Dose-response effects of in-feed antibiotics on growth performance and nutrient utilization in weaned pigs fed diets supplemented with yeast-based nucleotides

Dietary nucleotides are bioactive compounds with the potential to mitigate weaning-associated challenges in piglets. An experiment was conducted to determine the interaction effect of antimicrobial growth promoters(AGP) and a nucleotide-rich yeast extract(NRYE) on growth performance and apparent total tract digestibility(ATTD) of dry matter(DM), crude protein(CP) and gross energy(GE),and to establish whether NRYE supplementation may completely or partially replace AGP in diets for weaned pigs. In phase 1 and 2, corn, wheat, canola meal and soybean meal based diets, which were formulated to contain 0.0 or 0.1% NRYE with 0, 25, 50, 75 or 100% of the recommended AGP dosage, were fed to 108 twenty-one day old piglets(initial body weight 7.11 ± 0.9 kg; mean ±SD) from d 1 to 14 and15 to 28, respectively. Overall, increasing AGP level in NRYE supplemented diets linearly decreased average daily gain(ADG)(P = 0.002) and gain-to-feed ratio(G:F)(P = 0.007); and quadratically decreased ATTD of DM(P = 0.001), CP(P =0.003) and G:F(P = 0.017) during phase 2. Compared with control and pigs fed NRYE with 100% of recommended AGP dosage, pigs fed 0.1% NRYE without AGP had greater(P 0.05) ADG and G:F in phase 2 and overall. In conclusion, supplementing 0.1% NRYE improved growth performance of pigs but this beneficial effect was reduced by increasing dietary AGP dosage.     

Effects of Armillariella tabescens mycelia on the growth performance and intestinal immune response and microflora of early‐weaned pigs

This study was performed to evaluate effects of Armillariella tabescens (A. tabescens) on the growth performance and intestinal immune response and microflora in early‐weaned pigs when used as feed additive. A. tabescens mycelia were added to basal diets at concentrations of 0%, 0.1%, 0.3% or 0.9% (w/w). A total of 144 commercial cross‐bred piglets were randomly allocated to one of these four diets and fed for 30 days. The growth performance of early‐weaned piglets displayed improvement with diets containing 0.1% and 0.3% dried mycelia powder from A. tabescens. Supplementing with 0.1% or 0.3% A. tabescens mycelia induced a 2.6‐ and three‐fold increase in secretory immunoglobulin A (sIgA) content in the jejunal mucosa, respectively, but had only a marginal effect on sIgA in the ileal mucosa. Expression of interleukin‐2, interferon‐γ, and tumor necrosis factor‐α in the jejunal mucosa were elevated with A. tabescens mycelia administration. Increased amounts of Lactobacillus spp. and Bifidobacterium spp. in the jejunum, and decreased amounts of Escherichia coli in the jejunum and ileum were observed with the administration of A. tabescens‐containing diets. This study demonstrated that A. tabescens had beneficial effects on the growth performance and intestinal microflora of early‐weaned pigs.     

The effects of mycotoxins, fungal food contaminants, on the intestinal epithelial cell-derived innate immune response

Mycotoxins are structurally diverse fungal metabolites that can contaminate a variety of dietary components consumed by animals and humans. It is considered that 25% of the world crop production is contaminated by mycotoxins. The clinical toxicological syndromes caused by ingestion of moderate to high amounts of mycotoxins and their effect on the immune system have been well characterized. However, no particular attention has been focused on the effects of mycotoxins on the local intestinal immune response. Because of their location, intestinal epithelial cells (IECs) could be exposed to high doses of mycotoxins. As a component of the innate local immune response, intestinal epithelial cells have developed a variety of mechanisms which act to reduce the risk of infection by microorganisms or intoxication by toxic compounds. This review summarises the innate immune response developed by intestinal epithelial cells and reports the literature concerning the effects of mycotoxins on them. Particularly, the effects of mycotoxins on the maintenance of a physical barrier by epithelial cells will be discussed together with their effect on extrinsic protective components of the innate intestinal immunity: mucus secretion, antimicrobial peptide generation, IgA and pro-inflammatory cytokine release.     

