The Experts below are selected from a list of 228 Experts worldwide ranked by ideXlab platform
Evelyne Forano - One of the best experts on this subject based on the ideXlab platform.
-
live yeasts enhance Fibre Degradation in the cow rumen through an increase in plant substrate colonization by fibrolytic bacteria and fungi
Journal of Applied Microbiology, 2016Co-Authors: Frederique Chaucheyrasdurand, A. Ameilbonne, A. Bichat, Faisury Ossa, Pascale Mosoni, Evelyne ForanoAbstract:AimsTo monitor the effect of a live yeast additive on feedstuff colonization by targeted fibrolytic micro-organisms and Fibre Degradation in the cow rumen. Methods and ResultsAbundance of adhering fibrolytic bacteria and fungi on feedstuffs incubated in sacco in the cow rumen was quantified by qPCR and neutral detergent Fibre (NDF) Degradation was measured. Saccharomyces cerevisiae I-1077 (SC) increased the abundance of Fibre-associated Fibrobacter succinogenes on wheat bran (WB) and that of Ruminococcus flavefaciens on alfalfa hay (AH) and wheat silage (WS). The greatest effect was observed on the abundance of Butyrivibrio fibrisolvens on AH and soya hulls (SH) (P<0001). Fungal biomass increased on AH, SH, WS and WB in the presence of SC. NDF Degradation of AH and SH was improved (P<005) with SC supplementation. ConclusionsLive yeasts enhanced microbial colonization of fibrous materials, the degree of enhancement depended on their nature and composition. As an effect on rumen pH was not likely to be solely involved, the underlying mechanisms could involve nutrient supply or oxygen scavenging by the live yeast cells. Significance and Impact of the StudyDistribution of this microbial additive could be an interesting tool to increase Fibre digestion in the rumen and thereby improve cow feed efficiency.
-
Live yeasts enhance Fibre Degradation in the cow rumen through an increase in plant substrate colonization by fibrolytic bacteria and fungi
Journal of Applied Microbiology, 2016Co-Authors: F. Chaucheyras-durand, A. Ameilbonne, A. Bichat, Faisury Ossa, Pascale Mosoni, Evelyne ForanoAbstract:AIMS: To monitor the effect of a live yeast additive on feedstuff colonisation by targeted fibrolytic microorganisms and Fibre Degradation in the cow rumen.\n\nMETHODS AND RESULTS: Abundance of adhering fibrolytic bacteria and fungi on feedstuffs incubated in sacco in the cow rumen was quantified by qPCR and neutral detergent Fibre (NDF) Degradation was measured. Saccharomyces cerevisiae I-1077 (SC) increased the abundance of Fibre-associated Fibrobacter succinogenes on wheat bran (WB) and that of Ruminococcus flavefaciens on alfalfa hay (AH) and wheat silage (WS). The greatest effect was observed on the abundance of Butyrivibrio fibrisolvens on AH and soya hulls (SH) (P
-
methionine analogues hmb and hmbi increase the abundance of cellulolytic bacterial representatives in the rumen of cattle with no direct effects on Fibre Degradation
Animal Feed Science and Technology, 2013Co-Authors: C Martin, Evelyne Forano, C. Mirande, D P Morgavi, Estelle Devillard, Pascale MosoniAbstract:Abstract Supplementation of diets for ruminants with methionine analogues such as 2-hydroxy-4-(methylthio) butanoic acid (HMB) and its isopropyl ester (HMBi) positively affect milk composition and yield, potentially partly through ruminal actions. Our objective was to investigate effects of HMB and HMBi on the rumen microbial ecosystem, with special emphasis on fibrolytic activities and fibrolytic microorganisms. Six ruminally cannulated Holstein dry cows were randomly assigned to three treatments in a 3 × 3 Latin square design with two cows per cell. Cows were fed twice a day at 7.5 kg/d dry matter (DM) intake with a control diet based on hay and wheat (50/50 on a DM basis) supplemented or not with HMB (Rhodimet ® AT88, Adisseo at 1.25 g/kg DM intake) or HMBi (MetaSmart™, Adisseo, at 2.50 g/kg DM intake). Substrate degradability ( i.e. , corn grain, corn silage) was evaluated by in sacco incubation and effective degradability measurements of DM, crude protein, starch and neutral detergent Fibre. Fermentation products ( i.e. , volatile fatty acids (VFAs), ammonia, lactate) and fibrolytic enzyme activities ( i.e. , carboxymethylcellulase (CMCase), xylanase) were analyzed in rumen content samples before (−1 h) and after (+3 h) feeding. Protozoal populations were counted by microscopy. Abundances in total and fibrolytic bacteria Fibrobacter succinogenes , Ruminococcus flavefaciens and Ruminococcus albus in total rumen contents or adhering to in sacco residues were estimated using quantitative polymerase-chain reaction (qPCR). HMB and HMBi supplementation increased VFA concentrations in the rumen as well as the ruminal abundance of F. succinogenes (P=0.03) and R. flavefaciens (P=0.05), although these increases had no effect on the CMCase and xylanase activities of the rumen contents, nor on in sacco bacterial colonization and Degradation of the two corn substrates. Under our experimental conditions, Met analogues enhanced growth of two cellulolytic bacterial representatives, but did not improve rumen fibrolytic activity.
