Effect of dietary Bacillus subtilis on growth performance and serum biochemical and immune indexes in weaned piglets

Dietary supplementation with Clostridium autoethanogenum protein improves growth performance and promotes muscle protein synthesis by activating the mTOR signaling pathway of the broiler

The experiment aimed to evaluate the effects of different ratios of Clostridium autoethanogenum protein (CAP) used in the diets on the growth performance, muscle quality, serum indexes, and mTOR pathway of white feather broilers. Four hundred and eighty 1-day-old Arbor Acres (AA) broilers, comprising equal numbers of males and females, were randomly assigned to one of four treatments, and each treatment consisted of 12 replicates of 10 birds. Four diets were formulated based on isoenergetic and isonitrogenous principles. The control group (CAP 0) did not receive any CAP, while the experimental groups received 2% (CAP 2), 3% (CAP 3), and 4% (CAP 4) of CAP for six weeks. Compared with the CAP0, (1) The feed conversion ratio (FCR) was lower (p < 0.05), and the leg muscle yield was higher (p < 0.05) in the CAP3 and CAP4; (2) The serum levels of TP, ALB, T-AOC, and SOD were improved in the CAP3 (p < 0.05); (3) The expression of Lipin-1 gene was down-regulated and AMPKɑ2, Akt, and 4E-BP1 genes were up-regulated in the experiment group (p < 0.05); (4) The inclusion of 3% CAP in the diet increased the levels of 4E-BP1, S6K1, Akt, and AMPKɑ2 phosphorylation by modulating the mTOR signaling pathway (p < 0.05). In conclusion, broiler diets containing 3% CAP can activate the mTOR signaling pathway to promote muscle synthesis and improve growth performance.

Effects of a multistrain Bacillus-based direct-fed microbial on gastrointestinal permeability and biomarkers of inflammation during and following feed restriction in mid-lactation Holstein cows

Objectives were to evaluate the effects of a multistrain Bacillus-based (Bacillus subtilis and Bacillus pumilus blend) direct-fed microbial (DFM) on production, metabolism, inflammation biomarkers and gastrointestinal tract (GIT) permeability during and following feed restriction (FR) in mid-lactation Holstein cows. Multiparous cows (n = 36; 138 ± 53 DIM) were randomly assigned to 1 of 3 dietary treatments: 1) control (CON; 7.5 g/d rice hulls; n = 12), 2) DFM10 (10 g/d Bacillus DFM, 4.9 × 109 cfu/d; n = 12) or 3) DFM15 (15 g/d Bacillus DFM, 7.4 × 109 cfu/d; n = 12). Before study initiation, cows were fed their respective treatments for 32 d. Cows continued to receive treatments during the trial, which consisted of 3 experimental periods (P): P1 (5 d) served as baseline for P2 (5 d), during which all cows were restricted to 40% of P1 dry matter intake (DMI), and P3 (5 d), a "recovery" where cows were fed ad libitum. On d 4 of P1 and on d 2 and 5 of P2, GIT permeability was evaluated in vivo using the oral paracellular marker chromium (Cr)-EDTA. As anticipated, FR decreased milk production, decreased insulin, glucagon, and BUN but increased nonesterified fatty acids. During recovery, DMI rapidly increased on d 1 then subsequently decreased (4.9 kg) on d 2 before returning to baseline whereas milk yield slowly increased but remained decreased (13%) relative to P1. DFM10-fed cows had increased DMI and milk yield relative to DFM15 during P3 (10%). Overall, milk lactose content was increased in DFM cows relative to CON (0.10 percentage units), and DFM10 cows tended to have increased lactose yield relative to CON and DFM15 during P3 (8 and 10%, respectively). No overall treatment differences were observed for other milk composition variables. Circulating glucose was quadratically increased in DFM10 cows compared with CON and DFM15 during FR and recovery. Plasma Cr area under the curve was increased in all cows on d 2 (9%) and 5 (6%) relative to P1. Circulating lipopolysaccharide binding protein (LBP), serum amyloid A (SAA), and haptoglobin (Hp) increased in all cows during P2 compared with baseline (31%, 100%, and 9.0-fold, respectively). Circulating Hp concentrations continued to increase during P3 (274%). Overall, circulating LBP and Hp tended to be increased in DFM15 cows relative to DFM10 (29 and 81%, respectively), but no treatment differences were observed for SAA. Following feed reintroduction during P3, fecal pH initially decreased (0.62 units), but returned to baseline levels whereas fecal starch markedly increased (2.5-fold) and remained increased (82%). Absolute quantities of a fecal Butyryl-CoA CoA transferase (But) gene associated with butyrate synthesis, collected by fecal swab were increased in DFM10 cows compared with CON and DFM15-fed cows. In summary, FR increased GIT permeability, caused inflammation, and decreased production. Feeding DFM10 increased some key production and metabolism variables and upregulated a molecular biomarker of microbial hindgut butyrate synthesis, while DFM15 appeared to augment immune activation.

