Background Subacute ruminal acidosis(SARA)is a common metabolic disorder of high yielding dairy cows,and it is associated with dysbiosis of the rumen and gut microbiome and host inflammation.This study evaluated the i...Background Subacute ruminal acidosis(SARA)is a common metabolic disorder of high yielding dairy cows,and it is associated with dysbiosis of the rumen and gut microbiome and host inflammation.This study evaluated the impact of two postbiotics from Saccharomyces cerevisiae fermentation products(SCFP)on rumen liquid associated microbiota of lactating dairy cows subjected to repeated grain-based SARA challenges.A total of 32 rumen cannulated cows were randomly assigned to 4 treatments from 4 weeks before until 12 weeks after parturition.Treatment groups included a Control diet or diets supplemented with postbiotics(SCFPa,14 g/d Original XPC;SCFPb-1X,19 g/d Nutri Tek;SCFPb-2X,38 g/d Nutri Tek,Diamond V,Cedar Rapids,IA,USA).Grain-based SARA challenges were conducted during week 5(SARA1)and week 8(SARA2)after parturition by replacing 20%DM of the base total mixed ration(TMR)with pellets containing 50%ground barley and 50%ground wheat.Total DNA from rumen liquid samples was subjected to V3–V416S r RNA gene amplicon sequencing.Characteristics of rumen microbiota were compared among treatments and SARA stages.Results Both SARA challenges reduced the diversity and richness of rumen liquid microbiota,altered the overall composition(β-diversity),and its predicted functionality including carbohydrates and amino acids metabolic pathways.The SARA challenges also reduced the number of significant associations among different taxa,number of hub taxa and their composition in the microbial co-occurrence networks.Supplementation with SCFP postbiotics,in particular SCFPb-2X,enhanced the robustness of the rumen microbiota.The SCFP supplemented cows had less fluctuation in relative abundances of community members when exposed to SARA challenges.The SCFP supplementation promoted the populations of lactate utilizing and fibrolytic bacteria,including members of Ruminococcaceae and Lachnospiraceae,and also increased the numbers of hub taxa during non-SARA and SARA stages.Supplementation with SCFPb-2X prevented the fluctuations in the abundances of hub taxa that were positively correlated with the acetate concentration,andα-andβ-diversity metrics in rumen liquid digesta.Conclusions Induction of SARA challenges reduced microbiota richness and diversity and caused fluctuations in major bacterial phyla in rumen liquid microbiota in lactating dairy cows.Supplementation of SCFP postbiotics could attenuate adverse effects of SARA on rumen liquid microbiota.展开更多
The pyrolysis behaviors of Qingdao vacuum residue(QD-VR)and its SARA(saturates,aromatics,reins,and asphaltenes)fractions were evaluated by thermo-gravimetric with mass spectrometer(TG-MS).The pyrolysis kinetics were d...The pyrolysis behaviors of Qingdao vacuum residue(QD-VR)and its SARA(saturates,aromatics,reins,and asphaltenes)fractions were evaluated by thermo-gravimetric with mass spectrometer(TG-MS).The pyrolysis kinetics were determined by Friedman,one-parallel and four-parallel distributed activation energy model(DAEM),respectively.The results indicated that the pyrolysis behavior of QD-VR was similar to that of aromatics.For saturates,the release of H_(2),CH_(4),CO,and CO_(2) occurred in 80-400℃,while the temperature range for QD-VR and other fractions is 200-800℃.The average activation energy(Ea)via Friedman method was 179.72 kJ/mol and increased with the conversion ratio.One-parallel Gaussian DAEM was more suitable to describe the pyrolysis process of the single SARA fractions,while four-parallel Gaussian DAEM was more suitable to describe the pyrolysis process of heavy oil.Furthermore,comparing the weighted E_(a) from one-parallel(227.64 kJ/mol)and four-parallel Gaussian DAEM(204.63 kJ/mol),the results suggested that during pyrolysis process of heavy oil,there was an interaction between the SARA fractions,which could reduce the E_(a) of heavy oil pyrolysis.Specifically,during heavy oil pyrolysis,resins and asphaltenes could increase the E_(a) of saturates and aromatics,while saturates and aromatics could decrease the E_(a) of resins and asphaltenes.展开更多
