Nutritional quality improvement of soybean meal by Bacillus velezensis and Lactobacillus plantarum during two-stage solid- state fermentation

Effect of extrusion on energy and nutrient digestibility of lentil-based diets containing either supplemental plant or animal protein fed to growing pigs

Non-food grade and excess lentil grain production may be included in swine feeds to provide starch and protein and reduce feed cost. Extrusion processing may increase energy and nutrient digestibility of lentil-based diets containing either supplemental plant or animal protein sources. Therefore, the apparent ileal digestibility (AID) of crude protein (CP) and amino acids (AA), apparent total tract digestibility (ATTD) of gross energy (GE), and digestible energy (DE) value of lentil-based diets were assessed in growing pigs. Two diets were formulated to provide 2.4 Mcal net energy (NE)/kg and 4.35 g standardized ileal digestible lysine/Mcal NE: (1) soybean meal (SBM) diet, containing 50% lentil, 31% wheat, and 12.8% SBM; and (2) fish meal (FM) diet, containing 40% lentil, 45% wheat, and 10% FM. Following mixing, each diet batch was divided into two parts: one part remained as mash, whereas the other part was extruded using a single-screw extruder (400 rpm, 250 kg/h). Eight ileal-cannulated barrows (32.3 ± 1.5 kg) were fed the four diets at 2.8 times maintenance DE requirement (110 kcal per kg of body weight0.75) for four 9-d periods in a double 4 × 4 Latin square to achieve 8 observations per diet. Data were analyzed as a 2 × 2 factorial arrangement including protein source, post-mixing processing, and their interaction as fixed effects. The lentil sample contained 32.3% starch, 24.4% CP, 9.3% total dietary fiber, and 1.7 mg/g of trypsin inhibitor activity on as is-basis. Interactions between dietary protein source and post-mixing processing were not observed. Feeding FM diets resulted in greater (P < 0.05) AID of dry matter (DM), GE, and most AA, and ATTD of CP, but lower apparent hindgut fermentation of DM and GE than SBM diets. Extrusion increased (P < 0.05) the ATTD of GE and DE value of diets. The AID of CP and AA was 3.2 and 4.7%-units greater (P < 0.05), respectively, for the extruded than mash diets. In conclusion, feeding FM diets resulted in greater ileal digestibility of DM, GE, and AA than SBM diets. Extrusion increased the AID of CP and most AA, and DE value of lentil-based diets containing either supplemental plant protein or animal-protein, indicating that extrusion can increase the energy and protein value of plant-based diets fed to pigs.

Cellulase with Bacillus velezensis improves physicochemical characteristics, microbiota and metabolites of corn germ meal during two-stage co-fermentation

Corn germ meal (CGM) is one of the major byproducts of corn starch extraction. Although CGM has rich fiber content, it lacks good protein content and amino acid balance, and therefore cannot be fully utilized as animal feed. In this study, we investigated the processing effect of cellulase synergized with Bacillus velezensis on the nutritional value of pretreated CGM (PCGM) in two-stage solid-state fermentation (SSF). High-throughput sequencing technology was used to explore the dynamic changes in microbial diversity. The results showed that compared with four combinations of B. velezensis + Lactiplantibacillus plantarum (PCGM-BL), cellulase + L. plantarum (PCGM-CL),control group (PCGM-CK), and cellulase + B. velezensis + L. plantarum (PCGM-BCL), the fourth combination of PCGM-BCL significantly improved the nutritional characteristics of PCGM. After two-stage SSF (48 h), viable bacterial count and contents of crude protein (CP) and trichloroacetic acid-soluble protein (TCA-SP) all were increased in PCGM-BCL (p < 0.05), while the pH was reduced to 4.38 ± 0.02. In addition, compared with PCGM-BL, the cellulose degradation rate increased from 5.02 to 50.74%, increasing the amounts of short-chain fatty acids (216.61 ± 2.74 to 1727.55 ± 23.00 µg/g) and total amino acids (18.60 to 21.02%) in PCGM-BCL. Furthermore, high-throughput sequencing analysis revealed significant dynamic changes in microbial diversity. In the first stage of PCGM-BCL fermentation, Bacillus was the dominant genus (99.87%), which after 24 h of anaerobic fermentation changed to lactobacillus (37.45%). Kyoto Encylopaedia of Genes and Genomes (KEGG) metabolic pathway analysis revealed that the pathways related to the metabolism of carbohydrates, amino acids, cofactors, and vitamins accounted for more than 10% of the enriched pathways throughout the fermentation period. Concisely, we show that cellulase can effectively improve the nutritional value of PCGM when synergized with B. velezensis in two-stage SSF.

