Effect of extrusion on the structure and antigenicity of soybean β-conglycinin

β-Conglycinin,the main component of 7S globulin in soybean protein,is also a key soybean antigen protein that causes allergic reactions.Extrusion technologies have received considerable attention as amethod for modifying soybean protein allergens.This study investigated the changes inβ-conglycinin structure and antigenicity upon extrusion.Isoelectric precipitation,ammoniumsulfate precipitation,and sepharose CL-6B gel filtration were used to isolate and purifyβ-conglycinin from soybean powder,and single-factor and orthogonal tests were used to study the effects of water content,extrusion temperature,screw rotation speed,and feeding speed on the antigenicity ofβ-conglycinin after extrusion.Fourier transforminfrared spectrometry(FTIR)was then employed to analyze the structure ofβ-conglycinin after extrusion under the optimal conditions determined by the orthogonal test.The results showed that extrusion significantly reduced the antigenicity ofβ-conglycinin(P<0.05),and the degree of influence of the factors studied may be ordered as extrusion temperature>feeding speed>screw rotation speed>water content.The optimal parameters were temperature at 130°C,screwrotation speed at 140 r/min,and feeding speed at 35 g/min.Under these conditions,the contents ofα-helix,β-pleated sheet,andβ-turn structures inβ-conglycinin were significantly reduced(P<0.05),while the contents of random coils were significantly increased(P<0.05).The peak absorption intensity of amides I,II,and III also decreased.Taken together,the findings suggest that extrusion could be an effective method for reducing the antigenicity ofβ-conglycinin.

Study on enzymatic hydrolysis of soybean β-conglycinin using alkaline protease from Bacillus subtilis ACCC 01746 and antigenicity of its hydrolysates

Due to its beneficial health effects,the use of soybean protein has shown a continuous increase,but concerns regarding the allergenicity of soybean antigenic protein have also increased.This study aimed to evaluate the hydrolytic effects of a non-commercial alkaline protease isolated from the Bacillus subtilis ACCC 01746 on soybeanβ-conglycinin and the allergenicity of its hydrolysates.Alkaline protease of the strain was separated by precipitation method of organic solvents,and theβ-conglycinin was separated by alkali-solution and acid-isolation and purified by use of gel column.Using the degree of hydrolysis(DH)and inhibition rate as evaluation indexes,the enzymatic hydrolysis parameters ofβ-conglycinin was optimized by single factor and L_(9)(3^(4))orthogonal tests,so as to explore the effect of the protease on the hydrolysis degree and the antigenicity ofβ-conglycinin hydrolysates.The results showed that the native enzyme existed as an 18.3 kDa monomer with a 430 U/g maximum activity.The purity ofβ-conglycinin was 84.8%.The single-factor test results showed that DH showed the oppostie trendency with the inhibition rate,and the increase of protein concentration causedmonotone increasing and monotone decreasing of the inhibition rate and the DH,and the optimal protein concentration was 30 mg/mL.The optimization results showed that pH had the largest impacts on both DH and the inhibition rate,followed by enzyme dosage,hydrolysis temperature and hydrolysis time.Under the optimum hydrolysis conditions of protein concentration 30mg/mL,enzymedosage0.7%,hydrolysis time40min,temperature 55°C and pH8.5,the DH reached the highest of 76.28%,and the inhibition rate was the lowest of 27.03%,which was reduced greatly compared with that before optimization.These results suggested that alkaline protease appeared to show a relatively high effeciency in lowering soybean allergenicity,making it possible to produce low-allergenicity soybean protein.

