Dietary Bacillus subtilis B2A strain in laying hens challenged with Salmonella gallinarum: effects on egg production, egg quality, blood haptoglobin and targeted intestinal Salmonella shedding

Effect of dietary inclusion of Bacillus-based probiotics on performance, egg quality, and the faecal microbiota of laying hen

OBJECTIVE

Our study examined the impact of propriety blends of Bacillus strain probiotics on the performance, egg quality, and faecal microflora of laying hens.

METHODS

A total of 183 Institut de selection Animale (ISA) brown laying hens aged 23 weeks with an average body weight of 1,894±72 g were randomly allocated into 3 groups as control (corn-soybean meal based diet, CON), 0.5 g/kg Enterosure probiotics (ET1, 3×108 colony-forming unit [CFU]/kg feed), and 5 g/kg Enterosure probiotics (ET2, 3×109 CFU/kg feed) administered in mashed form. At the completion of each phase hen day egg production (HDEP), average egg weight (AEW), feed intake, and faecal microbiota were evaluated.

RESULTS

HDEP and AEW were higher (p<0.05) in the ET2-supplemented diet in phase 3 (week 9 to 12) compared with CON. Egg mass (EM) was higher (p<0.05) in phase 2 at ET2, and also higher (p<0.05) in phase 3 at the ET1 and ET2-supplemented diets compared with CON. Feed conversion ratio was lower (p<0.05) in phase 3 at the ET1 and ET2-supplemented diets, with ET2 being the lowest compared with ET1 and CON. Yolk colour was higher (p<0.05) in the ET-supplemented diets at phase 3 compared with CON. Bifidobacterium spp. was higher (p<0.05) in the ET2- supplemented diet compared with CON in phase 2, while in In phase 3, Lactobacillus spp. and Bifidobacterium spp. were higher (p<0.05) in the ET-supplemented diets compared with CON. Coliforms were lower (p<0.05) in the ETsupplemented diets compared with CON in phase 3.

CONCLUSION

The propriety blends of Bacillus strain probiotics supplements at 0.5 g/kg and 5 g/kg could improve the production and quality of eggs with more significance at 5 g/kg for HDEP, AEW and EM, which was achieved via the increase of beneficial microbiomes such as Lactobacillus spp., Bifidobacterium spp., and the decrease of pathogenic microbiomes like Escherichia coli and Coliforms which was speculated to improve gut barrier function and the reproductive hormone.

The targeted anti-Salmonella bacteriophage attenuated the inflammatory response of laying hens challenged with Salmonella Gallinarum

Fowl typhoid is a severe disease caused by Salmonella Gallinarum with considerable mortality and morbidity in laying hen farms. The current study has focused on controlling the infection in laying hens using anti-Salmonella spp. bacteriophage. The treatments included, PC, without challenge; NC, S. Gallinarum challenged (SGC); B5, 5 mg bacteriophage/kg + SGC; B10, 10 mg bacteriophage/kg + SGC. The Salmonella shedding, inflammatory responses, and gene expression of pro-inflammatory cytokines, toll-like receptor (TLR), and heat shock protein (HSP) in the jejunum, liver, and thigh muscle were tested in laying hens. Supplementation of bacteriophage reduced the abundance of S. Gallinarum in the excreta at d 3, 7, and 14. The abundance of S. Gallinarum was lower in the B10 than the B5 at d 7. Supplementation of bacteriophage decreased the abundance of S. Gallinarum in the oviduct, spleen, and cecum at d 14. The laying hens in the NC group showed an increased relative spleen weight compared with the PC and B10 treatments. Among the SGC treatments, the NC treatment showed higher gene expressions of IL-4 compared with the B5, higher gene expressions of interferon (IFNγ), TLR4, and tumor necrosis factor-α (TNF-α) compared with the B5 and B10, and higher gene expressions of HSP27 compared with the B10 in the jejunum. Dietary supplementation of B10 decreased the mRNA expressions of TLR4 and TNF-α compared with the B5 treatment in the jejunum. The NC treatment showed the highest gene expressions of HSP27, TLR4, and TNF-α in the liver. Dietary supplementation of B10 showed lower mRNA expressions of HSP27 compared with the B5 treatment in the liver. Moreover, the IFNγ and HSP27 were upregulated in the NC treatment compared with the B5 and B10 in the muscle. In conclusion, it can be suggested that bacteriophage is an effective supplement to control S. Gallinarum infection in laying hens and possibly lower horizontal contaminations in laying hen flocks.

