On the use of a probiotic (Bacillus subtilis - strain DSM 17299) as growth promoter in broiler diets

Effect of the use of probiotic Bacillus subtilis (QST 713) as a growth promoter in broilers: an alternative to bacitracin methylene disalicylate

The global poultry trend toward the more responsible use of antibiotics is becoming recurrent and has demanded the need to generate new natural alternatives. Probiotics have gained importance as an option to use as growth promoters. This study aimed to evaluate Bacillus subtillis QST713 as a substitute for an antibiotic growth promoter (BMD). A total of 150 male broilers were assigned to three dietary treatments: 1) control diet (CO), 2) control diet + 500 g/t of BMD (AGP), and 3) control diet + 100 g/t of B. subtilis QST713 (PB), respectively. Each treatment was monitored for 5 wk for the productive variables: body weight, accumulated feed consumption, food conversion, and European efficiency factor. At the end of each week, fresh fecal samples were cultured and quantified for E. coli, Enterococcus spp., and Lactobacillus spp. At the end of the trial, blood samples were analyzed for hemogram and intestinal samples (anterior portion) for histomorphometry. The data were statistically analyzed with an analysis of variance and subjected to a least significant difference test (Tukey). The zootechnical yields were similar in the AGP and PB groups (P ˃ 0.05); both superior to the control group. In the hematological profiles, no difference was observed between the experimental groups. E. coli and Enterococcus counts were significantly lower (P ˂ 0.05), and Lactobacillus counts were significantly (P ˂ 0.05) higher in the PB group, relative to CO and AGP groups. No differences (P ˃ 0.05) were found in bacterial counts between the CO and AGP groups. The intestinal mucosa and villi in the PB group were significantly (P ˂ 0.05) longer and with less deeper crypts than CO and AGP groups. We conclude that B. subtillis QST713, used at the suggested commercial dose (100 g/ton), is an effective growth-promoting alternative to BMD that modulates the microbiota and intestinal architecture, thus producing zootechnical yields consistent with BMD.

Bacillus amyloliquefaciens TL Downregulates the Ileal Expression of Genes Involved in Immune Responses in Broiler Chickens to Improve Growth Performance

Bacillus amyloliquefaciens TL promotes broiler chicken performance by improving nutrient absorption and utilization and reducing intestinal inflammation. In this study, RNA-sequencing (RNA-seq)-based transcriptomes of ileal tissues collected from probiotic-fed and control broiler chickens were analyzed to elucidate the effects of the probiotic B. amyloliquefaciens TL, as a feed additive, on the gut immune function. In total, 475 genes were significantly differentially expressed between the ileum of probiotic-fed and control birds. The expression of genes encoding pyruvate kinase, prothymosin-α, and heat stress proteins was high in the ileum of probiotic-fed birds (FPKM > 500), but not in the control group. The gene ontology functional enrichment and pathway enrichment analyses revealed that the uniquely expressed genes in the control group were mostly involved in immune responses, whereas those in the probiotic group were involved in fibroblast growth factor receptor signaling pathways and positive regulation of cell proliferation. Bacillus amyloliquefaciens TL downregulated the expression of certain proinflammatory factors and affected the cytokine–cytokine receptor interaction pathway. Furthermore, B. amyloliquefaciens TL in broiler diets altered the expression of genes involved in immune functions in the ileum. Thus, it might contribute to improved broiler growth by regulating the immune system and reducing intestinal damage in broilers.

Probiotic bacteria maintain normal growth mechanisms of heat stressed broiler chickens

