Effects of salinomycin and Bacillus subtilis on growth performance and immune responses in broiler chickens

Growth performance, organs weight, intestinal histomorphology, and oocyst shedding in broiler chickens offered novel single strain Bacillus subtilis isolated from camel dung and challenged with Eimeria

We evaluated a single strain Bacillus subtilis BS-9 direct-fed microbial (BSDFM) isolated from camel dung in Eimeria challenged broiler chickens. Seven-hundred d-old Ross 708 male chicks were placed in pens (25 birds/pen) and allocated to 2 treatments (n = 14). From d 0 to 13, control pens received untreated water (-BSDFM), and 2 treated pens received water and 2 mL x 108 colony forming unit/bird/d (+BSDFM); daily water intake (WI) was recorded. On d 9, birds in half (+Eimeria) of pens per treatment received of 1 mL of Eimeria maxima and Eimeria acervulina oocysts orally, and the other half (-Eimeria) sterile saline solution. Birds had ad libitum access to feed and a water line from d 14. Feed intake (FI), body weight (BW) and mortality were recorded for calculating BW gain (BWG) and feed conversion ratio (FCR). On d 14 and 35, samples of birds were necropsied for organ weight and intestinal measurements. Excreta samples were collected from d 14 to 19 for oocyst count. There was no treatment effect (P > 0.05) on growth performance or WI on d 0 to 9. There were interactions between BSDFM and Eimeria on d 19 (P = 0.014) and 29 (P = 0.036) BW with unchallenged +BSDFM birds being heavier than birds in the other treatments. The main effects (P < 0.05) on d 10 to 35 FI, BW, and BWG were such that +BSDFM increased and Eimeria decreased (P < 0.01) these parameters. There was interaction (P = 0.022) between BSDFM and Eimeria on d 10 to 35 FCR such that the FCR of challenged -BSDFM birds was poor than that of unchallenged counterparts, but none differed with +BSDFM birds. There was an interaction (P = 0.039) between BSDFM and Eimeria on d 14 bursa weight with challenged birds exhibiting heavier bursa than unchallenged +BSDFM birds. Eimeria reduced (P = 0.01) and BSDFM (P = 0.002) increased the villi height to crypt depth ratio. Results showed that BSDFM supplementation via water can support the growth performance of broiler chickens challenged with Eimeria and may be a strategy to reduce adverse effects of coccidiosis.

Effects of a complex probiotic preparation, Fengqiang Shengtai and coccidiosis vaccine on the performance and intestinal microbiota of broilers challenged with Eimeria spp

BACKGROUND

Coccidiosis, a prominent intestinal protozoan disease, carries significant economic implications for the poultry industry. The aim of this study was to evaluate the effects of Fengqiang Shengtai (BLES), a probiotics product, and coccidiosis vaccine in modulating the intestinal microbiome and providing insight into mitigating the occurrence and management of avian coccidiosis.

METHODS

Broilers included in the study were divided into four pre-treatment groups: the Pre-Con group (commercial diet), Pre-BLES group (BLES supplement), Pre-Vac group (coccidiosis vaccination) and Pre-Vac-BLES group (combined vaccination and BLES). Body weight gain, feed consumption and feed conversion ratio were monitored from age 25 to 55 days. Cecum contents were collected at 8 and 15 days of age for comparative analysis of intestinal microbiomes. In the Pre-BLES and Pre-Vac-BLES groups, probiotics were administered at a dose of 0.01 g per chicken between ages 3 to 6 days and 10-13 days. At 3 days of age, chickens in the Pre-Vac and Pre-Vac-BLES groups were vaccinated with 1700 sporulated oocysts of the live coccidiosis vaccine per chicken. At the age of 25 days, Eimeria spp. challenge experiments were performed based on the aforementioned immunization strategy, and the oocysts per gram (OPG) in the feces, intestinal lesion score and intestinal pathological characteristics were evaluated. Specifically, 30 chickens were randomly selected from each group and orally administered 34,000 sporulated oocysts of Eimeria spp. per chicken, re-defined as Eimeria group, BLES-Eimeria group, Vac-Eimeria group and Vac-BLES-Eimeria group, respectively. Additionally, 30 chickens were randomly selected from the Pre-Con group and included as negative control without Eimeria spp.

CHALLENGE

Intestinal microbiota was sequenced and analyzed when the broilers were 32 days old.

RESULTS

A significant improvement was observed in body weight gain of the broilers in the Pre-BLES and Pre-Vac-BLES group at 45 days of age. Analysis of the intestinal microbiota revealed a positive correlation between the experimental groups receiving BLES and coccidiosis vaccines at 8 and 15 days of age with the Enterococcus genus and Lachnospiraceae NK4A136 group, respectively. In addition to the reduced lesion score and OPG values, the combination of coccidiosis vaccine and BLES also reduced the intestinal epithelial abscission induced by coccidiosis vaccines. The results of intestinal microbial function prediction demonstrated that N-glycan biosynthesis and ferroptosis were the prominent signal pathways in the Vac-BLES-Eimeria group.

CONCLUSIONS

Taken together, the results of the present study suggest that supplementation of BLES with coccidiosis vaccine represents a promising strategy for improving growth performance, alleviating clinical manifestations and inducing favorable alterations to the intestinal microbiota in broiler chickens affected by coccidiosis.

The effect of Bacillus subtilis and its delivery route on hatch and growth performance, blood biochemistry, immune status, gut morphology, and microbiota of broiler chickens

This study evaluated the effect of probiotics (Bacillus subtilis fermentation extract) and its delivery route (in-feed or in ovo) on hatch and growth performance, blood biochemistry, immune status, gut morphology, and microbiota of broiler chickens. Hatching eggs were incubated for 21 d. On d 12, viable eggs were randomly allotted to 4 groups: the noninjected, in ovo saline (S), in ovo Bacillus subtilis 1 (P1), and in ovo Bacillus subtilis 2 (P2). On d 18, S, P1, and P2 groups received 0.2 mL saline diluent, 10 × 10⁶, and 20 × 10⁶ CFU of the bacterium via the amnion, respectively. At hatch, chicks were re-allotted to 5 new treatment groups: P1, P2, 0.005% in-feed Bacillus subtilis extract (P3), 0.05% in-feed bacitracin methylene disalicylate (BMD,), and corn-wheat-soybean diet negative control (NC) in 9 replicate pens (22 birds/pen) and raised for 35 d. Hatch parameters were assessed on d 0, and growth performance indices measured weekly. On d 25, 1 bird/cage was euthanized, and samples collected for further analysis. Data were analyzed by generalized linear model. Treatments S and P2 recorded higher (P = 0.01) chick BW/ Egg Weight values compared to the non-injected eggs. P3 and P2 reduced (P = 0.02) FI at week 5 compared to the NC treatment. However, no change in average body weight gain (ABG) and feed conversion ratio (FCR) were observed during the same period. At d 35, while BMD treatment showed a tendency (P = 0.09) to increase FI compared to the NC treatment, ABG and FCR were similar for all treatments. Blood sodium and chloride levels were increased (P < 0.05) by the BMD treatment compared to the NC treatment. Compared to other treatments, BMD and P3 treatments increased (P < 0.001) jejunal and ileal villus height to crypt depth ratios, respectively. However, P1 and P2 increased (P < 0.001) villus height to crypt depth ratio in the duodenum compared to NC treatment. Treatments did not affect gut microbial diversity; however, BMD treatment increased (P < 0.05) the proportion of bacteria in the genus Enterococcus in the ileum and reduced (P < 0.05) the proportion of bacteria in the genus Streptococcus in the ceca. All probiotics treatments (irrespective of route and dose) reduced (P < 0.001) the levels of serum IgG compared to the NC treatment. However, P1 and P2 had the lowest numerical decrease in serum IgG concentrations, suggesting that Bacillus subtilis (especially in ovo delivered) might provide broiler chickens with better immunological protection by neutralizing pathogenic organisms that could result in the production of natural antibodies.

