Dietary butyrate and valerate glycerides impact diarrhea severity and immune response of weaned piglets under ETEC F4-ETEC F18 coinfection conditions

Enterotoxigenic Escherichia coli (ETEC) causes post-weaning diarrhea in piglets, significantly impacting animal welfare and production efficiency. The two primary ETEC pathotypes associated with post-weaning diarrhea are ETEC F4 and ETEC F18. During the post-weaning period, piglets may be exposed to both ETEC F4 and ETEC F18. However, the effects of coinfection by both strains have not been studied. Short chain fatty acid feed additives, such as butyrate and valerate, are being investigated for their potential to improve animal performance and disease resistance. Therefore, this pilot experiment aimed to test the effects of butyrate glycerides or valerate glycerides on growth performance, diarrhea incidence, and immune responses of piglets under ETEC F4-ETEC F18 coinfection conditions. Twenty piglets were individually housed and assigned to one of the three dietary treatments immediately at weaning (21 to 24 d of age). The dietary treatments included control (basal diet formulation), control supplemented with 0.1% butyrate glycerides or 0.1% valerate glycerides. After a 7-d adaptation, all pigs were inoculated with ETEC F4 and ETEC F18 (0.5 × 109 CFU/1.5 mL dose for each strain) on three consecutive days. Pigs and feeders were weighed throughout the trial to measure growth performance. Fecal cultures were monitored for hemolytic coliforms, and blood samples were collected for whole blood and serum analysis. Pigs fed valerate glycerides tended (P = 0.095) to have higher final body weight compared with control. The overall severity of diarrhea was significantly (P < 0.05) lower in both treatment groups than control. Pigs fed valerate glycerides tended (P = 0.061) to have lower neutrophils and had significantly (P < 0.05) lower serum TNF-α on day 4 post-inoculation. This pilot experiment established an appropriate experimental dose for an ETEC F4-ETEC F18 coinfection disease model in weaned piglets. Results also suggest that butyrate glycerides and valerate glycerides alleviated diarrhea and regulated immune responses in piglets coinfected with ETEC F4 and ETEC F18.

Dietary supplementation of botanical blends enhanced performance and disease resistance of weaned pigs experimentally infected with enterotoxigenic Escherichia coli F18

Botanicals exhibit promising impacts on intestinal health, immune-regulation, and growth promotion in weaned pigs. However, these benefits may vary depending on major active components in the final feed additive products. Therefore, this study aimed to investigate two types of botanical blends (BB) that were comprised of 0.3% capsicum oleoresin and 12% garlic extracts from different sources on performance, diarrhea, and health of weaned piglets experimentally infected with a pathogenic Escherichia coli F18. Sixty weanling pigs (7.17 ± 0.97 kg body weight (BW)) blocked by weight and gender were assigned to one of five dietary treatments: negative control (NC), positive control (PC), or dietary supplementation with 100 mg/kg of BB1, 50 mg/kg or 100 mg/kg of BB2. This study lasted 28 d with 7 d before and 21 d after the first E. coli inoculation (day 0). All pigs, except negative control, were orally inoculated with 1010 cfu E. coli F18/3-mL dose for 3 consecutive days. Blood samples were collected periodically to analyze systemic immunity. Intestinal tissues and mucosa were collected on days 5 and 21 PI for analyzing histology and gene expression. All data, except for frequency of diarrhea, were analyzed by ANOVA using the PROC MIXED of SAS. The Chi-square test was used for analyzing frequency of diarrhea. Escherichia coli infection reduced (P < 0.05) growth rate and feed intake and increased (P < 0.05) frequency of diarrhea of weaned pigs throughout the experiment. Supplementation of 100 mg/kg BB1 or BB2 alleviated (P < 0.05) frequency of diarrhea of E. coli challenged pigs during the entire experiment. Escherichia coli infection also enhanced (P < 0.05) serum TNF-α and haptoglobin concentrations on day 4 post-inoculation (PI) but reduced (P < 0.05) duodenal villi height and area on day 5 PI, while pigs supplemented with 100 mg/kg BB1 or BB2 had lower (P < 0.05) serum TNF-α than pigs in PC on day 4 PI. Pigs fed with 100 mg/kg BB2 had higher (P < 0.05) jejunal villi height than pigs in PC on day 5 PI. Pigs fed with 100 mg/kg BB2 had reduced (P < 0.05) gene expression of IL1B, PTGS2, and TNFA in ileal mucosa than pigs in PC on day 21 PI. In conclusion, dietary supplementation of botanical blends at 100 mg/kg could enhance disease resistance of weaned pigs infected with E. coli F18 by enhancing intestinal morphology and regulating local and systemic immunity of pigs.