Probiotics have growth promoting effects even under periods of heat stress challenge. More information is needed to understand the mechanisms by which probiotics maintain the growth performance. The aim of this study was to evaluate the effect of a probiotic based on Bacillus subtilis bacteria on growth related mechanisms of broilers under heat stress conditions. Specifically, growth performance, skeletal bone characteristics, skeletal muscles size, intestinal villus-crypt structure, intestinal bacteria, growth hormone (GH), insulin-like growth factor-1 (IGF-1), cholesterol, and glucose. A total of 1200 one day old Ross 308 male broilers were randomly distributed into 4 treatments, with 12 replicates per treatment and 25 birds per replicate. A 2 × 2 factorial arrangement was used; the main factors were environmental temperature (thermoneutral or heat stress) and diet (control or control + B. subtilis; 3 × 10⁷ cfu/kg of feed). From d 22 to 35 of age, birds were either exposed to thermoneutral conditions (21 °C) or chronic heat stress (30 °C). During the same period, each group was divided into 2 subgroups and fed either the control diet or the B. subtilis supplemented diet. The results demonstrated that B. subtilis had positive effects (P < 0.05) on the body weight gain, feed conversion ratio, villus height, crypt depth, villus surface area, absorptive epithelial cell area and viable counts of intestinal beneficial bacteria. B. subtilis increased (P < 0.05) serum GH, IGF-1 and maintain normal levels of cholesterol and glucose under heat stress conditions. In addition, broilers fed B. subtilis under heat stress conditions exhibited higher (P < 0.05) skeletal muscles size and improved (P < 0.05) tibia traits and lower (P < 0.05) abdominal fat pads deposition compared with the controls. B. subtilis had no effect on rectal temperature under thermoneutral or heat stress conditions. It is concluded that B. subtilis can be used as growth promoters in broilers, particularly during the periods of heat stress conditions.

Effect of probiotic preparations (EM) on productive characteristics, carcass composition, and microbial contamination in a commercial broiler chicken farm

This experiment evaluated the effect of Pro-Biotyk (Em-15) and EMFarma™ probiotics on body weight, feed intake and conversion, carcass traits, and microbial contamination in a poultry house. The probiotic preparations caused a nonsignificant increase in body weight (42 days), feed intake, and feed conversion ratio (1-42 days) and a nonsignificant decrease in chicken mortality from 4 weeks of rearing. Chickens exposed to probiotics did not differ significantly in preslaughter body weight, carcass weight, dressing percentage, and the content of carcass components. The carcasses from experimental chickens had a lower percentage of breast muscle, leg muscle, abdominal fat, and neck, as well as a higher percentage of skin with subcutaneous fat, wings, and remainder of carcasses compared with the carcasses from control birds. The probiotic preparations used in this study were highly effective as auxiliary disinfectants.

Recent Advances in the Physiology of Spore Formation for Bacillus Probiotic Production

Spore-forming probiotic bacteria have received a wide and constantly increasing scientific and commercial interest. Among them, Bacillus species are the most studied and well-characterized Gram-positive bacteria. The use of bacilli as probiotic products is expanding especially rapidly due to their inherent ability to form endospores with unique survivability and tolerance to extreme environments and to produce a large number of valuable metabolites coupled with their bio-therapeutic potential demonstrating immune stimulation, antimicrobial activities and competitive exclusion. Ease of Bacillus spp. production and stability during processing and storage make them a suitable candidate for commercial manufacture of novel foods or dietary supplements for human and animal feeds for livestock, especially in the poultry and aquaculture industries. Therefore, the development of low-cost and competitive technologies for the production of spore-forming probiotic bacteria through understanding physiological peculiarities and mechanisms determining the growth and spore production by Bacillus spp. became necessary. This review summarizes the recent literature and our own data on the physiology of bacilli growth and spore production in the submerged and solid-state fermentation conditions, focusing on the common characteristics and unique properties of individual bacteria as well as on several approaches providing enhanced spore formation.

Dietary Supplementation With Bacillus subtilis Direct-Fed Microbials Alters Chicken Intestinal Metabolite Levels