An innovative method used for the identification of N-glycans on soybean allergenβ-conglycinins

β-Conglycinin is one of the major allergens existed in soybean.N-Glycans attached to theβ-conglycinin influenced the immunoreactivity and antigen presenting efficiency ofβ-conglycinin.In this study,we described a new method used to release and collect the N-glycans fromβ-conglycinin,and the N-glycans existed in linear epitopes ofβ-conglycinin were identified.Glycopeptides hydrolyzed fromβ-conglycinin were purified by cotton hydrophilic chromatography.Trifluoromethylsulfonic acid was then used to release glycans from glycopeptides,and new glycopeptides containing one single N-acety1-D-glucosamine(G1 cNAc)moiety were then utilized for mass spectrometry.Five glycosylation sites(Asn-199,Asn-455,Asn-215,Asn-489 and Asn-326)and 22 kinds of glycopeptides were identified.It is noteworthy that the peptide VVN^(#)ATSNL(where^(#)represents for the glycosylation site)was analyzed to be both glycopeptide and linear epitope.Our results provided a new method for the N-glycoform analysis of food allergens,and laid a foundation for understanding the relationship between glyco sylation and food allergy.

Identification of lncRNAs Associated withβ-conglycininα-null Allele Based on a Genome-wide Transcriptome Analysis ofα-null-type Hypoallergenic Soybean(Glycine max)Near-isogenic Lines

Soybean mutants withα-nullβ-conglycinin are associated with high nutritional value and low allergenic risk.Although long noncoding RNAs(lncRNAs)are increasingly recognized as functional regulatory components affecting eukaryotic gene expression,little is known about lnc RNA profiles inα-null-type hypoallergenic soybeans.In this study,a genome-wide integrative analysis of lncRNAs,m RNAs and epigenomic data in the soybean cgy-2(confirmedα-null)near-isogenic line(NIL)and its recurrent parent Dongnong47(DN47)was conducted.Nineteen novel lncRNAs that were differentially expressed(DE)only in the NIL at 18 days after flowering(i.e.,α-null-associated DE lncRNAs)were delected.Sixteen putative soybean stress-responsive lncRNAs were identified,and observed to regulate 257 stress-related genes DE in the NIL.This result indicated that theα-null allele might represent an intrinsic defect stress that altered the expression of various stress-related genes inα-null-type hypoallergenic soybean.Additionally,25 epigenetic-related lncRNAs regulated 831 DE epigenetic-related genes and simultaneously initiated multiple epigenetic activities,including ubiquitination,methylation and acetylation.Kyoto encyclopedia of genes and genomes(KEGG)analysis indicated that the biosynthesis of amino acids pathway was enriched with 83 DE genes regulated by nine DE lncRNAs.Changes in the expression of these lncRNAs and genes might be the reason for the altered amino acid composition in the NIL.Among all detected DE lncRNAs,MSTRG.12518 was the most conspicuousα-null-specific cis/trans-lnc RNA that played an efficient,versatile and vital role in the NIL.The data indicated that the lnc RNA profile differed between the NIL and DN47.Variations in lncRNAs,gene expression levels and DNA methylation states likely contributed to the intrinsic defect stress response mechanism inα-null-type hypoallergenic soybeans.

GmSTF accumulation mediated by DELLA protein GmRGAs contributes to coordinating light and gibberellin signaling to reduce plant height in soybean

Plant height influences plant architecture,lodging resistance,and yield performance.It is modulated by gibberellic acid(GA)metabolism and signaling.DELLA proteins,acting as central repressors of GA signaling,integrate various environmental and hormonal signals to regulate plant growth and development in Arabidopsis.We examined the role of two DELLA proteins,GmRGAa and GmRGAb,in soybean plant height control.Knockout of these proteins led to longer internodes and increased plant height,primarily by increasing cell elongation.GmRGAs functioned under different light conditions,including red,blue,and far-red light,to repress plant height.Interaction studies revealed that GmRGAs interacted with the blue light receptor GmCRY1b.Consistent with this,GmCRY1b partially regulated plant height via GmRGAs.Additionally,DELLA proteins were found to stabilize the protein GmSTF1/2,a key positive regulator of photomorphogenesis.This stabilization led to increased transcription of GmGA2ox-7b and subsequent reduction in plant height.This study enhances our understanding of DELLA-mediated plant height control,offering Gmrgaab mutants for soybean structure and yield optimization.