Bacillus Species as Direct-Fed Microbial Antibiotic Alternatives for Monogastric Production

Antibiotic growth promoters have been utilized for long time at subtherapeutic levels as feed supplements in monogastric animal rations. Because of their side-effects such as antibiotic resistance, reduction of beneficial bacteria in the gut, and dysbiosis, it is necessary to look for non-therapeutic alternatives. Probiotics play an important role as the key substitutes to antibacterial agents due to their many beneficial effects on the monogastric animal host. For instance, enhancement of the gut microbiota balance can contribute to improvement of feed utilization efficiency, nutrients absorption, growth rate, and economic profitability of livestock. Probiotics are defined as "live microorganisms that, when administered in adequate amounts, confer a health benefit on the host." They are available in diverse forms for use as feed supplements. Their utilization as feed additives assists in good digestion of feed ingredients and hence, making the nutrients available for promoting growth. Immunity can also be enhanced by supplementing probiotics to monogastrics diets. Moreover, probiotics can help in improving major meat quality traits and countering a variety of monogastric animals infectious diseases. A proper selection of the probiotic strains is required in order to confer optimal beneficial effects. The present review focuses on the general functional, safety, and technological screening criteria for selection of ideal Bacillus probiotics as feed supplements as well as their mechanism of action and beneficial effects on monogastric animals for improving production performance and health status.

Feeding Bacillus subtilis ATCC19659 to Broiler Chickens Enhances Growth Performance and Immune Function by Modulating Intestinal Morphology and Cecum Microbiota

This study investigated dietary supplementation with Bacillus subtilis (BS) ATCC19659 on growth performance, biochemical indices, intestinal morphology, and cecum microflora in broiler chicks. A total of 600 Arbor 1-day Acres broilers of either sex were allotted to 5 treatments: chicks were fed a corn- and soybean-based diet (CON); chicks were fed basal diet containing 500 mg ZnB/kg (ZnB); chicks were fed basal diet containing 1 × 10⁸ CFU/g feed of BS-ATCC19659 (BS-1); chicks were fed basal diet containing 3 × 10⁸ CFU/g feed of BS-ATCC19659 (BS-3); and chicks were fed basal diet containing 5 × 10⁸ CFU/g feed of BS-ATCC19659 (BS-5). Each treatment comprised 6 replicates with 20 birds for each replicate pen. Chicks in the BS-5 and BS-3 groups had higher body weight at the 21^st and 42^nd days and average daily gain from 1 to 21 days than that in the CON group (p < 0.05). Chicks in the BS-5 and ZnB groups had higher serum antioxidant activities and immunity response than those in the CON group (p < 0.05). Compared with the CON group, the liver mRNA abundance of GHR, TGF-β, IGF-1, IFN-γ, SOD, CAT, and GPX of chicks in three BS groups and the ileum villus length (μm) of chicks in BS-3 and ZnB groups was increased (p < 0.05). Compared with the CON group, the villus height-to-crypt depth ratio of the ileum of chicks in the BS-5 and BS-3 groups and the crypt depth and villus height-to-crypt depth ratio of the jejunum in the BS-5 and ZnB groups were increased (p < 0.05). The abundance of the Cyanobacteria phyla in the cecum decreased in response to treatment with both BS-ATCC19659 and ZnB groups (p < 0.05). Compared with the CON group, the cecum abundance of genera GCA-900066575 (Lachnospiraceae), Anaerofustis, and Papillibacter (Firmicutes phylum) in three BS groups were increased (p < 0.05); The abundance of genus Escherichia–Shigella reduced in the BS-3 group (p < 0.05). Compared with the CON group, the cecum abundance of genus Clostridia_unclassified in ZnB and BS-5 groups was decreased (p < 0.05) of broilers. Generally, Bacillus subtilis ATCC19659 as feed additive positively affected growth performance, immunity response, and cecal microflora of broilers.

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.

Dietary supplementation with Clostridium butyricum improves growth performance of broilers by regulating intestinal microbiota and mucosal epithelial cells

Clostridium butyricum has been widely considered an antibiotic substitute in recent years. It can promote growth performance, improve the immune response and enhance the intestinal barrier function of the host. In the present study, 1-d-old Arbor Acres (AA) broilers were fed C. butyricum (1 × 10⁹ cfu/kg) for 28 d. The transcriptomic characteristics of epithelial cells of the cecal mucosa were determined by RNA-sequence, and the cecal microbiota composition was explored by 16S ribosomal RNA gene sequencing. The changes in the intestinal mucosa of broilers were then analyzed by tissue staining. Gene Ontology (GO) annotations identified substance transport and processes and pathways that might participate in intestinal development and cell viability. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that the differentially expressed genes are involved in numerous pathways related to amino acid and vitamin metabolism and antioxidant and defensive functions, among others. The relative expression of some genes associated with intestinal barrier function (claudins 2, 15, 19, and 23, tight junction proteins 1, 2, and 3 and mucin 1) was significantly increased in the treatment group (P < 0.05 or P < 0.01). Moreover, the proportion of Firmicutes was higher in the C. butyricum-treated group, whereas the proportion of Proteobacteria was higher in the control group. At the genus level, the relative abundances of Butyricicoccus and Lactobacillus, among other bacteria, were increased after C. butyricum supplementation. The tissue staining analysis showed that the cecal mucosa of broilers was significantly ameliorated after the addition of C. butyricum (P < 0.05 or P < 0.01). These results showed that dietary supplementation with C. butyricum can enhance the antioxidant capacity, mucosal barrier function, and stabilize the cecal microbiota, resulting in improving the growth performance.

Coccidia-Microbiota Interactions and Their Effects on the Host

As a common parasitic disease in animals, coccidiosis substantially affects the health of the host, even in the absence of clinical symptoms and intestinal tract colonization. Gut microbiota is an important part of organisms and is closely related to the parasite and host. Parasitic infections often have adverse effects on the host, and their pathogenic effects are related to the parasite species, parasitic site and host-parasite interactions. Coccidia-microbiota-host interactions represent a complex network in which changes in one link may affect the other two factors. Furthermore, coccidia-microbiota interactions are not well understood and require further research. Here, we discuss the mechanisms by which coccidia interact directly or indirectly with the gut microbiota and the effects on the host. Understanding the mechanisms underlying coccidia-microbiota-host interactions is important to identify new probiotic strategies for the prevention and control of coccidiosis.

