In complex digestion and metabolism of rumen, rumen microbes play a decisive role. Currently, the relationship between rumen microbial system and rumen metabolism has not been understood comprehensively, which will be...In complex digestion and metabolism of rumen, rumen microbes play a decisive role. Currently, the relationship between rumen microbial system and rumen metabolism has not been understood comprehensively, which will be reviewed in the paper, with particular focus on digestion and metabolism of bacteria, fungi and protozoa in the rumen of ruminants.展开更多
Ferulic acid(FA)is one of the most abundant hydroxycinnamic acids in the plant world,especially in the cell wall of grain bran,in comparison with forage and crop residues.Previous studies noted that FA was mainly link...Ferulic acid(FA)is one of the most abundant hydroxycinnamic acids in the plant world,especially in the cell wall of grain bran,in comparison with forage and crop residues.Previous studies noted that FA was mainly linked with arabinoxylans and lignin in plant cell walls in ester and ether covalent forms.After forages were ingested by ruminant animals or encountered rumen microbial fermentation in vitro,these cross-linkages form physical and chemical barriers to protect cell-wall carbohydrates from microbial attack and enzymatic hydrolysis.Additionally,increasing studies noted that FA presented some toxic effect on microbial growth in the rumen.In recent decades,many studies have addressed the relationships of ester and/or ether-linked FA with rumen nutrient digestibility,and there is still some controversy whether these linkages could be used as a predicator of forage digestibility in ruminants.The authors in this review summarized the possible relationships between ester and/or ether-linked FA and fiber digestion in ruminants.Rumen microbes,especially bacteria and fungi,were found capable of breaking down the ester linkages within plant cell walls by secreting feruloyl and p-coumaroyl esterase,resulting in the release of free FA and improvement of cell wall digestibility.The increasing evidence noted that these esterases secreted by rumen microbes presented synergistic effects with xylanase and cellulase to effectively hydrolyze forage cell walls.Some released FA were absorbed through the rumen wall directly and entered into blood circulation and presented antioxidant effects on host animals.The others were partially catabolized into volatile fatty acids by rumen microbes,and the possible catabolic pathways discussed.To better understand plant cell wall degradation in the rumen,the metabolic fate of FA along with lignin decomposition mechanisms are needed to be explored via future microbial isolation and incubation studies with aims to maximize dietary fiber intake and enhance fiber digestion in ruminant animals.展开更多
Three goats fitted with cannula were used to provide rumen liquor to investigate the effects of limiting amino acids on rumen fermentation and microbial community in vitro. The removal method was used in the current e...Three goats fitted with cannula were used to provide rumen liquor to investigate the effects of limiting amino acids on rumen fermentation and microbial community in vitro. The removal method was used in the current experiments. Treatments are total essential amino acid （TEAA）, His-removal, Lys-removal, Met-removal, and branch chain amino acid （BCAA）- removal. Results indicated that, pH-value ranged between 5.9 and 6.8, with the highest mean value for the group with BCAA-removal （6.54） in the culture. Concentration of NH3-N ranged between 10.99 to 30.51 mg 100 mL^-1, with the group of TEAA recording the highest average NH3-N concentration （17.85 mg 100 mL^-1）. Yields of microbial protein and limiting degree on microbial growth varied with treatments （P 〈 0.01）, and the lowest accrued in treatment with BCAA-removal （0.1389, 0.1772, and 0.3161 mg mL^-1 for bacteria, protozoa, and mixed microbes, respectively）, compared to the group with TEAA, microbial production of mixed microbes decreased by 44.52%. As for micro-flora, protozoa to bacteria ratio was the lowest for the group with Lys-removal （89.12%）, while the highest for the group with BCAA-removal （127.60%） （P 〈 0.01）. Furthermore, PCR-SSCP analysis revealed that, microbial profile subjected to substrates within bacteria and protozoa groups. It was therefore concluded that, dietary amino acid influenced both rumen fermentation and microbial characteristics.展开更多
