Effects of exogenous lactic acid bacteria and maize meal on fermentation quality and microbial community of Orychophragmus violaceus silage.

Orychophragmus violaceus is a local Brassicaceae in China, while most of it is directly mowed and discarded after the ornamental period. In order to develop forage resources, this study firstly evaluated the potential preservation of O. violaceus silage. O. violaceus was harvested at full-bloom stage, and ensiled without (CK) or with maize meal (Y5), lactic acid bacteria inoculant (Z) and compound additive (Y5Z) for 60 d. Results of chemical and microbiological analysis showed that a large amount of lactic acid was produced and the final pH value was below 4.1 in silages regardless of additive application. CK silage was well preserved as indicated by the low levels of dry matter loss and butyric acid content, and the predominant genus were identified as Enterococcus and Pediococcus. Y5 silage had potential health risks for humans and animals as seen by frequent occurrence of pathogenic bacteria Clostridium and Achromobacter. Z and Y5Z silages were poorly preserved, resulting in great dry matter loss and butyric acid content. Considering the abundant acetic acid production, the dominant Lactobacillus might possess a heterofermentative pathway in Z and Y5Z silages. In conclusion, O. violaceus has the potential to be long stored as silage because of its sufficient water-soluble carbohydrates, while exogenous lactic acid bacteria and maize meal generally provided little positive effect. In future research, efficient homofermentative Lactobacillus strains were suggested to be screened to further enhance the ensiling process of O. violaceus silage.

High-output soft-contact fiber-structure triboelectric nanogenerator and its sterilization application.

Infectious diseases are spreading rapidly with the flow of the world's population, and the prevention of epidemic diseases is particularly important for public and personal health. Therefore, there is an urgent need to develop a simple, efficient and non-toxic method to control the spread of bacteria and viruses. The newly developed triboelectric nanogenerator (TENG) can generate a high voltage, which inhibits bacterial reproduction. However, the output performance is the main factor limiting real-world applications of TENGs. Herein, we report a soft-contact fiber-structure TENG to avoid insufficient friction states and to improve the output, especially at a high rotation speed. Rabbit hair, carbon nanotubes, polyvinylidene difluoride film and paper all contain fiber structures that are used to guarantee soft contact between the friction layers and improve the contact state and abrasion problem. Compared with a direct-contact triboelectric nanogenerator, the outputs of this soft-contact fiber-structure TENG are improved by about 350%. Meanwhile, the open-circuit voltage can be enhanced to 3440 V, which solves the matching problems when driving high-voltage devices. A TENG-driven ultraviolet sterilization system is then developed. The bactericidal rate of this sterilization system can reach 91%, which significantly reduces the risk of disease spread. This work improves a forward-looking strategy to improve the output and service life of the TENG. It also expands the applications of self-powered TENG sterilization systems.

Metagenomic analysis reveals the linkages between bacteria and the functional enzymes responsible for potential ammonia and biogenic amine production in alfalfa silage.

AIMS: To clarify the molecular mechanisms underlying ammonia (NH3 ) and biogenic amines (BAEs) formation in alfalfa silage, whole metagenomic sequencing analysis was performed to identify the linkages between functional bacteria and their responsible enzymes in alfalfa silage prepared with and without sucrose addition. METHODS AND RESULTS: Genes encoding nitrite reductase (nirB) resulting in NH3 formation were the most abundant and were mostly assigned to Enterobacter cloacae and Klebsiella oxytoca. Putrescine-related genes, classified mainly to encode ornithine decarboxylase (odcA), were predominantly carried by Escherichia coli, Ent. cloacae and Citrobacter sp. Escherichia coli and Kl. oxytoca were the important species responsible for cadaverine and tyramine formation. Ent. cloacae, E. coli, and Kl. oxytoca dominated the bacterial community in naturally fermented alfalfa silage, whilst sucrose-treated silages greatly inhibited the growth of these species by promoting the dominance of Lactobacillus plantarum, thus decreasing the concentrations of NH3 , cadaverine, putrescine and tyramine. CONCLUSIONS: Enterobacteriaceae bacteria are mainly responsible for the NH3 , putrescine, cadaverine and tyramine formations in alfalfa silage. SIGNIFICANCE AND IMPACT OF THE STUDY: Whole metagenomic sequencing analysis served as a useful tool to identify the linkages between functional bacteria and associated enzymes responsible for NH3 and BAEs formation.