Effect of lipid peroxidation on the allergenicity and functional properties of soybeanβ-conglycinin(7S)and glycinin(11S)

This study aimed to analyze the effect of lipid peroxidation on the allergenicity and functional properties of soybeanβ-conglycinin(7 S)and glycinin(11 S).Oxidation complexes were determined using the lipid peroxidation method.Functional properties were analyzed based on emulsifying and foaming properties.The potential allergenicity was evaluated by in vitro and in vivo methods.The results found that oxidation altered structures of the proteins and resulted in the formation of cross-linked protein polymers.The emulsion and foaming properties of the proteins were improved after oxidation.The IgE-binding capacity of 7 S and11 S reduced after oxidation.KU812 cell assays showed that both histamine and IL-4 release decreased after oxidation treatment.A mouse model showed that oxidation reduced the IgE,IgG,and IgG1 levels,as well as reduced histamine and mMCP-1 release in serum,which might suppress the allergic reaction.In conclusion,the lipid peroxidation treatment likely causes changes to the functional properties of soybean,decreasing the potential allergenicity of 7 S and 11 S.

Identification and fine mapping of qSW2 for leaf slow wilting in soybean

Drought is one of the abiotic stresses limiting the production of soybean(Glycine max).Elucidation of the genetic and molecular basis of the slow-wilting(SW)trait of this crop offers the prospect of its genetic improvement.A panel of 188 accessions and a set of recombinant inbred lines produced from a cross between cultivars Liaodou 14 and Liaodou 21 were used to identify quantitative-trait loci(QTL)associated with SW.Plants were genotyped by Specific-locus amplified fragment sequencing and seedling leaf wilting was assessed under three water-stress treatments.A genome-wide association study identified 26 SW-associated single-nucleotide polymorphisms(SNPs),including three located in a 248-kb linkage-disequilibrium(LD)block on chromosome 2.Linkage mapping revealed a major-effect QTL,qSW2,associated with all three treatments and adjacent to the LD block.Fine mapping in a BC_(2)F_(3) population derived from a backcross between Liaodou 21 and R26 confined qSW2 to a 60-kb interval.Gene expression and sequence variation analysis identified the gene Glyma.02 g218100,encoding an auxin transcription factor,as a candidate gene for qSW2.Our results will contribute significantly to improving drought-resistant soybean cultivars by providing genetic information and resources.

Emulsifying property,antioxidant activity,and bitterness of soybean protein isolate hydrolysate obtained by Corolase PP under high hydrostatic pressure

Enzymatic hydrolysis of proteins can enhance their emulsifying properties and antioxidant activities.However,the problem related to the hydrolysis of proteins was the generation of the bitter taste.Recently,high hydrostatic pressure(HHP)treatment has attracted much interest and has been used in several studies on protein modification.Hence,the study aimed to investigate the effects of enzymatic hydrolysis by Corolase PP under different pressure treatments(0.1,100,200,and 300 MPa for 1-5 h at 50℃)on the emulsifying property,antioxidant activity,and bitterness of soybean protein isolate hydrolysate(SPIH).As observed,the hydrolysate obtained at 200 MPa for 4 h had the highest emulsifying activity index(47.49 m^(2)/g)and emulsifying stability index(92.98%),and it had higher antioxidant activities(44.77%DPPH free radical scavenging activity,31.12%superoxide anion radical scavenging activity,and 61.50%copper ion chelating activity).At the same time,the enhancement of emulsion stability was related to the increase of zeta potential and the decrease of mean particle size.In addition,the hydrolysate obtained at 200 MPa for 4 h had a lower bitterness value and showed better palatability.This study has a broad application prospect in developing food ingredients and healthy foods.