This study investigated the effects of the degree of unsaturation（unsaturity） of long-chain fatty acids on microbial protein content and the activities of transaminases and dehydrogenase in vitro using goat rumen fl...This study investigated the effects of the degree of unsaturation（unsaturity） of long-chain fatty acids on microbial protein content and the activities of transaminases and dehydrogenase in vitro using goat rumen fluid as the cultural medium.Six types of fatty acids,stearic acid（C18：0,group A,control group）,oleic acid（C18：1,n-9,group B）,linoleic acid（C18：2,n-6,group C）,α-linolenic acid（C18：3,n-3,group D）,arachidonic acid（C20：4,n-6,group E）,and eicosapentaenoic acid（C20：5,n-3,group F）,were tested,and the inclusion ratio of each fatty acid was 3%（w/w） in total of culture substrate.Samples were taken at 0,3,6,9,12,18 and 24 h,respectively,during culture for analyses.Compared with stearic acid,linoleic acid,a-linolenic acid,and arachidonic acid increased the bacterial protein content,while oleic acid and eicosapentaenoic acid had no significant effects;the protozoal protein content was reduced for all the unsaturated fatty acids,and the magnitude of the reduction appeared to be associated with the degree of unsaturity of fatty acids.The total microbial protein content was dominantly accounted by the protozoal protein content（about 4-9 folds of the bacterial protein）,and only increased by linoleic acid,but reduced by oleic acid,arachidonic acid and eicosapentaenoic acid.There were no significant effects in the activities of both glutamic oxaloacetic transaminase（GOT） and glutamic-pyruvic transaminase（GPT） for all the other fatty acids,except for arachidonic acid which enhanced GOT activity and oleic acid which enhanced GPT activity.The total dehydrogenase activity was positively correlated with the degree of unsaturation of fatty acids.In conclusion,the inclusion of 3%of long-chain unsaturated fatty acids increased bacterial protein content,whereas reduced protozoal protein content and enhanced dehydrogenase activity.The fatty acids with more than three double bonds had detrimental effects on the microbial protein content.This work demonstrates for the first time the effect rule of the unsaturation degree of long-chain fatty acids on the rumen microbial protein in vitro.展开更多
The milk replacer feeding regime in dairy calves has a great impact on metabolic and immunological functioning and affects animal welfare and lifetime performance.The feeding regime influences the rumen microbial comp...The milk replacer feeding regime in dairy calves has a great impact on metabolic and immunological functioning and affects animal welfare and lifetime performance.The feeding regime influences the rumen microbial composition,and epithelium-associated microbes may interact with the immune system of the host.We examined the correlations between blood leukocyte counts and the rumen epithelium-associated microbiome in dairy calves fed 2 different milk replacer feeding intensities and if these factors related to metabolic traits.Fourteen newborn female dairy calves were allocated to a group receiving either 10%(n=7)or 20%(n=7)milk replacer of their body weight(on average 41 kg)and provided ad libitum access to grass hay and concentrate pellets.At 3 weeks of life,all calves were fitted with a rumen cannula.Calves were weaned at 12 weeks of life and received a total mixed ration for ad libitum intake.Pre-(8-10 weeks of life)and post-weaning(21-23 weeks of life),methane production was measured in respiration chambers,and rumen epithelium and blood were sampled for 16S rRNA sequencing and leukocyte analyses,respectively.Pre-weaning,the reduced milk replacer feeding intensity was accompanied with higher concentrate intake but lower growth performance(P<0.001),a higher abundance of amylolytic and lower abundance of cellulolytic epimural microbes.The group fed a low milk replacer intensity had also greater portions of monocytes(P=0.031),CD8^(+)(P<0.001),and CD14^(+)(P=0.044)leukocytes,suggesting elevated inflammatory conditions.Correlations between CD8^(+) T cells and rumen methanogens,Ruminococcaceae,and Lachnospiraceae were recorded,but these were not consistent throughout maturation.Post-weaning,differences in feed intake and rumen microbial composition converged among milk replacer groups,while differences in growth performance(P=0.040)and CD8^(+) cells(P<0.001)were still present.In conclusion,a reduced milk replacer feeding intensity in dairy calves compromised growth performance and immunity and this effect persisted in the long-term.Significant correlations between the proportion of leukocytes and distinct epimural microbe taxa indicated an interplay between rumen epimural colonization and immune functioning of the host.However,further research is required addressing this interplay between rumen epimural microbes and immune functioning in dairy calves.展开更多