Supplementation of oligosaccharide-based polymer enhanced growth and disease resistance of weaned pigs by modulating intestinal integrity and systemic immunity

Background

There is a great demand for antibiotic alternatives to maintain animal health and productivity. The objective of this experiment was to determine the efficacy of dietary supplementation of a blood group A6 type 1 antigen oligosaccharides-based polymer (Coligo) on growth performance, diarrhea severity, intestinal health, and systemic immunity of weaned pigs experimentally infected with an enterotoxigenic Escherichia coli (ETEC), when compared with antibiotics.

Results

Pigs in antibiotic carbadox or Coligo treatment groups had greater (P < 0.05) body weight on d 5 or d 11 post-inoculation (PI) than pigs in the control group, respectively. Supplementation of antibiotics or Coligo enhanced (P < 0.05) feed efficiency from d 0 to 5 PI and reduced (P < 0.05) frequency of diarrhea throughout the experiment, compared with pigs in the control group. Supplementation of antibiotics reduced (P < 0.05) fecal β-hemolytic coliforms on d 2, 5, and 8 PI. Pigs in antibiotics or Coligo groups had reduced (P < 0.05) neutrophil counts and serum haptoglobin concentration compared to pigs in the control group on d 2 and 5 PI. Pigs in Coligo had reduced (P < 0.05) total coliforms in mesenteric lymph nodes on d 5 and 11 PI, whereas pigs in antibiotics or Coligo groups had reduced (P < 0.05) total coliforms in spleen on d 11 PI compared with pigs in the control group. On d 5 PI, pigs in the Coligo group had greater (P < 0.05) gene expression of ZO1 in jejunal mucosa, but less (P < 0.05) mRNA expression of IL1B, IL6, and TNF in ileal mucosa, in comparison with pigs in the control group. Supplementation of antibiotics enhanced (P < 0.05) the gene expression of OCLN in jejunal mucosa but decreased (P < 0.05) IL1B and IL6 gene expression in ileal mucosa, compared with the control. On d 11 PI, supplementation of antibiotics or Coligo up-regulated (P < 0.05) gene expression of CLDN1 in jejunal mucosa, but Coligo reduced (P < 0.05) IL6 gene expression in ileal mucosa compared to pigs in the control group.

Conclusions

Supplementation of Coligo improved growth performance, alleviated diarrhea severity, and enhanced gut health in weaned pigs infected with ETEC F18 in a manner similar to in-feed antibiotics.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40104-021-00655-2.

Mint Oils: In Vitro Ability to Perform Anti-Inflammatory, Antioxidant, and Antimicrobial Activities and to Enhance Intestinal Barrier Integrity

The objectives of the study were to test the biological activities of peppermint and spearmint oils via (i) measuring in vitro anti-inflammatory effects with porcine alveolar macrophages (PAMs), (ii) determining the barrier integrity of IPEC-J2 by analyzing transepithelial electrical resistance (TEER), (iii) testing their antioxidant activities, and (iv) investigating the antimicrobial activity against enterotoxigenic Escherichia coli (ETEC) F18+. Briefly, (i) macrophages were seeded at 10⁶ cells/mL and treated (24 h) with mint oils and lipopolysaccharide (LPS). The treatments were 2 (0 or 1 μg/mL of LPS) × 5 (0, 25, 50, 100, 200 µg/mL of mint oils). The supernatants were collected for TNF-α and IL-1β measurement by ELISA; (ii) IPEC-J2 cells were seeded at 5 × 10⁵ cells/mL and treated with mint oils (0, 25, 50, 100, and 200 μg/mL). TEER (Ωcm²) was measured at 0, 24, 48, and 72 h; (iii) the antioxidant activity was assessed (0, 1, 50, 100, 200, 500, and 600 mg/mL) using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and reducing power assays; (iv) overnight-grown ETEC F18+ were quantified (CFU/mL) after supplementing with peppermint and spearmint oils (0, 1.44, 2.87, 5.75, 11.50, and 23.00 mg/mL). All data were analyzed using the MIXED procedure. Both mint oils significantly inhibited (p < 0.05) IL-1β and TNF-α secretion from LPS-stimulated PAMs. Mint oil treatments did not affect TEER in IPEC-J2. Spearmint and peppermint oils exhibited (p < 0.05) strong antioxidant activities in DPPH and reducing power assays. Both mint oils also dose-dependently inhibited (p < 0.05) the growth of ETEC F18+ in vitro. The results of the study indicated that both mint oils are great candidate feed additives due to their in vitro anti-inflammatory, antioxidant, and antimicrobial effects. Further research is needed to evaluate their efficacy in vivo.

