Bacillus amyloliquefaciens Ameliorates H2O2-Induced Oxidative Damage by Regulating Transporters, Tight Junctions, and Apoptosis Gene Expression in Cell Line IPEC-1

Recent advances and prospects of Bacillus amyloliquefaciens as microbial cell factories: from rational design to industrial applications

Bacillus amyloliquefaciens is one of the most characterized Gram-positive bacteria. This species has unique characteristics that are beneficial for industrial applications, including its utilization of: cheap carbon as a substrate, a transparent genetic background, and large-scale robustness in fermentation. Indeed, the productivity characteristics of B. amyloliquefaciens have been thoroughly analyzed and further optimized through systems biology and synthetic biology techniques. Following the analysis of multiple engineering design strategies, B. amyloliquefaciens is now considered an efficient cell factory capable of producing large quantities of multiple products from various raw materials. In this review, we discuss the significant potential advantages offered by B. amyloliquefaciens as a platform for metabolic engineering and industrial applications. In addition, we systematically summarize the recent laboratory research and industrial application of B. amyloliquefaciens, including: relevant advances in systems and synthetic biology, various strategies adopted to improve the cellular performances of synthetic chemicals, as well as the latest progress in the synthesis of certain important products by B. amyloliquefaciens. Finally, we propose the current challenges and essential strategies to usher in an era of broader B. amyloliquefaciens use as microbial cell factories.

Bacillus amyloliquefaciens SC06 in the diet improves egg quality of hens by altering intestinal microbiota and the effect is diminished by antimicrobial peptide

This experiment investigated the effects of Bacillus amyloliquefaciens SC06 (BaSC06) and its combination with antimicrobial peptide (AMP) on the laying performance, egg quality, intestinal physical barrier, antioxidative status and immunity of commercial Jingbai strain laying hens. The results showed that BaSC06 significantly improved laying performance and egg quality of laying hens. However, there was a tendency to increase laying performance and decrease egg quality for the addition of AMP compared to the BaSC06 group. Also, both BaSC06 and its combination with AMP treatment increased length of microvilli and the content of tight junction protein in jejunum, and BaSC06 combination with AMP treatment is better than BaSC06 treatment alone. Compared to control, most of the serum antioxidant enzyme activities were significantly increased in the BaSC06+AMP group, the BaSC06 group only increased the activity of GSH-Px. Short-chain fatty acid analysis showed that BSC06 significantly increased the content of butyric, isobutyric and isovaleric acid in the cecum. However, the content of most of the short-chain fatty acids was even lower than that of the control group after the addition of AMP. Microbiota analysis showed that BaSC06 increased the absolute abundance of the butyrate-producing gut bacteria Ruminococaaoeae UCG-005, while the addition of AMP reduced the number of microorganisms detected and weakened the effect of BaSC06. BaSC06 acts as an anti-inflammatory agent by regulating the gut microbiota, and AMP further attenuates the immune response by reducing the number of gut microbes based on improved intestinal microbiota composition.

Bacillus amyloliquefaciens 40 regulates piglet performance, antioxidant capacity, immune status and gut microbiota