Sara Kreek工作区位于苏里南中部,在全球构造上属太古-元古界的圭亚那地盾。圭亚那地盾上分布着大小几十个矿床(点),如圭亚那奥迈(Omai)大型金矿床,结合最新的勘查成果,对矿区地质、矿床地质特征进行了分析,总结了矿区地质特征、矿体特...Sara Kreek工作区位于苏里南中部,在全球构造上属太古-元古界的圭亚那地盾。圭亚那地盾上分布着大小几十个矿床(点),如圭亚那奥迈(Omai)大型金矿床,结合最新的勘查成果,对矿区地质、矿床地质特征进行了分析,总结了矿区地质特征、矿体特征、矿石特征及围岩蚀变特征,对本区的矿床成因及前景进行了讨论,本区成矿明显受地层、构造等因素的影响,本区绿岩带的原岩为中基性火山岩系,是矿体的成矿母岩,经剪切作用形成金矿体。蚀变以硅化、黄铁矿化蚀变最强,分布最广,与成矿关系最密切。韧性剪切带则是金矿体的控矿构造。研究认为,本矿区矿床成因类型为变质-沉积绿岩型金矿,Sara Kreek矿区找矿前景较好。展开更多
基金supported by grants from Natural Science and Engineering Research Council(NSERC)of Canada Collaborative Research and Development(CRD)programNSERC Discovery program,Dairy Farmers of Manitoba,and Diamond V,USA,to EK and JCP。
文摘Background Subacute ruminal acidosis(SARA)is a common metabolic disorder of high yielding dairy cows,and it is associated with dysbiosis of the rumen and gut microbiome and host inflammation.This study evaluated the impact of two postbiotics from Saccharomyces cerevisiae fermentation products(SCFP)on rumen liquid associated microbiota of lactating dairy cows subjected to repeated grain-based SARA challenges.A total of 32 rumen cannulated cows were randomly assigned to 4 treatments from 4 weeks before until 12 weeks after parturition.Treatment groups included a Control diet or diets supplemented with postbiotics(SCFPa,14 g/d Original XPC;SCFPb-1X,19 g/d Nutri Tek;SCFPb-2X,38 g/d Nutri Tek,Diamond V,Cedar Rapids,IA,USA).Grain-based SARA challenges were conducted during week 5(SARA1)and week 8(SARA2)after parturition by replacing 20%DM of the base total mixed ration(TMR)with pellets containing 50%ground barley and 50%ground wheat.Total DNA from rumen liquid samples was subjected to V3–V416S r RNA gene amplicon sequencing.Characteristics of rumen microbiota were compared among treatments and SARA stages.Results Both SARA challenges reduced the diversity and richness of rumen liquid microbiota,altered the overall composition(β-diversity),and its predicted functionality including carbohydrates and amino acids metabolic pathways.The SARA challenges also reduced the number of significant associations among different taxa,number of hub taxa and their composition in the microbial co-occurrence networks.Supplementation with SCFP postbiotics,in particular SCFPb-2X,enhanced the robustness of the rumen microbiota.The SCFP supplemented cows had less fluctuation in relative abundances of community members when exposed to SARA challenges.The SCFP supplementation promoted the populations of lactate utilizing and fibrolytic bacteria,including members of Ruminococcaceae and Lachnospiraceae,and also increased the numbers of hub taxa during non-SARA and SARA stages.Supplementation with SCFPb-2X prevented the fluctuations in the abundances of hub taxa that were positively correlated with the acetate concentration,andα-andβ-diversity metrics in rumen liquid digesta.Conclusions Induction of SARA challenges reduced microbiota richness and diversity and caused fluctuations in major bacterial phyla in rumen liquid microbiota in lactating dairy cows.Supplementation of SCFP postbiotics could attenuate adverse effects of SARA on rumen liquid microbiota.
基金the financial support of the National Natural Science Foundation(22278423,U1862107)Science Foundation of China University of Petroleum,Beijing(2462021QNXZ007).
文摘The pyrolysis behaviors of Qingdao vacuum residue(QD-VR)and its SARA(saturates,aromatics,reins,and asphaltenes)fractions were evaluated by thermo-gravimetric with mass spectrometer(TG-MS).The pyrolysis kinetics were determined by Friedman,one-parallel and four-parallel distributed activation energy model(DAEM),respectively.The results indicated that the pyrolysis behavior of QD-VR was similar to that of aromatics.For saturates,the release of H_(2),CH_(4),CO,and CO_(2) occurred in 80-400℃,while the temperature range for QD-VR and other fractions is 200-800℃.The average activation energy(Ea)via Friedman method was 179.72 kJ/mol and increased with the conversion ratio.One-parallel Gaussian DAEM was more suitable to describe the pyrolysis process of the single SARA fractions,while four-parallel Gaussian DAEM was more suitable to describe the pyrolysis process of heavy oil.Furthermore,comparing the weighted E_(a) from one-parallel(227.64 kJ/mol)and four-parallel Gaussian DAEM(204.63 kJ/mol),the results suggested that during pyrolysis process of heavy oil,there was an interaction between the SARA fractions,which could reduce the E_(a) of heavy oil pyrolysis.Specifically,during heavy oil pyrolysis,resins and asphaltenes could increase the E_(a) of saturates and aromatics,while saturates and aromatics could decrease the E_(a) of resins and asphaltenes.
