Dynamic changes of rumen microbiota and serum metabolome revealed increases in meat quality and growth performances of sheep fed bio‑fermented rice straw

Background Providing high-quality roughage is crucial for improvement of ruminant production because it is an essential component of their feed.Our previous study showed that feeding bio-fermented rice straw(BF)improved the feed intake and weight gain of sheep.However,it remains unclear why feeding BF to sheep increased their feed intake and weight gain.Therefore,the purposes of this research were to investigate how the rumen micro-biota and serum metabolome are dynamically changing after feeding BF,as well as how their changes influence the feed intake,digestibility,nutrient transport,meat quality and growth performances of sheep.Twelve growing Hu sheep were allocated into 3 groups:alfalfa hay fed group(AH:positive control),rice straw fed group(RS:negative control)and BF fed group(BF:treatment).Samples of rumen content,blood,rumen epithelium,muscle,feed offered and refusals were collected for the subsequent analysis.Results Feeding BF changed the microbial community and rumen fermentation,particularly increasing(P<0.05)relative abundance of Prevotella and propionate production,and decreasing(P<0.05)enteric methane yield.The histomorphology(height,width,area and thickness)of rumen papillae and gene expression for carbohydrate trans-port(MCT1),tight junction(claudin-1,claudin-4),and cell proliferation(CDK4,Cyclin A2,Cyclin E1)were improved(P<0.05)in sheep fed BF.Additionally,serum metabolome was also dynamically changed,which led to up-regulating(P<0.05)the primary bile acid biosynthesis and biosynthesis of unsaturated fatty acid in sheep fed BF.As a result,the higher(P<0.05)feed intake,digestibility,growth rate,feed efficiency,meat quality and mono-unsaturated fatty acid concentration in muscle,and the lower(P<0.05)feed cost per kg of live weight were achieved by feeding BF.Conclusions Feeding BF improved the growth performances and meat quality of sheep and reduced their feed cost.Therefore,bio-fermentation of rice straw could be an innovative way for improving ruminant production with mini-mizing production costs.

Common Organic Amendment (Rice Straw) Can Reduce Salinity Effects on Bean (Phaseolus vulgaris) Growth with or without Photoperiod Manipulation

Soil salinity is a major limiting factor for crop production in coastal areas of Bangladesh. Cheap and sustainable management of soil salinity is hence most sought out topics in agricultural research. Conceptualizing that idea in mind, a pot experiment was conducted in the Department of Soil, Water & Environment, University of Dhaka in order to analyze if common organic amendments (rice straw, saw dust) coupled with reduce photoperiod can mitigate salinity effect on the growth of bean (Phaseolus vulgaris). The experiment was set up following completely randomized design (CRD) with nine treatments and three replications containing Tc (Control), T1 (Ambient photoperiod + 110 mM Salinity treatment + Rice straw), T2 (Reduced photoperiod + 110 mM Salinity treatment + Rice straw), T3 (Ambient photoperiod + 220 mM Salinity treatment + Rice straw), T4 (Reduced photoperiod + 220 mM Salinity treatment + Rice straw), T5 (Ambient photoperiod + 110 mM Salinity treatment + Saw dust), T6 (Reduced photoperiod + 110 mM Salinity treatment + Saw dust), T7 (Ambient photoperiod + 220 mM Salinity treatment + Saw dust) and T8 (Reduced photoperiod + 220 mM Salinity treatment + Saw dust). Organic amendments were used separately at the rate of 12 ton/ha. The highest plant height (98.67 cm), root length (12.5 cm), pod number (10.33), leaf area (13.99 cm2), fresh weight (680 kg/ha), dry weight (316.67 kg/ha) were recorded with the treatment T1 while the second-best treatment was treatment T2 (with highest harvest index 0.040) and these results were statistically significant (p < 0.001). In post-harvest soil, pH, EC, OC, OM;available N, P, K, S;total Ca, Mg, Zn, Mn were increased significantly in treatment T1. The overall results illustrated that the best growth and yield performances were achieved in the treatment T1 and T2.