Effects of Bacillus cereus PAS38 on Immune-Related Differentially Expressed Genes of Spleen in Broilers

This study mainly explored the immunomodulatory mechanisms of the probiotic Bacillus cereus PAS38 (PB) on broiler spleen. A total of 120 avian white feather broilers were randomly divided into 4 groups (N = 30), as follows: control (CNTL, fed with basal diet), PB (fed with diet supplemented with probiotic B. cereus PAS38), vaccine (VAC, fed with basal diet and injected with Newcastle disease virus vaccine), and vaccine + PB group (PBVAC, fed with basal diet supplemented with B. cereus PAS38 and injected with NDV vaccine). The experiment was conducted for 42 days. Twelve spleens were collected from four different groups, weighed, and cut into histological sections, and transcriptome analysis was performed using RNA-seq. Results of the spleen and histological section relative weights showed that feeding with probiotic B. cereus PAS38 and vaccination had a similar tendency to promote spleen development. Compared with the CNTL group, 21 immune-related genes were significantly downregulated in the PB and PBVAC groups. These genes were mainly involved in attenuating inflammatory response. The upregulated antimicrobial peptide NK-lysin and guanylate-binding protein 1 expression levels indicated that this strain enhanced the body's antimicrobial capacity. B. cereus PAS38 also amplified the broilers' immune response to the vaccine, which mainly reflected on nonspecific immunity. Hence, probiotic B. cereus PAS38 can regulate and promote the immune function of broilers.

Understanding the interactions between Eimeria infection and gut microbiota, towards the control of chicken coccidiosis: a review

The gastrointestinal tract in poultry harbours a diverse microbial community that serves a crucial role in digestion and protection. Disruption of the gut environment due to Eimeria spp. parasite infection causes an imbalance in intestinal homeostasis, driving the increment of pathogens such as Clostridium species. Coccidiosis infection affects the composition and integrity of gut microbiota, resulting in elevated susceptibility to diseases that pose a serious threat to the overall health and productivity of chickens. Anticoccidial drugs have proven effective in curbing coccidiosis but with concerning drawbacks like drug resistance and drug residues in meat. The exploration of natural alternative strategies such as probiotics and phytochemicals is significant in controlling coccidiosis through modification and restoration of gut microbiota, without inducing drug resistance. Understanding the interaction between Eimeria parasites and gut microbiota is crucial for the control and prevention of coccidiosis, and the development of novel alternative treatments.

Dietary supplementation with Bacillus subtilis promotes growth performance of broilers by altering the dominant microbial community

The purpose of this study was to investigate the effects of Bacillus subtilis on growth performance, intestinal morphology, and cecal microbial composition of broilers. A total of 270 healthy one-day-old Arbor Acres male broiler chicks were randomly divided into 3 dietary treatment groups, with 6 replicates per group and 15 chickens per replicate. The dietary treatment groups were as follows: 1) basal diet, negative control group; 2) basal diet +250 g/t of zinc bacitracin, positive control group; and 3) basal diet +750 g/t of B. subtilis, B. subtilis group. Results of this experiment showed that compared with the negative control group, body weight at 42 d, average daily gain and European Production Efficiency Factor over the 42 d phase in the B. subtilis group and positive control group were significantly increased (P < 0.05); feed conversion rates in the B. subtilis group and positive control group were significantly decreased (P < 0.05); and average daily feed intake and mortality were not significantly different (P > 0.05). The villus height to crypt depth ratio in the ileum of the B. subtilis group was significantly higher (P < 0.05) than that of the negative control group. The results of cecal microflora at genus level were as follows. As compared with the negative control group, the abundance of Blautia, Faecalibacterium, Flavonifractor, and Hydrogenoanaerobacterium of the B. subtilis group and positive control group was significantly higher (P < 0.05), whereas the abundance of Odoribacter was significantly lower (P < 0.05). Moreover, abundance of the genera Romboutsia in the B. subtilis group was higher (P < 0.05) than that in the positive control group. The abundance of Flavonifractor, Erysipelatoclostridium, and Hydrogenoanaerobacterium were positively correlated with body weight and average daily gain by Spearman correlation analysis. In conclusion, dietary supplementation with B. subtilis improved growth performance of broilers which may be related to the increased abundance of Blautia, Faecalibacterium, Flavonifractor, Hydrogenoanaerobacterium, and Romboutsia, along with the decreased abundance of Odoribacter. In addition, the effect of B. subtilis was superior to zinc bacitracin in improving intestinal microbial composition of broilers. Therefore, B. subtilis may act as an effective antibiotic substitute in broilers.

Dietary Administration of the Bacillus subtilis Enhances Immune Responses and Disease Resistance in Chickens

Bacillus subtilis (B. subtilis) has a variety of proposed beneficial effects for chickens, including growth promotion and disease prevention. In this study, chickens were fed a diet containing B. subtilis for 21 days and growth performance, intestinal morphology, intestinal microbiota, immune responses, and disease resistance were investigated. After 21 days of feeding, chickens fed a diet containing B. subtilis had higher body weights. The concentrations of serum immunoglobulins IgA and IgM were significantly increased by B. subtilis in the diet. Moreover, chickens fed with B. subtilis had greater villus height (VH), shallower crypt depth (CD), and a higher VH/CD ratio in the jejunum than chickens fed a standard control diet. Diet with B. subtilis can balance intestinal microbiota, facilitate an increase in beneficial bacteria, and inhibit the pathogenic bacteria after 21 days of feeding. After an Escherichia coli (E. coli) challenge, the survival rate of chickens fed with B. subtilis was 66.67%, which was significantly higher than the controls. The E. coli contents in spleens and lungs from chickens fed a diet with B. subtilis were lower than those in controls. In addition, B. subtilis can trigger the toll-like receptor 4 and cause induction of proinflammatory cytokine (Il1β, Il6, and Il8) production to develop innate immune responses in chickens. In conclusion, diets containing B. subtilis can improve growth performance, serum immunoglobulin levels, the intestinal villus-crypt system, intestinal homeostasis, immune responses, and disease resistance against E. coli in chickens.

Probiotics mitigating subclinical necrotic enteritis (SNE) as potential alternatives to antibiotics in poultry

Subclinical necrotic enteritis (SNE) caused by Clostridium perfringens (CP), is an important disease in chickens, which causes huge economic losses by damaging the intestinal mucosa, decreasing digestion and absorption of nutrients. Use of antibiotics at a sub-therapeutic level as antimicrobial growth promoters in poultry feed prevents the birds from SNE and improves growth. Due to the ban on the use of antibiotics in 2006 as antimicrobial growth promoters have led to the reemergence of the disease. Worldwide numerous studies have been carried out to investigate the alternatives to antibiotics for the prevention of SNE. Possible alternatives to control SNE include probiotics, prebiotics, bacteriophages, essential oils, organic acids, secondary metabolites and other microbial products. Currently, probiotics are most extensively used in poultry production as an alternative to antibiotics. This review summarizes recent insights and experimental evidence on the use of different microorganisms like Bacillus, Lactic acid bacteria, Bifidobacteria, Enterococcus, yeast, etc. as valuable probiotics for prevention of SNE and potential molecular mechanisms responsible for ameliorating effects of probiotics against SNE.

Dietary Encapsulated Essential Oils Improve Production Performance of Coccidiosis-Vaccine-Challenged Broiler Chickens

Simple Summary

The in-feed antibiotics have been banned worldwide, and anticoccidial drugs are also expected to be removed from the formulated, complete feeds. Thus, looking for alternatives to anticoccidials has been on the increase. Essential oils are naturally derived substances containing the aromatic components of herbs and spices and exhibit antibacterial/anticoccidial, antioxidant, and immune modulating-effects, the properties in poultry. These beneficial biological properties of essential oils make them be considered potential anticoccidial agents. Forthermore, encapsulating essential oils is known to be an effective and efficient strategy to slowly release their active components upon passing the gastrointestinal tract. This study was conducted to examine the effects of encapsulated thymol- and carvacrol-based essential oils on productivity and gut health of chickens challenged with high dose of coccidiosis vaccine.