Direct-fed microbials (DFMs) are dietary supplements containing live microorganisms which confer a performance and health benefit to the host, but the mechanisms are unclear. Here, a metabolomics approach was used to identify changes in intestinal metabolite levels in chickens fed an unsupplemented diet or a diet supplemented with B. subtilis strain 1781 or strain 747. Body weight gains of chickens fed the B. subtilis-supplemented diets were increased up to 5.6% in the B. subtilis 1781 group and 7.6% in the B. subtilis 747 group compared with chickens fed the unsupplemented diet. Compared with unsupplemented controls, the levels of 83 metabolites were altered (p < 0.05) (25 increased, 58 decreased) in chickens given the B. subtilis 1781-supplemented diet, while 50 were altered (p < 0.05) (12 increased, 38 decreased) with the B. subtilis 747-supplemented diet. Twenty-two metabolites were altered (p < 0.05) (18 increased, 4 decreased) in the B. subtilis 1781 vs. B. subtilis 747 groups. A random forest analysis of the B. subtilis 1781 vs. control groups gave a predictive accuracy of 87.5%, while that of the B. subtilis 747 vs. control groups was 62.5%. A random forest analysis of the B. subtilis 1781 vs. B. subtilis 747 groups gave a predictive accuracy of 75.0%. Changes in the levels of these intestinal biochemicals provided a distinctive biochemical signature unique to each B. subtilis-supplemented group, and were characterized by alterations in the levels of dipeptides (alanylleucine, glutaminylleucine, phenylalanylalanine, valylglutamine), nucleosides (N1-methyladenosine, N6-methyladenosine, guanine, 2-deoxyguanosine), fatty acids (sebacate, valerylglycine, linoleoylcholine), and carbohydrates (fructose). These results provide the foundation for future studies to identify biochemicals that might be used to improve poultry growth performance in the absence of antibiotic growth promoters.

Beneficial effects of dietary supplementation of Bacillus strains on growth performance and gut health in chickens with mixed coccidiosis infection

The present study investigated the effects of dietary supplementation with several Bacillus strains on growth performance, intestinal inflammatory and anti-inflammatory cytokines, anti-oxidants and tight junction (TJ) protein mRNA expression in broiler chickens challenged with mixed coccidia infection (oocysts of Eimeria tenella, Eimeria maxima and Eimeria acervulina). Ten different Bacillus strains were screened for their beneficial effects on coccidiosis challenge by measuring relative body weight gain (RBWG), lesion score, and total oocyst count. Three out of ten Bacillus strains were evaluated in depth by measuring RBWG, lesion score, total oocyst count, and the gene expression of proinflammatory (IL-6 and IL-8), anti-inflammatory (IL-10 and TGF-β), anti-oxidant (SOD1 and HMOX1), and TJ (JAM2 and occludin) proteins. Our results showed that out of the ten different Bacillus strains, chickens fed with three strains, one Bacillus licheniformis and two Bacillus amyloliquefaciens, showed significantly higher RBWG, lower lesion scores (ceca, jejunum, and duodenum), and lower total fecal oocyst counts compared to non-Bacillus-fed control chickens. Post-coccidia challenge, the RBWG for the Bacillus-fed groups were 95-100 % as opposed to the control birds (70 %) at 6 days post infection (dpi) and 10 dpi. Similarly, the lesion scores for three organs were around 0.8-0.9 for the Bacillus-fed groups as opposed to control birds (lesion score range ∼1.4-2). The total oocyst counts were much lower in the Bacillus-fed group (10-20 folds lesser) than the control group. Furthermore, the Bacillus-fed groups showed differential gene expression at 3 dpi in different tissues, such as caecum, jejunum, and duodenum. Bacillus-fed chickens showed significant pro- and anti-inflammatory responses and higher expression of anti-oxidants and TJ proteins in the ceca, duodenum, and jejunum. Overall, our results demonstrated that dietary supplementation with Bacillus strains as direct-fed microbials (DFM) significantly improved the body weight gain after mixed coccidia challenge compared to non-Bacillus-fed and coccidia challenged control group. In conclusion, the results of this study are promising and indicate the many beneficial effects of DFM-supplementation in poultry diets to reduce the negative consequences of enteric diseases and to decrease economic losses imposed by coccidia infection in chickens.

Growth performance, apparent retention of components, and excreta dry matter content in Shaver White pullets (5 to 16 week of age) in response to dietary supplementation of graded levels of a single strain Bacillus subtilis probiotic

