The Effects of Direct-fed Microbial Supplementation, as an Alternative to Antibiotics, on Growth Performance, Intestinal Immune Status, and Epithelial Barrier Gene Expression in Broiler Chickens

The objective of this study was to investigate the effects of Bacillus subtilis-based probiotic supplementation in broiler chicken diets on growth performance, feed efficiency, intestinal cytokine, and tight junction (TJ) protein mRNA expression. Zero-day-old broiler chicks (n = 140) were randomly assigned to one of five dietary treatments: basal diet (CON); basal diet supplemented with either antibiotic bacitracin methylene disalicylate (BMD); or probiotics, namely, B. subtilis strain 1781 (PB1), a combination of B. subtilis strain 1104 + strain 747 (PB2), or B. subtilis strain 1781 + strain 747 (PB3). Body weight and feed intake were measured at 14 days of age, and the feed conversion ratio (FCR) was calculated. At 14 days of age, ileal samples were collected and used for intestinal cytokine, TJ protein, and mucin gene expression analysis using qRT-PCR. The chickens supplemented with antibiotic (BMD) and B. subtilis strain 1781 alone (PB1) had significantly higher body weights compared to controls of the same age. Dietary supplementation with antibiotic (BMD) or probiotics (PB1, PB2, PB3) significantly improved the feed efficiency as evidenced by decreased FCR compared to controls. No differences were observed in the expression of IL1β, IL17F, IFNγ, and MUC2 gene among the different treatment groups. However, elevated expression of IL6 (BMD, PB1, PB2), IL8 (PB2), and TNFSF15 (PB1, PB2, PB3) compared to controls was observed in the ileum. IL2 and IL10 expression was upregulated in chicks in the PB2 and PB3 groups, and IL4 was elevated in the PB1 group. IL13 was elevated in all probiotic-fed groups (PB1, PB2, PB3). Probiotic supplementation was also shown to significantly increase the expression of TJ proteins JAM2, ZO1 (PB2, PB3), and occludin (PB1, PB2). Taken together, B. subtilis supplementation altered intestinal immune activity and influenced gut barrier integrity through increased tight junction gene expression.

The effect of a Bacillus-based direct-fed microbial supplemented to sows on the gastrointestinal microbiota of their neonatal piglets

Direct-fed microbials (DFM) supplemented in sow diets may confer health benefits to the host and their piglets by reducing pathogens in the sow and environment. In this study we evaluated the effect of a Bacillus-based DFM on the gastrointestinal microbiota of neonatal piglets. A total of 208 sows were divided into 2 treatments: a control diet and the control diet supplemented with a Bacillus subtilis-based DFM (3.75 × 10(5) cfu/g feed). Twenty-one piglets sampled from each sow treatment group were euthanized on d 3 of lactation followed by an additional 15 piglets per treatment on d 10 of lactation. Litters from DFM-supplemented sows had greater (P = 0.02) weaning weights and a tendency (P = 0.09) for improvement in litter ADG. Sows supplemented with the DFM weaned more pigs (P = 0.06) than control sows which was reflected in numerically lower but not statistically different (P = 0.12) decrease in piglet mortality in DFM litters. Terminal RFLP was used to characterize gastrointestinal (GI) microbial populations in the ileum and colon of the piglets. Terminal restriction fragments (T-RF) were compared between control and DFM treatments. There was a greater incidence and quantity of T-RF B423 and H330 (binary P = 0.01, 0.08; quantitative P = 0.01, 0.05, respectively), putatively identified as Lactobacillus gasseri/johnsonii, in the ileum of pigs nursing sows supplemented with DFM at d 3. Terminal restriction fragment peaks B423 and H330 were also greater (binary P = 0.01, 0.08; quantitative P = 0.01, 0.01, respectively) in the colon of pigs nursing sows supplemented with DFM at d 3. Peaks M495 and B394, putatively identified as E. coli, were greater (binary P = 0.01, 0.04; quantitative P = 0.01, 0.01, respectively) in the colon of the control pigs at d 3. At d 10, both the presence and quantity of Lactobacillus species were greater (P < 0.05) in the colon of pigs with the DFM treatment. Additionally, there was a tendency for T-RF B227 and H257 (binary P = 0.07, 0.07, respectively), putatively identified as Clostridium perfringens, to be present in the ileum of the control pigs at d 10 compared with treated pigs. Results of this study reveal that the developing gastrointestinal microbiota of a neonatal piglet can be affected by DFM supplementation to the sow.