Development of a Novel Extrusion Process for Preparing Rice Straw/LLDPE Composites

Straw utilization is a key issue related to agricultural production and air pollution control.In this study,a novel extrusion process was proposed to improve the physical and mechanical properties of the straw-reinforced linear low-density polyethylene(LLDPE)composite.Instead of crushing the straw and mixing it with plastic matrix,the new method mixes straw with plastic matrix in its original form.The intact long rice straws were parallelly spread on the LLDPE film and then rolled up together into a prefabricated roll.The rolls experienced three extrusion processes as follows:(1)twin-screw melting,cooling and crushing,single-screw extruding;(2)twin-screw melting and single-screw extruding;(3)directly single-screw extruding.The testing results showed that the straw/LLDPE composite(with a ratio of 6:4)prepared by Method(2)exhibited optimized properties.Characterization by scanning electron microscopy indicated that the damage to rice straw fibers was relatively minor,the orientation of long fibers was good,and the binding of fibers with the LLDPE matrix was excellent in this case.The results of dynamic mechanical testing(DMA),differential scanning calorimetry(DSC)and thermogravimetric(TG)analysis demonstrated that composites prepared by the new process exhibited significantly improved thermal stability and energy storage modulus,compared with those prepared by conventional processes(e.g.,extruded straw particles/LLDPE composite).The new proposed method yielded significantly enhanced mechanical properties while reducing dust pollution.

Effects of Rice Straw Steam-explosion Spent Liquor on the Growth of Cabbage Seedlings

The direct use of spent liquor from pulping and papermaking engineering,which is abundant in active organic matter,can avoid resource wastage and environmental pollution.In this study,the effects of soaking solution and filtrate from steam-exploded rice straw on seed germination and the early development of cabbage were investigated.The results have shown that soaking solution and filtrate stimulated early cabbage growth at low concentrations.Optimal germination potential and the rate of soaking solution-treated cabbage seeds increased by 8%and 5%,respectively;meanwhile,that of the filtrate-treated cabbage seeds increased by 11%and 5%,respectively.Promotion of root growth by steam-exploded rice straw spent liquor was expressed in lateral root multiplication.The fresh weight of cabbage seedlings treated with the soaking solution/filtrate increased by more than 50%and the dry weight over 20%.Comparatively,the stimulation of filtrate on seed germination and early development of cabbage is superior to that of the soaking solution.Steam-exploded rice straw spent liquor is rich in bioactive lignin and oligosaccharides,which makes it a promising biostimulant for promoting crop growth.

Study on Biogas Production Using Anaerobic Fermentation of Rice Straw

[Objective] The aim was to improve the biogas production rate,and improve the use ratio of rice straws to the furthest.[Method] Single-factor method was adopted to analyze the influence of inoculated amount,total solid content and carbon-nitrogen ratio on biogas production in biogas station of Nanjing University of Technology.[Result] It was found that the most optimum condition was：inoculated amount of 34%,total solid content of 6%,and carbon-nitrogen ratio of 25：1.According to the experimental verification,the total biogas yield in experimental group increased by 27.6% over the control group.[Conclusion] The research provided the reference of the further industrialization production of biogas using straw.

Preparation and Adsorption Properties of Activated Carbon from Glutinous Rice Straw by KOH Method

[Objective] This study aimed to improve comprehensive utilization value of glutinous rice straw and to develop new raw material for preparation of activated carbon. [Method] Using potassium hydroxide as activator and glutinous rice straw as raw material, activated carbon was prepared. [Result] The optimum technological conditions for preparation of activated carbon from glutinous rice straw were as fol- lows： activator concentration of 2 mol/L, activation time of 60 min, activation tem- perature of 600 ℃ and carbonization temperature of 450℃. The adsorption values of methylene blue and iodine by activated carbon prepared from glutinous rico straw were 10.21 ml/0.1 g and 920.74 mg/g respectively under the optimal conditions. The quality of the prepared activated carbon met the grade two of water quality purifica- tion-using activated carbon quality standard. [Conclusion] This study will provide certain references for comprehensive utilization of glutinous rice straw and preparation of high-performance activated carbon.

