Improvement of the Nutritional Quality and Fibrinolytic Enzyme Activity of Soybean Meal by Fermentation of B acillus subtilis

Mechanism of action, benefits, and research gap in fermented soybean meal utilization as a high-quality protein source for livestock and poultry

Animal nutritionists have incessantly worked towards providing livestock with high-quality plant protein feed resources. Soybean meal (SBM) has been an essential and predominantly adopted vegetable protein source in livestock feeding for a long time; however, several SBM antinutrients could potentially impair the animal's performance and growth, limiting its use. Several processing methods have been employed to remove SBM antinutrients, including fermentation with fungal or bacterial microorganisms. According to the literature, fermentation, a traditional food processing method, could improve SBM's nutritional and functional properties, making it more suitable and beneficial to livestock. The current interest in health-promoting functional feed, which can enhance the growth of animals, improve their immune system, and promote physiological benefits more than conventional feed, coupled with the ban on the use of antimicrobial growth promoters, has caused a renewed interest in the use of fermented SBM (FSBM) in livestock diets. This review details the mechanism of SBM fermentation and its impacts on animal health and discusses the recent trend in the application and emerging advantages to livestock while shedding light on the research gap that needs to be critically addressed in future studies. FSBM appears to be a multifunctional high-quality plant protein source for animals. Besides removing soybean antinutrients, beneficial bioactive peptides and digestive enzymes are produced during fermentation, providing probiotics, antioxidants, and immunomodulatory effects. Critical aspects regarding FSBM feeding to animals remain uncharted, such as the duration of fermentation, the influence of feeding on digestive tissue development, choice of microbial strain, and possible environmental impact.

Low-intensity ultrasound-assisted adaptive laboratory evolution of Bacillus velezensis for enhanced production of peptides

This work aimed to explore low-intensity ultrasound-assisted adaptive laboratory evolution (US-ALE) of Bacillus velezensis and fermentation performance of mutant strains were investigated by nitrogen transformation metabolism. Results showed ultrasound accelerated the process of adaptive evolution and enhanced cell dry weight, amylase and protease activity of mutant strains, accompanied with the improved transformation abilities of NO-3-N to NH4+-N. Compared with original strain, the total peptide-N, peptide-N (<3 kDa) and autolytic peptide-N of mutant strains increased by the maximum 23.17%, 66.07% and 30.30%, respectively, based on ideal fermentation medium. According to the actual liquid-state fermentation of soybean meal and corn gluten meal with mutant strains, the highest peptide yields of 50.63% and 23.67% were noticed in mutant strain US-ALE-BV3, accompanied with the improved amino acid composition by bacterial autolysis technology. Thus, this study showed that low-intensity ultrasound could accelerate the process of adaptive evolution and US-ALE will provide more possibilities for modifying fermentation strains.

Study on the antioxidant activity of peptides from soybean meal by fermentation based on the chemical method and AAPH-induced oxidative stress

Preparation and antioxidant activities of soybean peptides using solid fermentation to decrease the content of trypsin inhibitor (TI) and antigen protein were investigated in this study. The results showed the optimal fermentation conditions were as follows: fermentation time 48 h, the ratio of material to solvent 1:2, inoculum size 12%, and the ratio of Lactic acid bacteria and Aspergillus oryzae 2:1. The hydrolysate was were divided into four components of <1, 1-3, 3-5, and >5 kDa by ultrafiltration based on molecular weight, and the <1 kDa peptides expressed the highest antioxidant activities. Meanwhile, the cell antioxidant activity of the <1 kDa soybean peptides was investigated using AAPH-induced erythrocyte hemolysis, which effectively inhibited erythrocyte hemolysis with the inhibit rate of 85.8% through inhibition of the ROS intracellular generation. In addition, soybean peptides could significantly restore the intracellular antioxidant enzymes (SOD, GSH-Px, and CAT) activities, as well as inhibited intracellular MDA generation and depletion of GSH. The intracellular antioxidant detoxifying mechanism of soybean peptides was associated with both non-enzymatic and enzymatic defense systems. According to this study, fermentation could effectively improve the antioxidant activities of soybean peptides.

