Understanding the composition of the microbial community and its functional capacity during weaning is important for pig production as bacteria play important roles in the pig’s health and growth performance. However, limited information is available regarding the composition and function of the gut microbiome of piglets in early-life. Therefore, we performed 16S rRNA gene and whole metagenome shotgun sequencing of DNA from fecal samples from healthy piglets during weaning to measure microbiome shifts, and to identify the potential contribution of the early-life microbiota in shaping piglet health with a focus on microbial stress responses, carbohydrate and amino acid metabolism. The analysis of 16S rRNA genes and whole metagenome shotgun sequencing revealed significant compositional and functional differences between the fecal microbiome in nursing and weaned piglets. The fecal microbiome of the nursing piglets showed higher relative abundance of bacteria in the genus Bacteroides with abundant gene families related to the utilization of lactose and galactose. Prevotella and Lactobacillus were enriched in weaned piglets with an enrichment for the gene families associated with carbohydrate and amino acid metabolism. In addition, an analysis of the functional capacity of the fecal microbiome showed higher abundances of genes associated with heat shock and oxidative stress in the metagenome of weaned piglets compared to nursing piglets. Overall, our data show that microbial shifts and changes in functional capacities of the piglet fecal microbiome resulted in potential reductions in the effects of stress, including dietary changes that occur during weaning. These results provide us with new insights into the piglet gut microbiome that contributes to the growth of the animal.

A study was conducted to evaluate the effects of 3 different plant extracts on diarrhea, immune response, intestinal morphology, and growth performance of weaned pigs experimentally infected with a pathogenic F-18 Escherichia coli (E. coli). Sixty-four weaned pigs (6.3 ± 0.2 kg BW, and 21 d old) were housed in individual pens in disease containment chambers for 15 d: 4 d before and 11 d after the first inoculation (d 0). Treatments were in a 2 × 4 factorial arrangement: with or without an F-18 E. coli challenge (toxins: heat-labile toxin, heat-stable toxin b, and Shiga-like toxin 2; 10¹⁰ cfu/3 mL oral dose; daily for 3 d from d 0) and 4 diets [a nursery basal diet (CON) or 10 ppm of capsicum oleoresin, garlic botanical, or turmeric oleoresin]. The growth performance was measured on d 0 to 5, 5 to 11, and 0 to 11. Diarrhea score (1, normal, to 5, watery diarrhea) was recorded for each pig daily. Frequency of diarrhea was the percentage of pig days with a diarrhea score of 3 or greater. Blood was collected on d 0, 5, and 11 to measure total and differential white blood cell counts and serum tumor necrosis factor (TNF)-α, IL-10, transforming growth factor (TGF)-β, C-reactive protein, and haptoglobin. On d 5 and 11, half of the pigs were euthanized to measure villi height and crypt depth of the small intestine and macrophage and neutrophil number in the ileum. The E. coli infection increased (P < 0.05) diarrhea score, frequency of diarrhea, white blood cell counts, serum TNF-α and haptoglobin, and ileal macrophages and neutrophils but reduced (P < 0.05) villi height and the ratio of villi height to crypt depth of the small intestine on d 5. In the challenged group, feeding plant extracts reduced (P < 0.05) average diarrhea score from d 0 to 2 and d 6 to 11 and frequency of diarrhea and decreased (P < 0.05) TNF-α and haptoglobin on d 5, white blood cell counts and neutrophils on d 11, and ileal macrophages and neutrophils on d 5. Feeding plant extracts increased (P < 0.05) ileal villi height on d 5 but did not affect growth performance compared with the CON. In the sham group, feeding plant extract also reduced (P < 0.05) diarrhea score, frequency of diarrhea, and ileal macrophages compared with the CON. In conclusion, the 3 plant extracts tested reduced diarrhea and inflammation caused by E. coli infection, which may be beneficial to pig health.