CRISPR/CasRx-mediated resistance to Soybean mosaic virus in soybean

Soybean mosaic virus(SMV),an RNA virus,is the most common and destructive pathogenic virus in soybean fields.The newly developed CRISPR/Cas immune system has provided a novel strategy for improving plant resistance to viruses;hence,this study aimed to engineer SMV resistance in soybean using this system.Specifically,multiple sgRNAs were designed to target positive-and/or negative-sense strands of the SMV HC-Pro gene.Subsequently,the corresponding CRISPR/CasRx vectors were constructed and transformed into soybeans.After inoculation with SMV,39.02%,35.77%,and 18.70%of T_(1)plants were confirmed to be highly resistant(HR),resistant(R),and mildly resistant(MR)to SMV,respectively,whereas only 6.50%were identified as susceptible(S).Additionally,qRT-PCR and DAS-ELISA showed that,both at 15 and 30 d post-inoculation(dpi),SMV accumulation significantly decreased or was even undetectable in HR and R plants,followed by MR and S plants.Additionally,the expression level of the CasRx gene varied in almost all T_(1)plants with different resistance level,both at 15 and 30 dpi.Furthermore,when SMV resistance was evaluated in the T_(2)generation,the results were similar to those recorded for the T_(1)generation.These findings provide new insights into the application of the CRISPR/CasRx system for soybean improvement and offer a promising alternative strategy for breeding for resistance to biotic stress that will contribute to the development of SMV-immune soybean germplasm to accelerate progress towards greater soybean crop productivity.

Assessing the Efficacy of Wheat-Soybean Based Intercropping System at Different Plant Densities in Bambili, Cameroon

Wheat is one of the most important cereals in the world, serving as a staple for millions globally. In the wake of the geopolitical crisis between Russia and Ukraine, it has become incumbent for many countries to invest in wheat production. Improving cropping systems for wheat production is paramount. Intercropping cereals with legumes has tremendous advantages. Therefore, this study was designed to optimize wheat production by intercropping it with soybean at different densities. Between March and August 2023, a randomized complete block design trial was conducted in Bambili, North West of Cameroon with treatments T1 (wheat monocrop at 200,000 plants ha−1), T2 (soybean monocrop at 250,000 plants ha−1), T3 (200,000 wheat and 125,000 soybean ha−1), T4 (100,000 wheat and 250,000 soybean ha−1), T5 (200,000 wheat and 250,000 soybean ha−1) and T6 (100,000 wheat and 125,000 soybean ha−1). Results revealed that growth parameters of wheat were not significantly influenced by monocrop or intercrop. The yield of wheat was significantly higher in the monocrop than the intercrop treatments, with slight variation amongst the intercrop treatments. Soybean yield was higher in the monocrop than in the intercrop, with no variations amongst the intercrop treatments. Only the land equivalence ratio (LER) for T5 was greater than 1.0. The competitive ratio for T5 was 0.54 for wheat and 1.90 for soybean, comparatively lower than the other monocrop treatments. Intercropping wheat and soybean at 200,000:250,000 ratio is recommended.

Identification of Rhizobia Isolated from Nodules of Mexican Commercial Soybean Varieties

Rhizobia, crucial for nitrogen fixation in leguminous plants, play a vital role in soybean cultivation. This study, conducted in Mexico, a major soybean importer, aimed to identify bacteria from nodules of five soybean varieties in high-production regions. Multilocus sequence analysis (MLSA) was employed for enhanced species resolution. The study identified six Bradyrhizobium species: Bradyrhizobium japonicum USDA 110, Bradyrhizobium japonicum USDA 6, Bradyrhizobium elkanii USDA 76, Bradyrhizobium neotropicale, Bradyrhizobium lablabi, and Bradyrhizobium icense. Bradyrhizobium japonicum USDA 110 predominated in the soils, displaying symbiotic preference for the Huasteca 400 variety. However, phylogenetic analysis didn't reveal a clear association between strains, soil, and soybean variety. This research sheds light on the diversity of rhizobia in Mexican soybean cultivation, contributing to the understanding of symbiotic relationships in soybean production systems.

Mapping and identification of QTLs for seed fatty acids in soybean(Glycine max L.)