Aquafeed fermentation improves dietary nutritional quality and benefits feeding behavior, meat flavor, and intestinal microbiota of Chinese mitten crab (Eriocheir sinensis)

Normally, proper fermentation can be an efficient and widely used method to improve feed quality in animal rearing; however, the studies on crustaceans, especially Eriocheir sinensis, remain limited. This study aimed to investigate whether feed fermentation could meliorate dietary nutritional value and benefit E. sinensis rearing. First, non-fermented feed (NFD) and fermented feed (FD) were produced and assessed, respectively. Then, the "Y" maze feed choice behavior test (180 times; 30 times, 6 rounds) was conducted to assess the attractiveness of these 2 feeds for crabs. Finally, a total of 80 crabs (44.10 ± 0.80 g) were randomly assigned into 2 groups with 4 replicates, and fed the experimental diets for 8 weeks to evaluate the effects of each feed on growth, antioxidant capacity, meat flavor, and intestinal microbiota. In this study, FD showed higher levels of crude protein (P < 0.01), soluble protein (P < 0.01), amino acids (P < 0.05), lactic acid (P < 0.001), and lower levels of crude fiber (P < 0.05) and antinutritional factors (agglutinin, trypsin inhibitor, glycinin, and β-conglycinin) (P < 0.001) than NFD. Additionally, FD was more attractive to crabs than NFD (P < 0.01) and it stimulated the appetite of crabs more than NFD (P < 0.05). The growth performance, feed efficiency, and digestive enzyme activity of FD-fed crabs were significantly higher than those of NFD-fed crabs (P < 0.05). The electronic sensory measurements and free amino acid profiles revealed that the FD diet had positive impacts on the meat flavor of crabs, particularly in "sweet" and "umami" tastes. Moreover, the antioxidant capacity of FD-fed crabs was significantly higher than that of NFD-fed crabs (P < 0.05). Fermented feed also affected the diversity and composition of intestinal microflora. The functional prediction of microbial communities showed that crabs fed FD had a better microecological environment in the intestine. In conclusion, the fermentation of aquafeed could be an effective approach to enhance feed quality and therefore benefit E. sinensis rearing.

Modeling and in-vivo evaluation of fibrinolytic enzyme produced by Bacillus subtilis Egy under solid state fermentation

Blood clot formation increases cases of myocardial infarction (AMI) and stroke, thus urges directing much research works for treatment and prevention of the causes. One of these directions is the microbial production of fibrinolytic enzymes as thrombolytic agents. In the current work, Bacillus subtilis Egy has been used for enzyme production under solid state fermentation. Among twelve nutrient meals in addition to wheat bran as a control fodder yeast yielded the highest enzyme activity reaching 114U/g. Applying statistical model for optimization of enzyme production revealed that 3.6%, fodder yeast; 40%, moisture content; 6 days, incubation period and 2%, inoculum size were the optimum conditions for maximum fibrinolytic enzyme production (141.02 U/g) by Bacillus subtilis Egy under solid-state fermentation The model was significant and data were experimentally validated. The produced fibrinolytic enzyme was evaluated for in vitro and in vivo cytotoxicity. In-vivo examination of the enzyme resulted in no mortality during the first 24 h after treatment. After 14 days, the results revealed no significant changes detected in hematological parameters (RBCs, MCV, hemoglobin except WBCs which showed an increase for both sexes. Histopathological examination of liver and kidney of rats received oral and subcutaneous treatments showed normal architecture. The data showed the applicability of the produced enzyme for the treatment of blood clot with no significant effect on living cells or on physiological functions.