The Jerusalem artichoke polysaccharide(JAP)acts as a prebiotic in ruminants.This study investigated the effects of dietary JAP supplementation on growth performance,meat traits,rumen microbes,and metabolome of fatteni...The Jerusalem artichoke polysaccharide(JAP)acts as a prebiotic in ruminants.This study investigated the effects of dietary JAP supplementation on growth performance,meat traits,rumen microbes,and metabolome of fattening lambs.A total of 72 healthy crossbred ram lambs(Small Tail Han sheep×Black Bone sheep),aged three months(body weight=26.21±2.14 kg),were randomly assigned to 12 pens.The pens were evenly divided into two groups:one receiving a basal diet(the CON group)and the other receiving a basal diet supplemented with 0.5%JAP(the JAP group).Compared to the CON group,the JAP group exhibited higher final body weight(P=0.028),average daily gain(ADG)(P=0.013),and carcass weight(P=0.004),as well as a significantly lower feed conversion ratio(FCR)(P=0.015).Compared to the CON group,the concentration of ruminal propionic acid in the JAP group increased(P<0.001),while that of ammonia nitrogen(NH3–N)decreased(P<0.001).Additionally,the JAP group showed increased(P=0.024)serum total protein content and decreased(P=0.005)serum triglyceride content when compared with CON group.Furthermore,higher levels of tryptophan(P=0.040)and erucic acid(C22:1n9)(P=0.010)were detected in the longissimus dorsi muscle of the JAP group compared to the CON group.JAP supplementation altered the rumen microbiota composition at the genus level.This included increases in the relative abundances of Prevotella(P<0.001),Succiniclasticum(P=0.001),UCG-002(P=0.003),Veillonellaceae_UCG-001(P<0.001),Prevotellaceae_UCG-001(P<0.001),and Selenomonas(P<0.001).There were also decreases in the relative abundances of Methanobrevibacter(P=0.014),Rikenellaceae_RC9_gut_group(P<0.001),Olsenella(P<0.001),Ruminococcus(P=0.001),Christensenellaceae_R-7_group(P<0.001),Treponema(P<0.001),Lachnospiraceae_NK3A20_group(P=0.002),Saccharofermentans(P=0.032),Acetitomaculum(P=0.028),[Ruminococcus]_gauvreauii_group(P<0.001),UCG-005(P=0.003),Syntrophococcus(P<0.001),and Methanosphaera(P<0.001).A total of 23 differential metabolites were identified,enriched in 11 metabolic pathways,particularly those related to protein and lipid metabolism between the two groups.In conclusion,dietary JAP affected rumen microbes and metabolites,influenced protein and fat metabolism,improved the fatty acid and amino acid composition in meat,and enhanced the growth and production performance of fattening lambs.展开更多
With an increasing demand for high-quality,eco-friendly food products and growing concerns over ecological conservation,the development of ecology-based alternatives for ruminant production in China is urgently needed...With an increasing demand for high-quality,eco-friendly food products and growing concerns over ecological conservation,the development of ecology-based alternatives for ruminant production in China is urgently needed.This review discusses the capabilities for integrating grassland grazing into existing livestock farming systems to meet the contemporary human needs for high-quality foods and ecologically stable environments.Additionally,this review provides a critical analysis of the challenges and future directions associated with grassland-based ruminant farming systems.Integrating nutritional manipulation with grazing manipulation is critical for improving the productivity of grassland-based ecosystems and natural ecological functions.Biodiversity is the primary determinant of grassland ecosystem functions,while the composition and function of rumen microbiomes determine ruminant production performance.Future studies should focus on the following aspects:1)how livestock grazing regulates grassland biodiversity and the mechanisms of grassland biodiversity maintenance,offering an important scientific basis for guiding grazing manipulation practices,including grazing intensity,livestock types,and grazing management practices;to 2)characterize the microbial ecology within the rumen of grazing ruminants to offer clarified instruction for the nutritional manipulation of grazing ruminants.Our recommendation includes creating a transdisciplinary system that integrates ecology,animal nutrition,and animal behavior to develop grassland-based ruminant farming systems sustainably,thereby achieving high-quality animal production and environmentally sustainable goals.展开更多
基金Supported by National Natural Science Foundation of China(31040081)
文摘In complex digestion and metabolism of rumen, rumen microbes play a decisive role. Currently, the relationship between rumen microbial system and rumen metabolism has not been understood comprehensively, which will be reviewed in the paper, with particular focus on digestion and metabolism of bacteria, fungi and protozoa in the rumen of ruminants.