Triboelectric Nanogenerator as a Probe for Measuring the Charge Transfer between Liquid and Solid Surfaces.

The phenomenon of triboelectricity involves the flow of charged species across an interface, but conclusively establishing the nature of the charge transfer has proven extremely difficult, especially for the liquid-solid cases. Herein, we developed a self-powered droplet triboelectric nanogenerator (droplet-TENG) with spatially arranged electrodes as a probe for measuring the charge transfer process between liquid and solid interfaces. The information on the electric signal on spatially arranged electrodes shows that the charge transfer between droplets and the solid is an accumulation process during the dropping and that the electron is the dominant charge-transfer species. Such a droplet-TENG showed a high sensitivity to the ratio of solvents in the mixed organic solution, and we postulated this is due to the possibility of generation of a hydrogen bond, affecting the electric signal on the spatially arranged electrodes. This work demonstrated a chemical sensing application based on the self-powered droplet triboelectric nanogenerator.

Replacing Alfalfa with Paper Mulberry in Total Mixed Ration Silages: Effects on Ensiling Characteristics, Protein Degradation, and In Vitro Digestibility.

To develop an alternative high-protein forage resource to alleviate ruminant feed shortages, we investigated the effects of replacing alfalfa (Medicago sativa L.) with different ratios of paper mulberry (Broussonetia papyrifera L., RY) on fermentation quality, protein degradation, and in vitro digestibility of total mixed ration (TMR) silage. The TMR were made with alfalfa and RY mixtures (36.0%), maize meal (35.0%), oat grass (10.0%), soybean meal (7.5%), brewers' grain (5.0%), wheat bran (5.0%), premix (1.0%), and salt (0.5%) on a dry matter basis, respectively. The alfalfa and RY mixtures were made in the following ratios of dry matter: 36:0 (RY0), 27:9 (RY9), 18:18 (RY18), 9:27 (RY27), and 0:36 (RY36). After ensiling for 7, 14, 28, and 56 days, fermentation quality, protein degradation, and microbial counts were examined, and chemical composition and in vitro digestibility were analyzed after 56 days of ensiling. All TMR silages, irrespective of the substitution level of RY, were well preserved with low pH and ammonia nitrogen content, high lactic acid content, and undetectable butyric acid. After ensiling, the condensed tannin content for RY18 silages was higher than the control, but non-protein nitrogen, peptide nitrogen, and free amino acid nitrogen contents was lower, while the fraction B1 (buffer-soluble protein) was not different among all the silages. Dry matter and crude protein digestibility for RY27 and RY36 silages was lower than the control, but there was no difference between control and RY18 silages. This study suggested that ensiling RY with alfalfa inhibited true protein degradation, but decreased in vitro dry matter and crude protein digestibility of TMR silages, and that 18:18 is the optimal ratio.

Effects of grazing mixed-grass pastures on growth performance, immune responses, and intestinal microbiota in free-range Beijing-you chickens.

There is an increasing interest in free-range poultry with the increasing focus on food safety and animal welfare. This study was conducted to evaluate the effects of grazing mixed-grass pastures on growth performance, immune responses, and intestinal microbiota in free-range laying chickens. Ten-week-old female Beijing-you chickens were blocked by the BW and randomly assigned to 3 free-range systems in poplar plantations for 120 d: forage-removed paddocks with a high stocking density of 5 m2/hen (control [CK]); mixed-grass pastures with a low stocking density of 6 m2/hen ;or mixed-grass pastures with a high stocking density of 5 m2/hen. Intestinal microbial community analysis was performed by 16S rRNA gene sequencing using Illumina MiSeq. The results revealed that no differences (P > 0.05) were found between the 3 raising systems for the BW and ADG. Chickens grazing mixed-grass pastures exhibited decreased (P > 0.05) mortality and improved immune responses as evidenced by increased T-lymphocyte proliferation (P > 0.05) and immunoglobulin A (P > 0.05) and immunoglobulin M concentrations (P < 0.05) compared with those raised in forage-removed paddocks. Metagenomic analysis indicated that grazing mixed-grass pastures regulated the intestinal microbiota by increasing the prevalence of beneficial bacteria, such as Lactobacillus, Bacteroides, and Faecalibacterium, and reducing potentially pathogenic bacteria population, such as the Rikenellaceae_RC9_gut_group compared with the CK. Therefore, this study indicated that grazing mixed-grass pastures could positively influence intestinal microbiota that may contribute to the overall growth and immunity of free-range chickens and that a low stocking density of 6 m2/hen was optimal to Beijing-you chickens grazing mixed-grass pastures.

