Bacillus subtilis based probiotic improved bone mass and altered brain serotoninergic and dopaminergic systems in broiler chickens

Increased dietary 5-hydroxytryptophan reduces fearfulness in red junglefowl hens (Gallus gallus)

Our production animals typically suffer poor welfare, which can be revealed by measuring the affective state these animals are in. Negative affective state is linked to poorer welfare, and can be measured as fearfulness. While continuing to research how to improve animal welfare, a compliment to reduce negative affective state could therefore be to reduce individuals' fearfulness, similar to how negative affective states are medicated in humans. A proposed mechanism for this is via the monoaminergic systems. This is based on previous studies across species that have linked the serotonergic system and fear-related behaviour. We here aimed to experimentally manipulate the serotonergic system in red junglefowl hens (Gallus gallus), the main ancestor of all domesticated chickens. We measured fearfulness as latency remaining immobile in a tonic immobility test, and did so both before and after our experimental manipulation. We set out to experimentally manipulate the serotonergic system via sub-chronic dietary treatment of 5-hydroxytryptophan (the precursor to serotonin). Our dietary manipulation of 5-hydroxytryptophan significantly reduced measured fearfulness in the manipulated hens, while latency in tonic immobility did not significantly change in our unmanipulated, control hens. This finding is promising since it indicates that increased tryptophan levels can be used to reduce fearfulness. Additionally, our result suggests that this can be done non-invasively via food (instead of injections), thus presenting a potentially feasible manipulation also for larger settings. Nevertheless, the serotonergic system is complex and its role in modulating behaviour in the fowl should be explored further to evaluate our findings, and more directly explored also in a production setting.

Research Note: Probiotic, Bacillus subtilis, alleviates neuroinflammation in the hippocampus via the gut microbiota-brain axis in heat-stressed chickens

High ambient temperature (heat stress, HS) is one of the critical environmental factors causing gut microbiota dysbiosis and increasing gut permeability, consequently inciting neuroinflammation in humans and various animals including chickens. The aim of this study was to examine if a probiotic, Bacillus subtilis, can reduce neuroinflammation in heat-stressed broiler chickens. Two hundred and forty 1-d-old broiler chicks were randomly assigned to 48 pens among 4 treatments in 2 identical, thermal-controlled rooms (n = 12): Thermoneutral (TN)-regular diet (RD), TN-PD (the regular diet mixed with a probiotic at 250 ppm), HS-RD, and HS-PD. The probiotic diet was fed from d 1, and HS at 32°C for 10-h daily was applied from d 15 for a 43-day trial. Results showed that compared to the TN broilers, the HS broilers had higher hippocampal interleukin (IL)-6, toll-like receptor (TLR)4, and heat shock protein (HSP)70 at both mRNA and protein levels regardless of dietary treatment (P < 0.05). In addition, the HS-PD broilers had higher levels of hippocampal IL-8 (P < 0.05) than the TN-PD broilers. Within the HS groups, compared to the HS-RD broilers, the HS-PD broilers had lower levels of IL-6, IL-8, HSP70, and TLR4 (P < 0.05) in the hippocampus. Within the TN groups, the TN-PD broilers had lower IL-8 at both mRNA expressions and protein levels (P < 0.05) but higher TLR4 protein levels (P < 0.05) in the hippocampus as compared to the TN-RD broilers. These results indicate that dietary supplementation of the Bacillus subtilis-based probiotic may reduce HS-induced brain inflammatory reactions in broilers via the gut-brain-immune axis. These results indicate the potential use of probiotics as a management strategy for reducing the impact of HS on poultry production.

The associations of gut microbiota, endocrine system and bone metabolism

Gut microbiota is of great importance in human health, and its roles in the maintenance of skeletal homeostasis have long been recognized as the "gut-bone axis." Recent evidence has indicated intercorrelations between gut microbiota, endocrine system and bone metabolism. This review article discussed the complex interactions between gut microbiota and bone metabolism-related hormones, including sex steroids, insulin-like growth factors, 5-hydroxytryptamine, parathyroid hormone, glucagon-like peptides, peptide YY, etc. Although the underlying mechanisms still need further investigation, the regulatory effect of gut microbiota on bone health via interplaying with endocrine system may provide a new paradigm for the better management of musculoskeletal disorders.