The effects of dietary Bacillus subtilis supplementation, as an alternative to antibiotics, on growth performance, intestinal immunity, and epithelial barrier integrity in broiler chickens infected with Eimeria maxima

The objective of this study was to investigate the effects of dietary Bacillus subtilis supplementation on growth performance, jejunal lesion scores, oocyst shedding, and cytokine and tight junction protein expression in broiler chickens infected with Eimeria maxima. A total of 196 male day-old Ross 708 broilers were given a nonexperimental diet until 14 D of age. Then, all chickens were randomly assigned to one of seven dietary treatments: 2 basal diets (CON and NC); CON + virginiamycin (AB1); CON + bacitracin methylene disalicylate (BMD; AB2); CON + B. subtilis 1781 (PB1); CON + B. subtilis 747 (PB2); or CON + B. subtilis 1781 + 747 (PB3). At day 21, all chickens except those in the CON group were orally inoculated with E. maxima oocysts. At 7 D after E. maxima infection, the body weight gains of chickens fed PB2 and PB3 increased (P = 0.032) as much as those in chickens fed AB2. The body weight gain and feed efficiency of chickens fed PB2 were significantly increased (P < 0.001), and PB2 chickens showed (P = 0.005) the lowest lesion scores after E. maxima infection. Chickens fed PB2 showed (P < 0.05) lower mRNA expression of IL-1β in infected chicken groups. Chickens in the AB1, AB2, PB1, PB2, and PB3 groups showed (P < 0.05) greater mRNA expression of junctional adhesion molecule 2 in jejunal tissue, whereas occludin expression increased (P < 0.05) in the jejunal tissue of chickens fed AB2 or PB2. Dietary B. subtilis supplementation significantly improved the growth performance of young chickens to a level comparable with that induced by virginiamycin or BMD without E. maxima infection. After infection with E. maxima, dietary virginiamycin and BMD significantly enhanced the epithelial barrier integrity, and the dietary B. subtilis 747 showed significantly enhanced growth performance, intestinal immunity, and epithelial barrier integrity. Together our results indicated that certain strains of B. subtilis provide beneficial effects on the growth of young broiler chickens and have the potential to replace antibiotic growth promoters.

Lactobacillus brevis strain 1E1 administered to piglets through milk supplementation prior to weaning maintains intestinal integrity after the weaning event

Early colonisation in the gastrointestinal tract by commensal microbes influences the progressive development and maturity of digestive and immune system functionality in the neonate. Application of strategically selected direct-fed microbials to neonatal pigs may provide an opportunity to dictate a portion of the intestinal microbial community and exert a beneficial influence on these developmental processes. Experiments were conducted to determine the effects of early administration of Lactobacillus brevis strain 1E1 to neonatal piglets (n=224) via a milk supplement system on gastrointestinal microbial counts, villous architecture, and immune cell phenotypes during the lactation phase and after weaning. Pigs administered the direct-fed microbial had lower Escherichia coli counts in the jejunum and ileum (P<0.05), and lower coliform counts in the jejunum compared to unsupplemented pigs (P<0.05). The villous height:crypt depth ratio was greater in the ileum at 9 days of age when pigs were provided L. brevis 1E1 compared to unsupplemented pigs (P<0.05), as well as in the duodenum of pigs supplemented with L. brevis 1E1 at 22 days of age (P<0.05). The number of leukocytes expressing CD2 (P<0.05), CD4 (P=0.07) and MHC-II (P=0.07) was lower in the jejunum of pigs administered L. brevis 1E1 compared to unsupplemented pigs, however direct-fed microbial treatment had no effect on the number of leukocytes expressing CD8, CD25 or SWC3. These data demonstrate that early colonisation of the porcine gastrointestinal tract with L. brevis strain 1E1 during the lactation phase influences the progression of intestinal structure, immune system development, and pathogen establishment, indicating a relationship between early microbial colonisation and development of intestinal maturity and integrity.