Effects of different wheat bran fermentation sources on growth performance, nutrient digestibility, serum antioxidant capacity and fecal microbiota in growing pigs

The present study aimed to evaluate the application of different wheat bran fermentation sources in growing pigs. A total of 320 pigs (43 ± 0.21 kg), were randomly allocated to 5 groups in a 21-d trial. The control group was fed a basal diet (CON) containing raw wheat bran, and the other four treatments were fed the diets in which the raw wheat bran in the basal diet was substituted with Aspergillus niger (WBA), Bacillus licheniformis (WBB), Candida utilis (WBC), and Lactobacillus plantarum (WBL) fermented wheat bran, respectively. The results showed that compared to the CON group, the crude fiber and pH values were decreased (p < 0.05), while the gross energy (GE), crude protein (CP), and lactic acid values were increased (p < 0.05) in all the wheat bran fermented by different strains. Compared with other treatments, feeding B. licheniformis fermented wheat bran had higher final weight, average daily gain, as well as lower feed-to-gain ratio. Compared with CON group, pigs fed with fermented wheat bran diets had higher dry matter, CP, and GE availability, serum total protein, albumin and superoxide dismutase levels, and fecal Lactobacillus counts, as well as lower malondialdehyde level and fecal Escherichia coli count. Collectively, our findings suggested that feeding fermented wheat bran, especially B. licheniformis fermented wheat bran, showed beneficial effects on the growth performance, nutrient digestibility, serum antioxidant capacity, and the gut microbiota structure of growing pigs.

Comparative genomic and transcriptome analysis of Bacillus velezensis CL-4 fermented corn germ meal

Bacillus, an excellent organic-degrading agent, can degrade lignocellulose. Notably, some B. velezensis strains encode lignocellulases. However, their ability to degrade lignocellulose in fermented feed is not much appreciated. This study performed a comparative genomic analysis of twenty-three B. velezensis strains to find common carbohydrate-active enzymes (CAZymes) encoding genes and evaluated their potential to degrade lignocellulose. The comparative genomic and CAZyme database-based analyses identified several potential CAZymes genes that degrade cellulose (GH1, GH4, GH5, GH13, GH16, GH32, PL1, and PL9), hemicellulose (GH11, GH26, GH43, GH51, and CE3) and lignin (AA4, AA6, AA7, and AA10). Furthermore, Illumina RNA-seq transcriptome analysis revealed the expression of more than 1794 genes in B. velezensis CL-4 fermented corn germ meal at 48 h (FCGM 48 h). Gene ontology analysis of expressed genes revealed their enrichment in hydrolase activity (breaking the glycosyl bonds during carbohydrate metabolism), indicating the upregulation of CAZymes. In total, 58 differentially upregulated CAZymes-encoding genes were identified in FCGM 48 h compared to FCGM 0 h. The upregulated CAZymes-encoding genes were related to cellulose (6-phospho-β-galactosidase and 6-phospho-α-glucosidase), starch (α-glucosidase and α-amylase), pectin (pectin lyase), and hemicellulose (arabinan endo-1,5-α-L-arabinosidase, xylan 1,4-beta-xylosidase, α-N-arabinofuranosidase, and acetyl xylan esterase). Importantly, arabinoxylan degradation mainly occurred in FCGM 48 h, followed by partial degradation of cellulose, pectin, and starch. This study can support the development of enzymatic cocktails for the solid-state fermented feed (SFF).