Certain plant extracts are bioactive substances of some foods or traditional herbs, known to possess antioxidant, antibacterial, and perhaps immunoregulatory effects. This study investigated the in vitro anti-inflammatory effects of 7 plant extracts (anethol, capsicum oleoresin, carvacrol, cinnamaldehyde, eugenol, garlicon, and turmeric oleoresin) on porcine alveolar macrophages collected from weaned pigs (n = 6 donor pigs) by bronchoalveolar lavage. The experimental design for this assay was a 2 [with or without 1 μg lipopolysaccharide (LPS)/mL] × 5 (5 different amounts of each plant extract) factorial arrangements in a randomized complete block design. The application of plant extracts were 0, 25, 50, 100, and 200 μg/mL, except for cinnamaldehyde and turmeric oleoresin, which were 0, 2.5, 5, 10, and 20 μg/mL. The 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) assay was used to determine the number of live cells, Griess assay was applied to detect nitric oxide (NO) production, and ELISA was used to measure tumor necrosis factor-α (TNF-α), IL-1β, transforming growth factor-β (TGF-β), and IL-10 in the cell culture supernatants of macrophages. The LPS increased (P < 0.001) the secretion of TNF-α, IL-1β, and TGF-β. Without LPS, anethol and capsicum oleoresin increased (linear, P < 0.001) cell viability of macrophages, whereas other plant extracts reduced (linear, P < 0.001) it. Anethol, capsicum oleoresin, and carvacrol enhanced (linear, P < 0.001) the cell proliferation of LPS-treated macrophages. Without LPS, anethol, capsicum oleoresin, cinnamaldehyde, or turmeric oleoresin stimulated TNF-α secretion, whereas all plant extracts except eugenol enhanced IL-1β concentration in the supernatants of macrophages. However, all plant extracts suppressed (linear, P < 0.001) TNF-α, and all plant extracts except turmeric oleoresin decreased (linear, P < 0.05) IL-1β secretion from LPS-treated macrophages. Anethol and capsicum oleoresin decreased (linear, P < 0.001) TGF-β from macrophages in the absence of LPS, but the other plant extracts increased it. Anethol, capsicum oleoresin, and carvacrol also suppressed (linear, P < 0.001) TGF-β from macrophages with LPS stimulation; the other plant extracts enhanced or did not affect it. The anti-inflammatory cytokine, IL-10, was not detected in any supernatants. Only very low amounts of NO were detected in the supernatants of macrophages. In conclusion, the TNF-α results indicate all plant extracts tested here may have anti-inflammatory effects to varying degrees.

Two experiments were conducted to determine whether 3 different clays in the nursery diet reduce diarrhea of weaned pigs experimentally infected with a pathogenic Escherichia coli. Weaned pigs (21 d old) were housed in individual pens of disease containment chambers for 16 d [4 d before and 12 d after the first challenge (d 0)]. The treatments were in a factorial arrangement: 1) with or without an E. coli challenge (F-18 E. coli strain; heat-labile, heat-stable, and Shiga-like toxins; 10¹⁰ cfu/3 mL oral dose daily for 3 d from d 0) and 2) dietary treatments. The ADG, ADFI, and G:F were measured for each interval (d 0 to 6, 6 to 12, and 0 to 12). Diarrhea score (DS; 1 = normal; 5 = watery diarrhea) was recorded for each pig daily. Feces were collected on d 0, 3, 6, 9, and 12 and plated on blood agar to differentiate β-hemolytic coliforms (HC) from total coliforms (TC) and on MacConkey agar to verify E. coli. Their populations on blood agar were assessed visually using a score (0 = no growth; 8 = very heavy bacterial growth) and expressed as a ratio of HC to TC scores (RHT). Blood was collected on d 0, 6, and 12 to measure total and differential white blood cell (WBC) counts, packed cell volume (PCV), and total protein (TP). In Exp. 1 (8 treatments; 6 replicates), 48 pigs (6.9 ± 1.0 kg of BW) and 4 diets [a nursery control diet (CON), CON + 0.3% smectite (SM), CON + 0.6% SM, and CON until d 0 and then CON + 0.3% SM] were used. The SM treatments did not affect growth rate of the pigs for the overall period. In the E. coli challenged group, the SM treatments reduced DS for the overall period (1.77 vs. 2.01; P < 0.05) and RHT on d 6 (0.60 vs. 0.87; P < 0.05) and d 9 (0.14 vs. 0.28; P = 0.083), and altered differential WBC on d 6 (neutrophils, 48 vs. 39%, P = 0.092; lymphocytes, 49 vs. 58%, P = 0.082) compared with the CON treatment. In Exp. 2 (16 treatments; 8 replicates), 128 pigs (6.7 ± 0.8 kg of BW) and 8 diets [CON and 7 clay treatments (CON + 0.3% SM, kaolinite, and zeolite individually and all possible combinations to total 0.3% of the diet)] were used. The clay treatments did not affect growth rate of the pigs. In the E. coli challenged group, the clay treatments reduced DS for the overall period (1.63 vs. 3.00; P < 0.05), RHT on d 9 (0.32 vs. 0.76; P < 0.05) and d 12 (0.13 vs. 0.39; P = 0.094), and total WBC on d 6 (15.2 vs. 17.7 × 10³/μL; P = 0.069) compared with the control treatment. In conclusion, dietary clays alleviated diarrhea of weaned pigs.