Administered in adequate amounts, probiotics can be an alternative to antibiotic growth promoters in poultry production. This study evaluated dose response of a single strain of Bacillus subtilis (SSB, DSM29784) on growth performance, apparent retention (AR) of components, and excreta DM content in pullets. A basal corn-soybean meal diet was formulated to meet the specifications for grower (week 5 to 10) and developer (week 11 to 16) phases. In each phase, SSB was added to the basal diet to create 4 test diets: 0 (control, CON), 1.1E+08 (low; LSSB), 2.2E+08 (medium; MSSB), or 1.1E+09 (high; HSSB) CFU of SSB/kg of feed. All diets had TiO2 (0.5%) as a digestibility marker. A total of 720 day-old Shaver White chicks were placed in 48 cages (15 pullets per cage) and reared on a commercial antibiotic free diet for a 4-wk period. At the beginning of week 5, treatments were allocated based on cage BW (n = 12). Birds had free access to feed and water throughout. The BW, BW uniformity, feed intake (FI) and FCR were obtained weekly. Excreta was collected at the end of each phase for AR of DM, organic matter, CP, neutral detergent fiber, minerals, and AME, as well as excreta DM content. In response to SSB inclusion, BW improved in a linear (P < 0.005) and quadratic (P < 0.0001) manner in grower. FI decreased in a linear and quadratic pattern (P < 0.05, week 8 to 10) in grower, and linearly (P < 0.05) across the developer phase. Overall FCR improved in linear and quadratic pattern (P < 0.01) in the grower phase. In both the phases, AME improved in a quadratic pattern (P < 0.05). Inclusion of SSB had a linear reduction (P < 0.0001) in excreta moisture content in the grower phase. In summary, these results demonstrate that B. subtilis probiotic improved performance through enhanced nutrient utilization and reduced excreta moisture content indicating improved pullet gut health.

Use of probiotics in diets of wild-type chickens and its effects on performance

SUMMARY The objective of this study was to evaluate the performance of male colonial chickens fed diet supplemented with commercial probiotic (Calsporin ®). A total of 210 male chicks Label Rouge lineage were used and they were raised in experimental shed up to 30 days old. These birds had free access to the pickets of Tifton-85, from 31-90 days of age. The experimental design was completely randomized, two treatments, one containing feed supplemented with probiotic Bacillus subtillis (300 g t-1 Bacillus subtillis 1×109 UFCg-1) and another one without it, with ten replications per treatment, consisting of 21 chickens/replication. The mean of body weight (BW), weight gain (WG), feed intake (FI), feed conversion (FC), mortality and viability were evaluated. The data were submitted to variance analysis and the averages of the treatments were compared by the F-test at 5% of significance. The addition of probiotic (300 g t-1 Bacillus subtillis 1×109 UFCg-1) in the diet of Label Rouge broilers did not interfere in the MW, WG, and FC variables in the total period from 1 to 90 days (P>0.05); the MFI variable differed (P <0.05), with higher consumption in chickens receiving the diet with the probiotic. The inclusion of probiotic in the wild-type chicken ration did not improve the productive performance of poultries possibly due to a low challenge by pathogenic microorganisms in the environments in which they were raised.

Bacillus spp. as direct-fed microbial antibiotic alternatives to enhance growth, immunity, and gut health in poultry

The increasing occurrence of antibiotic-resistant bacteria combined with regulatory pressure and consumer demands for foods produced without antibiotics has caused the agricultural industry to restrict its practice of using antibiotic growth promoters (AGP) in food animals. The poultry industry is not immune to this trend, and has been actively seeking natural alternatives to AGP that will improve the health and growth performance of commercial poultry flocks. Bacillus probiotics have been gaining in popularity in recent years as an AGP alternative because of their health-promoting benefits and ability to survive the harsh manufacturing conditions of chicken feed production. This review provides an overview of several modes of action of some Bacillus direct-fed microbials as probiotics. Among the benefits of these direct-fed microbials are their production of naturally synthesized antimicrobial peptides, gut flora modulation to promote beneficial microbiota along the gastrointestinal tract, and various immunological and gut morphological alterations. The modes of action for increased performance are not well defined, and growth promotion is not equal across all Bacillus species or within strains. Appropriate screening and characterization of Bacillus isolates prior to commercialization are necessary to maximize poultry growth to meet the ultimate goal of eliminating AGP usage in animal husbandry.