Quantifying heat stress; the roles on metabolic status and intestinal integrity in poultry, a review

Heat stress adversely affects intestinal barrier integrity ranging from minor enterocyte injury to fatal inflammatory heat shocks. The current review discusses the physiological mechanisms of the adaptive response of poultry and the nutritional interventions to improve intestinal integrity during heat stress. There are several possible metabolic mechanisms of protection including stress adaptation signaling pathways, blood flow, intestinal barrier permeability, epithelial cell proliferation, antioxidant status, microbiota composition, expression of heat shock proteins, inflammatory responses, and energy metabolism. The current review discusses the methods of intestinal permeability determination in order to estimate the extent of damage in the farm. There is a lack of knowledge about the nutritional strategies and the interaction between nutrients to reduce intestinal barrier damage and elucidate mechanisms in heat stress.

Bacillaene Mediates the Inhibitory Effect of Bacillus subtilis on Campylobacter jejuni Biofilms

Biofilms are the predominant bacterial lifestyle and can protect microorganisms from environmental stresses. Multispecies biofilms can affect the survival of enteric pathogens that contaminate food products, and thus, investigating the underlying mechanisms of multispecies biofilms is essential for food safety and human health. In this study, we investigated the ability of the natural isolate Bacillus subtilis PS-216 to restrain Campylobacter jejuni biofilm formation and adhesion to abiotic surfaces as well as to disrupt preestablished C. jejuni biofilms. Using confocal laser scanning microscopy and colony counts, we demonstrate that the presence of B. subtilis PS-216 prevents C. jejuni biofilm formation, decreases growth of the pathogen by 4.2 log₁₀, and disperses 26-h-old preestablished C. jejuni biofilms. Furthermore, the coinoculation of B. subtilis and C. jejuni interferes with the adhesion of C. jejuni to abiotic surfaces, reducing it by 2.4 log₁₀. We also show that contact-independent mechanisms contribute to the inhibitory effect of B. subtilis PS-216 on C. jejuni biofilm. Using B. subtilis mutants in genes coding for nonribosomal peptides and polyketides revealed that bacillaene significantly contributes to the inhibitory effect of B. subtilis PS-216. In summary, we show a strong potential for the use of B. subtilis PS-216 against C. jejuni biofilm formation and adhesion to abiotic surfaces. Our research could bring forward novel applications of B. subtilis in animal production and thus contribute to food safety. IMPORTANCE Campylobacter jejuni is an intestinal commensal in animals (including broiler chickens) but also the most frequent cause of bacterial foodborne infection in humans. This pathogen forms biofilms which enhance survival of C. jejuni in food processing and thus threaten human health. Probiotic bacteria represent a potential alternative in the prevention and control of foodborne infections. The beneficial bacterium Bacillus subtilis has an excellent probiotic potential to reduce C. jejuni in the animal gastrointestinal tract. However, data on the effect of B. subtilis on C. jejuni biofilms are scarce. Our study shows that the B. subtilis natural isolate PS-216 prevents adhesion to the abiotic surfaces and the development of submerged C. jejuni biofilm during coculture and destroys the preestablished C. jejuni biofilm. These insights are important for development of novel applications of B. subtilis that will reduce the use of antibiotics in human and animal health and increase productivity in animal breeding.