Trace amounts of antibiotic exacerbated diarrhea and systemic inflammation of weaned pigs infected with a pathogenic Escherichia coli

The experiment was conducted to investigate the effects of trace amounts of antibiotic on growth performance, diarrhea, systemic immunity, and intestinal health of weaned pigs experimentally infected with an enterotoxigenic Escherichia coli. Weaned pigs (n = 34, 6.88 ± 1.03 kg body weight [BW]) were individually housed in disease containment rooms and randomly allotted to one of the three dietary treatments: nursery basal diet (CON) and two additional diets supplemented with 0.5 or 50 mg/kg carbadox to the nursery basal diet (TRA or REC), respectively. The experiment lasted 18 d with 7 d before and 11 d after the first E. coli inoculation. The E. coli F18 inoculum was orally provided to all pigs with a dose of 1010 colony-forming unit (CFU)/3 mL for three consecutive days. Fecal and blood samples were collected on day 0 before inoculation and days 2, 5, 8, and 11 postinoculation (PI) to test the percentage of β-hemolytic coliforms in total coliforms and complete blood cell count, respectively. Sixteen pigs were euthanized on day 5 PI, whereas the remaining pigs were euthanized at the end of the experiment to collect the jejunal and ileal mucosa and mesenteric lymph node for gene expression and bacterial translocation, respectively. Pigs in REC had greater (P < 0.05) final BW and lower (P < 0.05) overall frequency of diarrhea compared with pigs in the CON and TRA groups. Pigs in TRA had the lowest (P < 0.05) average daily gain and feed efficiency from day 0 to 5 PI, highest (P < 0.05) percentage of β-hemolytic coliforms in fecal samples on days 2 and 5 PI, and greatest (P < 0.05) bacterial colonies in mesenteric lymph nodes on day 11 PI compared with pigs in the CON and REC groups. Pigs in TRA had the greatest (P < 0.05) neutrophils on day 5 PI and higher (P < 0.05) white blood cell counts and lymphocytes than other groups on day 11 PI. Pigs in TRA had the greatest (P < 0.05) serum C-reactive protein on days 2 and 5 PI and serum tumor necrosis factor-α on day 5 PI, compared with pigs in the CON and REC groups. Pigs fed REC had increased (P < 0.05) mRNA expression of zona occludens-1 (ZO-1) and occludin (OCDN) and reduced (P < 0.05) interleukin-1 beta (IL1B), interleukin-6 (IL6), and tumor necrosis factor-alpha (TNFA) in ileal mucosa on day 5 PI, compared with the CON, whereas TRA upregulated (P < 0.05) mRNA expression of IL1B, IL6, and cyclooxygenase-2 (COX2) in the ileal mucosa on day 11 PI, compared with the REC. In conclusion, trace amounts of antibiotic may exacerbate the detrimental effects of E. coli infection on pig performance by increasing diarrhea and systemic inflammation of weanling pigs.