Abstract

The present study was conducted to evaluate the encapsulated essential oils (EEO) as an alternative to anticoccidials using a coccidiosis vaccine challenged model in broiler chickens. A total of 600 one-day-old male broiler chicks were provided with no added corn/soybean-meal-based control diet or diets that contained either salinomycin (SAL) or thymol- and carvacrol-based EEO at 60 and 120 mg per kg of diet. Before challenge at 21 days, each treatment had 10 replicates except for the no-added control group, which had 20 replicates. On day 21, half of the control groups were orally challenged with a coccidiosis vaccine at 25 times higher than the recommended vaccine dose. During 22 to 28 days (i.e., one-week post coccidiosis vaccine challenge), the challenged chickens had a decrease (P < 0.05) in body weight gain and feed intake but an increase in feed conversion ratio compared with the non-challenged, naïve control chickens. However, dietary EEO significantly counteracted (P < 0.05) coccidiosis-vaccine-induced depression in body weight gain and feed intake. Inclusion of dietary EEO linearly decreased (P < 0.05) the concentrations of the volatile fatty acids. Dietary SAL and EEO affected gut morphology in chickens at 20 days post-hatch. Dietary EEO linearly (P = 0.073) increased serum catalase activity as the inclusion level increased. Collectively, our study shows that dietary EEO increased coccidiosis-vaccine-induced growth depression and altered gut physiology in broiler chickens. Our study adds to the accumulating evidence that dietary EEO is proven to be an effective alternative to anticoccidials for broiler chickens.

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.

Use of Bacillus subtilis PB6 enriched with choline to improve growth performance, immune status, histological parameters and intestinal microbiota of broiler chickens

Context Probiotics used in poultry nutrition may promote the propagation of beneficial bacteria and limit the growth of pathogens, improving the body’s resistance to disease. Aims The aim of the study was to establish the dose and timing of administration of a probiotic preparation containing live cultures of Bacillus subtilis PB6 and choline that would have the most beneficial effect on histological parameters and microbiological status of the intestine, immune status, and growth performance of broiler chickens. Methods In total, 980 one-day-old Ross 308 male chickens, divided into seven groups of 140 (each group with seven replications of 20 individuals), were used in the experiment. The birds were reared until Day 42 of life. In the control group, birds received water without addition of the probiotic preparation. In three continuous treatments, birds received the probiotic preparation in their water at doses of 0.05, 0.1 or 0.25 g/L from Day 1 to Day 42 of rearing. In three periodic treatments, birds received the same doses of the probiotic preparation, but only during Days 1–7, 15–21 and 29–35 of rearing. Key results Addition of the probiotic preparation to the drinking water of broiler chickens increased the total number of aerobic bacteria as well as the length of the intestinal villi and the depth of the crypts. It also reduced the number of fungi and coliform bacteria. In addition, increases were noted in the lysozyme content, the phagocytic index, and the level of immunoglobulin A. Conclusions The probiotic preparation containing B. subtilis and choline administered continuously at a dose of 0.25 g/L in water throughout the rearing period had the most beneficial effect on the composition of the microbiome, and improved the mucous membrane structure of the intestine (increasing villus length and intestinal crypt depth), immunity, and growth performance of the broiler chickens. Implications The use of probiotics in poultry nutrition improves the health of animals and makes breeding more profitable. Administration of this probiotic improves disease resistance, jejunal histological parameters, and intestinal microflora of broiler chickens.

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.

Dietary Antibiotic Growth Promoters Down-Regulate Intestinal Inflammatory Cytokine Expression in Chickens Challenged With LPS or Co-infected With Eimeria maxima and Clostridium perfringens

Subtherapeutic levels of dietary antibiotics increase growth performance in domestic animals, but the mechanisms are poorly understood. Here, 1-week-old broiler chickens were challenged with LPS (experiment 1), or co-infected with Eimeria maxima and Clostridium perfringens as an experimental model of necrotic enteritis (experiment 2), and fed a standard basal diet or a basal diet supplemented with virginiamycin or bacitracin methylene disalicylate. In experiment 1, LPS-challenged chickens fed the unsupplemented diet had decreased body weight gains, compared with unsupplemented controls given the PBS control. In contrast, antibiotic supplementation increased body weight gains in both the LPS-challenged and PBS groups, compared with the antibiotic-free diet. LPS-challenged chickens fed the unsupplemented diet had increased expression levels of intestinal tight junction proteins (ZO1, JAM2), MUC2 gel-forming mucin, and inflammatory cytokines (IL-1β, IL-2, IL-6, IL-8, IL-17A) at 24 h post-challenge, compared with unsupplemented chickens given the PBS control. However, LPS-challenged chickens fed the antibiotic-supplemented diets had decreased levels of intestinal inflammatory cytokine transcripts, compared with LPS-challenged chickens given the unsupplemented basal diet. In experiment 2, E. maxima/C. perfringens-co-infected chickens fed the antibiotic-supplemented diets had increased body weight gains, decreased intestinal pathology, and greater intestinal crypt depth, compared with co-infected chickens given the unsupplemented diet. Further, similar to LPS challenge, E. maxima/C. perfringens-co-infection of chickens fed the antibiotic-supplemented diets decreased expression levels of intestinal inflammatory cytokines, compared with co-infected chickens given the unsupplemented diet. These results support the hypothesis that dietary antibiotic growth promoters might increase poultry growth, in part, through down-regulation of pathogen-induced inflammatory responses.

Bacillus subtilis Strain DSM 29784 Modulates the Cecal Microbiome, Concentration of Short-Chain Fatty Acids, and Apparent Retention of Dietary Components in Shaver White Chickens during Grower, Developer, and Laying Phases

This study investigated the efficacy of a single strain of Bacillus subtilis (SSB) in modulating the composition of cecal microbiota and its link to the concentration of short-chain fatty acids (SCFA) and apparent retention (AR) of components. A total of 720, 4-week-old Shaver White chicks were allotted to control (CON), 1.1E+08 (low, LSSB), 2.2E+08 (medium, MSSB), or 1.1E+09 (high, HSSB) CFU/kg of diet groups. At grower (10-week), developer (16-week), and laying (28-week) phases, excreta and cecal digesta samples were taken for AR, microbial, and SCFA analyses. Microbial analysis involved high-throughput sequencing of the V3-V4 hypervariable regions of 16S rRNA gene. Bacterial diversity decreased (P < 0.05) at the developer phase as the SSB dose increased; however, a distinct clustering pattern (P < 0.05) of bacterial community was noted. Bacteroides and Faecalibacterium were differentially enriched in the developer for SSB-fed compared to CON-fed birds. Although no differences in microbial diversity were detected in grower and layer phases, different species of Clostridium (XVIII, XIVa, IV, and XIVb)-major butyrate producers-were identified in all phases, with stronger effect sizes for SSB-fed compared to CON-fed birds. Isobutyric acid was elevated in dose response (P = 0.034) in layer phase. In addition, the relative abundances of Alistipes, Lactobacillus, and Bifidobacterium were positively correlated (P < 0.05), with AR of most components for SSB-fed birds in the pullet phase. The results suggested that supplementing chickens' diet with B. subtilis DSM 29784 may selectively enrich beneficial bacterial communities, which in turn are critical in promoting the growth and performance of hens.IMPORTANCE In egg-laying chickens, the trend in the move away from the cage to alternative housing systems and restriction in antimicrobial use requires alternative approaches to maintain health and prevent diseases. There is increased research and commercial interest toward alternative gut health solutions while improving the performance and product safety in poultry production systems. One such approach, in recognition of the importance of the gut microbial community, is the use of microbes as feed supplements (such as probiotics). Unlike meat-type chickens, studies assessing the efficacy of such microbial supplements are limited for egg-laying chickens. Thus, by conducting a comprehensive assessment of the hen microbiota in response to various levels of B. subtilis DSM 29784 during the pullet phase (grower and developer) and the layer phase, the present study demonstrates the importance of direct-fed microbes in modulating gut microbiome, which may relate to improved performance efficiency in the pullet and layer phases.