-
use of yeast probiotics in ruminants effects and mechanisms of action on rumen ph Fibre Degradation and microbiota according to the diet
2012Co-Authors: Frederique Chaucheyrasdurand, Eric Chevaux, C Martin, Evelyne ForanoAbstract:© 2012 Chaucheyras-Durand et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Use of Yeast Probiotics in Ruminants: Effects and Mechanisms of Action on Rumen pH, Fibre Degradation, and Microbiota According to the Diet
-
Dietary Fibre Degradation and fermentation by two xylanolytic bacteria Bacteroides xylanisolvens XB1AT and Roseburia intestinalis XB6B4 from the human intestine
Journal of applied microbiology, 2010Co-Authors: C. Mirande, Evelyne Forano, E. Kadlecikova, Mária Matulová, P. Capek, A. Bernalier‐donadille, Christel Béra-mailletAbstract:AimsZ: To characterize Fibre Degradation, colonization and fermentation, and xylanase activity of two xylanolytic bacteria Bacteroides xylanisolvens XB1AT and Roseburia intestinalis XB6B4 from the human colon. Methods and Results: The bacteria grew well on all the substrates chosen to represent dietary Fibres: wheat and corn bran, pea, cabbage and leek Fibres, and also on purified xylans. Roseburia intestinalis colonized the substrates more efficiently than Bact. xylanisolvens. For the two bacteria, 80–99% of the total xylanase activity was associated with the cells whatever the substrate and time of growth. Optimal specific activities of cells were obtained on oat spelt xylan; they were higher than those previously measured for xylanolytic bacteria from the human gut. Roseburia intestinalis produced high molecular mass xylanases (100–70 kDa), while Bact. xylanisolvens produced lower molecular mass enzymes, including a cell-associated xylanase of 37 kDa. Conclusions: The two bacteria display very high xylanolytic activity on the different substrates. Differences were observed on substrate attachment and enzyme systems, suggesting that the two species occupy different niches within the gut microbiota. Significance and Impact of the Study: This study characterizes xylan Degradation by two major species of the human intestine.
Diletta Sciti - One of the best experts on this subject based on the ideXlab platform.
-
is spark plasma sintering suitable for the densification of continuous carbon Fibre uhtcmcs
Journal of The European Ceramic Society, 2020Co-Authors: Luca Zoli, Pietro Galizia, Antonio Vinci, C F Gutierrezgonzalez, Sergio Rivera, Diletta ScitiAbstract:Abstract For the first time we show that spark plasma sintering can efficiently replace hot pressing for the densification of UHTCMCs, in the present case ZrB2/SiC composites reinforced with continuous carbon Fibres. To this purpose, the same materials were first produced by hot pressing as baseline samples and then by spark plasma sintering (SPS) to compare microstructure and basic mechanical properties. A special emphasis was given to the study of interfaces, in case of both coated and uncoated carbon Fibres. SPS allowed for faster sintering but required an adjustment of the temperature to avoid Fibre Degradation compared to hot pressing. With similar porosity levels, we observed a slight decrease of flexural strength (300 vs 470 MPa), and an improvement of fracture toughness (15 vs 10 MPa√m) for SPSed samples. SPS was proved to be an effective method for the consolidation of continuous Fibre reinforced UHTC composites.