PSIX-17 Investigating the biological activities of sodium cellobionate produced from cellulosic biomass

A novel method has been developed to easily hydrolyze cellulose to sodium cellobionate in a filamentous fungas, Neurospora crassa. The objectives of this experiment were to investigate the in vitro biological activities of sodium cellobionate. Antioxidant activity was evaluated with 3 chemical-based assays, including DPPH radical scavenging assay (DPPH), Trolox equivalent antioxidant capacity assay (TEAC), and ferric reducing antioxidant power assay (FRAP). Antimicrobial activity was determined as minimum inhibitory concentration (MIC) that prevented growth of tested bacteria, including four gram-negative bacteria (Escherichia coli F18 and ATCC 25922, and Salmonella Typhimurium ATCC 14028 and a wild strain isolated from cull diary cows in California) and one gram-positive bacteria (Enterococcus faecalis ATCC 29212). Anti-inflammatory activity was tested by analyzing TNF-α production with porcine alveolar macrophages that were challenged with lipopolysaccharide. A porcine intestinal epithelial cell line, IPEC-J2, was also used to test the effects of cellobionate on cell proliferation of intestinal epithelial cells. The tested doses of sodium cellobionate were 0, 0.04, 0.20, 1.00, 2.00, 4.00, 20.00, and 40.00 mg/mL. All assays were performed with over 6 replicates, except that MIC assays were performed as triplicate. All data were analyzed by PROC MIXED of SAS. Sodium cellobionate did not have radical scavenging capacity, but had weak FRAP (9.68 μM L-Cysteine equivalent) and TEAC (69% reduction) at the dose of 40 mg/mL. MIC results revealed that sodium cellobionate did not inhibit the growth of all tested bacteria, indicating it does not have antimicrobial activity within the range of tested doses. Sodium cellobionate did not exhibit anti-inflammatory activities, but significantly enhanced (P &lt; 0.05) intestinal epithelial cell proliferation in vitro by 24.00%, 39.64%, and 25.98% when the doses were 1.00, 2.00, and 4.00 mg/mL, respectively. Results of this experiment indicate that cellobionate has limited biological activities in vitro, except that this biomass product could strongly stimulate the proliferation of intestinal epithelial cells. Future research will focus on the potential impacts of sodium cellobionate on intestinal physiology in vivo.

Bacillus subtilis: a potential growth promoter in weaned pigs in comparison to carbadox

The study was conducted to investigate the efficacy of a probiotic Bacillus subtilis strain on growth performance, diarrhea, systemic immunity, and intestinal health of weaned pigs experimentally infected with an enterotoxigenic Escherichia coli and to compare the efficacy of B. subtilis with that of carbadox. Weaned pigs (n = 48, 6.17 ± 0.36 kg body weight [BW]) were individually housed in disease containment rooms and randomly allotted to one of four dietary treatments: negative control (NC, control diet without E. coli challenge), positive control (PC, control diet with E. coli challenge), and supplementation of 50 mg/kg of carbadox (antibiotic growth promotor [AGP]) or 2.56 × 109 CFU/kg of B. subtilis probiotics (PRO). The experiment lasted for 28 d with 7 d before and 21 d after the first E. coli inoculation. Fecal and blood samples were collected on days 0, 3, 7, 14, and 21 post inoculation (PI) to analyze β-hemolytic coliforms and complete blood cell count, respectively. Diarrhea score was recorded daily for each pig to calculate the frequency of diarrhea. All pigs were euthanized at day 21 PI to collect jejunal and ileal mucosa for gene expression analysis. Pigs in AGP had greater (P < 0.05) BW on days 7, 14, and 21 PI than pigs in PC and PRO groups. Supplementation of PRO enhanced pigs' BW on day 21 PI compared with the PC. Escherichia coli F18 challenge reduced (P < 0.05) average daily gain (ADG) and feed efficiency from day 0 to 21 PI, while supplementation of carbadox or PRO enhanced ADG and feed efficiency in E. coli F18-challenged pigs from day 0 to 21 PI. Pigs in AGP and PRO groups had reduced (P < 0.05) frequency of diarrhea throughout the experiment and fecal β-hemolytic coliforms on day 7 PI than pigs in the PC. Pigs in PRO had greater (P < 0.05) gene expression of CLDN1 in jejunal mucosa than pigs in the PC. Supplementation of carbadox or PRO reduced (P < 0.05) the gene expression of IL6 and PTGS2 in ileal mucosa of E. coli-infected pigs compared with pigs in the PC. Pigs in the PRO group had lower (P < 0.05) white blood cell number and neutrophil count, and serum haptoglobin concentration on day 7 PI, and less (P < 0.05) monocyte count on day 14 PI, compared with PC. In conclusion, supplementation of probiotic B. subtilis could enhance disease resistance and promote the growth performance of weaned pigs under disease challenge conditions. The potential mechanisms include but not limited to enhanced gut barrier integrity and local and systemic immune responses of weaned pigs.