Intestinal Morphologic and Microbiota Responses to Dietary Bacillus spp. in a Broiler Chicken Model

Dietary inclusion of probiotic Bacillus spp. beneficially affect the broiler chickens by balancing the properties of the indigenous microbiota causing better growth performance. The effects of three Bacillus spp. on the growth performance, intestinal morphology and the compositions of jejunal microflora were investigated in broiler chickens. A total of 480 1-day-old male Arbor Acres broilers were randomly divided into four groups. All groups had six replicates and 20 birds were included in each replicate. The control birds were fed with a corn-soybean basal diet, while three treatment diets were supplemented with Bacillus coagulans TBC169, B. subtilis PB6, and B. subtilis DSM32315 with a dosage of 1 × 109 cfu/kg, respectively. The experiment lasted for 42 days. The compositions and diversity of jejunal microflora were analyzed by MiSeq high-throughput sequencing. The B. coagulans TBC169 group showed marked improvements of growth performance, nutrient digestibility and intestinal morphology compared with the other B. subtilis treatments. B. coagulans TBC169 supplementation improved the average body weight (BW), average daily weight gain (ADG), total tract apparent digestibility of crude protein and gross energy (GE), and reduced feed conversion rate (FCR) compared with the control group (P < 0.05). The villus height to crypt depth ratio (VH/CD) of jejunum and duodenum was increased in the birds fed with B. coagulans TBC169 compared with the control group (P < 0.05). However, two B. subtilis treatments presented more positive variation of the jejunum microflora of chickens than that in the B. coagulans TBC169 group. B. subtilis PB6 and B. subtilis DSM32315 treatments improved the diversity of jejunal microbiota on day 21 compared with the control (P < 0.05), while which were decreased on day 42 (P < 0.05). The supplementation with B. coagulans TBC169 significantly improved the proportion of Firmicutes, otherwise two B. subtilis significantly improved the proportion of Proteobacteria, Bacteroidetes, Actinobacteria, and Acidobacteria at the phylum level during starter phase and decreased the proportion of Bacteroidetes during growing phase compared with the control. The supplementation with B.subtilis DSM32315 significantly improved the proportion of Clostridiales during starter phase, whereas two B. subtilis significantly improved the proportion of Pseudomonas, Burkholderia, Prevotella, DA101 during growing phase at the genus level compared with the control. In conclusion, the dietary supplementation with probiotic Bacillus spp. strains improved body weight and intestinal morphology in broiler chickens, which might be associated with the gut microbiota.

Effects of Bacillus subtilis C-3102 on production, hatching performance, egg quality, serum antioxidant capacity and immune response of laying breeders

To investigate the supplemental effects of Bacillus subtilis C-3102 on the production, hatching performance, egg quality, serum antioxidant capacity and immune response of laying breeders, a total of 480 Xuefeng black-bone (25-week-old) hens were randomly assigned into four treatment groups: Hens fed the basal diets with 0 (CON), 3.0 × 10⁵ (BS-1), 6.0 × 10⁵  cfu/g (BS-2) and 9.0 × 10⁵ (BS-3) cfu/g of B. subtilis C-3102. As the B. subtilis C-3102 level increased, egg weight (linear, p < 0.01; quadratic, p = 0.003), fertility (linear, p = 0.021; quadratic, p = 0.059), hatchability (linear, p = 0.038; quadratic, p = 0.119) and yolk colour (linear, p = 0.006; quadratic, p = 0.021) increased in a linear or quadratic manner. Yolk index increased quadratically (linear, p = 0.054; quadratic, p = 0.017), and eggshell thickness (linear, p = 0.036; quadratic, p = 0.128), the activity of GSH-Px (linear, p = 0.024; quadratic, p = 0.078), the concentration of IgM (linear, p = 0.016; quadratic, p = 0.056) and the level of AIV-Ab (linear, p = 0.034; quadratic, p = 0.103) in the serum increased linearly as dietary supplementation of B. subtilis C-3102 increased. The results showed that dietary treatments did not affect egg production, feed conversion ratio, egg mass, hatchability of fertile eggs, eggshell-breaking strength, egg-shape index, yolk percentage, Haugh unit, T-SOD, T-AOC, MDA, IgA and IgG concentrations and the level of NDV-Ab in the serum. In conclusion, dietary supplementation of 9.0 × 10⁵  cfu/g B. subtilis C-3102 in laying breeders diets may be a feasible means of effectively increasing egg weight, fertility and hatchability, and improving egg quality such as eggshell thickness, yolk index and yolk colour. Besides, B. subtilis C-3102 can enhance the activity of GSH-Px, the concentration of IgM and the level of AIV-Ab in the serum.

Effects of Bacillus subtilis and zinc on the growth performance, internal organ development, and intestinal morphology of male broilers with or without subclinical coccidia challenge

Effects of antibiotic (bacitracin), anticoccidial (narasin), and alternative (Bacillus subtilis and zinc) feed additives on growth performance, internal organ development, and intestinal morphology of commercial broilers with or without subclinical coccidia challenge were determined. A total of 1,344 1-day-old male Ross × Ross 708 broilers were randomly distributed into 12 treatments (6 diets × 2 challenge treatments, 8 replication pens/treatment) in 96 floor pens. The 6 dietary treatments were as follows: a control diet (corn and soybean-meal basal diet), a probiotic diet (basal diet + Bacillus subtilis), a zinc diet (basal diet + 100 ppm zinc), a probiotic and zinc combined diet, an anticoccidial diet (basal diet + narasin), and a practical diet (basal diet + narasin + bacitracin). On day 21, each chick in the challenge treatment was gavaged with a 10× dose of a commercial vaccine containing live Eimeria oocytes, whereas each chick in the non-challenge treatment was gavaged with equivalent distilled water. The subclinical coccidia challenge increased the relative weights of pancreas and decreased the ileal crypt depth of broilers at 26 d of age, increased feed conversion ratios from day 15 to 28 and 29 to 40, and increased the relative weights of duodenum and bursa on day 54. As compared to other diets, anticoccidial and practical diets increased BW gain and decreased feed conversion ratio from day 15 to 28, and increased the day 40 carcass weights. As compared to control diets, probiotic diets decreased BW gain and increased the mortality from day 15 to 28; however, probiotic diets did not affect the overall growth performance from day 0 to 54 or carcass yield on day 54. Growth measurements during periods of day 29 to 40 and day 41 to 54 were not affected by any feed additive. From this study, a subclinical coccidia challenge enlarged specific internal organs and compromised the feed conversion ability of broilers. Dietary Bacillus subtilis did not affect overall growth rate or carcass yield of broilers under subclinical coccidia challenge.