Effect of heating, microbial fermentation, and enzymatic hydrolysis of soybean meal on growth performance, nutrient digestibility, and intestinal microbiota of weaned piglets

The macromolecular proteins, anti-nutritional factors, and allergens contained in soybean meal (SBM) have a negative impact on the growth of weaned piglets. The objective of this study was to investigate the effects of heating, microbial fermentation, and enzymatically hydrolyzed SBM on the growth performance, nutrient digestibility, serum biochemistry, intestinal morphology, volatile fatty acids, and microbiota of weaned piglets. After the preparation of soaked SBM (SSBM), enzymatically hydrolyzed SBM (ESBM), and microbial fermented and enzymatically hydrolyzed SBM (MESBM), 72 weaned piglets were randomly allocated to three groups for a 21-d trial. In the three groups, 17% of conventional SBM in basal corn-soybean meal diet was replaced by an equivalent amount of SSBM (control group), ESBM, or MESBM. The results showed that the contents of glycinin, β-conglycinin, trypsin inhibitor, and proteins above 20 kDa were significantly decreased in ESBM and MESBM, compared with SSBM, and the surface of ESBM and MESBM had more pores and fragmented structure. In the second week and throughout the entire experimental period, the diarrhea index was reduced (P < 0.01) in ESBM and MESBM in contrast with SSBM. Furthermore, the inclusion of ESBM and MESBM in the diet improved the apparent total tract digestibility of dry matter and crude protein (P < 0.05), and increased the abundances of the genera Lactobacillus and Clostridium_sensu_stricto_1, respectively. Metagenomic sequencing further identified that members of six species of Proteobacteria, four species of Clostridiales, and three species of Negativiautes were enriched in the colon of piglets fed MESBM, while two bacterial species, Lachnoclostridium and Lactobacillus_points, were enriched in the colon of piglets fed ESBM. In conclusion, replacing SSBM with ESBM or MESBM in the diet decreased the diarrhea index, which could be associated with improved nutrient digestibility and microbial composition.

Effects of Fermentation on the Apparent Metabolizable Energy and Standardized Ileal Digestibility of Amino Acids in Soybean Meal Fed to Broiler Chickens

Two experiments were conducted to test the hypothesis that the apparent metabolizable energy (AME) and standardized ileal digestibility (SID) of amino acids (AA) in fermented soybean meal (FSBM) are greater than those in soybean meal (SBM). FSBM was produced by fermenting SBM with a mixture of Bacillus amyloliquefaciens, Lactobacillus acidophilus, and Saccharomyces cerevisiae. The fermentation process decreased trypsin inhibitor and crude fiber levels by 67.80% and 7.56%, while it increased the total amino acid content by 2.56%. In the first experiment, a substitution method was used to determine the AME and nitrogen-corrected AME (AMEn) of SBM and FSBM. A corn-SBM basal diet and two test diets consisting of 70% of the basal diet plus 30% SBM or FSBM were formulated. The results show that fermentation did not have an effect on the AME and AMEn concentrations of SBM (p > 0.05); the respective AME and AMEn values were 10.29 and 10.62 MJ/kg (DM basis) and 9.09 and 9.23 MJ/kg for SBM and FSBM. In the second experiment, a nitrogen-free diet was formulated to measure the endogenous AA flow, and the other two semi-purified diets containing SBM or FSBM as the sole source of AA were formulated. The results show that the AID and SID of isoleucine, leucine, phenylalanine, valine, cysteine, tyrosine, and aspartic acid were greater in FSBM than in SBM (p < 0.05). In conclusion, the fermentation of SBM by a mixture of B. amyloliquefaciens, L. acidophilus, and S. cerevisiae can improve its nutritional values and is a promising protein resource for broiler production.