Influence of the Gut Microbiome on Feed Intake of Farm Animals

With the advancement of microbiome research, the requirement to consider the intestinal microbiome as the “last organ” of an animal emerged. Through the production of metabolites and/or the stimulation of the host’s hormone and neurotransmitter synthesis, the gut microbiota can potentially affect the host’s eating behavior both long and short-term. Based on current evidence, the major mediators appear to be short-chain fatty acids (SCFA), peptide hormones such as peptide YY (PYY) and glucagon-like peptide-1 (GLP-1), as well as the amino acid tryptophan with the associated neurotransmitter serotonin, dopamine and γ-Aminobutyrate (GABA). The influence appears to extend into central neuronal networks and the expression of taste receptors. An interconnection of metabolic processes with mechanisms of taste sensation suggests that the gut microbiota may even influence the sensations of their host. This review provides a summary of the current status of microbiome research in farm animals with respect to general appetite regulation and microbiota-related observations made on the influence on feed intake. This is briefly contrasted with the existing findings from research with rodent models in order to identify future research needs. Increasing our understanding of appetite regulation could improve the management of feed intake, feed frustration and anorexia related to unhealthy conditions in farm animals.

The Impact of Probiotic Bacillus subtilis on Injurious Behavior in Laying Hens

Simple Summary

Injurious behavior prevention is a critical issue in the poultry industry due to increasing social stress, leading to negative effects on bird production and survivability, consequently enhancing gut microbiota dysbiosis and neuroinflammation via the microbiota–gut–brain axis. Probiotics have been used as potential therapeutic psychobiotics to treat or improve neuropsychiatric disorders or symptoms by boosting cognitive and behavioral processes and reducing stress reactions in humans and various experimental animals. The current data will first report that probiotic Bacillus subtilis reduces stress-induced injurious behavior in laying hens via regulating microbiota–gut–brain function with the potential to be an alternative to beak trimming during poultry egg production.

Abstract

Intestinal microbiota functions such as an endocrine organ to regulate host physiological homeostasis and behavioral exhibition in stress responses via regulating the gut–brain axis in humans and other mammals. In humans, stress-induced dysbiosis of the gut microbiota leads to intestinal permeability, subsequently affecting the clinical course of neuropsychiatric disorders, increasing the frequency of aggression and related violent behaviors. Probiotics, as direct-fed microorganism, have been used as dietary supplements or functional foods to target gut microbiota (microbiome) for the prevention or therapeutic treatment of mental diseases including social stress-induced psychiatric disorders such as depression, anxiety, impulsivity, and schizophrenia. Similar function of the probiotics may present in laying hens due to the intestinal microbiota having a similar function between avian and mammals. In laying hens, some management practices such as hens reared in conventional cages or at a high stocking density may cause stress, leading to injurious behaviors such as aggressive pecking, severe feather pecking, and cannibalism, which is a critical issue facing the poultry industry due to negative effects on hen health and welfare with devastating economic consequences. We discuss the current development of using probiotic Bacillus subtilis to prevent or reduce injurious behavior in laying hens.

Immune-microbiome interplay and its implications in neurodegenerative disorders

The neurodegeneration and its related CNS pathologies need an urgent toolbox to minimize the global mental health burden. The neuroimmune system critically regulates the brain maturation and survival of neurons across the nervous system. The chronic manipulated immunological drive can accelerate the neuronal pathology hence promoting the burden of neurodegenerative disorders. The gut is home for trillions of microorganisms having a mutual relationship with the host system. The gut-brain axis is a unique biochemical pathway through which the gut residing microbes connects with the brain cells and regulates various physiological and pathological cascades. The gut microbiota and CNS communicate using a common language that synchronizes the tuning of immune cells. The intestinal gut microbial community has a profound role in the maturation of the immune system as well as the development of the nervous system. We have critically summarised the clinical and preclinical reports from the past a decade emphasising that the significant changes in gut microbiota can enhance the host susceptibility towards neurodegenerative disorders. In this review, we have discussed how the gut microbiota-mediated immune response inclines the host physiology towards neurodegeneration and indicated the gut microbiota as a potential future candidate for the management of neurodegenerative disorders.