基金the financial supports for Sheep Feed Evaluation&Feed Table Establishment from the Ministry of Agriculture and Rural Affairs of China(Project No.ZR20MAC10/9)National Natural Science Foundation of China(Project No.31072054).
文摘Ferulic acid(FA)is one of the most abundant hydroxycinnamic acids in the plant world,especially in the cell wall of grain bran,in comparison with forage and crop residues.Previous studies noted that FA was mainly linked with arabinoxylans and lignin in plant cell walls in ester and ether covalent forms.After forages were ingested by ruminant animals or encountered rumen microbial fermentation in vitro,these cross-linkages form physical and chemical barriers to protect cell-wall carbohydrates from microbial attack and enzymatic hydrolysis.Additionally,increasing studies noted that FA presented some toxic effect on microbial growth in the rumen.In recent decades,many studies have addressed the relationships of ester and/or ether-linked FA with rumen nutrient digestibility,and there is still some controversy whether these linkages could be used as a predicator of forage digestibility in ruminants.The authors in this review summarized the possible relationships between ester and/or ether-linked FA and fiber digestion in ruminants.Rumen microbes,especially bacteria and fungi,were found capable of breaking down the ester linkages within plant cell walls by secreting feruloyl and p-coumaroyl esterase,resulting in the release of free FA and improvement of cell wall digestibility.The increasing evidence noted that these esterases secreted by rumen microbes presented synergistic effects with xylanase and cellulase to effectively hydrolyze forage cell walls.Some released FA were absorbed through the rumen wall directly and entered into blood circulation and presented antioxidant effects on host animals.The others were partially catabolized into volatile fatty acids by rumen microbes,and the possible catabolic pathways discussed.To better understand plant cell wall degradation in the rumen,the metabolic fate of FA along with lignin decomposition mechanisms are needed to be explored via future microbial isolation and incubation studies with aims to maximize dietary fiber intake and enhance fiber digestion in ruminant animals.
基金carried out in the framework of the Research on Regulating Mechanism of Amino Acid Composition of Rumen Microorganism in Ruminant Projectthe financial support from the National Natural Science Foundation of China (30571344)
文摘Three goats fitted with cannula were used to provide rumen liquor to investigate the effects of limiting amino acids on rumen fermentation and microbial community in vitro. The removal method was used in the current experiments. Treatments are total essential amino acid （TEAA）, His-removal, Lys-removal, Met-removal, and branch chain amino acid （BCAA）- removal. Results indicated that, pH-value ranged between 5.9 and 6.8, with the highest mean value for the group with BCAA-removal （6.54） in the culture. Concentration of NH3-N ranged between 10.99 to 30.51 mg 100 mL^-1, with the group of TEAA recording the highest average NH3-N concentration （17.85 mg 100 mL^-1）. Yields of microbial protein and limiting degree on microbial growth varied with treatments （P 〈 0.01）, and the lowest accrued in treatment with BCAA-removal （0.1389, 0.1772, and 0.3161 mg mL^-1 for bacteria, protozoa, and mixed microbes, respectively）, compared to the group with TEAA, microbial production of mixed microbes decreased by 44.52%. As for micro-flora, protozoa to bacteria ratio was the lowest for the group with Lys-removal （89.12%）, while the highest for the group with BCAA-removal （127.60%） （P 〈 0.01）. Furthermore, PCR-SSCP analysis revealed that, microbial profile subjected to substrates within bacteria and protozoa groups. It was therefore concluded that, dietary amino acid influenced both rumen fermentation and microbial characteristics.