Combination of an Enzymatically Hydrolyzed Yeast and Yeast Culture with a Direct-fed Microbial in the Feeds of Broiler Chickens

A balance trial experiment was carried out to evaluate the potential relationship between an enzymatically hydrolyzed yeast (EHY) and yeast culture combined with a live Bacillus subtilis (Bs) on the productive parameters, ileal digestibility, retention of nutrient and energy and villus morphology in broilers. Seventy two 28 d old, Ross B308 male broilers were assigned to a factorial combination of 2 levels of EHY (0 and 1 kg/ton of feed) and 2 levels of Bs (0 and 125 g/ton of feed). The experiment lasted 2 weeks. Several treatment interactions were observed. EHY-fed broilers showed the lowest feed intake and feed conversion ratio whereas Bs-fed broilers showed the highest feed intake and intermediate feed conversion ratio (EHY and BS interaction, p<0.05). Also, EHY-fed broilers had greater ileal digestibility of dry matter (EHY and BS interaction, p<0.01) and energy (EHY and BS interaction, p<0.05) but these responses were counterbalanced by the combination of EHY and Bs. The thickness of the mucosa was similar between the control and EHY-fed broilers, but was lowest when Bs was added alone (EHY and BS interaction, p<0.01). The thickness of the villus was greater in EHY plus Bs-fed broilers, intermediate for the control and lower for Bs or EHY-fed broilers (EHY and BS interaction, p<0.05). The area of the villus was greater in the control and EHY plus Bs-fed broilers (EHY and BS interaction, p<0.05). In addition, EHY-fed broilers showed greater breast yield and nitrogen retention (p<0.01) and ashes digestibility (p<0.05). On the other hand, Bs-fed broilers had greater carcass and breast weight, nitrogen retention, energy excretion and villus height (p<0.05). In summary, EHY and Bs enhanced some growth, carcass and nutrient retention responses, but did not show any synergic relationship in these responses. Opposite to this, the results suggest that the positive effect of EHY on the feed conversion and digestibility of nutrients were counterbalanced by the addition of Bs.

Effect of supplementation of Bacillus subtilis LS 1-2 to broiler diets on growth performance, nutrient retention, caecal microbiology and small intestinal morphology

Present study investigated the effect of dietary supplementation of Bacillus subtilis LS 1-2 on growth performance, apparent nutrient retention, caecal microbial population and intestinal morphology in broilers. Three hundred and twenty day-old Ross broiler chicks were randomly allotted to four treatments on the basis of BW in a randomized complete block design. Experimental diets were fed in two phases: starter (d 0-21) and finisher (d 22-35). Dietary treatments were basal diet supplemented with 0% (control), 0.15%, 0.30% and 0.45% B. subtilis LS 1-2. Supplementation of increasing levels of B. subtilis LS 1-2 showed linear improvement (P<0.05) in growth performance and apparent nutrient retention. At d 35, birds supplemented with increasing levels of B. subtilis LS 1-2 showed decrease in caecal Clostridium and Coliform count (linear, P<0.05). Moreover, supplementation of B. subtilis LS 1-2 increased (linear, P<0.05) villus height and villus height to crypt depth ratio in both duodenum and ileum. Results obtained in the present study indicate that B. subtilis LS 1-2 can be used as a growth promoter in broiler diets and can improve intestinal microbial balance and gut health of broilers.

Evaluation of a direct-fed microbial product effect on the prevalence and load of Escherichia coli O157:H7 in feedlot cattle

Direct-fed microbials (DFM) have been identified as potential preharvest interventions for the reduction of foodborne bacterial pathogens such as Escherichia coli O157:H7. This study evaluated the efficacy of a DFM consisting of Bacillus subtilis strain 166 as an antimicrobial intervention strategy for the reduction of prevalence and load of E. coli O157:H7 in feces and on hides of feedlot cattle. Cattle (n = 526) were divided among 16 feedlot pens. Half of the pens received the DFM, and the other half did not. Hide and fecal samples were collected from each animal on days 28, 63, and 84 of the feeding trial. Over the course of the 84-day feeding period, there were no significant differences observed between treatments for either hide or fecal prevalence of E. coli O157:H7, or for the percentage of animals that were shedding E. coli O157:H7 at high levels (> or =200 CFU/g) in their feces or harboring E. coli O157:H7 at high levels (> or =40 CFU/cm(2)) on their hides. In addition, there was no significant difference between the average daily gains for the treated and control groups, with both groups averaging 1.3 kg/day. We concluded that the DFM tested would not be an effective preharvest intervention against E. coli O157:H7.