Microbial community dynamics during alfalfa silage with or without clostridial fermentation.

This study was conducted to examine the effects of Lactobacillus plantarum (LP) and sucrose (S) on clostridial community dynamics and correlation between clostridia and other bacteria in alfalfa silage during ensiling. Fresh alfalfa was directly ensiled without (CK) or with additives (LP, S, LP + S) for 7, 14, 28 and 56 days. Clostridial and bacterial communities were evaluated by next-generation sequencing. Severe clostridial fermentation occurred in CK, as evidenced by the high contents of butyric acid, ammonia nitrogen, and clostridia counts, whereas all additives, particularly LP + S, decreased silage pH and restrained clostridial fermentation. Clostridium perfringens and Clostridium butyricum might act as the main initiators of clostridial fermentation, with Clostridium tyrobutyricum functioning as the promoters of fermentation until the end of ensiling. Clostridium tyrobutyricum (33.5 to 98.0%) dominated the clostridial community in CK from 14 to 56 days, whereas it was below 17.7% in LP + S. Clostridium was negatively correlated with the genus Lactobacillus, but positively correlated with the genera Enterococcus, Lactococcus and Leuconostoc. Insufficient acidification promoted the vigorous growth of C. tyrobutyricum of silage in later stages, which was mainly responsible for the clostridial fermentation of alfalfa silage.

Effects of Surface Functional Groups on Electron Transfer at Liquid-Solid Interfacial Contact Electrification.

Contact electrification (CE) at interfaces is sensitive to the functional groups on the solid surface, but its mechanism is poorly understood, especially for the liquid-solid cases. A core controversy is the identity of the charge carriers (electrons or/and ions) in the CE between liquids and solids. Here, the CE between SiO2 surfaces with different functional groups and different liquids, including DI water and organic solutions, is systematically studied, and the contribution of electron transfer is distinguished from that of ion transfer according to the charge decay behavior at surfaces at specific temperature, because electron release follows the thermionic emission theory. It is revealed that electron transfer plays an important role in the CE between liquids and functional group modified SiO2. Moreover, the electron transfer between the DI water and the SiO2 is found highly related to the electron affinity of the functional groups on the SiO2 surfaces, while the electron transfer between organic solutions and the SiO2 is independent of the functional groups, due to the limited ability of organic solutions to donate or gain electrons. An energy band model for the electron transfer between liquids and solids is further proposed, in which the effects of functional groups are considered. The discoveries in this work support the "two-step" model about the formation of an electric double-layer (Wang model), in which the electron transfer occurs first when the liquids contact the solids for the very first time.

Yeast population dynamics on air exposure in total mixed ration silage with sweet potato residue.

To investigate the yeast population dynamics during air exposure in total mixed ration (TMR) silage containing sweet potato residue. TMR were ensiled in laboratory silos (1 kg) with or without two lactic acid bacteria strains, Lactobacillus plantarum (LP), and Lactobacillus amylovorus (LA). Fermentation characteristics were measured and yeast population was investigated by ITS1 region gene sequencing using Illumina MiSeq platform. All treatments were well ensiled, and L. amylovorus improved aerobic stability. During aerobic exposure, Pichia kudriavzevii was detected with increased relative abundance in all treatments and more relative abundant in LP. Pichia fermentans was more relative abundant in control. Higher relative abundance of Pichia anomala was detected in deteriorating LP. The relative abundance of Pichia ohmeri increased during later aerobic exposure in the control and LA, with a significant increase in the count of yeast population. Despite Cryptococcus was detected more relative abundant during early stage of aerobic exposure, the yeast population was below the detection limit. Aerobic deterioration was characterized by an increase in operational taxonomic units of Pichia. High relative abundance of P. anomala and P. kudriavzevii made aerobic deterioration easier. Inhibition of P. fermentans might be an effective strategy for improving the aerobic stability to some instance.