Dose-Dependent Effects of Supplementing a Two-Strain Bacillus subtilis Probiotic on Growth Performance, Blood Parameters, Fecal Metabolites, and Microbiome in Nursery Pigs

This experiment was conducted to evaluate the effects of dietary supplementation level of a two-strain Bacillus subtilis probiotic on growth performance, blood parameters, fecal metabolites, and microbiome in nursery pigs. A total of 54 weaned piglets were allotted to three treatments in three replicate pens with six pigs/pen for a 28 d feeding trial. The treatments were as follows: control: no probiotic supplementation; Pro1x: B. subtilis supplementation at 1.875 × 105 CFU/g diet; and Pro10x: B. subtilis supplementation at 1.875 × 106 CFU/g diet. Body weight at d 14 postweaning (p = 0.06) and average daily gain for d 0 to 14 postweaning (p < 0.05) were greater in the Pro1x treatment than in the other treatments. Blood glucose levels were greater in both probiotic treatments than in the control treatment at d 14 postweaning (p < 0.05). In the fecal short-chain fatty acid (SCFA) concentrations, the butyrate concentrations were greater in the Pro1x treatment than in the other treatments (p < 0.05), and the acetate, propionate, and total SCFA concentrations were greater in the Pro1x treatment than in the Pro10x treatment (p < 0.05). The beta diversity of fecal microbiome composition at d 14 postweaning based on Unweighted Unifrac analysis was dissimilar between the Pro1x and Pro10x treatments (p < 0.05). In conclusion, dietary B. subtilis supplementation of two strains selected to reduce effects of pathogenic Escherichia coli to nursery diets at 1.875 × 105 CFU/g diet improved the growth rate in the early postweaning period, increased fecal SCFA concentrations and altered the fecal microbial community composition. A higher dose of B. subtilis did not improve the performance parameters over those of the control piglets.

Mechanisms and applications of probiotics in prevention and treatment of swine diseases

Probiotics can improve animal health by regulating intestinal flora balance, improving the structure of the intestinal mucosa, and enhancing intestinal barrier function. At present, the use of probiotics has been a research hotspot in prevention and treatment of different diseases at home and abroad. This review has summarized the researchers and applications of probiotics in prevention and treatment of swine diseases, and elaborated the relevant mechanisms of probiotics, which aims to provide a reference for probiotics better applications to the prevention and treatment of swine diseases.

Spraying compound probiotics improves growth performance and immunity and modulates gut microbiota and blood metabolites of suckling piglets