基金financially supported by the Innovation Foundation for Undergraduate of Yangzhou University,China (201311117034)the Domestic Cooperative Innovation ofIndustry-University-Research(XT20140012)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),China
文摘This study investigated the effects of the degree of unsaturation（unsaturity） of long-chain fatty acids on microbial protein content and the activities of transaminases and dehydrogenase in vitro using goat rumen fluid as the cultural medium.Six types of fatty acids,stearic acid（C18：0,group A,control group）,oleic acid（C18：1,n-9,group B）,linoleic acid（C18：2,n-6,group C）,α-linolenic acid（C18：3,n-3,group D）,arachidonic acid（C20：4,n-6,group E）,and eicosapentaenoic acid（C20：5,n-3,group F）,were tested,and the inclusion ratio of each fatty acid was 3%（w/w） in total of culture substrate.Samples were taken at 0,3,6,9,12,18 and 24 h,respectively,during culture for analyses.Compared with stearic acid,linoleic acid,a-linolenic acid,and arachidonic acid increased the bacterial protein content,while oleic acid and eicosapentaenoic acid had no significant effects;the protozoal protein content was reduced for all the unsaturated fatty acids,and the magnitude of the reduction appeared to be associated with the degree of unsaturity of fatty acids.The total microbial protein content was dominantly accounted by the protozoal protein content（about 4-9 folds of the bacterial protein）,and only increased by linoleic acid,but reduced by oleic acid,arachidonic acid and eicosapentaenoic acid.There were no significant effects in the activities of both glutamic oxaloacetic transaminase（GOT） and glutamic-pyruvic transaminase（GPT） for all the other fatty acids,except for arachidonic acid which enhanced GOT activity and oleic acid which enhanced GPT activity.The total dehydrogenase activity was positively correlated with the degree of unsaturation of fatty acids.In conclusion,the inclusion of 3%of long-chain unsaturated fatty acids increased bacterial protein content,whereas reduced protozoal protein content and enhanced dehydrogenase activity.The fatty acids with more than three double bonds had detrimental effects on the microbial protein content.This work demonstrates for the first time the effect rule of the unsaturation degree of long-chain fatty acids on the rumen microbial protein in vitro.
基金FACCE-JPI program and received funding from the German Federal Ministry of Food and Agriculture(BMEL)through the Federal Office for Agriculture and Food(BLE,Bonn,Germany),grant number 2814ERA04Athe epimural microbiome analysis was financially supported the FBN seed funding program.
文摘The milk replacer feeding regime in dairy calves has a great impact on metabolic and immunological functioning and affects animal welfare and lifetime performance.The feeding regime influences the rumen microbial composition,and epithelium-associated microbes may interact with the immune system of the host.We examined the correlations between blood leukocyte counts and the rumen epithelium-associated microbiome in dairy calves fed 2 different milk replacer feeding intensities and if these factors related to metabolic traits.Fourteen newborn female dairy calves were allocated to a group receiving either 10%(n=7)or 20%(n=7)milk replacer of their body weight(on average 41 kg)and provided ad libitum access to grass hay and concentrate pellets.At 3 weeks of life,all calves were fitted with a rumen cannula.Calves were weaned at 12 weeks of life and received a total mixed ration for ad libitum intake.Pre-(8-10 weeks of life)and post-weaning(21-23 weeks of life),methane production was measured in respiration chambers,and rumen epithelium and blood were sampled for 16S rRNA sequencing and leukocyte analyses,respectively.Pre-weaning,the reduced milk replacer feeding intensity was accompanied with higher concentrate intake but lower growth performance(P<0.001),a higher abundance of amylolytic and lower abundance of cellulolytic epimural microbes.The group fed a low milk replacer intensity had also greater portions of monocytes(P=0.031),CD8^(+)(P<0.001),and CD14^(+)(P=0.044)leukocytes,suggesting elevated inflammatory conditions.Correlations between CD8^(+) T cells and rumen methanogens,Ruminococcaceae,and Lachnospiraceae were recorded,but these were not consistent throughout maturation.Post-weaning,differences in feed intake and rumen microbial composition converged among milk replacer groups,while differences in growth performance(P=0.040)and CD8^(+) cells(P<0.001)were still present.In conclusion,a reduced milk replacer feeding intensity in dairy calves compromised growth performance and immunity and this effect persisted in the long-term.Significant correlations between the proportion of leukocytes and distinct epimural microbe taxa indicated an interplay between rumen epimural colonization and immune functioning of the host.However,further research is required addressing this interplay between rumen epimural microbes and immune functioning in dairy calves.