Scanning Probing of the Tribovoltaic Effect at the Sliding Interface of Two Semiconductors.

Contact electrification (CE or triboelectrification) is a common phenomenon, which can occur for almost all types of materials. In previous studies, the CE between insulators and metals has been widely discussed, while CE involving semiconductors is only recently. Here, a tribo-current is generated by sliding an N-type diamond coated tip on a P-type or N-type Si wafers. The density of surface states of the Si wafer is changed by introducing different densities of doping. It is found that the tribo-current between two sliding semiconductors increases with increasing density of surface states of the semiconductor and the sliding load. The results suggest that the tribo-current is induced by the tribovoltaic effect, in which the electron-hole pairs at the sliding interface are excited by the energy release during friction, which may be due to the transition of electrons between the surface states during contact, or bond formation across the sliding interface. The electron-hole pairs at the sliding interface are subsequently separated by the built-in electric field at the PN or NN heterojunctions, which results in a tribo-current, in analogy to that which occurs in the photovoltaic effect.

Metagenome analyses reveal the role of Clostridium perfringens in alfalfa silage anaerobic deterioration.

The clostridial fermentation caused by the outgrowth of Clostridia was mainly responsible for the silage anaerobic deterioration. Our previous results showed that Clostridium perfringens dominated the clostridial community in poor-fermented alfalfa silage. This study was conducted to further examine the role of C. perfringens in silage anaerobic deterioration through fermentation products and the microbial community analyses. Direct-cut alfalfa was ensiled with C. perfringens contamination (CKC) or with the addition of Lactobacillus plantarum, sucrose and C. perfringens (LSC). Contamination with C. perfringens enhanced the clostridial fermentation in CKC silage, as indicated by high contents of butyric acid, ammonia nitrogen and Clostridia, while LSC silage was well preserved. The genera Bifidobacterium, Garciella and Clostridium dominated the bacterial community in CKC silage, while predominate genus was replaced by Lactobacillus in LSC silage. The clostridial community in CKC silage was dominated by Garciella sp. (26.9 to 58.1%) and C. tyrobutyricum (24.4 to 48.6%), while the relative abundance of C. perfringens was below 5.0%. Therefore, the effect of Clostridia contamination on ensiling fermentation was dependent on the ensilability of the silage material. Garciella sp. and C. tyrobutyricum, rather than C. perfringens, played dominant role in the clostridial fermentation in CKC silage.

A lower cost method of preparing corn stover for Irpex lacteus treatment by ensiling with lactic acid bacteria.

OBJECTIVE: This study investigated a method of preparing corn stover for Irpex lacteus (I. lacteus) treatment to improve its in vitro rumen degradability under non-sterile conditions. METHODS: Corn stover was inoculated with Lactobacillus plantarum (L. plantarum), Lactobacillus buchneri (L. buchneri), and an equal mixture of these strains, and ensiled for 0, 3, 7, 14, and 28 days. After each period, a portion of the silage was sampled to assess the silage quality, and another portion of the silage was further treated with I. lacteus at 28°C for 28 d. All the samples were analyzed for fermentation quality, chemical composition, and in vitro gas production (IVGP) as a measure of rumen fermentation capacity. RESULTS: Lactic acid bacteria (LAB) was found to improve the silage quality of the corn stover, and the corn stover silage inoculated with L. plantarum produced more lactic acid and higher IVGP than other silage groups. The I. lacteus colonies flourished in the early stage of corn stover silage, especially on the 3-d corn stover silage inoculated with both L. plantarum and L. buchneri. This led to an 18% decrease in the acid detergent lignin content, and a 49.6% increase in IVGP compared with the raw stover. CONCLUSION: The combination of ensiling with the mixed LAB inoculation and I. lacteus treatment provided a cost-effective method for the improvement of the IVGP of corn stover from 164.8 mL/g organic matter (OM) to 246.6 mL/g OM.

Characteristics of proteolytic microorganisms and their effects on proteolysis in total mixed ration silages of soybean curd residue.