169 Susceptibility of several species of gram-negative and gram-positive bacteria to organic acids and their derivatives

The objective of this experiment was to determine the in vitro antimicrobial activity of several organic acids and their derivatives against gram-positive (G+) and gram-negative (G-) bacteria. Monopropionin, monovalerin, monolaurin, and sodium formate were tested at 10 to 12 concentrations from 0.001 to 2.50 mg/L; monobutyrin was tested at 16 concentrations from 0.001 to 5.00 mg/L; butyric acid and valeric acid were tested at 8 concentrations from 0.001 to 0.35 mg/L; while formic acid was tested at 8 concentrations from 0.001 to 1.00 mg/L. The tested bacteria included G- bacteria (Escherichia coli, Salmonella typhimurium, and Campylobacter jejuni) and G+ bacteria (Enterococcus faecalis, Clostridia perfringens, Streptococcus pneumonia, and Streptococcus suis). Antimicrobial activity of tested compounds was expressed as minimum inhibitory concentration (MIC) that prevented growth of tested bacteria in treated culture broth. Butyric acid, valeric acid, and formic acid at highest tested concentrations inhibited the growth of all bacterial strains. The MICs of the three acids varied among bacterial strains with lowest MIC of 0.05–0.10 mg/L on two strains of Campylobacter. Sodium formate at highest tested concentrations did not inhibit the growth of E. coli, S. typhimurium, and E. faecalis but the compound inhibited the growth of other tested bacteria with MIC values from 0.20 to 1.88 mg/L. The MIC values of monovalerin, monolaurin, and monobutyrin ranged between 0.001 and 1.50 mg/L on all bacterial strains with the exception that monobutyrin did not inhibit C. jejuni (ATCC 33560) growth at the highest concentration tested (5.0 mg/L). Monopropionin at tested concentrations did not inhibit the growth of all tested bacteria with the exception of 1.13 mg/L as MIC on C. perfringens (ATCC 12915). The MIC tests indicate that all organic acids and their derivatives, except monopropionin, tested in this experiment exhibited strong antimicrobial effects in vitro against tested bacterial strains.

140 Effects of Bacillus subtilis probiotics on growth performance, diarrhea, and fecal β-hemolytic coliforms of weaned pigs experimentally infected with an enterotoxigenic Escherichia coli

The objective of this experiment was to investigate the effects of Bacillus subtilis on growth performance, diarrhea and fecal β-hemolytic coliforms of weaned pigs experimentally infected with a strain of E. coli (F18, express genes of LT, STb, and SLT 2 toxins). Weaned pigs (n = 48, 6.17 ± 0.36 kg BW) were individually housed in disease containment rooms and randomly allotted to one of four dietary treatments: negative control (NC, control diet without E. coli challenge), positive control (PC, control diet with E. coli challenge), and supplementation of 50 mg/kg of carbadox or 500 mg/kg of Bacillus subtilis probiotics. The experiment lasted 28 d with 7 d before and 21 d after the first E. coli inoculation. The F18 E. coli were given to pigs at 1010 CFU/3 mL dose for three consecutive d. Diarrhea score was daily recorded for each pig to calculate frequency of diarrhea. Fecal samples were collected on d 0, 3, 7, 14, and 21 PI to analyze β-hemolytic coliforms. Data were analyzed using the Mixed Procedure of SAS. Pigs supplemented with carbadox had greater (P < 0.05) body weight on d 7, 14, and 21 PI than pigs in the PC and probiotics group. Supplementation of probiotics enhanced pig body weight on d 21 PI, compared with the PC. E. coli challenge reduced (P < 0.05) ADG and feed efficiency from d 0 to 21 PI, while supplementation of antibiotics or probiotics enhanced ADG and feed efficiency from d 0 to 21 PI. Pigs in carbadox and probiotics groups had reduced (P < 0.05) frequency of diarrhea throughout the experiment and fecal β-hemolytic coliforms on d 7 PI than pigs in the PC. In conclusion, supplementation of Bacillus subtilis could enhance disease resistance and promote growth performance of weaned pigs under disease challenge condition.