Supplemental Bacillus subtilis DSM 32315 manipulates intestinal structure and microbial composition in broiler chickens

Knowledge about the modulation of gut microbiota improves our understanding of the underlying mechanism by which probiotic treatment benefits the chickens. This study examined the effects of Bacillus subtilis DSM 32315 on intestinal structure and microbial composition in broilers. Broiler chicks were fed basal diets without or with B. subtilis supplementation (1.0 × 10⁹ spores/kg of diet). Supplemental B. subtilis increased average body weight and average daily gain, as well as elevated villus height and villus height to crypt depth ratio of ileum in broilers. Multi-dimension analysis showed a certain degree of separation between the cecal microbiota from treatment and control groups. Increased Firmicutes abundance and reduced Bacteroidetes abundance in cecum were observed responded to B. subtilis addition, which also increased the abundances of Christensenellaceae and Caulobacteraceae, and simultaneously decreased the abundances of potentially harmful bacteria such as Vampirovibrio, Escherichia/Shigella and Parabacteroides. Network analysis signified that B. subtilis addition improved the interaction pattern within cecal microbiota of broilers, however, it exerted little influence on the metabolic pathways of cecal microbiota by comparison of the functional prediction of metagenomes. In conclusion, supplemental B. subtilis DSM 32315 improved growth performance and intestinal structure of broilers, which could be at least partially responsible by the manipulation of cecal microbial composition.

Dietary effects of Bacillus subtilis fmbj on growth performance, small intestinal morphology, and its antioxidant capacity of broilers

This paper aimed to study the dietary effects of Bacillus subtilis fmbj (BS fmbj) on growth performance, small intestinal histomorphology, and its antioxidant capacity of broilers at 21 d of raising. A total of 300 1-d old male Arbor Acres broilers were randomly assigned to 5 groups: broilers fed the basal diets with 0 g/kg BS fmbj (CON), 0.2 g/kg BS fmbj (BS-1), 0.3 g/kg BS fmbj (BS-2), 0.4 g/kg BS fmbj (BS-3), and 0.5 g/kg BS fmbj (BS-4). The results showed that there were no differences in the growth performance among treatments during the trail. Dietary BS fmbj in broiler diets increased (P < 0.05) the serum immunoglobulin A (IgA) and immunoglobulin G (IgG) concentration, and enhanced the secretory immunoglobulin A (sIgA) level of small intestine (jejunum and ileum) compared with those in the CON group. The BS groups could improve (P < 0.05) the values of villus length, villus width, crypt depth, and villus area of small intestine compared with that in the CON group. Compared with the CON group, the BS group increased (P < 0.05) small intestinal antioxidant capacity and its mitochondrial antioxidant capacity, and also improved the antioxidant related-gene expression. The BS group exerted a lower (P < 0.05) level of oxidative damages in small intestine than that of the CON group. In conclusion, dietary BS fmbj in broiler diets was potential to improve the small intestinal histomorphology, small intestinal antioxidant capacity, and its mitochondrial antioxidant capacity. Thus this BS fmbj might be considered to be an important additive for the poultry industry.

Effect of dietary Bacillus coagulans supplementation on growth performance and immune responses of broiler chickens challenged by Salmonella enteritidis

This study was conducted to evaluate the protective efficacy of dietary Bacillus coagulans (B. coagulans) supplementation in birds receiving Salmonella enteritidis (SE). Two hundred and forty 1-day-old Cobb broilers were randomly assigned to 2 × 2 factorial arrangements of treatments with 2 levels of dietary B. coagulans (0 or 400 mg/kg) and 2 levels of SE challenge (0 or 1 × 109 SE between d 9 to 11). Results showed that SE infection did not affect growth performance, but caused intestinal inflammation and barrier function impairment by reducing intestinal goblet cells and beneficial bacteria numbers, increasing cecal Salmonella colonization and liver Salmonella invasion, downregulating jejunal mucin-2 (at 7 and 17 d post-infection, DPI), TLR2 (at 7 and 17 DPI), TLR4 (at 17 DPI), TNFSF15 (at 7 and 17 DPI) gene mRNA levels, and upregulating jejunal IFN-γ mRNA levels (at 17 DPI) compared to uninfected birds. Moreover, SE infection also elevated the concentration of jejunal anti-Salmonella IgA and sera anti-Salmonella IgG compared to uninfected birds. However, chickens received B. coagulans diets showed significant increase in body weight gain and weight gain to feed intake ratio from d 15 to 21, alkaline phosphatase activity (at 7 DPI), cecal Lactobacilli and Bifidobacterium numbers (at 7 DPI; at 17 DPI), villous height: crypt ratio (at 17 DPI), and goblet cell numbers (at 7 and 17 DPI), whereas exhibiting reduced jejunal crypt depth (at 17 DPI), cecal Escherichia coli (at 7, 17, and 31 DPI), and Salmonella (at 7 and 17 DPI) levels compared with the non-supplemented birds, regardless of SE infection. In addition, B. coagulans supplement upregulated lysozyme mRNA levels (at 17 DPI), downregulated IFN-γ mRNA levels (at 7 and 17 DPI), showed an increased trend in Fowlicidin-2 mRNA levels (at 7 DPI) and a reduced trend in liver Salmonella load compared to the non-supplemented control. These data indicated that B. coagulans has a protective effect in SE infected broilers.

Effects of three probiotic Bacillus on growth performance, digestive enzyme activities, antioxidative capacity, serum immunity, and biochemical parameters in broilers

This study was conducted to evaluate the effects of three Bacillus strains on growth performance, digestive enzyme activities, antioxidative capacity, serum immunity, and biochemical parameters in broilers. A total of 360 one-day-old Ross 308 chicks were randomly allocated into four groups with three replicates per group (n = 30). The control group was fed a basal diet, whereas the other groups fed basal diet supplemented with either Bacillus subtilis natto or Bacillus licheniformis or Bacillus cereus (10⁸  cfu/kg) for 42 days, respectively. The results revealed that the probiotic-treated groups markedly improved final body weight, daily weight gain, and the activities of trypsin, amylase, lipase and total protease (p < 0.05). Moreover, chicks fed probiotics had higher serum glutathione peroxidase activity and O₂ ^- level, as well as hepatic catalase and superoxide dismutase activities, whereas malondialdehyde levels in serum and liver were reduced (p < 0.05). The significant increased IgA (p < 0.05) was observed in the probiotics groups as compared to the control group. In addition, dietary administration of probiotic strain markedly reduced the levels of serum ammonia, uric acid, total cholesterol, and triglyceride. Taken together, these three probiotic Bacillus showed beneficial effects on chickens with minor strain specificity.