OBJECTIVE: The objective of this study was to isolate proteolytic microorganisms and evaluate their effects on proteolysis in total mixed ration (TMR) silages of soybean curd residue. METHODS: TMRs were formulated with soybean curd residue, alfalfa or Leymus chinensis hay, corn meal, soybean meal, a vitamin-mineral supplement, and salt in a ratio of 25.0:40.0:30.0:4.0:0.5:0.5, respectively, on a basis of dry matter (DM). The microbial proteinases during ensiling were characterized, the dominate strains associated with proteolysis were identified, and their enzymatic characterization were evaluated in alfalfa (A-TMR) and Leymus chinensis (L-TMR) TMR silages containing soybean curd residue. RESULTS: Both A-TMR and L-TMR silages were well preserved, with low pH and high lactic acid concentrations. The aerobic bacteria and yeast counts in both TMR silages decreased to about 105 cfu g-1 FM (Fresh matter) and below the detection limit, respectively. The lactic acid bacteria count increased to 109 cfu g-1 FM. The total microbial proteinases activities reached their maximums during the early ensiling stage and then reduced in both TMR silages with fermentation prolonged. Metalloproteinase was the main proteinase when the total proteinases activities reached their maximums, and when ensiling terminated, metallo and serine proteinases played equally important parts in proteolysis in both TMR silages. Strains in the genera Curtobacterium and Paenibacillus were identified as the most dominant proteolytic bacteria in A-TMR and L-TMR, respectively, and both their proteinases were mainly with metalloproteinase characteristics. In the latter ensiling phase, Enterococcus faecium strains became the major sources of proteolytic enzymes in both TMR silages. Their proteinases were mainly of metallo and serine proteinases classes in this experiment. CONCLUSION: Proteolytic aerobic bacteria were substituted by proteolytic lactic acid bacteria during ensiling, and the microbial serine and metallo proteinases in these strains played leading roles in proteolysis in TMR silages.

Novel strategy to improve the colonizing ability of Irpex lacteus in non-sterile wheat straw for enhanced rumen and enzymatic digestibility.

Pretreatment with white rot fungi is a promising method to enhance the digestibility of lignocelluloses; however, sterilization of feedstocks prior to inoculation is one of the costliest steps. To improve the colonizing ability of white rot fungi under non-sterile condition, Irpex lacteus, Pleurotus ostreatus, and Phanerochaete chrysosporium were inoculated in the wheat straw ensiled for 28 days and incubated for 56 days to determine the changes in microbe counts, organic acid content, chemical composition, and rumen and enzymatic digestibility. Results showed that ensiling produced abundant organic acids and suppressed most microbes in wheat straw. Significant growth of I. lacteus was observed after 3 days of incubation, and molds were only detectable at day 7 in the group. At the end of incubation, aerobic bacteria and lactic acid bacteria decreased by 18% and 38% in the wheat straw treated with I. lacteus, but molds, aerobic bacteria, and lactic acid bacteria thrived in those treated with P. ostreatus and P. chrysosporium. Even more, P. ostreatus and P. chrysosporium increased the lignin content of the ensiled wheat straw by 34% and 65%. However, I. lacteus selectively degraded lignin by 28% and improved the rumen and enzymatic digestibility by 18% and 34%. The finding indicates that ensiling prior to fermentation with I. lacteus is an effective method to control spoilage microbes and to enhance the rumen and enzymatic digestibility of wheat straw.

Effects of dietary supplementation of alfalfa meal on growth performance, carcass characteristics, meat and egg quality, and intestinal microbiota in Beijing-you chicken.

This study was conducted to investigate the effects of alfalfa meal supplementation on growth performance, carcass characteristics, meat and egg quality, and intestinal microbiota in chickens. A total of 600 healthy 20-wk female Beijing-you chickens (a local Chinese chicken breed) were selected and randomly assigned into 4 dietary treatments: 0, 5, 8, and 10% alfalfa meal supplementation. Chickens were raised in a free-range system for 56 d. Microbiota inhabiting 3 different intestinal sections (duodenum, ileum, and cecum) was determined using high-throughput sequencing. The results showed that chickens given alfalfa meal had lower (P < 0.05) feed conversion ratio, mortality, abdominal fat yield, and yolk cholesterol content, and higher (P < 0.05) breast muscle contents of inosine monophosphate, total amino acids, essential amino acids, non-essential amino acids, delicious amino acids, yolk protein, albumen protein, and yolk color compared to those given no alfalfa meal. The Lactobacillus was the dominant genus in both duodenum and ileum, while the microbiota in cecum was mainly composed of the Bacteroides. Although small changes in the dominant intestinal microbiota of chickens fed with or without alfalfa meal were observed, supplementation of alfalfa meal tended to stimulate the proliferation of beneficial bacteria, such as the Lactobacillus and Bacteroides, and inhibit potential pathogens, including the Clostridium. Therefore, dietary supplementation of alfalfa meal was feasible to Beijing-you chickens raised in a free-range system, and 10% was recommended as the relatively optimal level.