Enzymatically treated yeast bolstered growth performance of broiler chicks from young broiler breeders linked to improved indices of intestinal function, integrity, and immunity

Older breeder chicks (OBC) are heavier and robust at hatch than younger breeder chicks (YBC). However, the implications of broiler breeder age on chick intestinal function and the role of functional feedstuffs are unexplored. We evaluated the effects of broiler breeder age and the impact of feeding YBC enzymatically treated yeast on growth, nutrient utilization, and indices of intestinal function. Fertile Ross 708 eggs: 2,250 (56.5 ± 3.4g) from 30-wk-old (YBC) and 550 (64.2 ± 4.2 g) from 47-wk-old (OBC) were hatched and placed in 48 pens (44 chicks/pen) containing equal males and females for growth and intestinal function evaluation and 36 cages (5 chicks/cage) for metabolizable energy (AME). Five corn and soybean meal-based diets were formulated to contain 0, 0.05, 0.10, 0.20, and 0.40% HY40 for a 3-phase feeding program (starter: days 0–10, grower: days 11–24, and finisher; days 25–42). Grower phase diets also contained a 0.3% TiO₂ indigestible marker. The diets were allocated within YBC in a completely randomized block design (n = 8 for pens; n = 6 for cages). The OBC were fed a 0% yeast diet. Feed and water were provided freely; BW and feed intake were monitored, and excreta samples were collected on days 17 to 21 for apparent retention (AR). Birds were necropsied for plasma, jejunal tissues, organs weight, and ceca digesta. The OBC were heavier (P < 0.01) than YBC at hatch. Final BW of OBC and YBC fed, ≥0.10% yeast, was similar (P > 0.05). The OBC had similar FCR (P > 0.05) to YBC fed 0 to 0.10% yeast but higher (P = 0.003) than for YBC fed ≥0.20% yeast. Jejunal villi height to crypt depth ratio (VCR) and IgA were higher in OBC than 0% yeast (P = 0.01). Yeast increased VCR, bursa weight, jejunal, and plasma IgA (P = 0.01). The YBC fed ≥0.10% yeast had higher (P < 0.05) AR of crude protein, and gross energy than OBC and YBC fed 0 or 0.05% yeast. In conclusion, yeast improved YBC performance to the level of OBC linked to improved intestinal function, integrity, and immunity.

Mineral Content, Functional, Thermo-Pasting, and Microstructural Properties of Spontaneously Fermented Finger Millet Flours

Finger millet is a cereal grain which is superior to wheat and rice in terms of dietary fibre, minerals, and micronutrients. Fermentation is one of the oldest methods of food processing, and it has been used to ferment cereal grains such as finger millet (FM) for centuries. The aim of this study was to investigate the impact of spontaneous fermentation (SF) on mineral content, functional, thermo-pasting, and microstructural properties of light- and dark-brown FM flours. Spontaneous fermentation exhibited a significant increase in the macro-minerals and micro-minerals of FM flours. In terms of functional properties, SF decreased the packed bulk density and swelling capacity, and it increased the water/oil absorption capacity of both FM flours. Spontaneous fermentation had no effect on the cold paste viscosity of FM flours. However, significant decreases from 421.61 to 265.33 cP and 320.67 to 253.67 cP were observed in the cooked paste viscosity of light- and dark-brown FM flours, respectively. Moreover, SF induced alterations in the thermal properties of FM flours as increments in gelatinisation temperatures and gelatinisation enthalpy were observed. The results of pasting properties exhibited the low peak viscosities (1709.67 and 2695.67 cP), through viscosities (1349.67 and 2480.33 cP), and final viscosities (1616.33 and 2754.67 cP), along with high breakdown viscosities (360.00 and 215.33 cP) and setback viscosity (349.33 and 274.33 cP), of spontaneously fermented FM flours. Scanning electron microscopy showed that SF influenced changes in the microstructural properties of FM flours. The changes induced by SF in FM flours suggest that flours can be used in the food industry to produce weaning foods, jelly foods, and gluten-free products that are rich in minerals.