Probiotics Treatment of Leg Diseases in Broiler Chickens: a Review

Normal development and growth of bones are critical for poultry. With the rapid growth experienced by broiler chickens, higher incidences of leg weakness and lameness are common problems in adolescent meat-type poultry that present huge economic and welfare issues. Leg disorders such as angular bone deformities and tibial dyschondroplasia have become common in broilers and are associated with poor growth, high mortality rates, increased carcass condemnation, and downgrading at slaughter. Probiotics have shown promise for a variety of health purposes, including preventing diarrhea, elevating carcass quality, and promoting growth of the poultry. In addition, recent studies have indicated that probiotics can maintain the homeostasis of the gut microbiota and improve the health of the gastrointestinal tract, which confers a potentially beneficial effect on bone health. This review mainly describes the occurrence of broiler leg disease and the role of probiotics in bone health through regulating the gut microbiota and improving intestinal function, thus providing a relevant theoretical basis for probiotics to hinder the development of skeletal disorders in broiler chickens.

Effects of Bacillus subtilis on Production Performance, Bone Physiological Property, and Hematology Indexes in Laying Hens

Simple Summary

Due to breeding for high egg production, laying hens are at great risk for developing osteoporosis. To develop an effective feed additive for reducing the bone damage and associated pain and economic loss has become a critical issue affecting the poultry industry. The aim of this study was to investigate the effects of Bacillus subtills as a feed supplement on production performance and bone pathophysiological characteristics of laying hens. The results showed that Bacillus subtilis increases marketable eggs, protects bone health, changes the distribution of phosphorus between blood and bone, and increases estrogen but decreases interleukin-1 and tumor necrosis factor-α concentrations in blood. Results indicate that Bacillus subtilis can be used as a dietary supplement to increase marketable egg production and bone health of laying hens by inhibiting gut and systemic inflammation via the microbiota-gut-immune and the microbiota-gut-bone axes.

Abstract

This study was to investigate the effects of Bacillus subtilis on production performance and bone pathophysiological characteristics of layers. Twenty-four 48-week-old Lohmann Pink-shell laying hens were randomly divided into two groups: a basic diet (control) and the basic diet mixed with Bacillus subtilis (0.5 g/kg) for a 60-day trial. Statistically, independent-sample t-test was used to assess the treatment differences. The results showed that Bacillus subtilis supplementation improved the percent of marketable eggs (p < 0.05) with reduced numbers of broken and soft-shelled eggs but had no effects on egg weight, height of albumen, yolk color, and Haugh unit (p > 0.05). Bacillus subtilis supplement also elevated maximum load (p = 0.06), maximum stress (p = 0.01), stiffness (p < 0.01), and Young’s modulus (p < 0.01) but suppressed maximum strain (p = 0.06) in the femur. In addition, compared with control birds, phosphorous concentration (p < 0.01) was reduced in serum at day 61 but increased in the femur (p < 0.05) in Bacillus subtilis fed birds. Bacillus subtilis fed birds also had lower magnesium concentrations in both femur (p = 0.04) and feces (p = 0.09). Furthermore, Bacillus subtilis increased plasma estrogen concentration (p = 0.01) and femur TNF receptor superfamily member 11b (OPG) expression (p < 0.05) but reduced plasma IL-1 (p < 0.01) and TNF-α (p < 0.01) concentrations. These results indicate that Bacillus subtilis could be used as a health promotor to reduce overproduction-induced inflammation and associated bone damage and to increase marketable egg production. The data provide evidence for developing a management strategy to use Bacillus subtilis as a feed additive to improve marketable egg production and health and welfare status of laying hens.

Probiotics: an Antibiotic Replacement Strategy for Healthy Broilers and Productive Rearing