Valorization of agro-industrial wastes into animal feed through microbial fermentation: A review of the global and Ghanaian case

Agricultural and industrial activities around the world lead to the production of large quantities of agro-industrial wastes (e.g., peels of cassava, pineapple, plantain, banana, and yam, as well as rice husks, rice bran , corn husks, corn cobs, palm kernel cake, soybean meal, wheat bran, etc.). These agro-industrial wastes are discarded indiscriminately, thereby polluting the environment and becoming hazardous to human and animal health. Solid-state fermentation (SSF), a microbial fermentation process, is a viable, efficient approach that transforms discarded agro-industrial wastes into a plethora of useful value-added bioproducts. There is growing interest in the application of SSF in valorizing agro-industrial wastes for the production of fermented, protein-rich animal feed within the livestock industry. SSF reduces anti-nutritional factors whose presence hinders the digestibility and bioavailability of nutrients in agro-industrial wastes. Thus, the application of SSF improves the nutrient contents and quality of valorized agro-industrial wastes as animal feed. Fermented animal feed production may be safer, cheaper and enhance the overall growth performance and health of animals. SSF, therefore, as a strategic approach in a circular bioeconomy, presents economic and practical advantages that guarantee efficient recycling and valorization of agro-industrial wastes that ameliorate environmental pollution. This paper reviews the status of global and local Ghanaian biotransformation and valorization of agro-industrial wastes through SSF for the production of nutrient-rich animal feed.

High and Economical Nattokinase Production with Acetoin as a Useful Byproduct from Soybean Milk and Glucose

Nattokinase (NK) is a potent fibrinolytic enzyme with wide pharmaceutical and nutraceutical applications. Safe and high NK-yielding strains are urgently needed. In this study, the best strain NDF was isolated from one of the 11 natto samples and then identified as Bacillus subtilis. The effects of carbon and nitrogen sources on NK production were investigated, and glucose and soybean milk were finally selected as the optimal carbon and nitrogen sources, respectively. Acetoin, a valuable compound with versatile usages, was detected as the main byproduct of carbon overflow. In a 6-L fermenter, NK and acetoin reached their peak concentrations simultaneously (10,220 IU/mL and 25.9 g/L, respectively) at 25 h in a culture medium containing 180 g/L of soybean milk and 105 g/L of glucose. The NK product was verified by sequencing of the aprN gene and SDS-PAGE analysis. Only very limited kinds of proteins were found in the supernatant of the fermentation broth, and NK was one of the main bands. This study has developed an economical and high NK production method with acetoin as a useful byproduct.

Effects of a new fermented soya bean meal on growth performance, serum biochemistry profile, intestinal immune status and digestive enzyme activities in piglets

BACKGROUND

Fermented soya bean meal (FSBM) is believed to have improved nutritional qualities compared with soya bean meal (SBM) and is also cheaper than soya protein concentration (SPC) and fish meal (FM). Therefore, the present study was conducted to compare the effects of FSBM replacing SBM, SPC and FM in diets on growth performance, serum biochemistry profile, short-chain fatty acid concentrations in digesta, intestinal mucosal enzyme activities, intestinal proinflammatory cytokine concentrations and morphology in weaned piglets. One hundred and twenty 28-day-old piglets (Duroc × Landrace × Yorkshire, body weight: 6.73 ± 1.14 kg) were randomly allocated to four treatment diets (six replicate pens with five piglets per pen) containing SBM, SPC, FM or FSBM as the protein source, respectively.

RESULTS

Dietary FSBM supplementation improved average daily gain (p < 0.05), gain to feed ratio (p < 0.05), and digestibility of dry matter, gross energy, crude protein and organic matter (p < 0.05) in pigs compared with those fed SBM during 0-14 days and reduced diarrhoea rate (p < 0.05) compared with those fed SBM and FM during 0-14 days. Moreover, pigs fed FBSM had greater IgA and IgM contents and antioxidase activities than those provided SBM and SPC on day 14. In addition, the butyrate concentration in the cecum of pigs fed FSBM was greater than those fed the other diets (p < 0.05), and the trypsin activity in duodenum and jejunum of pigs provided FSBM was greater than those fed SBM (p < 0.05). Moreover, higher villus height (p < 0.05) and villus height to crypt depth ratio (p < 0.05) and lower crypt depth (p < 0.05) in the duodenum of pigs fed FSBM were observed, and pigs fed FSBM had a lower (p < 0.05) TNF-α concentration in jejunum compared with those fed SBM.

CONCLUSIONS

In conclusion, dietary FSBM supplementation to replace SBM, SPC and FM could improve piglets' growth performance, intestinal health and immune function.