One factor that shapes the establishment of early neonatal intestinal microbiota is environmental microbial exposure, and probiotic application has been shown to promote health and growth of piglets. Thus, this study hypothesized that environmental probiotic application in early days of life would be beneficial to newborn piglets. This study aimed to investigate the effect of spraying a compound probiotic fermented liquid (CPFL) into the living environment of piglets on their early growth performance and immunity. This work included 68 piglets, which were randomized into probiotic and control groups. Blood and fecal samples were collected at 0, 3, 7, 14, and 21 days of age. Spraying CPFL significantly reshaped the microbiota composition of the delivery room environment, increased piglets' daily weight gain and weaning weight (P<0.001), and modulated piglets' serum cytokine levels (increases in IgA, IgG, and IL-10; decrease in IFN-γ; P<0.05 in each case) in piglets. Additionally, spraying CPFL during early days of life modified piglets' gut microbiota structure and diversity, increased the abundance of some potentially beneficial bacteria (such as Bacteroides uniformis, Butyricimonas virosa, Parabacteroides distasonis, and Phascolarctobacterium succinatutens) and decreased the abundance of Escherichia coli (P<0.05). Interestingly, CPFL application also significantly enhanced the gut microbial bioactive potential and levels of several serum metabolites involved in the metabolism of vitamins (B2, B3, B6, and E), medium/long-chain fatty acids (caproic, tetradecanoic, and peptadecanoic acids), and dicarboxylic acids (azelaic and sebacic acids). Our study demonstrated that spraying CPFL significantly could improve piglets' growth performance and immunity, and the beneficial effects are associated with changes in the gut microbiota and host metabolism. Our study has provided novel data for future development of probiotic-based health-promoting strategies and expanded our knowledge of probiotic application in animal husbandry.

Effect of the Inclusion of Bacillus spp. in Growing-Finishing Pigs' Diets: A Meta-Analysis

This meta-analysis determined the effect of Bacillus spp. on growth performance of growing−finishing pigs and then assessed causes for the heterogeneity of responses detected using meta-regression. A database of 22 articles published from 2000 to 2020 was identified, and 9 articles fitted the selection criteria and were integrated in the final database. Statistical analysis was performed to analyze the effect size for ADG, average daily feed intake (ADFI), and F:G ratio using a standardized means difference (SMD) at a 95% confidence interval. A meta-regression analysis was used to investigate the cause of heterogeneity, using the individual SMD for each study assessment as the outcome and the associated SE as the measure of variance. Dietary Bacillus spp. supplementation had no effect on ADFI (SMD: −0.052, p = 0.138) and numerically increased ADG (SMD: 0.113, p = 0.081) and reduced the F:G ratio SMD: −0.127, p < 0.001). Meta-regression outcomes suggested that the number of animals per group was an essential component promoting heterogeneity in ADG. Overall, the inclusion of Bacillus spp. (median 486 mg/d) in growing−finishing pigs can increase ADG and can decrease the F:G ratio.

A Novel Probiotic Bacillus subtilis Strain Confers Cytoprotection to Host Pig Intestinal Epithelial Cells during Enterotoxic Escherichia coli Infection

Enteric infections caused by enterotoxic Escherichia coli (ETEC) negatively impact the growth performance of piglets during weaning, resulting in significant economic losses for the producers. With the ban on antibiotic usage in livestock production, probiotics have gained a lot of attention as a potential alternative. However, strain specificity and limited knowledge on the host-specific targets limit their efficacy in preventing ETEC-related postweaning enteric infections. We recently isolated and characterized a novel probiotic Bacillus subtilis bacterium (CP9) that demonstrated antimicrobial activity. Here, we report anti-ETEC properties of CP9 and its impact on metabolic activity of swine intestinal epithelial (IPEC-J2) cells. Our results showed that pre- or coincubation with CP9 protected IPEC-J2 cells from ETEC-induced cytotoxicity. CP9 significantly attenuated ETEC-induced inflammatory response by reducing ETEC-induced nitric oxide production and relative mRNA expression of the Toll-like receptors (TLRs; TLR2, TLR4, and TLR9), proinflammatory tumor necrosis factor alpha, interleukins (ILs; IL-6 and IL-8), augmenting anti-inflammatory granulocyte-macrophage colony-stimulating factor and host defense peptide mucin 1 (MUC1) mRNA levels. We also show that CP9 significantly (P < 0.05) reduced caspase-3 activity, reinstated cell proliferation and increased relative expression of tight junction genes, claudin-1, occludin, and zona occludens-1 in ETEC-infected cells. Finally, metabolomic analysis revealed that CP9 exposure induced metabolic modulation in IPEC J2 cells with the greatest impact seen in alanine, aspartate, and glutamate metabolism; pyrimidine metabolism; nicotinate and nicotinamide metabolism; glutathione metabolism; the citrate cycle (TCA cycle); and arginine and proline metabolism. Our study shows that CP9 incubation attenuated ETEC-induced cytotoxicity in IPEC-J2 cells and offers insight into potential application of this probiotic for ETEC infection control. IMPORTANCE ETEC remains one of the leading causes of postweaning diarrhea and mortality in swine production. Due to the rising concerns with the antibiotic use in livestock, alternative interventions need to be developed. In this study, we analyzed the cytoprotective effect of a novel probiotic strain in combating ETEC infection in swine intestinal cells, along with assessing its mechanism of action. To our knowledge, this is also the first study to analyze the metabolic impact of a probiotic on intestinal cells. Results from this study should provide effective cues in developing a probiotic intervention for ameliorating ETEC infection and improving overall gut health in swine production.