Pathogens develop resistance to antibiotics at a rate much faster than the discovery of new antimicrobial compounds. Reports of multidrug-resistant bacteria isolated from broilers, and the possibility that these strains may spread diseases amongst humans, prompted many European countries to ban the inclusion of antibiotics in feed. Probiotics added to broiler feed controlled a number of bacterial infections. A combination of Enterococcus faecium, Pediococcus acidilactici, Bacillus animalis, Lactobacillus salivarius and Lactobacillus reuteri decreased the colonisation of Campylobacter jejuni and Salmonella Enteritidis in the gastro-intestinal tract (GIT) of broilers, whereas Bacillus subtilis improved feed conversion, intestinal morphology, stimulated the immune system and inhibited the colonisation of Campylobacter jejuni, Escherichia coli and Salmonella Minnesota. Lactobacillus salivarius and Pediococcus parvulus improved weight gain, bone characteristics, intestinal morphology and immune response, and decreased the colonisation of S. Enteritidis. Lactobacillus crispatus, L. salivarius, Lactobacillus gallinarum, Lactobacillus johnsonii, Enterococcus faecalis and Bacillus amyloliquefaciens decreased the Salmonella count and led to an increase in lysozyme and T lymphocytes. Probiotics may also improve feed digestion through production of phytases, lipases, amylases and proteases or stimulate the GIT to secrete digestive enzymes. Some strains increase the nutritional value of feed by production of vitamins, exopolysaccharides and antioxidants. Bacteriocins, if produced, regulate pathogen numbers in the GIT and keep pro-inflammatory and anti-inflammatory reactions in balance.

Lactobacillus rhamnosus JYLR-005 Prevents Thiram-Induced Tibial Dyschondroplasia by Enhancing Bone-Related Growth Performance in Chickens

Tibial dyschondroplasia (TD) is a leg disorder caused by the abnormal development of the tibia in fast-growing poultry. Lactobacillus rhamnosus (L. rhamnosus) strains have been reported to have effects on increasing bone growth and improving osteoporosis in animals. However, whether L. rhamnosus JYLR-005 can improve bone growth in TD chickens remains unclear. In this study, we noted that L. rhamnosus JYLR-005 could not reduce the suppression of the production performance of TD broilers (p > 0.05) but had a slight protective effect on the broiler survival rate (χ² = 5.571, p = 0.062). However, for thiram-induced TD broiler chickens, L. rhamnosus JYLR-005 could promote tibia growth by increasing tibia-related parameters, including the tibia weight (day 11, p = 0.040), tibia length (day 15, p = 0.013), and tibia mean diameter (day 15, p = 0.035). Moreover, L. rhamnosus JYLR-005 supplementation improved the normal growth and development of the tibial growth plate by maintaining the morphological structure of the chondrocytes and restored the balance of calcium and phosphorus. Taken together, these findings provide a proof of principle that L. rhamnosus JYLR-005 may represent a therapeutic strategy to treat leg disease in chickens.

Overview of the Use of Probiotics in Poultry Production

Simple Summary

Probiotics are feed additives that have gained popularity in poultry production following the ban of antibiotic growth promoters (AGP). They are one of the more universal feed additives and can be easily combine with other additives. Probiotics, above all, have many advantages, including stimulation of the host microflora or immunomodulation. The statement “immunity comes from the intestines” has become more important in the poultry industry because probiotics have proven helpful in the fight against diseases of bacterial origin and against zoonoses. Positive effects on the organism have already been studied at the cellular level, where probiotics were responsible for changes in gene expression, leading to alleviation of heat stress. In addition to the health benefits, the utility value of the animals increases. The numerous advantages are overshadowed by a few drawbacks, which include the possibility of lowering semen quality in roosters and the diversity of production processes affecting the persistence of the probiotic. In addition to bird health, probiotics have improved the taste and quality of poultry products. Future prospects are promising as scientists are working to maximize the positive effects of probiotics by increasing the integrity of probiotics within the bird organism, taking into account, among others, bacterial metabolites.

Abstract

In recent years, probiotics have become more popular in the world of dietary supplements and feed additives within the poultry industry, acting as antibiotic substitutes. Above all, probiotics are universal feed additives that can be used in conjunction with other additives to promote improved performance and health. Their positive effects can be observed directly in the gastrointestinal tract and indirectly in immunomodulation of the poultry immune system. Nutritional effects seen in flocks given probiotics include increased laying and egg quality, increased daily increments, and improved feed conversion ratio (FCR). There has also been an improvement in the quality of meat. This suggests producers can improve production results through the use of probiotics. In addition to these production effects, bird immunity is improved by allowing the organism to better protect itself against pathogens and stress. The lack of accuracy in the formulation of non-European preparations needs to be further developed due to unknown interactions between probiotic bacteria strains as well as their metabolites. The versatility of probiotics and the fact that the bacteria used in their production are an integral part of animal digestive tracts make them a safe feed additives. Despite restrictions from the European Union, probiotics have potential to improve production and health within the poultry industry and beyond. The following article will review the use of probiotics in poultry production.