Role of Fibrinolytic Enzymes in Anti-Thrombosis Therapy

Thrombosis, a major cause of deaths in this modern era responsible for 31% of all global deaths reported by WHO in 2017, is due to the aggregation of fibrin in blood vessels which leads to myocardial infarction or other cardiovascular diseases (CVDs). Classical agents such as anti-platelet, anti-coagulant drugs or other enzymes used for thrombosis treatment at present could leads to unwanted side effects including bleeding complication, hemorrhage and allergy. Furthermore, their high cost is a burden for patients, especially for those from low and middle-income countries. Hence, there is an urgent need to develop novel and low-cost drugs for thrombosis treatment. Fibrinolytic enzymes, including plasmin like proteins such as proteases, nattokinase, and lumbrokinase, as well as plasminogen activators such as urokinase plasminogen activator, and tissue-type plasminogen activator, could eliminate thrombi with high efficacy rate and do not have significant drawbacks by directly degrading the fibrin. Furthermore, they could be produced with high-yield and in a cost-effective manner from microorganisms as well as other sources. Hence, they have been considered as potential compounds for thrombosis therapy. Herein, we will discuss about natural mechanism of fibrinolysis and thrombus formation, the production of fibrinolytic enzymes from different sources and their application as drugs for thrombosis therapy.

Analysis in protein profile, antioxidant activity and structure-activity relationship based on ultrasound-assisted liquid-state fermentation of soybean meal with Bacillus subtilis

This study investigated effects of ultrasound on the contents of peptide and soluble protein, antioxidant activity, functionalities and structural characteristics of fermented soybean meal (FSBM) with Bacillus subtilis systematically. The results showed that there were significant effects of ultrasound treatments (frequency, treatment time and power density) on the contents of peptide and soluble protein (p < 0.05). Under the optimum ultrasound conditions (power density of 0.08 W/mL, frequency of 33 kHz and treatment time of 1 h) by single factor experiment, the contents of peptide and soluble protein increased by 31.27% and 18.79% compared to those of the control, respectively. Additionally, the in vitro antioxidant activity (•OH scavenging rate, Fe2+ chelating capacity and DPPH radical scavenging rate) and functional properties (emulsifying activity and emulsifying stability) of FSBM were found to be noticeably improved by ultrasound (p < 0.05). The fourier transform infrared (FTIR) spectroscopy revealed that ultrasound caused protein molecules to unfold with a decrease content of α-helix and β-turn and an increase in the proportion of β-sheet and random coil. Besides, atomic force microscope (AFM) results indicated that ultrasonication generally increased the surface roughness of protein and the protein sonicated with higher frequency (≥33 kHz) exhibited a greater height compared to lower frequency ultrasonication. Structure-activity relationship analysis illustrated that there was a good linear relationship between •OH scavenging rate and β-sheet/β-turn with Pearson's correlation coefficient r of -0.86/0.90. Collectively, the selection of ultrasonic parameters is essential for the preparation of functional protein and bioactive peptide by enhancing fermentation of agroindustrial by-products.

Partial Substitution of Fermented Soybean Meal for Soybean Meal Influences the Carcass Traits and Meat Quality of Broiler Chickens

Simple Summary

Fungal and bacterial fermentation improves the nutritional quality of soybean meal (SBM). The beneficial effects of fermented soybean meal (FSBM) on growth performance and gut health of broiler chickens have been demonstrated. However, FSBM is usually used in pre-starter diets of broiler chickens due to the high cost. In the present study, the SBM in diets was partially replaced by FSBM to evaluate its effect on the growth performance, carcass traits, and meat quality of broiler chickens. The growth performance and major carcass traits were not significantly affected by FSBM treatments. Different levels (2.5%, 5.0%, and 7.5%) of FSBM supplementation influenced the meat color, pH, nutritional composition, and antioxidant properties. The improvement of meat quality would extend the shelf life of meat and increase consumer acceptability to chicken. The 2.5% FSBM was recommended in a broiler diet.