Evaluation of genetic resistance to Salmonella Pullorum in three chicken lines

Resistance to diseases varies considerably among populations of the same species and can be ascribed to both genetic and environmental factors. Salmonella Pullorum (SP) is responsible for significant losses in the poultry industry, especially in developing countries. To better understand SP resistance in chicken populations with different genetic backgrounds, we orally challenged 3 chicken lines with SP-a highly selected commercial breed (Rhode Island Red, RIR), a local Chinese chicken (Beijing You, BY), and a synthetic layer line (dwarf, DW)-at 4 d of age. Two traits related to SP resistance, survival, and bacterial carriage in the spleen were evaluated after infection. Survival rates were recorded up to 40 d of age when all chickens still alive were killed to verify the presence of SP in the spleen to determine carrier state. Mortalities for RIR, BY, and DW chicks were 25.1%, 8.3%, and 22.7%, respectively, and the corresponding carrier-states in the spleens were 17.9%, 0.6%, and 15.8%. Survival and carrier-state heritabilities were estimated using an animal threshold model. Survival heritability was 0.197, 0.091, and 0.167 in RIR, BY, and DW populations, respectively, and the heritabilities of carrier state for DW and RIR were 0.32 and 0.16, respectively. This is the first time that the heritability of the SP carrier state has been evaluated in chickens. Our study provides experimental evidence that chickens with various genetic background exhibited significantly different SP-resistant activities and heritabilities. These results may be useful for selecting lines with better disease resistance.

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.

Dietary synbiotic incorporation as an alternative to antibiotic improves growth performance, intestinal morphology, immunity and antioxidant capacity of broilers

BACKGROUD

The present study aimed to investigate the effects of dietary synbiotic supplementation as an alternative to antibiotics on growth performance, intestinal morphology, immunity and oxidative status of broilers. One-day-old male chicks were allocated to three treatments and given a basal diet free from antibiotic (Control group) and a basal diet supplemented with either chlortetracycline or synbiotic for 42 days, respectively.

RESULTS

Compared to the control group, the supplementation of synbiotic increased the average daily gain and gain:feed ratio of broilers from 22 to 42 days and 1 to 42 days of age, as well as the relative weight of the thymus and the secretory immunoglobulin A level in the jejunum and ileum at 42 days of age, with the values of these parameters being similar to the antibiotic group. Dietary synbiotic inclusion promoted the ratio of ileal villus height to crypt depth of broilers at 21 days of age. The supplementation of synbiotic also reduced the ileal malondialdehyde accumulation of broilers at 42 days of age to a level comparable with that of the antibiotic group.

CONCLUSION

Dietary synbiotic supplementation as an alternative to antibiotic could exert beneficial consequences on growth performance, intestinal morphology, immunity and the antioxidant capacity of broilers. © 2017 Society of Chemical Industry.

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.

Effects of Bacillus coagulans supplementation on the growth performance and gut health of broiler chickens with Clostridium perfringens-induced necrotic enteritis

Background

The poultry industry is in need of effective antibiotic alternatives to control outbreaks of necrotic enteritis (NE) due to Clostridium perfringens.

Methods

This study was conducted to investigate the effects of feeding Bacillus coagulans on the growth performance and gut health of broiler chickens with C. perfringens-induced NE. Two hundred and forty 1-day-old broiler chicks were randomly assigned to a 2 × 2 factorial arrangement with two dietary B. coagulans levels (0 or 4 × 10⁹ CFU/kg of diet) and two disease challenge statuses (control or NE challenged).

Results

NE-induced reduction in body weight gain was relieved by the addition of B. coagulans into broiler diets compared with the NE-infected birds. NE infection damaged intestinal morphological structure, promoted intestinal C. perfringens growth and liver invasion, and enhanced anti-C. perfringens specific sIgA concentrations in the gut and specific IgG levels in serum compared with the uninfected birds. NE infection significantly (P < 0.05) decreased mucin-2 (at 14 d post-infection (DPI), toll -like receptor 2 (TLR2, at 7 and 14 DPI), TLR4 (at 7 and 14 DPI), tumor necrosis factor super family 15 (TNFSF15, at 7 and 14 DPI), lysozyme (LYZ, at 14 DPI) and fowlicidin-2 (at 7 and 14 DPI) mRNA levels, whereas it dramatically (P = 0.001) increased IFN-γ mRNA levels at 7 DPI. However, challenged birds fed diets supplemented with B. coagulans showed a significant (P < 0.01) decrease in gut lesion scores, decreased C. perfringens numbers in the cecum and liver, and an increase in fowlicidin-2 mRNA levels in compared with the uninfected birds. In addition, compared with the non-supplemented group, dietary inclusion of B. coagulans improved intestinal barrier structure, further increased specific sIgA levels and alkaline phosphatase (IAP) activity in the jejunum, enhanced the expression of jejunum lysozyme mRNA, and inhibited the growth, colonization, and invasion of C. perfringens; in contrast, it reduced serum-specific IgG concentrations and jejunum IFN-γ mRNA levels.

Conclusion

These results indicated that dietary B. coagulans supplementation appeared to be effective in preventing the occurrence and reducing the severity of C. perfringens-induced NE in broiler chickens.

Disruption in the cecal microbiota of chickens challenged with Clostridium perfringens and other factors was alleviated by Bacillus licheniformis supplementation

Clostridium perfringens can induce necrotic enteritis of chickens, which causes large economic losses every year. Bacillus licheniformis, a probiotic, can inhibit the growth of pathogenic bacteria such as Clostridium perfringens, thereby improving the health status of chickens. However, from a microbial ecology perspective, the mechanisms by which alterations to the gut microbiota improve health remain unknown. In this study, we used Illumina MiSeq sequencing to investigate the cecal microbiota of a negative control group (NC), a C. perfringens and Eimeria challenge group with fishmeal supplementation (PC), a group supplemented with fishmeal and infected with coccidia (FC), and group PC with B. licheniformis supplementation (BL). We found that the health status of C. perfringens-challenged chickens was compromised, and that B. licheniformis improved the growth of the chickens challenged with pathogens. Microbial diversity analysis and taxonomic profiling of groups NC, PC, and FC revealed a disturbed cecal microflora of the birds with C. perfringens. We also characterized the microbiota of the chickens in the BL group using several methods. Principal coordinate analysis demonstrated that, compared with group PC, the bacterial community structure of group BL was more similar to that of group NC. Linear discriminant analysis with effect size revealed less differentially represented bacterial taxa between groups BL and NC than between groups PC and NC. In addition, groups BL and NC appeared to have similar overrepresented microbial taxa (such as Bacteroides, Helicobacter, Megamonas, and Akkermansia) compared with group PC. Finally, a phylogenetic investigation of communities by reconstruction of unobserved states analysis indicated that large differences existed between group PC and groups NC and BL. In conclusion, pre-treatment with B. licheniformis reduced the disturbance of the cecal microbiome induced by challenge with C. perfringens and other factors in broiler chickens.

A Bacillus subtilis strain as probiotic in poultry: selection based on in vitro functional properties and enzymatic potentialities

We have proposed and validate an in vitro probiotic selection, based on enzymatic potentialities associated to well-established probiotic functional properties. A new Bacillus subtilis HB2 isolate, selected based on its high extracellular enzyme production, was chosen as a probiotic candidate for application as animal feed supplement. The HB2 strain showed an excellent acid and bile salts tolerance, a strong adhesion to chick enterocytes and produced antimicrobials against pathogens. An in vivo trial in poultry farming was conducted to evaluate the HB2 probiotic performance. After 35 days, HB2 achieved the higher growth performance than the control groups. The mortality and the feed conversion ratio were significantly decreased. Finally, the HB2 treated group showed wet litter and less severe ammonia odor in the atmosphere. Our study provides new insights into the importance of enzymatic potentialities, associated with the common functional properties, as a novel approach for probiotic selection.