Exploring the bone sparing effects of postbiotics in the post-menopausal rat model

Background

Post-menopausal osteoporosis is a concern of health organizations, and current treatments do not seem enough. Postbiotics as bioactive compounds produced by probiotics may be an attractive alternative for bone health. In this study, we prepared, formulated, and compared the effects of cell lysate and supernatant of five native probiotic strains (Lactobacillus acidophilus, Lactobacillus reuteri, Lactobacillus casei, Bifidobacterium longum, and Bacillus coagulans) in ovariectomized (OVX) rats.

Methods

The probiotic strains were isolated, and their cell-free supernatants and biomasses as postbiotics were extracted and formulated using standard microbial processes. The Sprague-Dawley rats were fed by 1 × 10⁹ CFU/ml/day postbiotic preparations for 4 weeks immediately after ovariectomy. Dual-energy X-ray absorptiometry (DEXA) scans were accomplished to evaluate femur, spine, and tibia BMD. The serum biochemical markers [calcium, phosphorus, and alkaline phosphatase] were assessed.

Results

Postbiotics could considerably improve the global and femur area in OVX rats. In the case of global bone mineral density (BMD), Lactobacillus casei lysate and supernatant, Bacillus coagulans lysate and supernatant, lysate of Bifidobacterium longum and Lactobacillus acidophilus, and Lactobacillus reuteri supernatant significantly increased BMD. We found Bacillus coagulans supernatant meaningfully enriched tibia BMD.

Conclusion

Postbiotic could ameliorate bone loss resulting from estrogen deficiency. Also, the effects of postbiotics on different bone sites are strain-dependent. More clinical studies need to explore the optimal administrative dose and duration of the specific postbiotics in protecting bone loss.

Bacillus subtilis-based probiotic promotes bone growth by inhibition of inflammation in broilers subjected to cyclic heating episodes

Heat stress as an environmental stressor causes abnormal bone remodeling and microarchitectural deterioration. The objective of this study was to investigate the effects of a Bacillus subtilis–based probiotic on bone mass of broilers subjected to cycling high ambient temperature. One hundred and twenty 1-day-old Ross 708 male broiler chicks were randomly assigned to 2 dietary treatments (12 pens per treatment): control diet and the control diet plus 250-ppm probiotic consisting of 3 strains of Bacillus subtilis. Room temperature was gradually decreased from 35°C on day 1 by 0.5°C/d until day 15, when ambient temperature was increased from 28°C to 32°C for 10 h (07:00 h–17:00 h) daily until day 44. Samples of blood, leg bones (tibia and femur), and brains (raphe nuclei and hypothalamus) were collected at day 43, while latency to lie test was conducted at day 44. Compared with controls, probiotic supplementation increased bone mineral content, weight, size, weight to length index, and reduced robusticity index in the tibia and femur (P < 0.05) of broilers subjected to heat stress. Serum concentrations of c-terminal telopeptide of type I collagen (CTX) were reduced (P = 0.02) by the probiotic supplementation, while ionized calcium, phosphate, and osteocalcin were not affected (P > 0.05). Moreover, tumor necrosis factor-α (TNF-α) in probiotic fed broilers was decreased (P = 0.003) without changes of plasma interleukin (IL)-6, IL-10, interferon-γ, and corticosterone concentrations. There were no treatment effects on the concentrations of peripheral serotonin and central serotonin and catecholamines (norepinephrine, epinephrine, and dopamine) as well as their metabolites. These results may indicate that dietary supplementation of Bacillus subtilis–based probiotic increases bone growth in broilers under a cyclic heating episode probably via inhibition of bone resorption, resulting from downregulation of the circulating TNF-α and CTX. Dietary probiotic supplementation may be a management strategy for increasing skeletal health of broilers under hot weather.