Fermentation of NaHCO3-treated corn germ meal by Bacillus velezensis CL-4 promotes lignocellulose degradation and nutrient utilization

Sodium bicarbonate pretreatment and solid-state fermentation (SSF) were used to maximize the nutritional value of corn germ meal (CGM) by inoculating it with Bacillus velezensis CL-4 (isolated from chicken cecal contents and capable of degrading lignocellulose). Based on genome sequencing, B. velezensis CL-4 has a 4,063,558 bp ring chromosome and 46.27% GC content. Furthermore, genes associated with degradation of lignocellulose degradation were detected. Pretreatment of CGM (PCGM) with sodium bicarbonate (optimized to 0.06 g/mL) neutralized low pH. Fermented and pretreated CGM (FPCGM) contained more crude protein (CP), soluble protein of trichloroacetic acid (TCA-SP), and total amino acids (aa) than CGM and PCGM. Degradation rates of cellulose and hemicellulose were reduced by 21.33 and 71.35%, respectively, after 48 h fermentation. Based on electron microscopy, FPCGM destroys the surface structure and adds small debris of the CGM substrate, due to lignocellulose breakdown. Furthermore, 2-oxoadipic acid and dimethyl sulfone were the most important metabolites during pretreatment. Concentrations of adenosine, cytidine, guanosine, S-methyl-5'-thioadenosine, and adenine decreased significantly after 48 h fermentation, whereas concentrations of probiotics, enzymes, and fatty acids (including palmitic, 16-hydroxypalmitic, and linoleic acids) were significantly improved after fermentation. In conclusion, the novel pretreatment of CGM provided a proof of concept for using B. velezensis CL-4 to degrade lignocellulose components, improve nutritional characteristics of CGM, and expand CGM lignocellulosic biological feed production. KEY POINTS: • Sodium bicarbonate (baking soda) can be used as an economical and green additive to pretreat corn germ meal; • Fermentation with B. velezensis degrades the cellulose and hemicellulose component of corn germ meal and improves its feed quality; • As a novel qualified presumption of safety (QPS) strain, B. velezensis should have broad potential applications in food and feed industries.

Improving the nutritional value and bioactivity of soybean meal in solid-state fermentation using Bacillus strains newly isolated from the gut of the termite Termes propinquus

The present study aimed to isolate and characterize proteolytic Bacillus spp. from termite guts to test the possibility of application for improving the nutritional value and bioactivity of fermented soybean meal (FSBM). Aerobic endospore-forming bacteria were isolated from the gut of the termite Termes propinquus. Ten isolates with high levels of soy milk degradation were selected and tested for extracellular enzyme production. Among them, two isolates, Tp-5 and Tp-7, exhibited all tested hydrolytic enzyme activities (cellulase, xylanase, pectinase, amylase, protease, lipase and phytase), weak alpha hemolytic and also antagonistic activities against fish pathogenic species of Aeromonas and Streptococcus. Both phylogenetic and biochemical analyses indicated that they were closely related to Bacillus amyloliquefaciens. During solid-state fermentation of SBM, Tp-5 and Tp-7 exhibited the highest protease activity (1127.2 and 1552.4 U g-1, respectively) at 36 h, and the resulting FSBMs showed a significant increase in crude protein content and free radical-scavenging ability (P < 0.05), as well as an improvement in the composition of amino acids, metabolites and other nutrients, while indigestible materials such as fiber, lignin and hemicellulose were decreased. The potential strains, especially Tp-7, improved the nutritional value of FSBM by their strong hydrolytic and antioxidant activities, together with reducing antinutritional components.