Effect of Irpex lacteus, Pleurotus ostreatus and Pleurotus cystidiosus pretreatment of corn stover on its improvement of the in vitro rumen fermentation.

BACKGROUND: The present work investigated changes in corn stover pretreated with different white rot fungi. Corn stover was inoculated with Irpex lacteus, Pleurotus ostreatus and Pleurotus cystidiosus prior to incubation under solid-state fermentation conditions at 28 °C for 42 days. Changes in the chemical composition, in vitro rumen degradability, lignocellulolytic enzyme activity and multi-scale structure of the corn stover were analysed. RESULTS: Content of all lignocellulose components decreased to a certain extent after fungal pretreatment. The total gas production of sterilized corn stover treated with I. lacteus for 42 days increased from 200 to 289 mL g-1 organic matter. Moreover, the cellulase activity was highest at the later stage of I. lacteus pretreatment. Multi-scale structural analysis indicated that white rot fungal pretreatment, and in particular that of I. lacteus, increased and enlarged substrate porosity and caused changes in the structure of corn stover. CONCLUSION: Irpex lacteus pretreatment improved the nutritional value of corn stover as a ruminant feed by degrading both cellulose and acid-insoluble lignin as well as changing the structure of the cell walls. © 2018 Society of Chemical Industry.

Characterization of culturable yeast species associating with whole crop corn and total mixed ration silage.

OBJECTIVE: This study investigated the association of yeast species with improved aerobic stability of total mixed ration (TMR) silages with prolonged ensiling, and clarified the characteristics of yeast species and their role during aerobic deterioration. METHODS: Whole crop corn (WCC) silages and TMR silages formulated with WCC were ensiled for 7, 14, 28, and 56 d and used for an aerobic stability test. Predominant yeast species were isolated from different periods and identified by sequencing analyses of the 26S rRNA gene D1/D2 domain. Characteristics (assimilation and tolerance) of the yeast species and their role during aerobic deterioration were investigated. RESULTS: In addition to species of Candida glabrata and Pichia kudriavzevii (P. kudriavzevii) previously isolated in WCC and TMR, Pichia manshurica (P. manshurica), Candida ethanolica (C. ethanolica), and Zygosaccharomyces bailii (Z. bailii) isolated at great frequency during deterioration, were capable of assimilating lactic or acetic acid and tolerant to acetic acid and might function more in deteriorating TMR silages at early fermentation (7 d and 14 d). With ensiling prolonged to 28 d, silages became more (p<0.01) stable when exposed to air, coinciding with the inhibition of yeast to below the detection limit. Species of P. manshurica that were predominant in deteriorating WCC silages were not detectable in TMR silages. In addition, the predominant yeast species of Z. bailii in deteriorating TMR silages at later fermentation (28 d and 56 d) were not observed in both WCC and WCC silages. CONCLUSION: The inhibition of yeasts, particularly P. kudriavzevii, probably account for the improved aerobic stability of TMR silages at later fermentation. Fewer species seemed to be involved in aerobic deterioration of silages at later fermentation and Z. bailii was most likely to initiate the aerobic deterioration of TMR silages at later fermentation. The use of WCC in TMR might not influence the predominant yeast species during aerobic deterioration of TMR silages.

Effects of microbial enzymes on starch and hemicellulose degradation in total mixed ration silages.

