Background Previous research has shown that dietary supplementation of Bacillus spp. probiotics exerts beneficial effects on animals’ growth. However, limited studies have evaluated the efficacy of Bacillus spp. on weaned pigs and their effects on host gut health and microbiome, and systemic immunity using a disease challenge model. The objective of this experiment was to investigate the effects of two Bacillus spp. strains (Bacillus subtilis DSM 32540 and Bacillus pumilus DSM 32539) on growth performance, diarrhea, intestinal health, microbiome, and systemic immunity of weaned pigs experimentally infected with an enterotoxigenic Escherichia coli (ETEC). Results Pigs in PRO1 (Bacillus subtilis DSM 32540) had greater (P < 0.05) body weight on d 7 and 14 PI, greater (P < 0.05) ADG from d 0 to 7 and d 7 to 14 PI, compared with pigs in CON (Control). Pigs in PRO1 had milder (P < 0.05) diarrhea on d 2 and 3 PI compared with pigs in CON. However, no differences were observed in growth performance and diarrhea score between PRO2 (Bacillus pumilus DSM 32539) and CON groups. Supplementation of PRO1 decreased (P < 0.05) lymphocyte counts on d 7 and 14 PI, compared with CON. Supplementation of PRO1 and PRO2 both reduced (P < 0.05) total coliforms in mesenteric lymph nodes on d 21 PI. Pigs in PRO2 had greater (P < 0.05) goblet cell number and sulfomucin percentage in duodenal villi and greater (P < 0.05) sialomucin percentage in jejunal villi than pigs in CON. Supplementation of PRO1 up-regulated (P < 0.05) MUC2 gene expression in jejunal mucosa and reduced (P < 0.05) PTGS-2 and IL1B gene expression in ileal mucosa on d 21 PI, compared with CON. Pigs in PRO1 had reduced (P < 0.05) relative abundance of families Lachnospiraceae, Peptostreptococcaceae and Pasteurellaceae in the ileum. Conclusions Supplementation of Bacillus subtilis DSM 32540 improved growth performance, alleviated diarrhea severity, enhanced gut health, and reduced systemic inflammation of weaned pigs infected with ETEC F18. Although Bacillus pumilus DSM 32539 was able to alleviate systemic inflammation, it had limited impacts on growth performance and severity of diarrhea of ETEC F18 challenged weaned pigs.

Background Iron oversupplementation in healthy term infants may adversely affect growth and cognitive development. Objective We hypothesized that early-life iron excess causes systemic and central nervous system iron overload, and compromises social behavior. Methods The nursing pig was used as a translational model in a completely randomized study. On postnatal day (PD) 1, 24 pigs (1.57 ± 0.28 kg mean ± standard deviation body wt) were assigned to the following treatment groups: 1) nonsupplemented iron-deficient group (NON); 2) control group (CON), intramuscularly injected with iron dextran (100 mg Fe) on PD2; 3) moderate iron group (MOD), orally administered ferrous sulfate at 10 mg Fe · kg body wt–1 · d–1; and 4) high iron group (HIG), orally administered ferrous sulfate at 50 mg Fe · kg–1 · d–1. Piglets were nursed by sows during the study from PD1 to PD21. Tissue iron was analyzed by atomic absorption spectrophotometry. Messenger RNA and protein expression of iron regulator and transporters were analyzed by quantitative reverse transcriptase-polymerase chain reaction and Western blot. A sociability test was performed on PD19–20. Results Both MOD and HIG treatments (5.51 and 9.85 µmol/g tissue), but not CON (0.54 µmol/g), increased hepatic iron as compared with NON (0.25 µmol/g, P < 0.05). Similarly, the hippocampal iron concentrations in the MOD and HIG groups were 14.9% and 31.8% higher than that of NON, respectively (P < 0.05). In comparison with NON, MOD and HIG treatment repressed DMT1 in duodenal mucosa by 4- and 46-fold, respectively (P < 0.05); HIG drastically induced HAMP in liver by 540-fold (P < 0.05); iron-supplemented groups reduced TFRC in the hippocampus by <1-fold (P < 0.05). However, duodenal expression of ferroportin, the predominant transporter in basal membrane, was not affected by treatment. Despite normal sociability, the MOD and HIG pigs displayed deficits in social novelty recognition (P = 0.004). Conclusions Duodenal ferroportin was hyporesponsive to iron excess (MOD and HIG), which caused hippocampal iron overload and impaired social novelty recognition in nursing pigs.