Soybean is one of the most important sources of vegetable oil.The oil content and fatty acid ratio have attracted significant attention due to their impacts on the shelf-life of soybean oil products and consumer health.In this study,a high-density genetic map derived from Guizao 1 and Brazil 13 was used to analyze the quantitative trait loci of palmitic acid(PA),stearic acid(SA),oleic acid(OA),linoleic acid(LA),linolenic acid(LNA),and oil content(OC).A total of 54 stable QTLs were detected in the genetic map linkage analysis,which shared six bin intervals.Among them,the bin interval on chromosome 13(bin106-bin118 and bin123-bin125)was found to include stable QTLs in multiple environments that were linked to OA,LA,and LNA.Eight differentially expressed genes(DEGs)within these QTL intervals were determined as candidate genes according to the combination of parental resequencing,bioinformatics and RNA sequencing data.All these results are conducive to breeding soybean with the ideal fatty acid ratio for food,and provide the genetic basis for mining genes related to the fatty acid and oil content traits in soybean.

J-family genes redundantly regulate flowering time and increase yield in soybean

Soybean(Glycine max)is a short-day crop whose flowering time is regulated by photoperiod.The longjuvenile trait extends its vegetative phase and increases yield under short-day conditions.Natural variation in J,the major locus controlling this trait,modulates flowering time.We report that the three J-family genes influence soybean flowering time,with the triple mutant Guangzhou Mammoth-2 flowering late under short days by inhibiting transcription of E1-family genes.J-family genes offer promising allelic combinations for breeding.

Soybean maize strip intercropping:A solution for maintaining food security in China

The practice of intercropping leguminous and gramineous crops is used for promoting sustainable agriculture,optimizing resource utilization,enhancing biodiversity,and reducing reliance on petroleum products.However,promoting conventional intercropping strategies in modern agriculture can prove challenging.The innovative technology of soybean maize strip intercropping(SMSI)has been proposed as a solution.This system has produced remarkable results in improving domestic soybean and maize production for both food security and sustainable agriculture.In this article,we provide an overview of SMSI and explain how it differs from traditional intercropping.We also discuss the core principles that foster higher yields and the prospects for its future development.

Drought-triggered repression of miR166 promotes drought tolerance in soybean

Drought stress limits agricultural productivity worldwide.Identifying and characterizing genetic components of drought stress-tolerance networks may improve crop resistance to drought stress.We show that the regulatory module formed by miR166 and its target gene,ATHB14-LIKE,functions in the regulation of drought tolerance in soybean(Glycine max).Drought stress represses the accumulation of miR166,leading to upregulation of its target genes.Optimal knockdown of miR166 in the stable transgenic line GmSTTM166 conferred drought tolerance without affecting yield.Expression of ABA signaling pathway genes was regulated by the miR166-mediated regulatory pathway,and ATHB14-LIKE directly activates some of these genes.There is a feedback regulation between ATHB14-LIKE and MIR166 genes,and ATHB14-LIKE inhibits MIR166 expression.These findings reveal that drought-triggered regulation of the miR166-mediated regulatory pathway increases plants drought resistance,providing new insights into drought stress regulatory network in soybean.

Application of organic manure as a potential strategy to alleviate the limitation of microbial resources in soybean rhizospheric and bulk soils