OBJECTIVE: This study investigated the association of enzyme-producing microbes and their enzymes with starch and hemicellulose degradation during fermentation of total mixed ration (TMR) silage. METHODS: The TMRs were prepared with soybean curd residue, alfalfa hay (ATMR) or Leymus chinensis hay (LTMR), corn meal, soybean meal, vitamin-mineral supplements, and salt at a ratio of 25:40:30:4:0.5:0.5 on a dry matter basis. Laboratory-scale bag silos were randomly opened after 1, 3, 7, 14, 28, and 56 days of ensiling and subjected to analyses of fermentation quality, carbohydrates loss, microbial amylase and hemicellulase activities, succession of dominant amylolytic or hemicellulolytic microbes, and their microbial and enzymatic properties. RESULTS: Both ATMR and LTMR silages were well preserved, with low pH and high lactic acid concentrations. In addition to the substantial loss of water soluble carbohydrates, loss of starch and hemicellulose was also observed in both TMR silages with prolonged ensiling. The microbial amylase activity remained detectable throughout the ensiling in both TMR silages, whereas the microbial hemicellulase activity progressively decreased until it was inactive at day 14 post-ensiling in both TMR silages. During the early stage of fermentation, the main amylase-producing microbes were Bacillus amyloliquefaciens (B. amyloliquefaciens), B. cereus, B. licheniformis, and B. subtilis in ATMR silage and B. flexus, B. licheniformis, and Paenibacillus xylanexedens (P. xylanexedens) in LTMR silage, whereas Enterococcus faecium was closely associated with starch hydrolysis at the later stage of fermentation in both TMR silages. B. amyloliquefaciens, B. licheniformis, and B. subtilis and B. licheniformis, B. pumilus, and P. xylanexedens were the main source of microbial hemicellulase during the early stage of fermentation in ATMR and LTMR silages, respectively. CONCLUSION: The microbial amylase contributes to starch hydrolysis during the ensiling process in both TMR silages, whereas the microbial hemicellulase participates in the hemicellulose degradation only at the early stage of ensiling.

Dynamics Associated with Prolonged Ensiling and Aerobic Deterioration of Total Mixed Ration Silage Containing Whole Crop Corn.

This study investigated the dynamics associated with prolonged ensiling and aerobic deterioration of whole crop corn (WCC) silages and total mixed ration (TMR) silages containing WCC (C-TMR silages) to clarify the differences that account for the enhanced aerobic stability of TMR silages. Laboratory-scale barrel silos were randomly opened after 7, 14, 28, and 56 d of ensiling and were subjected to analyses of fermentation quality, microbial and temperature dynamics during aerobic exposure. WCC and C-TMR silages were both well preserved and microorganisms were inhibited with prolonged ensiling, including lactic acid bacteria. Yeast were inhibited to below the detection limit of 500 cfu/g fresh matter within 28 d of ensiling. Aerobic stability of both silages was enhanced with prolonged ensiling, whereas C-TMR silages were more aerobically stable than WCC silages for the same ensiling period. Besides the high moisture content, the weak aerobic stability of WCC silage is likely attributable to the higher lactic acid content and yeast count, which result from the high water-soluble carbohydrates content in WCC. After silo opening, yeast were the first to propagate and the increase in yeast levels is greater than that of other microorganisms in silages before deterioration. Besides, increased levels of aerobic bacteria were also detected before heating of WCC silages. The temperature dynamics also indicated that yeast are closely associated with the onset of the aerobic deterioration of C-TMR silage, whereas for WCC silages, besides yeast, aerobic bacteria also function in the aerobic deterioration. Therefore, the inclusion of WCC might contribute to the survival of yeast during ensiling but not influence the role of yeast in deterioration of C-TMR silages.

Should aspirin be used for primary prevention of colorectal cancer in the general population?

Objectives: The objective of this narrative review is to determine if aspirin is indicated for primary prevention of colorectal cancer in the general population. Methods: A Pubmed search was conducted and 19 articles were included for this review. Results and Discussion: In deciding if aspirin should be recommended for chemoprevention, we need to consider its efficacy, safety profile, patient compliance and cost-effectiveness. Most of the observation studies suggested that aspirin had a protective effect against colorectal cancer. However, randomised control trials had not shown such benefit. For the general population, the harms of aspirin outweigh the potential benefits. A long duration of 5-10 years of regular aspirin intake seemed to be required for significant protective effect. As such, compliance in the long term for an otherwise well patient is an issue. While some cost-effectiveness analyses suggested that colonoscopic screening was more cost-effective than aspirin use, others suggested that a combination of low-dose aspirin with colonoscopy was cost-effective, especially for proximal colorectal cancer. Conclusion: Based on the data from RCTs thus far, aspirin should not be recommended as a chemo-preventive agent against colorectal cancer for the general population.