparison with the ZnSO4 added in the piglets' feed. However, different Zn supplementation forms had no effect on the mRNA expressions of Zip4 and ZnT1 transporters. In conclusion, Zn-Met added in feed and ZnSO4 dissolved in drinking water had higher bioavailability in piglets.