基金supported by the the National Key R&D program of China-Korea cooperative project(2019YFE0107700,NRF-2019K1 A3 A1 A20081146)the Forage Industrial Innovation Team Project(SDAIT-23-05)the Key R&D program of Shandong Province(2022 TZXD0018).
文摘The Jerusalem artichoke polysaccharide(JAP)acts as a prebiotic in ruminants.This study investigated the effects of dietary JAP supplementation on growth performance,meat traits,rumen microbes,and metabolome of fattening lambs.A total of 72 healthy crossbred ram lambs(Small Tail Han sheep×Black Bone sheep),aged three months(body weight=26.21±2.14 kg),were randomly assigned to 12 pens.The pens were evenly divided into two groups:one receiving a basal diet(the CON group)and the other receiving a basal diet supplemented with 0.5%JAP(the JAP group).Compared to the CON group,the JAP group exhibited higher final body weight(P=0.028),average daily gain(ADG)(P=0.013),and carcass weight(P=0.004),as well as a significantly lower feed conversion ratio(FCR)(P=0.015).Compared to the CON group,the concentration of ruminal propionic acid in the JAP group increased(P<0.001),while that of ammonia nitrogen(NH3–N)decreased(P<0.001).Additionally,the JAP group showed increased(P=0.024)serum total protein content and decreased(P=0.005)serum triglyceride content when compared with CON group.Furthermore,higher levels of tryptophan(P=0.040)and erucic acid(C22:1n9)(P=0.010)were detected in the longissimus dorsi muscle of the JAP group compared to the CON group.JAP supplementation altered the rumen microbiota composition at the genus level.This included increases in the relative abundances of Prevotella(P<0.001),Succiniclasticum(P=0.001),UCG-002(P=0.003),Veillonellaceae_UCG-001(P<0.001),Prevotellaceae_UCG-001(P<0.001),and Selenomonas(P<0.001).There were also decreases in the relative abundances of Methanobrevibacter(P=0.014),Rikenellaceae_RC9_gut_group(P<0.001),Olsenella(P<0.001),Ruminococcus(P=0.001),Christensenellaceae_R-7_group(P<0.001),Treponema(P<0.001),Lachnospiraceae_NK3A20_group(P=0.002),Saccharofermentans(P=0.032),Acetitomaculum(P=0.028),[Ruminococcus]_gauvreauii_group(P<0.001),UCG-005(P=0.003),Syntrophococcus(P<0.001),and Methanosphaera(P<0.001).A total of 23 differential metabolites were identified,enriched in 11 metabolic pathways,particularly those related to protein and lipid metabolism between the two groups.In conclusion,dietary JAP affected rumen microbes and metabolites,influenced protein and fat metabolism,improved the fatty acid and amino acid composition in meat,and enhanced the growth and production performance of fattening lambs.
基金the National Natural Science Foundation of China(No.31772652,31802113)the Program for Introducing Talents to Universities(B16011)the Ministry of Education Innovation Team Development Plan(2013-373).
文摘With an increasing demand for high-quality,eco-friendly food products and growing concerns over ecological conservation,the development of ecology-based alternatives for ruminant production in China is urgently needed.This review discusses the capabilities for integrating grassland grazing into existing livestock farming systems to meet the contemporary human needs for high-quality foods and ecologically stable environments.Additionally,this review provides a critical analysis of the challenges and future directions associated with grassland-based ruminant farming systems.Integrating nutritional manipulation with grazing manipulation is critical for improving the productivity of grassland-based ecosystems and natural ecological functions.Biodiversity is the primary determinant of grassland ecosystem functions,while the composition and function of rumen microbiomes determine ruminant production performance.Future studies should focus on the following aspects:1)how livestock grazing regulates grassland biodiversity and the mechanisms of grassland biodiversity maintenance,offering an important scientific basis for guiding grazing manipulation practices,including grazing intensity,livestock types,and grazing management practices;to 2)characterize the microbial ecology within the rumen of grazing ruminants to offer clarified instruction for the nutritional manipulation of grazing ruminants.Our recommendation includes creating a transdisciplinary system that integrates ecology,animal nutrition,and animal behavior to develop grassland-based ruminant farming systems sustainably,thereby achieving high-quality animal production and environmentally sustainable goals.