-
mechanical behaviour of carbon Fibre reinforced tac sic and zrc sic composites up to 2100 c
Journal of The European Ceramic Society, 2019Co-Authors: Antonio Vinci, Greg Hilmas, Jeremy Lee Watts, Luca Zoli, Diletta Sciti, William G FahrenholtzAbstract:Abstract The microstructure and elevated temperature mechanical properties of continuous carbon Fibre reinforced ZrC and TaC composites were investigated. Silicon carbide was added to both compositions to aid sintering during hot pressing. Fibres were homogeneously distributed and no Fibre Degradation was observed at the interface with the ceramic matrix even after testing at 2100 °C. The flexural strength increased from 260 to 300 MPa at room temperature to ∼450 MPa at 1500 °C, which was attributed to stress relaxation. At 1800 °C, the strength decreased to ∼410 MPa for both samples. At 2100 °C plastic deformation resulted in lower strength at the proportional limit (210–320 MPa), but relatively high ultimate strength (370–440 MPa). The sample containing ZrC had a lower ultimate strength, but higher failure strain at 2100 °C due to the weak Fibre/matrix interface that resulted in Fibre-dominated composite behaviour.
-
rapid spark plasma sintering to produce dense uhtcs reinforced with undamaged carbon Fibres
Materials & Design, 2017Co-Authors: Luca Zoli, Antonio Vinci, Michael J. Reece, Diletta Sciti, Laura Silvestroni, Salvatore GrassoAbstract:Abstract Short Fibre reinforced ceramic composites, based on ZrB2 with a carbon Fibre content of 45 vol%, were produced by ball-milling and rapid Spark Plasma Sintering (SPS) at 1800–2300 °C by varying the holding times. Careful control of the sintering parameters, such as the heating rate, dwell temperature and holding time are required to produce a fully dense matrix and avoid Fibre Degradation. The sintered materials were characterized in terms of relative density, morphology of the Fibres and microstructural features of the matrix. The final residual porosity ranged from 16 to 3 vol%. The carbon Fibres maintained their original morphology and the matrix consisted of ZrB2, SiC and ZrC phases. In spite of the good adhesion between the Fibre surface and the matrix promoted by SPS processing, extensive Fibre pull-out was observed in the fracture surfaces of all of the composites sintered at or below 1900 °C.
Antonio Vinci - One of the best experts on this subject based on the ideXlab platform.
-
is spark plasma sintering suitable for the densification of continuous carbon Fibre uhtcmcs
Journal of The European Ceramic Society, 2020Co-Authors: Luca Zoli, Pietro Galizia, Antonio Vinci, C F Gutierrezgonzalez, Sergio Rivera, Diletta ScitiAbstract:Abstract For the first time we show that spark plasma sintering can efficiently replace hot pressing for the densification of UHTCMCs, in the present case ZrB2/SiC composites reinforced with continuous carbon Fibres. To this purpose, the same materials were first produced by hot pressing as baseline samples and then by spark plasma sintering (SPS) to compare microstructure and basic mechanical properties. A special emphasis was given to the study of interfaces, in case of both coated and uncoated carbon Fibres. SPS allowed for faster sintering but required an adjustment of the temperature to avoid Fibre Degradation compared to hot pressing. With similar porosity levels, we observed a slight decrease of flexural strength (300 vs 470 MPa), and an improvement of fracture toughness (15 vs 10 MPa√m) for SPSed samples. SPS was proved to be an effective method for the consolidation of continuous Fibre reinforced UHTC composites.