Metabolic activity of Bacillus coagulans R11 and the health benefits of and potential pathogen inhibition by this species in the intestines of laying hens under lead exposure

Probiotics are widely used in agricultural breeding for care and maintenance of animal health, especially Bacillus coagulans, a new and popular species that could replace Lactobacillus. However, lead contamination in feed might influence the beneficial function. In the present study, Bacillus coagulans R11 was used as a model bacterium to investigate the effect of lead on changes in metabolites and genes, which could influence the beneficial function on laying hen. At the laboratory scale, transcriptomics and metabolomics were used to screen the main metabolites and related genes under lead exposure. The results showed that 4-acetamidobutanoic acid, dodecanoic acid, L-3-phenyllactic acid, apigenin and daidzein, which are antioxidants and antibacterial agents, were the main metabolites, even in the 100 ppm lead exposure group (the levels of these metabolites were 1.17-, 1.10-, 4.80-, 1.43- and 1.67-fold higher in the 100 ppm group than in pure culture medium). Twenty-three genes associated with the syntheses of the above 5 main metabolites were identified. Further animal experiments showed that B. coagulans R11 feeding of laying hens under lead exposure could prevent oxidative damage by increasing T-AOC and T-SOD activity and reducing the MDA concentration in serum and reducing the abundances of potential pathogens (Escherichia coli, Pseudomonas aeruginosa and Salmonella). Further analysis also showed that the inhibition of pathogen growth was due to the regulation of gene expression, as observed by transcriptomics, and these genes were associated with the abovementioned 5 main metabolites. However, the laying rate decreased by 10.53% compared with that of the control group when the lead exposure concentration was 100 mg/kg. The present study suggested that Bacillus coagulans R11 could help prevent oxidative damage and inhibit pathogen growth in laying hens to maintain a healthy intestinal environment for daily breeding, but under high-lead conditions, Bacillus coagulans R11 feeding could decrease the laying rate.

Early-life microbiota transplantation affects behavioural responses, serotonin and immune characteristics in chicken lines divergently selected on feather pecking

Gut microbiota influences host behaviour and physiology, such as anxiety, stress, serotonergic and immune systems. These behavioural and physiological characteristics are related to feather pecking (FP), a damaging behaviour in chickens that reduces animal welfare and productivity. Moreover, high FP (HFP) and low FP (LFP) lines differed in microbiota composition. However, it is unknown whether microbiota can influence the development of FP. For the first time, we identified the effects of microbiota transplantation on FP, and behavioural and physiological characteristics related to FP. HFP and LFP chicks received sterile saline (control), HFP or LFP microbiota transplantation during the first two weeks post-hatch. Microbiota transplantation influenced behavioural responses of the HFP line during treatment and of the LFP line after treatment. In both lines, homologous microbiota transplantation (i.e., receiving microbiota from their line) resulted in more active behavioural responses. Furthermore, microbiota transplantation influenced immune characteristics (natural antibodies) in both lines and peripheral serotonin in the LFP line. However, limited effects on microbiota composition, stress response (corticosterone) and FP were noted. Thus, early-life microbiota transplantation had immediate and long-term effects on behavioural responses and long-term effects on immune characteristics and peripheral serotonin; however, the effects were dependent on host genotype. Since early-life microbiota transplantation influenced behavioural and physiological characteristics that are related to FP, it could thus influence the development of FP later in life.

Could probiotics be the panacea alternative to the use of antimicrobials in livestock diets?

Probiotics are most frequently derived from the natural microbiota of healthy animals. These bacteria and their metabolic products are viewed as nutritional tools for promoting animal health and productivity, disease prevention and therapy, and food safety in an era defined by increasingly widespread antimicrobial resistance in bacterial pathogens. In contemporary livestock production, antimicrobial usage is indispensable for animal welfare, and employed to enhance growth and feed efficiency. Given the importance of antimicrobials in both human and veterinary medicine, their effective replacement with direct-fed microbials or probiotics could help reduce antimicrobial use, perhaps restoring or extending the usefulness of these precious drugs against serious infections. Thus, probiotic research in livestock is rapidly evolving, aspiring to produce local and systemic health benefits on par with antimicrobials. Although many studies have clearly demonstrated the potential of probiotics to positively affect animal health and inhibit pathogens, experimental evidence suggests that probiotics' successes are modest, conditional, strain-dependent, and transient. Here, we explore current understanding, trends, and emerging applications of probiotic research and usage in major livestock species, and highlight successes in animal health and performance.