Study on Main Chemical Compositions of Rice Straw in Three Different Areas of Jiangsu Province

[Objective] The research was aimed to study the main chemical composi- tions of rice straw in the three different areas of Jiangsu Province. [Method] The cellulose, hemicellulose, lignin and crude ash of rice straw collected in Huaian, Changzhou and Zhenjiang of Jiangsu Province during 2011-2013 were determined. [Result] The change trends of cellulose and hemicellulose in three arrears in differ- ent years were consistent. The cellulose content increased after falling, and hemi- cellulose content presented declining tendency. The lignin content of rice straw fist rose then declined in Huaian and Changzhou in different years, while it presented the declining tendency in Zhenjiang. The ash content of rice straw changed little and was all less than 65% in the three areas in different years. And the chemical composition of rice straw changed significantly in different years. [Conclusion] The research could provide basis for high added-value use of crop straw.

Effect of Long-Term Rice Straw Return on Soil Glomalin, Carbon and Nitrogen

A long-term experiment was conducted to investigate how long-term fertilization and rice straw incorporation into soil affect soil glomalin, C and N. The combined application of chemical fertilizer and straw resulted in a significant increase in both soil easily extractable glomalin (EEG) and total glomalin (TG) concentrations, as compared with application of only chemical fertilizer or no fertilizer application. The EEG and TG concentrations of the NPKS (nitrogen, phosphorus, and potassium fertilizer application + rice straw return) plot were 4.68% and 5.67% higher than those of the CK (unfertilized control) plot, and 9.87% and 6.23% higher than those of the NPK (nitrogen, phosphorus, and potassium fertilizer applied annually) plot, respectively. Application of only chemical fertilizer did not cause a statistically significant change of soil glomalin compared with no fertilizer application. The changes of soil organic C (SOC) and total N (TN) contents demonstrated a similar trend to soil glomalin in these plots. The SOC and TN contents of NPKS plot were 15.01% and 9.18% higher than those of the CK plot, and 8.85% and 14.76% higher than those of the NPK plot, respectively. Rice straw return also enhanced the contents of microbial biomass C (MBC) and microbial biomass N (MBN) in the NPKS plot by 7.76% for MBC and 31.42% for MBN compared with the CK plot, and 12.66% for MBC and 15.07% for MBN compared with the NPK plots, respectively. Application of only chemical fertilizer, however, increased MBN concentration, but decreased MBC concentration in soil.

Process of rice straw degradation and dynamic trend of pH by the microbial community MC1

The process of the rice straw degradation in the fermentor with aeration at 290 ml/h was studied. The results of dissolved oxygen （DO） indicated that the optimum DO during cellulose degradation by microbial community MC1 ranged from 0.01 to 0.12 mg/L. The change model ofpH values was as follows： irrespective of the initial pH of the medium, pH values decreased rapidly to approximate 6.0 after being inoculated within 48 h when cellulose was strongly degraded, and then increased slowly to 8.0--9.0 until cellulose was degraded completely. During the degradation process, 15 kinds of organic compounds were checked out by GC-MS. Most of them were organic acids. Quantity analysis was carried out, and the maximum content compound was ethyl acetate which reached 13.56 g/L on the day 4. The cellulose degradation quantity and ratio analyses showed that less quantity （under batch fermentation conditions） and longer interval （under semi-fermentation conditions） of rice straw added to fermentation system were contributed to matching the change model of pH, and increasing the quantity and ratio of rice straw degradation during cellulose degrading process. The highest degradation ratio was observed under the condition office straw added one time every five days （under semi-fermentation conditions）.

The effects of fermentation and adsorption using lactic acid bacteria culture broth on the feed quality of rice straw

To improve the nutritional value and the palatability of air-dried rice straw, culture broth of the lactic acid bacteria community SFC-2 was used to examine the effects of two different treatments, fermentation and adsorption. Air-dried and chopped rice straw was treated with either fermentation for 30 d after adding 1.5 L nutrient solution（50 m L inocula L–1, 1.2×1012 CFU m L–1 inocula） kg–1 straw dry matter, or spraying a large amount of culture broth（1.5 L kg–1 straw dry matter, 1.5×1011 CFU m L–1 culture broth） on the straw and allowing it to adsorb for 30 min. The feed quality and aerobic stability of the resulting forage were examined. Both treatments improved the feed quality of rice straw, and adsorption was better than fermentation for preserving nutrients and improving digestibility, as evidenced by higher dry matter（DM） and crude protein（CP） concentrations, lower neutral detergent fiber（NDF）, acid detergent fiber（ADF） and NH3-N concentrations, as well as higher lactic acid production and in vitro digestibility of DM（IVDMD）. The aerobic stability of the adsorbed straw and the fermented straw was 392 and 480 h, respectively. After being exposed to air, chemical components and microbial community of the fermented straw were more stable than the adsorbed straw.