The development and vigor of soil microorganisms in terrestrial ecosystems are frequently constrained by the limited availability of essential elements such as carbon(C),nitrogen(N),and phosphorus(P).In this study,we investigated the impact of long-term application of varying levels of organic manure,low(7.5 Mg ha^(−1)yr^(−1)),moderate(15.0 Mg ha^(−1)yr^(−1)),and high(22.5 Mg ha^(−1)yr^(−1)),on the stoichiometry of enzymes and the structures of the microbial communities in soybean rhizospheric and bulk soils.The main goal of this research was to examine how soil microbial resource limitations in the rhizosphere respond to different long-term fertilization strategies.The soil enzymatic activities were quantified,and the structure of the microbial community was assessed by analyzing phospholipid fatty acid profiles.When compared to the bulk soil,the rhizospheric soil had significant increases in microbial biomass carbon(MBC),nitrogen(MBN),and phosphorus(MBP),with MBC increasing by 54.19 to 72.86%,MBN by 47.30 to 48.17%,and MBP by 17.37 to 208.47%.Compared with the unfertilized control(CK),the total microbial biomasses of the rhizospheric(increased by 22.80 to 90.82%)and bulk soils(increased by 10.57 to 60.54%)both exhibited increases with the application of organic manure,and the rhizospheric biomass was higher than that of bulk soil.Compared with bulk soil,the activities of C-,N-and P-acquiring enzymes of rhizospheric soil increased by 22.49,14.88,and 29.45%under high levels of organic manure,respectively.Analyses of vector length,vector angle,and scatter plots revealed that both rhizospheric and bulk soils exhibited limitations in terms of both carbon(C)and phosphorus(P)availability.The results of partial least-squares path modelling indicated that the rhizospheric soil exhibited a more pronounced response to the rate of manure application than the bulk soil.The varying reactions of rhizospheric and bulk soils to the extended application of organic manure underscore the crucial function of the rhizosphere in mitigating limitations related to microbial resources,particularly in the context of different organic manure application rates.

Wild soybean(Glycine soja)transcription factor GsWRKY40 plays positive roles in plant salt tolerance

Wild soybean(Glycine soja),a relative of cultivated soybean,shows high adaptability to adverse environmental conditions.We identified and characterized a wild soybean transcription factor gene,GsWRKY40,that promotes plant salt stress.GsWRKY40 was highly expressed in wild soybean roots and was up-regulated by salt treatment.GsWRKY40 was localized in nucleus and demonstrated DNA-binding activities but without transcriptional activation.Mutation and overexpression of GsWRKY40 altered salt tolerance of Arabidopsis plants.To understand the molecular mechanism of GsWRKY40 in regulating plant salt resistance,we screened a cDNA library and identified a GsWRKY40 interacting protein GsbHLH92 by using yeast two-hybrid approach.The physical interaction of GsWRKY40 and GsbHLH92 was confirmed by co-immunoprecipitation(co-IP),GST pull-down,and bimolecular fluorescence complementation(BiFC)techniques.Intriguingly,co-overexpression of GsWRKY40 and GsbHLH92 resulted in higher salt tolerance and lower ROS levels than overexpression of GsWRKY40 or GsbHLH92 in composite soybean plants,suggesting that GsWRKY40 and GsbHLH92 may synergistically regulate plant salt resistance through inhibiting ROS production.qRT-PCR data indicated that the expression level of GmSPOD1 gene encoding peroxidase was cooperatively regulated by GsWRKY40 and GsbHLH92,which was confirmed by using a dual luciferase report system and yeast one-hybrid experiment.Our study reveals a pathway that GsWRKY40 and GsbHLH92 collaboratively up-regulate plant salt resistance through impeding GmSPOD1 expression and reducing ROS levels,providing a novel perspective on the regulatory mechanisms underlying plant tolerance to abiotic stresses.

A telomere-to-telomere genome assembly of Zhonghuang 13,a widely-grown soybean variety from the original center of Glycine max

Soybean(Glycine max)stands as a globally significant agricultural crop,and the comprehensive assembly of its genome is of paramount importance for unraveling its biological characteristics and evolutionary history.Nevertheless,previous soybean genome assemblies have harbored gaps and incompleteness,which have constrained in-depth investigations into soybean.Here,we present Telomere-to-Telomere(T2T)assembly of the Chinese soybean cultivar Zhonghuang 13(ZH13)genome,termed ZH13-T2T,utilizing PacBio Hifi and ONT ultralong reads.We employed a multi-assembler approach,integrating Hifiasm,NextDenovo,and Canu,to minimize biases and enhance assembly accuracy.The assembly spans 1,015,024,879 bp,effectively resolving all 393 gaps that previously plagued the reference genome.Our annotation efforts identified 50,564 high-confidence protein-coding genes,707 of which are novel.ZH13-T2T revealed longer chromosomes,421 not-aligned regions(NARs),112 structure variations(SVs),and a substantial expansion of repetitive element compared to earlier assemblies.Specifically,we identified 25.67 Mb of tandem repeats,an enrichment of 5S and 48S rDNAs,and characterized their genotypic diversity.In summary,we deliver the first complete Chinese soybean cultivar T2T genome.The comprehensive annotation,along with precise centromere and telomere characterization,as well as insights into structural variations,further enhance our understanding of soybean genetics and evolution.