Effects of Lactobacillus salivarius isolated from feces of fast-growing pigs on intestinal microbiota and morphology of suckling piglets

The study determined the effects of Lactobacillus salivarius (LS) administered early in the life of suckling piglets on their growth performance, gut morphology, and gut microbiota. Thirty litters of 3-day-old crossbreed piglets were randomly assigned to one of the three treatments, and treatments were commenced on day 3 after birth. During the whole period of the experiment, the piglets were kept with their mothers and left to suckle ad libitum while being supplemented with a milk formula with or without the bacterial probiotic supplemented. The control group (CON) was not treated with probiotics, the HLS group was treated with LS144 (HLS) screened from feces of fast-growing pigs with high body mass index (BMI) while the NLS group was supplemented with LS160 (NLS) screened from feces obtained from pigs of normal BMI. At the weaning time, a higher abundance of Actinobacteria, Lentisphaerae, and Elusimicrobia phyla were observed in NLS piglets, whereas the abundance of Fibrobacteres phylum was significantly reduced in NLS and HLS piglets compared with the CON. A greater abundance of Lactobacillus was detected in the HLS treatment compared with the CON. The abundance of Bacteroides and Fibrobacter was higher in the CON piglets compared with the HLS and NLS piglets. Compared with the CON group, the oral administration of LS significantly increased the number of Lactobacillus and villus height in the duodenum, jejunum, and ileum. Moreover, the villus height of the duodenum was significantly improved in the HLS treatment compared with the NLS treatment. Based on the findings in the neonatal piglet model, we suggest that oral supplementation of LS, particularly LS isolated from high BMI pigs, could be beneficial by improving the intestinal villus height.

Effects of dietary Bacillus subtilis RX7 and B2A supplementation on productive performance, egg quality, blood profiles, and excreta Salmonella counts in laying hens

An experiment was carried out to investigate the effect of Bacillus subtilis RX7 and B2A supplementation on egg production, egg quality, blood profile, and excreta Salmonella population in laying hens. A total of 192 Hy-Line Brown laying hens (40-wk-old) were randomly assigned into four dietary treatments, each of which was replicated eight times with six hens per replicate in a 5 wk trial. The dietary treatments were NC, which is a basal diet without antibiotics or Bacillus subtilis; PC, which is an NC + 0.5 g kg−1 antibiotic (virginiamycin) diet; BSR, which is an NC + 0.5 g kg−1 Bacillus subtilis RX7 (1.0 × 109 colony forming units g−1); and BSB, which is an NC + 0.5 g kg−1 Bacillus subtilis B2A (1.0 × 109 colony forming units g−1). The results showed that hens receiving BSB diets had increased (P < 0.05) eggshell thickness over hens fed the NC, PC, and BSR diets (week 3). The excreta Salmonella counts in the PC, BSR, and BSB groups were lower than the NC group (P < 0.05). These results indicate that dietary inclusion of Bacillus subtilis RX7 and B2A strains effectively decreased excreta Salmonella counts without any detrimental effects on the performance of laying hens.

The Gut Microbiota of Laying Hens and Its Manipulation with Prebiotics and Probiotics To Enhance Gut Health and Food Safety

The microbiota plays a vital role in maintaining gut health and influences the overall performance of chickens. Most gut microbiota-related studies have been performed in broilers, which have different microbial communities compared to those of layers. The normal gut microbiota of laying chickens is dominated by Proteobacteria, Firmicutes, Bacteroidetes, Fusobacteria, and Actinobacteria at the phylum level. The composition of the gut microbiota changes with chicken age, genotype, and production system. The metabolites of gut microbiota, such as short-chain fatty acids, indole, tryptamine, vitamins, and bacteriocins, are involved in host-microbiota cross talk, maintenance of barrier function, and immune homeostasis. Resident gut microbiota members also limit and control the colonization of foodborne pathogens. In-feed supplementations of prebiotics and probiotics strengthen the gut microbiota for improved host performance and colonization resistance to gut pathogens, such as Salmonella and Campylobacter The mechanisms of action of prebiotics and probiotics come through the production of organic acids, activation of the host immune system, and production of antimicrobial agents. Probiotic candidates, including Lactobacillus, Bifidobacterium, Bacillus, Saccharomyces, and Faecalibacterium isolates, have shown promising results toward enhancing food safety and gut health. Additionally, a range of complex carbohydrates, including mannose oligosaccharides, fructo-oligosaccharides, and galacto-oligosaccharides, and inulin are promising candidates for improving gut health. Here, we review the potential roles of prebiotics and probiotics in the reshaping of the gut microbiota of layer chickens to enhance gut health and food safety.

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.