Stimulatory effects of biosurfactant produced by Pseudomonas aeruginosa BSZ-07 on rice straw decomposing

Biosurfactant,produced by Pseudomonas aeruginosa BSZ-07,was added to the dee straw decomposing process to enhance the production of reducing sugars.Observed by Fourier Transform InfraRed(FT-IR)and Nuclear Magnetic Resonance(NMR)analysis, the purified biosurfactant was considered as a mixture of RL1 and RL2,which are two different types of rhamnolipids.Two different adding methods,adding the purified rhamnolipid and the on-site production of it were compared.The results showed that 0.5 g/L was the optimum co...

Effects of Rice Straw and Its Biochar Addition on Soil Labile Carbon and Soil Organic Carbon

Whether the biochar amendment could affect soil organic matter （SOM） turnover and hence soil carbon （C） stock remains poorly understood. Effects of the addition of ^13C-labelled rice straw or its pyrolysed biochar at 250 or 350℃ to a sugarcane soil （Ferrosol） on soil labile C （dissolved organic C, DOC; microbial biomass C, MBC; and mineralizable C, MC） and soil organic C （SOC） were investigated after 112 d of laboratory incubation at 25℃. Four treatments were examined as （1） the control soil without amendment （Soil）; （2） soil plus ^13C-labelled rice straw （Soil＋Straw）; （3） soil plus 250℃ biochar （Soil＋B250） and （4） soil plus 350℃biochar （Soil＋B350）. Compared to un-pyrolysed straw, biochars generally had an increased aryl C, carboxyl C, C and nitrogen concentrations, a decreased O-alkyl C and C：N ratio, but similar alkyl C and δ^13C （1 742- 1 877 %）. Among treatments, significant higher DOC, MBC and MC derived from the new C （straw or biochar） ranked as Soil＋Straw〉Soil＋B250〉Soil＋B350, whilst significant higher SOC from the new C as Soil＋B250〉Soil＋Straw≈Soil＋B350. Compared to Soil, DOC and MBC derived from the native soil were decreased under straw or biochar addition, whilst MC from the native soil was increased under straw addition but decreased under biochar addition. Meanwhile, native SOC was similar among the treatments, irrespective of the straw or biochar addition. Compared to Soil, significant higher total DOC and total MBC were under Soil＋Straw, but not under Soil＋B250 and Soil＋B350, whilst significant higher total MC and total SOC were under straw or biochar addition, except for MC under Soil＋B350. Our results demonstrated that the application of biochar to soil may be an appropriate management practice for increasing soil C storage.

Influence of rice straw burning on the levels of polycyclic aromatic hydrocarbons in agricultural county of Taiwan

Atmospheric particulate and polycyclic aromatic hydrocarbons （PAHs） size distribution were measured at Jhu-Shan （a rural site） and Sin-Gang （a town site） in central Taiwan during the rice straw burning and non-burning periods. The concentrations of total PAHs accounting for a roughly 58% （34%） increment in the concentrations of total PAHs due to rice-straw burning. Combustion-related PAHs during burning periods were 1.54-2.57 times higher than those during non-burning periods. The mass median diameter （MMD） of 0.88-1.21 μm in the particulate phase suggested that rice-straw burning generated the increase in coarse particle number. Chemical mass balance （CMB） receptor model analyses showed that the primary pollution sources at the two sites were similar. However, ricestraw burning emission was specifically identified as a significant source of PAH during burning periods at the two sites. Open burning of rice straws was estimated to contribute approximately 6.3%-24.6% to total atmospheric PAHs at the two sites.