Effects of Bacillus licheniformis and Bacillus subtilis on Gut Barrier Function, Proinflammatory Response, ROS Production and Pathogen Inhibition Properties in IPEC-J2—Escherichia coli/Salmonella Typhimurium Co-Culture

The emergence of antimicrobial resistance raises serious concerns worldwide. Probiotics offer a promising alternative to enhance growth promotion in farm animals; however, their mode of action still needs to be elucidated. The IPEC-J2 cell line (porcine intestinal epithelial cells) is an appropriate tool to study the effect of probiotics on intestinal epithelial cells. In our experiments, IPEC-J2 cells were challenged by two gastrointestinal (GI) infection causing agents, Escherichia coli (E. coli) or Salmonella enterica ser. Typhimurium (S. Typhimurium). We focused on determining the effect of pre-, co-, and post-treatment with two probiotic candidates, Bacillus licheniformis or Bacillus subtilis, on the barrier function, proinflammatory cytokine (IL-6 and IL-8) response, and intracellular reactive oxygen species (ROS) production of IPEC-J2 cells, in addition to the adhesion inhibition effect. Bacillus licheniformis (B. licheniformis) and Bacillus subtilis (B. subtilis) proved to be anti-inflammatory and had an antioxidant effect under certain treatment combinations, and further effectively inhibited the adhesion of pathogenic bacteria. Interestingly, they had little effect on paracellular permeability. Based on our results, Bacillus licheniformis and Bacillus subtilis are both promising candidates to contribute to the beneficial effects of probiotic multispecies mixtures.

Bacillus spp. Probiotic Strains as a Potential Tool for Limiting the Use of Antibiotics, and Improving the Growth and Health of Pigs and Chickens

The pressure to increasingly optimize the breeding of livestock monogastric animals resulted in antimicrobials often being misused in an attempt to improve growth performance and counteract diseases in these animals, leading to an increase in the problem of antibiotic resistance. To tackle this problem, the use of probiotics, also known as direct in-feed microbials (DFM), seems to be one of the most promising strategies. Among probiotics, the interest in Bacillus strains has been intensively increased in recent decades in pigs and poultry. The aim of the present review was to evaluate the effectiveness of Bacillus strains as probiotics and as a potential strategy for reducing the misuse of antibiotics in monogastric animals. Thus, the potential modes of action, and the effects on the performance and health of pigs (weaning pigs, lactation and gestation sows) and broilers are discussed. These searches yielded 131 articles (published before January 2021). The present review showed that Bacillus strains could favor growth in terms of the average daily gain (ADG) of post-weaning piglets and broilers, and reduce the incidence of post-weaning diarrhea in pigs by 30% and mortality in broilers by 6-8%. The benefits of Bacillus strains on these parameters showed results comparable to the benefit obtained by the use of antibiotics. Furthermore, the use of Bacillus strains gives promising results in enhancing the local adaptative immune response and in reducing the oxidative stress of broilers. Fewer data were available regarding the effect on sows. Discordant effects have been reported regarding the effect on body weight (BW) and feed intake while a number of studies have supported the hypothesis that feeding probiotics to sows could benefit their reproductive performance, namely the BW and ADG of the litters. Taken all the above-mentioned facts together, this review confirmed the effectiveness of Bacillus strains as probiotics in young pigs and broilers, favoring their health and contributing to a reduction in the misuse of direct in-feed antibiotics. The continuous development and research regarding probiotics will support a decrease in the misuse of antibiotics in livestock production in order to endorse a more sustainable rearing system in the near future.