Dynamics Changes of Microorganisms Community and Fermentation Quality in Soybean Meal Prepared with Lactic Acid Bacteria and Artemisia argyi through Fermentation and Aerobic Exposure Processes

This study evaluated the effects of Lactiplantibacillus plantarum subsp. plantarum ZA3, Artemisia argyi and their combination, on the fermentation characteristics, microbial community, mycotoxins and crude flavonoids content of fermented soybean meal during fermentation (under anaerobic conditions) and aerobic exposure (under aerobic conditions). The results showed that ZA3, Artemisia argyi and ZA3+ Artemisia argyi groups had lower pH values and higher lactic acid concentrations compared with controls, and additives increased the abundance of Lactiplantibacillus and decreased those of Acetobacter and Enterobacter; in particular, Artemisia argyi and ZA3+ Artemisia argyi reduced the abundance of fungi, such as Aspergillus, Pichia, Fusarium, Cladosporium and Xeromyces. Meanwhile, the contents of mycotoxins were lower in treated groups, and even mycotoxins in the control were significantly reduced after 30 d (p < 0.05). Crude flavonoids that were correlated positively with Lactococcus and negatively with Bacillus, Aspergillus, Enterobacter and Kazachstania were significantly higher in the Artemisia argyi and ZA3+ Artemisia argyi groups (p < 0.05).

Anaerobic Solid-State Fermentation of Soybean Meal With Bacillus sp. to Improve Nutritional Quality

The study evaluated the impact of fermentation with Bacillus sp. on the nutritional quality of soybean meal (SBM) and the changes of bacterial community structure during fermentation. High protease-producing strains were screened to degrade SBM macromolecular protein and anti-nutritional factors (ANFs). Unsterilized SBM then underwent an anaerobic solid-state fermentation method to evaluate the effects of fermentation. Results showed that for the nine high-producing protease strains that were screened, acid-soluble protein (ASP) contents in fermented SBM increased, with the highest value found to be 13.48%, which was fermented using strain N-11. N-11 was identified as Bacillus subtilis. N-11 fermentation reduced ANFs such as glycinin and β-conglycinin by 82.38 and 88.32%, respectively. During N-11 fermentation, the bacterial richness and diversity in SBM increased but not significantly. The high-yield protease strain B. subtilis N-11 selected in this experiment improved the nutritional quality of SBM through fermentation, and it can be used for industrial large-scale production.

A Review of the Effects and Production of Spore-Forming Probiotics for Poultry

Simple Summary

Spore-forming probiotics are widely used in the poultry industry for their beneficial impact on host health. The main feature that separates spore-forming probiotics from the more common lactic acid probiotics is their high resistance to external and internal factors, resulting in higher viability in the host and correspondingly, greater efficiency. Their most important effect is the ability to confront pathogens, which makes them a perfect substitute for antibiotics. In this review, we cover and discuss the interactions of spore-forming probiotic bacteria with poultry as the host, their health promotion effects and mechanisms of action, impact on poultry productivity parameters, and ways to manufacture the probiotic formulation. The key focus of this review is the lack of reproducibility in poultry research studies on the evaluation of probiotics’ effects, which should be solved by developing and publishing a set of standard protocols in the professional community for conducting probiotic trials in poultry.

Abstract

One of the main problems in the poultry industry is the search for a viable replacement for antibiotic growth promoters. This issue requires a “one health” approach because the uncontrolled use of antibiotics in poultry can lead to the development of antimicrobial resistance, which is a concern not only in animals, but for humans as well. One of the promising ways to overcome this challenge is found in probiotics due to their wide range of features and mechanisms of action for health promotion. Moreover, spore-forming probiotics are suitable for use in the poultry industry because of their unique ability, encapsulation, granting them protection from the harshest conditions and resulting in improved availability for hosts’ organisms. This review summarizes the information on gastrointestinal tract microbiota of poultry and their interaction with commensal and probiotic spore-forming bacteria. One of the most important topics of this review is the absence of uniformity in spore-forming probiotic trials in poultry. In our opinion, this problem can be solved by the creation of standards and checklists for these kinds of trials such as those used for pre-clinical and clinical trials in human medicine. Last but not least, this review covers problems and challenges related to spore-forming probiotic manufacturing.