Importance of the gastrointestinal life cycle of Bacillus for probiotic functionality

Bacillus spp. are widely used in animal production for their probiotic properties. In many animal species, feed supplementation with specific Bacillus strains can provide numerous benefits including improvement in digestibility, the gut microbiota and immune modulation, and growth performance. Bacilli are fed to animals as spores that can sustain the harsh feed processing and long storage. However, the spores are metabolically quiescent and it is widely accepted that probiotics should be in a metabolically active state to perform certain probiotic functions like secretion of antimicrobial compounds and enzymes, synthesis of short chain fatty acids, and competition for essential nutrients. These functions should become active in the host gastrointestinal tract (GIT) soon after digestion of spores in order to contribute to microbiota and host metabolism. Considering that bacterial spores are metabolically dormant and many health benefits are provided by vegetative cells, it is of particular interest to discuss the life cycle of Bacillus in animal GIT. This review aims to capture the main characteristics of spores and vegetative cells and to discuss the latest knowledge in the life cycle of beneficial Bacillus in various intestinal environments. Furthermore, we review how the life cycle may influence probiotic functions of Bacillus and their benefits for human and animal health.

Dietary Bacillus subtilis-based direct-fed microbials alleviate LPS-induced intestinal immunological stress and improve intestinal barrier gene expression in commercial broiler chickens

This study investigated the effects of Bacillus subtilis-based probiotics on the performance, modulation of host inflammatory responses and intestinal barrier gene expression of broilers subjected to LPS challenge. Chickens were randomly allocated to one of the 3 dietary treatment groups - control, antibiotic, or probiotic. At 14days, half of the chickens in each treatment were injected with LPS (1mg/kg body weight), and the other half injected with sterile PBS. Chickens fed probiotics weighed significantly more than controls at 15days of age, irrespective of immune challenge. LPS challenge significantly reduced weight gain at 24h post-injection, and the probiotics did not alleviate the LPS-induced reduction of weight gain. Serum α-1-AGP levels were significantly higher in LPS-injected chickens, and probiotic supplementation significantly reduced their levels. The percentages of CD4+ lymphocytes were significantly increased in probiotic groups in the absence of immunological challenge but were reduced during LPS challenge compared to controls. CD8+ lymphocytes were significantly reduced in probiotic-fed birds. The LPS-induced increase in the expression of cytokines IL8 and TNFSF15 was reduced by probiotic supplementation, and IL17F, iNOS expression was found to be significantly elevated in probiotic-fed birds subjected to LPS challenge. The reduced gene expression of tight junction proteins (JAM2, occludin and ZO1) and MUC2 induced by LPS challenge was reversed by probiotic supplementation. The results indicate that B. subtilis-based probiotics differentially regulate intestinal immune and tight junction protein mRNA expression during states of LPS-mediated immunological challenge.

Study of Bacillus subtilis on growth performance, nutrition metabolism and intestinal microflora of 1 to 42 d broiler chickens

To study the influence of different levels of Bacillus subtilis on growth performance, nutrition metabolism and intestinal microflora of 1 to 42 d Arbor Acres (AA) broilers, a total of 800 one-day-old healthy broilers were randomly divided into 5 groups with 4 replicates per group and 40 broilers per replicate. Broilers were fed a basic diet (group 1) which acted as the control group, and 4 other groups (2 to 5) were fed the basal diet with B. subtilis added at concentrations of 100, 150, 200 and 250 mg/kg, respectively for 42 days. The results showed as follow: the average daily gain (ADG) of group 4 was significantly higher than (P < 0.05) that of group 1, and the average daily feed intake (ADFI) of group 5 was the highest but the differences between groups were not significant (P > 0.05). The feed to gain ratio (F/G) of all the experimental groups was lower than that of the control and the difference was significant in group 4 (P < 0.05). In addition, supplementation of B. subtilis increased the apparent metabolism of crude protein (P > 0.05), crude fat (P > 0.05), dry matter (P > 0.05) and organic matter (P < 0.05). B. subtilis decreased the Escherichia coli and Salmonella populations in the cecum. This shows that adding B. subtilis to the broiler diet can improve the growth performance, increase feed efficiency, regulate serum index and reduce harmful bacteria in the intestinal tract. Based on our study, it could be recommended that addition of B. subtilis at 200 mg/kg could improve the growth performance of broilers.

The regulation effects of danofloxacin on pig immune stress induced by LPS

Danofloxacin (DAN) is one of the Fluoroquinolone drugs (FQs) that has been widely used in the control and prevention of bacterial infectious disease in animal production. Most of the FQs have an obvious protective effect against lipopolysaccharide (LPS) induced Immune stress. However, the effect of DAN on the host immune system of animals remains unknown. In this study, a fever piglet model was built and a systematic survey of the response of inflammatory genes and mediators to DAN treatment and LPS induction was performed in the pig. The results indicated that the IL-1β, TNF-α, IL-6, NO (nitric oxide), and PGE2 (prostaglandin E2) levels were significantly suppressed in plasma and porcine alveolar macrophage 3D4/2 cells compared with the LPS treatment group. Interestingly, the IL-10 production was further stimulated by DAN treatment in the LPS challenged piglet. Our results suggested that DAN could relieve acute inflammation through inhibiting the activation of inflammatory genes introduced by LPS.

Effect of Bacillus subtilis CGMCC 1.1086 on the growth performance and intestinal microbiota of broilers

AIMS

Probiotics have been proved to be the most preferred and effective alternative to antibiotics as growth promoter and pathogens inhibitor in poultry industry. In this study Bacillus subtilis CGMCC 1.1086 as a probiotic bacterium was administered in diet and its effects on both the growth performance and the caecal microbiota of broilers were evaluated.

METHODS AND RESULTS

A total of 240 male Arbor Acres (AA) broilers were randomly allocated into two treatment groups of basal diet without any addition of probiotics and basal diet containing B. subtilis CGMCC 1.1086. The body weight of broilers was measured individually at 32, 39 and 46 days of bird age. Furthermore, MiSeq high-throughput sequencing analysis of 16S rRNA was used to investigate the bacterial community structure in the caeca of broilers. The results indicated that broilers receiving diet supplemented with B. subtilis CGMCC 1.1086 showed 27·7% higher daily weight gain than those of control during 2 weeks. The feed conversion ratio (FCR) of B. subtilis CGMCC 1.1086 group was also improved by 10·3%. In the caeca of broilers fed with B. subtilis CGMCC 1.1086, the relative abundance of Alistipes, Odoribacter, Ruminococcus, Blautia and Desulfovibrio were higher, while the potential pathogens such as Staphylococcus and Escherichia-Shigella were lower than those of control.

CONCLUSIONS

The probiotic B. subtilis CGMCC 1.1086 can effectively improve the growth performance and FCR of broilers via the beneficial modulation of caecal microbiota.

SIGNIFICANCE AND IMPACT OF THE STUDY

The effect of B. subtilis on growth performance of broilers was evaluated and the relationship between growth and caecal microbiota was revealed. The results of this study help to promote application of probiotics in poultry industry.