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 (E. coli), and to compare the efficacy of Bacillus subtilis with that of carbadox. 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 (AGP) or 2.56 × 10 9 CFU/kg of Bacillus subtilis probiotics (PRO). The experiment lasted for 28 days with 7 days before and 21 days after the first E. coli inoculation. Fecal and blood samples were collected on d 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 d 21 PI to collect jejunal and ileal mucosa for gene expression analysis. Pigs in AGP had greater (P &lt; 0.05) body weight on d 7, 14, and 21 PI than pigs in PC and PRO groups. Supplementation of PRO enhanced pigs’ body weight on d 21 PI, compared with the PC. E. coli F18 challenge reduced (P &lt; 0.05) ADG and feed efficiency from d 0 to 21 PI, while supplementation of carbadox or PRO enhanced ADG and feed efficiency in E. coli F18 challenged pigs from d 0 to 21 PI. Pigs in AGP and PRO groups had reduced (P &lt; 0.05) frequency of diarrhea throughout the experiment and fecal β-hemolytic coliforms on d 7 PI than pigs in the PC. Pigs in PRO had greater (P &lt; 0.05) gene expression of CLDN1 in jejunal mucosa than pigs in the PC. Supplementation of carbadox or PRO reduced (P &lt; 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 PRO group had lower (P &lt; 0.05) white blood cell number and neutrophil count, and serum haptoglobin concentration on d 7 PI, and less (P &lt; 0.05) monocyte count on d 14 PI, compared with PC. In conclusion, supplementation of probiotic Bacillus subtilis sp. could enhance disease resistance and promote growth performance of weaned pigs under disease challenge condition. The potential mechanisms include but not limited to enhanced gut barrier integrity and local and systemic immune responses of weaned pigs.

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 three dietary treatments: nursery basal diet (CON) and 2 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 10 10 cfu/3 mL for 3 consecutive days. Fecal and blood samples were collected on d 0 before inoculation, and d 2, 5, 8, and 11 post-inoculation (PI) to test the percentage of β-hemolytic coliforms in total coliforms and complete blood cell count, respectively. Sixteen pigs were euthanized on d 5 PI, whereas the remaining pigs were euthanized at the end of the experiment to collect jejunal and ileal mucosa and mesenteric lymph node for gene expression and bacterial translocation, respectively. Pigs in REC had greater (P &lt; 0.05) final BW and lower (P &lt; 0.05) overall frequency of diarrhea, compared with pigs in CON and TRA groups. Pigs in TRA had the lowest (P &lt; 0.05) average daily gain (ADG) and feed efficiency from d 0 to 5 PI, highest (P &lt; 0.05) percentage of β-hemolytic coliforms in fecal samples on d 2 and 5 PI, and greatest (P &lt; 0.05) bacterial colonies in mesenteric lymph nodes on d 11 PI, compared with pigs in CON and REC. Pigs in TRA had the greatest (P &lt; 0.05) neutrophils on d 5 PI and higher (P &lt; 0.05) white blood cell counts and lymphocytes than other groups on d 11 PI. Pigs in TRA had the greatest (P &lt; 0.05) serum C-reactive protein on d 2 and 5 PI and serum TNF-α on d 5 PI, compared with pigs in the CON and REC. Pigs were fed REC had increased (P &lt; 0.05) mRNA expression of ZO-1 and OCDN, and reduced (P &lt; 0.05) IL1B, IL6, and TNFA in ileal mucosa on d 5 PI, compared with the CON, whereas TRA up-regulated (P &lt; 0.05) mRNA expression of IL1B, IL6, and PTGS2 in ileal mucosa on d 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.

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