Biomineralization of soil with crude soybean urease using different calcium salts

Calcium salt is an important contributing factor for calcium-based biomineralization.To study the effect of calcium salt on soil biomineralization using crude soybean urease,the calcium salts,including the calcium chloride (CaCl_(2)),calcium acetate ((CH_(3)COO)_(2)Ca) and calcium nitrate (Ca(NO_(3))_(2)),were used to prepare the biotreatment solution to carry out the biomineralization tests in this paper.Two series of biomineralization tests in solution and sand column,respectively,were conducted.Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were performed to determine the microscopic characteristics of the precipitated calcium carbonate (CaCO_(3)) crystals.The experimental results indicate that the biomineralization effect is the best for the CaCl2 case,followed by (CH_(3)COO)_(2)Ca,and worst for Ca(NO_(3))_(2) under the test conditions of this study (i.e.1 mol/L of calcium salt-urea).The mechanism for the effect of the calcium salt on the biomineralization of crude soybean urease mainly involves: (1) inhibition of urease activity,and (2) influence on the crystal size and morphology of CaCO_(3).Besides Ca^(2+) ,the anions in solution can inhibit the activity of crude soybean urease,and NO_(3)− has a stronger inhibitory effect on the urease activity compared with both CH_(3)COO^(−) and Cl^(−) .The co-inhibition of Ca^(2+) and NO_(3)− on the activity of urease is the key reason for the worst biomineralization of the Ca(NO_(3))_(2) case in this study.The difference in biomineralization between the CaCl_(2) and (CH_(3)COO)_(2) Ca cases is strongly correlated with the crystal morphology of the precipitated CaCO_(3).

Standardized ileal digestibility of amino acids in soybean meal fed to non-pregnant and pregnant sows

Background Two studies were designed to determine standard ileal crude protein(CP)and amino acid(AA)digestibility of soybean meal(SBM)from different origins fed to non-pregnant and pregnant sows.Seven solvent-extracted SBMs from soybeans produced in the USA,Brazil,and China were selected.In Exp.1,eight different diets were created:a nitrogen(N)-free diet and 7 experimental diets containing SBM from different origins as the only N source.Eight non-pregnant,multiparous sows were arranged in an 8×8 Latin square design(8 periods and 8 diets).In Exp.2,the diet formula was the same as in Exp.1.Eight gestating sows(parity 3)were assigned to 4 different diets in a replicated 4×3 Youden square design(three periods and four diets)in mid-gestation and again in late-gestation stages.Results When fed to non-pregnant and late-gestating sows,the standardized ileal digestibility(SID)of CP and most AAs from different SBM were not significantly different(P>0.05).When fed to mid-gestating sows,the SID values for Arg,His,Lys,Phe,Cys,Gly,Ser,and Tyr in SBM 1 were lower than in SBM 4 and 5(P<0.05),whereas SID for Leu from SBM 5 was higher than in SBM 1 and 4(P<0.05).SID values for Ile,Ala,and Asp from SBM 4 were lower than in SBM 1 and 5(P<0.05).Sows had significantly greater SID values for Lys,Ala,and Asp during mid-gestation when compared with late-gestation stages(P<0.05).Mid-gestating sows had greater SID value for Val and lower SID value for Tyr when compared with non-pregnant and late-gestating sows(P<0.01),whereas non-pregnant sows had significantly greater SID value for Met when compared with gestating sows(P<0.01).Conclusions When fed to mid-gestating sows,the SID values for most AAs varied among SBM samples.The SID values for Lys,Met,Val,Ala,Asp,and Tyr in SBM were affected by sow gestation stages.Our findings provide a cornerstone for accurate SBM use in sow diets.