Probiotics can improve animal growth performance and intestinal health. Bacillus species, Lactobacillus species, Bifidobacterium species, yeast etc. are the common types of probiotics. However, understanding the effects of probiotics on the immune status and gut microbiota of weaning piglets and how the probiotics exert their impact are still limited. This study aimed to investigate the effects of Bacillus amyloliquefaciens 40 (BA40) on the performance, immune status and gut microbiota of piglets. A total of 12 litters of newborn piglets were randomly divided into 3 groups. Piglets in control group were orally dosed with phosphate buffered saline; BA40 group and probiotics group were orally gavaged with resuspension BA40 and a probiotics product, respectively. The results showed that BA40 treatment significantly decreased (P < 0.05) the diarrhea incidence (from d 5 to 40), diamine oxidase, D-lactate, interleukin (IL)-1β and interferon-γ concentrations compared with control group and probiotics group. Meanwhile BA40 dramatically increased the total antioxidant capacity, IL-10 and secretory immunoglobulin-A concentrations in contrast to control group. For the microbial composition, BA40 modulated the microbiota by improving the abundance of Bacteroides, Phascolarctobacterium (producing short-chain fatty acids) and Desulfovibrio and reducing the proliferation of pathogens (Streptococcus, Tyzzerella, Vellionella and paraeggerthella). Meanwhile, a metabolic function prediction explained that carbohydrate metabolism and amino acid metabolism enriched in BA40 group in contrast to control group and probiotics group. For correlation analysis, the results demonstrated that BA40-enriched Phascolarctobacterium and Desulfovibrio provide insights into strategies for elevating the health status and performance of weaned piglets. Altogether, BA40 exerted stronger ability in decreasing diarrhea incidence and improved antioxidant activity, gut barrier function and immune status of piglets than the other treatments. Our study provided the experimental and theoretical basis for the application of BA40 in pig production.

Effects of three probiotics and their interactions on the growth performance of and nutrient absorption in broilers

The purpose of this study was to investigate the effects of three probiotics and their interactions on growth performance, intestinal digestion and absorption, and nutrient transporters in broilers. A total of 350 one-day-old male Arbor Acres broilers were randomly divided into seven groups: the control group (broilers receiving normal drinking water), groups P1, P2 and P3 (broilers receiving drinking water with 1% Lactobacillus casei, Lactobacillus acidophilus and Bifidobacterium lactis , respectively) and groups CP1, CP2 and CP3 (broilers receiving drinking water with a 1% compound probiotic mixture in 2:1:1, 1:2:1, 1:1:2 ratios, respectively). The feeding period was divided into two experimental periods: 1∼21 days and 22∼42 days. Compared to those in the control group, the broiler slaughter indexes and average daily feed intakes in the probiotics groups were not significantly different (P > 0.05), but the villus height in the small intestine increased significantly, and the crypt depth decreased significantly (P < 0.05). In the 1- to 21-day, experimental period, the broiler average daily gains in groups CP2 and CP3 were significantly greater than that in the control group. Amylase, lipase, and trypsin activities in the jejunum in groups CP and P3 increased significantly. GLUT2 mRNA expression in the probiotics group was significantly incresaed compared with that in the control group (P < 0.05). In the 22- to 42-day period, the average daily gain in the CP group was significantly greater than that in the control group. Amylase activity in the CP2 group, and lipase and trypsin activities in the CP, P1 and P3 groups increased significantly. The GLUT2 mRNA expression in the CP group increased significantly (P < 0.05). In summary, three probiotics and their interactions improved the digestibility and absorption of nutrients by increasing the activities of digestive enzymes, improving the morphology of the digestive tract, and upregulating the expression of GLUT2 mRNA in the intestinalcell membrane to improve the production performance in broilers.

Modulations of genes related to gut integrity, apoptosis, and immunity underlie the beneficial effects of Bacillus amyloliquefaciens CECT 5940 in broilers fed diets with different protein levels in a necrotic enteritis challenge model

Background

The ban of in-feed antimicrobial additives has negatively affected the poultry industry by causing necrotic enteritis (NE) to emerge in the flocks. Alternatives such as Bacillus probiotics have shown to be effective on eliminating the negative effects of this disease. Two experiments were conducted to investigate the effect of Bacillus amyloliquefaciens CECT 5940 (BA) in broiler chickens under NE challenge and/or fed diets with different protein levels.

Methods

In both experiments, 480 day-old mix-sexed Ross-308 broilers were arranged in a 2 × 2 factorial arrangement of treatments. In experiment 1, the factors were NE challenge (yes or no) and probiotic (yes or no). In experiment 2, the factors were dietary crude protein levels (standard or reduced) and probiotic (yes or no) and were used under NE challenge condition. Oral administration of Eimeria oocysts (day 9) followed by inoculation with Clostridium perfringens (day 14 and 15) was used to induce NE challenge. On day 16, two birds from each treatment were gavaged with fluorescein isothiocyanate-dextran (FITC-d) and blood samples were collected for gut integrity evaluation, and jejunal samples were collected for gene expression assay.