Evaluation of the combined effects of different dose levels of Zinc oxide with probiotics complex supplementation on the growth performance,nutrient digestibility,faecal microbiota,noxious gas emissions and faecal score of weaning pigs

This study was conducted to assess the effects of different dose levels of zinc oxide (ZnO) combined with probiotics complex supplementation on the growth, performance, nutrient digestibility, faecal lactobacillus and Enterobacteria counts, noxious gas emissions and faecal score of weaned piglets. A total of 180 crossbred weaning pigs ([Yorkshire × Landrace] × Duroc; 6.61 ± 1.29 kg [mean ± SE]; 28 days old) were used in a 42-day trial. All pigs were randomly allotted to 1 of 4 treatment diets based on initial BW and sex (9 replicate pens/treatment; 2 gilts and 3 barrows/pen). Dietary treatment groups were as follows: CON, basal diet +ZnO 3,000 ppm; BZS, basal diet +ZnO 2,100 ppm +0.1% SynerZymeF10; BZS1, basal diet +ZnO 1,200 ppm +0.1% SynerZymeF10; BZS2, basal diet +ZnO 300 ppm +0.1% SynerZymeF10. During the phase 3, decreasing the ZnO concentration led to a linear reduction in ADG (p = 0.044), and the ADG was lower (p < 0.05) in BZS2 compared with CON treatment during the whole experimental period. The effects of dietary ZnO with probiotics complex were not detected (p > 0.05) on nutrient digestibility, Lactobacillus and E. coli counts, faecal gas emissions and faecal scores. In conclusion, the diet supplementation of ZnO (1,200 ppm) with probiotics complex has been shown to have comparable efficacy to ZnO (3,000 ppm) diet on growth performance, nutrient digestibility, faecal microbiota, noxious gas emissions and faecal score of weaning pigs.     

Effect of δ-aminolevulinic acid on growth performance, nutrient digestibility, blood parameters and the immune response of weanling pigs challenged with Escherichia coli lipopolysaccharide

This study investigated the effects of dietary δ-aminolevulinic acid (ALA) on growth performance, nutrient digestibility, blood parameters and whether ALA improved the immune response of weanling pigs challenged with Escherichia coli lipopolysaccharide (LPS). Eighty pigs (body weight = 7.21 ± 0.51 kg) were allotted to four dietary treatments, with four pens per treatment and five pigs per pen. Basal diets were supplemented with 0, 5, 10, and 15 mg/kg ALA (as-fed basis) and fed for 35 days. At the end of the feeding period, 10 pigs were selected from both the 0- and 10-mg/kg ALA treatment groups; five were injected i.p. with LPS (50 μg/kg BW) and the other five pigs with an equivalent amount of sterile saline, resulting a 2 × 2 factorial arrangement. Blood sample and rectal temperature data were collected at 0, 2, 4 and 12 h after challenge. Growth performance was not affected by dietary treatments over the total experimental period. However, dry matter (DM) and nitrogen (N) digestibility was improved in the 15-mg/kg ALA treatment group at day 35 (P < 0.05). Serum hemoglobin (Hb) and iron levels were also increased, with the 10-mg/kg ALA treatment showing the highest concentration (P < 0.05). On day 35, red (RBC) and white blood cell (WBC) counts were elevated, with the 5- and 10-mg/kg ALA treatments having the highest counts (P < 0.05). During challenge, LPS injection elevated rectal temperature at 2 and 4 h postchallenge (P < 0.05). Plasma cortisol concentration was also increased by LPS injection at 2 and 4 h postchallenge and an ALA-alleviating effect was evident at 2 h postchallenge (P < 0.01). Concentration of plasma insulin-like growth factor-I (IGF-I) was increased in the ALA-supplemented treatments at 2 h postchallenge (P < 0.05). LPS injection increased plasma tumor necrosis factor-α (TNF-α) concentrations at 2, 4 and 12 h (P < 0.01), while an ALA-alleviating effect was observed at 2 and 4 h postchallenge (P < 0.05 and P < 0.10, respectively). Challenge with LPS decreased WBC counts at 2 and 4 h postchallenge (P < 0.01). At 12 h postchallenge, RBC, WBC and lymphocyte counts were affected by LPS challenge, while an ALA effect was only observed on WBC count (P < 0.05). In conclusion, dietary supplementation of ALA in weanling pigs can improve DM and N digestibilities, and iron status and have a beneficial effect on the immune response during inflammatory challenge.