Effects of rice straw on the cell viability, photosynthesis, and growth of Microcystis aeruginosa

Rice straw is supposed to be an environment-friendly biomaterial for inhibiting the growth of harmful blooms of the cyanobacterium Microcystis aeruginosa. However, its potential mechanism is not well known. To explore this mechanism, the growth, cell viability(esterase activity, membrane potential, and membrane integrity), photosynthesis, and cell size of M. aeruginosa were determined using fl ow cytometry and Phyto-PAM after exposure to rice straw extracts(RSE). The results show that doses from 2.0 to 10.0 g/L of RSE effi ciently inhibited the alga for 15 days, while the physiologic and morphologic responses of the cyanobacteria were time-dependent. RSE interfered with the cell membrane potential, cell size, and in vivo chlorophyll- a fl uorescence on the fi rst day. After 7 days of exposure, RSE was transported into the cytosol, which disrupted enzyme activity and photosynthesis. The cyanobacteria then started to repair its physiology(enzyme activity, photosynthesis) and remained viable, suggesting that rice straw act as an algistatic agent.

Combined pretreatment using CaO and liquid fraction of digestate of rice straw: Anaerobic digestion performance and electron transfer

To improve anaerobic digestion(AD)efficiency of rice straw,solid alkaline CaO and the liquid fraction of digestate(LFD)were used as pretreatment agents of rice straw.The results showed that AD performance of rice straw with CaOLFD pretreatment was optimal in different pretreatment methods of the CaO+LFD,CaOLFD,LFD+CaO,CaO,and LFD.The maximum methane yield(314 ml(g VS)^(-1))and the highest VFAs concentration(14851 mg·L^(-1) on day 3)of the CaOLFD pretreatment group were 81%and 118%higher than that of the control group,respectively.Under the action of solid alkaline CaO,the bacteria of Clostridium,Atopostipes,Sphaerochaeta,Tissierella,Thiopseudomonas,Rikenellaceae,and Sedimentibacter could build up co-cultures with the archaeal of Methanosaeta,Methanobacterium,and Methanosarcina performing direct interspecies electron transfer(DIET)and improving AD performance of rice straw.Therefore,the combined pretreatment using CaO and LFD could not only pretreat rice straw but also stimulate co-cultures of microorganism to establish DIET enhancing AD efficiency.

Management of rice straw with relay cropping of Chinese milk vetch improved double-rice cropping system production in southern China

Improved utilization of rice(Oryza sativa L.)straw and Chinese milk vetch(Astragalus sinicus L.,vetch)has positive effects on rice production.So far,few studies have investigated the productivity of vetch under different residue management practices in double-rice cropping system.The effects of rice straw on the growth and nutrient accumulation of vetch across seven years(2011–2017)and the subsequent effects of rice straw and vetch on two succeeding rice crops in a vetch–rice–rice cropping system,with the vetch established by relay cropping,were examined.The seven-year double-rice experiment consisted of the following treatments:(1)100%chemical fertilizer(F-F100);(2)only vetch without chemical fertilizer(M-Con);(3)80%chemical fertilizer plus vetch plus a low-cutting height(low-retained stubble)with the removal of straw(M-F80);(4)80%chemical fertilizer plus vetch plus a low-cutting height with the retention of straw(M-F80-LR);(5)80%chemical fertilizer plus vetch plus a high-cutting height(high-retained stubble)with the retention of straw(M-F80-HR);and(6)no fertilizer(F-Con).The yields of the two rice crops after vetch were not affected by either the cutting height of stubble with retention of straw or by the management of straw(retention vs.removal)with low-cutting height of stubble.The yields of the two rice crops after vetch were significantly higher for M-F80-HR than for M-F80-LR,but the relative contributions of the high-cutting height and straw retention to the higher rice yield could not be determined in this study.The yield stability of the double-rice grain in M-F80-HR was also increased,as determined by a sustainable yield index.Significant increases in vetch biomass and nutrient uptake were observed in the fertilized treatments during the rice season compared with the unfertilized treatments.In M-F80-HR plots,improvements in the growing environment of the vetch by conserving soil water content were associated with the highest vetch biomass,nutrient uptake,and yield stability of vetch biomass.These increased nutrient inputs partially replaced the demand for chemical fertilizer and stimulated the rice yields.It can be concluded that retaining higher-cutting stubble residues with straw retention could be the best straw management practice for increasing the vetch biomass and nutrient use efficiency,thereby allowing utilization of high-cutting height with retention of straw and vetch to improve the stability of rice productivity in a double-rice cropping system.