Results

In experiment 1, BA supplementation decreased caspase-3 (CASP3) (P < 0.001) and caspase-8 (CASP8) (P < 0.05) and increased occludin (OCLD) (P < 0.05) expression regardless of the challenge. Additionally, BA supplementation downregulated interfron-γ (IFN-γ) expression (P < 0.01) and upregulated immunoglobulin-G (IgG) (P < 0.01) and immunoglobulin-M (IgM) (P < 0.05) only in challenged birds. In experiment 2, the expression of genes encoding mucin-2 (MUC2) (P < 0.001), tight junction protein-1 (TJP1) (P < 0.05) and OCLD (P < 0.05) were upregulated by the addition of BA in the diet, regardless of the crude protein level. Further, BA supplementation downregulated INF-γ (P < 0.01) and upregulated immunoglobulin-A (IgA) (P < 0.05), IgM (P < 0.05) and IgG (P < 0.01) regardless of the crude protein level.

Conclusion

These findings suggest that supplementation of BA in broiler diets can improve gut health by modulation of genes related to the mucosal barrier, tight junction, and immunity in broilers challenged by unfavourable conditions such as NE challenge.

Effects of spermine on ileal physical barrier, antioxidant capacity, metabolic profile and large intestinal bacteria in piglets

Spermine, a polyamine, exerts important roles in alleviating oxidative damage, improving immunity, increasing antioxidant status and digestive enzyme activities, and promoting the development of small intestine. However, information is not available regarding the effects of spermine supplementation on gut barrier function, intestinal microbiota and metabolic profile in piglets. Therefore, this study was designed to explore the effect of spermine administration on these parameters. The experiment was conducted on twenty 12 day-old suckling piglets, which were allocated either to the group fed basal formula milk (control group) or to that fed a basal formula milk that contained spermine (0.4 mmol kg⁻¹ BW per day) for 3 days. Caecal and colonic digesta and ileal tissues were collected at the end of the three-day feeding experiment. The results were as follows: (1) supplementation with spermine increased glutathione S-transferase (GST) capacity by 27.84% and glutathione content by 18.68% in the ileum (P < 0.05). (2) Glutathione peroxidase 1 (GPx1), catalase (CAT), GST, nuclear factor erythroid 2-related factor 2 (Nrf2) and Kelch-like ECH-associated protein1 (Keap1) mRNA levels in ileum were increased in the spermine-supplemented group in contrast to those in the control group (P < 0.05). (3) The spermine-supplemented group increased zonula occludens-1 (ZO-1) (by 42.0%), ZO-2 (by 101.0%), occludin (by 84.0%), claudin 2 (by 98.0%), claudin 3 (by 121.0%), claudin 12 (by 47.0%), claudin 14 (by 68.0%) and claudin 16 (by 73.0%) mRNA levels in ileum relative to the control group (P < 0.05). (4) Supplementation with spermine increased ZO-2 and occludin mRNA levels in ileum by reducing myosin light chain kinase (MLCK) (by 23.0%) mRNA level. (5) Spermine supplementation increased choline, glycerolphosphocholine, creatine and serine levels, and decrease alanine, glutamate, lysine, phenylalanine, threonine, lactate, tyrosine levels in ileum (P < 0.05). (6) The population of Lactobacilli, Bifidobacteria and total bacteria increased, but the number of Escherichia coli decreased in the caecal and colonic digesta after spermine supplementation (P < 0.05). In summary, dietary spermine supplementation promotes ileal health by enhancing antioxidant properties, improving ileal barrier function, modulating metabolic profiles, and maintaining large intestinal microbial homeostasis.

Spermine, a polyamine, exerts important roles in alleviating oxidative damage, improving immunity, increasing antioxidant status and digestive enzyme activities, and promoting the development of small intestine.