Abstract

The usage of fermented soybean meal (FSBM) in poultry feed is limited due to the high cost. The present study was conducted to examine the carcass traits and meat quality of broiler chickens that were fed diets with partial replacement of soybean meal (SBM) with FSBM. The 336 one-day-old chicks were assigned to four groups with 0% (control), 2.5%, 5.0%, and 7.5% FSBM addition in corn-SBM-based diets. Compared with the control, 2.5% and 5.0% FSBM decreased leg muscle yield, breast drip loss, and cooking loss (p < 0.05). The 7.5% FSBM increased the ultimate pH of breast and thigh muscles, and all FSBM treatments decreased muscle lightness and breast malondialdehyde content (p < 0.05). The 2.5% FSBM increased breast total superoxide dismutase activity, while 7.5% FSBM reduced breast hydrogen peroxide level (p < 0.05). All FSBM treatments elevated breast contents of bitter and sour tasting amino acids, and 2.5% and 7.5% FSBM increased breast glutamic acid and total free amino acids (p < 0.05). The 5.0% and 7.5% FSBM elevated thigh isoleucine and leucine contents (p < 0.05). In conclusion, FSBM replacing SBM affected meat quality with the decrease of lightness and increase of pH, water-holding capacity, antioxidant properties, and free amino acids.

Degradation of major allergens and allergenicity reduction of soybean meal through solid-state fermentation with microorganisms

In this study, we determined whether solid-state fermentation could degrade major allergens and reduce potential allergenicity of soybean meal (SBM). Solid-state fermentation was realized through a mixture of Lactobacillus casei, yeast, and Bacillus subtilis. High-performance liquid chromatography, size exclusion-high-performance liquid chromatography, and capillary liquid chromatography/tandem mass spectrometry coupled with electrospray ionization were used to examine the total amino acids and molecular weight distribution of the fermented soybean meal (FSBM). In addition, the potential allergenicity of FSBM was assessed by conducting in vitro competitive inhibition ELISA and oral sensitization and challenge of a BALB/c mice model. The results indicated that the total amino acid content increased and soy protein was degraded into polypeptides with low molecular weights that were derived from the hydrolysis of the allergen sequences N232-D383, G253-I265, E169-S215, G68-G98, A365-I375, and V153-A167. Moreover, the FSBM group exhibited a lower in vitro immunoglobulin E (IgE)-binding capacity than the SBM group. The BALB/c model indicated that the FSBM group manifested milder damage to the intestine, lower mMCP-1 and IgE levels, and higher IFN-γ levels as compared to the SBM group. These findings suggested that the potential allergenicity of SBM was reduced by the solid-state fermentation induced by the mixture of Lactobacillus casei, yeast, and Bacillus subtilis.

Effects of Bacillus fermentation on the protein microstructure and anti-nutritional factors of soybean meal

This study evaluated the effects of Bacillus fermentation on soybean meal protein (SBMP) microstructure and major anti-nutritional factors (ANFs) in soybean meal (SBM). The Bacillus siamensis isolate JL8 producing high yield of protease at 519·1 U g-1 was selected for the laboratory production of fermented soybean meal (FSBM). After 24 h fermentation, the FSBM showed better properties compared with those of SBM, the ANFs such as glycinin, β-conglycinin and trypsin inhibitor significantly decreased by 86·0, 70·3 and 95·01%, while in vitro digestibility and absorbability increased by 8·7 and 18·9% respectively. Scanning electron microscopy (SEM) image of fermented soybean meal protein showed smaller aggregates and looser network than that of SBMP. Secondary structure examination of proteins revealed fermentation significantly decreased the content of β-sheet structure by 43·2% and increased the random coil structure by 59·9%. It is demonstrated that Bacillus fermentation improved the nutritional quality of SBM through degrading ANFs and changing the microstructure of SBMP.

SIGNIFICANCE AND IMPACT OF THE STUDY

There is limited information about the structural property changes of soybean protein during fermentation. In this study, physicochemical analysis of soybean meal protein showed evidence that the increase in in vitro digestibility and absorbability of fermented soybean meal reflected the decrease in β-conformation and destruction of original structure in soybean meal protein. The results directly gained the understanding of nutritional quality improvement of soybean meal by Bacillus fermentation, and supply the potential use of Bacillus siamensis for fermented soybean meal production.