Mechanism Study of Rice Straw Pyrolysis by Fourier Transform Infrared Technique

The pyrolysis mechanism of rice straw (RS) was investigated using a tube reactor with Fourier trans-form infrared (FTIR) spectroscopy and thermogravimetric analyzer. The results show that the maximum pyrolysis rate increases with increasing heating rate and the corresponding temperature also increases. The three-pseudocomponent model could describe the pyrolysis behavior of rice straw accurately. The main pyrolysis gas products are H2O, CO2, CO, CH4, HCHO (formaldehyde), HCOOH (formic acid), CH3OH (methanol), C6H5OH (phenol), etc. The releasing of H2O, CO2, CO and CH4 mainly focuses at 220-400°C. The H2O formation process is separated into two stages corresponding to the evaporation of free water and the formation of primary volatiles. The release of CO2 first increases with increasing temperature and gets the maximum at 309°C. The releasing behavior of CO is similar to H2O and CO2 between 200 and 400°C. The production of CH4 happens, compared to CO2 and CO, at higher temperatures of 275-400°C with the maximum at 309°C. When the temperature exceeds 200°C, hy-droxyl and aliphatic C H groups decrease significantly, while C O, olefinic C C bonds and ether structures in-crease first in the chars and then the aromatic structure develops with rising temperature. Above 500°C, the material becomes increasingly more aromatic and the ether groups decreases with an increase of temperature. The aromati-zation process starts at ≈350°C and continues to higher temperatures.

Biorefinery of bacterial cellulose from rice straw:enhanced enzymatic saccharification by ionic liquid pretreatment

The pretreatment of rice straw is often used to enhance the hydrolysis. 1-allyl-3-methylimidazolium chloride （ [ AMIM ] C1） is a kind of low viscous, nontoxic and recyclable ionic liquid. It was used to treat rice straw and improve the enzymatic hydrolysis of rice straw in this study. The factors influencing the pretreatment were as follows： the dosage of rice straw in [ AMIM ] Cl, crush mesh of rice straw, pretreatment temperature and time. After the pretreatment with a 3 % （the weight ratio of rice straw to ionic liquid） rice straw dosage in [AMIM]Cl at 110 ℃ for 1 h, the yield of reducing sugar of regenerated rice straw by 33 U/mL cellulase hydrolysis was 53.3 %, which was two times higher than that of un-treated rice straw （23.7 % ）. More researches regarding straw biorefinery to bacterial cellulose are being performed in the lab and prospective results will be published in near future.

Prediction of Fiber Composition and Silicificationfor Rice Straw with Near Infrared ReflectanceSpectroscopy (NIRS) Technique

The silicification of rice straw is a factor that affects the grain production and straw nutritive quality. The procedure of chemical analysis for silicon in straw is, however, time and labor consuming, and slightly poor in accuracy. The study has attempted to apply near infrared reflectance spectroscopy (NIRS) technique as an advanced alternative to predict the fiber composition and silicification in rice straw. Ninety-two samples from different seasons and varieties were collected over the Fujian Province. Their chemical analyses were carried on the aspects of hemicellulose, cellulose, lignin, extractable and non-extractable silicon, and the results were used as a database for NIRS analyses. The prediction model was developed through modified partial least square regression (MPLS) for a calibration program. The factors that may affect the calibration, cross-validation and the prediction for the application of NIRS on rice straw were also discussed.

Effect of Plasticizers on Properties of Rice Straw Fiber Film

In order to improve the properties of rice straw fiber film, one factor contrast test method was employed. Plasticizer type was chosen as input variable, dry tension strength and elongation, wet tension strength and elongation, bursting strength and tearing strength were chosen as indexes. The results showed that there were significant differences among the means of dry tension strength, dry elongation and bursting strength of different plasticizers; there were not significant differences among the means of wet tension strength, wet elongation and tearing strength of different plasticizers; for dry tension strength and elongation, glycerol had a significant difference with sorbitol and PEG, no significant difference was observed between sorbitol and PEG, dry tension strength added glycerol had been reduced 6.8% compared with that added sorbitol, reduced 9.5% compared with that added PEG; elongation had been improved 6.1% and 9.4%, respectively; for bursting strength, sorbitol had a significant difference with glycerol and PEG, no significant difference was observed between glycerol and PEG; bursting strength added glycerol and added PEG had been improved 6.9% and 5.6%, respectively compared with that of the added sorbitol. The results provided a theoretical reference for further improving the straw fiber film manufacturing process.