-
mechanical behaviour of carbon Fibre reinforced tac sic and zrc sic composites up to 2100 c
Journal of The European Ceramic Society, 2019Co-Authors: Antonio Vinci, Greg Hilmas, Jeremy Lee Watts, Luca Zoli, Diletta Sciti, William G FahrenholtzAbstract:Abstract The microstructure and elevated temperature mechanical properties of continuous carbon Fibre reinforced ZrC and TaC composites were investigated. Silicon carbide was added to both compositions to aid sintering during hot pressing. Fibres were homogeneously distributed and no Fibre Degradation was observed at the interface with the ceramic matrix even after testing at 2100 °C. The flexural strength increased from 260 to 300 MPa at room temperature to ∼450 MPa at 1500 °C, which was attributed to stress relaxation. At 1800 °C, the strength decreased to ∼410 MPa for both samples. At 2100 °C plastic deformation resulted in lower strength at the proportional limit (210–320 MPa), but relatively high ultimate strength (370–440 MPa). The sample containing ZrC had a lower ultimate strength, but higher failure strain at 2100 °C due to the weak Fibre/matrix interface that resulted in Fibre-dominated composite behaviour.
-
rapid spark plasma sintering to produce dense uhtcs reinforced with undamaged carbon Fibres
Materials & Design, 2017Co-Authors: Luca Zoli, Antonio Vinci, Michael J. Reece, Diletta Sciti, Laura Silvestroni, Salvatore GrassoAbstract:Abstract Short Fibre reinforced ceramic composites, based on ZrB2 with a carbon Fibre content of 45 vol%, were produced by ball-milling and rapid Spark Plasma Sintering (SPS) at 1800–2300 °C by varying the holding times. Careful control of the sintering parameters, such as the heating rate, dwell temperature and holding time are required to produce a fully dense matrix and avoid Fibre Degradation. The sintered materials were characterized in terms of relative density, morphology of the Fibres and microstructural features of the matrix. The final residual porosity ranged from 16 to 3 vol%. The carbon Fibres maintained their original morphology and the matrix consisted of ZrB2, SiC and ZrC phases. In spite of the good adhesion between the Fibre surface and the matrix promoted by SPS processing, extensive Fibre pull-out was observed in the fracture surfaces of all of the composites sintered at or below 1900 °C.
Luca Zoli - One of the best experts on this subject based on the ideXlab platform.
-
is spark plasma sintering suitable for the densification of continuous carbon Fibre uhtcmcs
Journal of The European Ceramic Society, 2020Co-Authors: Luca Zoli, Pietro Galizia, Antonio Vinci, C F Gutierrezgonzalez, Sergio Rivera, Diletta ScitiAbstract:Abstract For the first time we show that spark plasma sintering can efficiently replace hot pressing for the densification of UHTCMCs, in the present case ZrB2/SiC composites reinforced with continuous carbon Fibres. To this purpose, the same materials were first produced by hot pressing as baseline samples and then by spark plasma sintering (SPS) to compare microstructure and basic mechanical properties. A special emphasis was given to the study of interfaces, in case of both coated and uncoated carbon Fibres. SPS allowed for faster sintering but required an adjustment of the temperature to avoid Fibre Degradation compared to hot pressing. With similar porosity levels, we observed a slight decrease of flexural strength (300 vs 470 MPa), and an improvement of fracture toughness (15 vs 10 MPa√m) for SPSed samples. SPS was proved to be an effective method for the consolidation of continuous Fibre reinforced UHTC composites.
-
mechanical behaviour of carbon Fibre reinforced tac sic and zrc sic composites up to 2100 c
Journal of The European Ceramic Society, 2019Co-Authors: Antonio Vinci, Greg Hilmas, Jeremy Lee Watts, Luca Zoli, Diletta Sciti, William G FahrenholtzAbstract:Abstract The microstructure and elevated temperature mechanical properties of continuous carbon Fibre reinforced ZrC and TaC composites were investigated. Silicon carbide was added to both compositions to aid sintering during hot pressing. Fibres were homogeneously distributed and no Fibre Degradation was observed at the interface with the ceramic matrix even after testing at 2100 °C. The flexural strength increased from 260 to 300 MPa at room temperature to ∼450 MPa at 1500 °C, which was attributed to stress relaxation. At 1800 °C, the strength decreased to ∼410 MPa for both samples. At 2100 °C plastic deformation resulted in lower strength at the proportional limit (210–320 MPa), but relatively high ultimate strength (370–440 MPa). The sample containing ZrC had a lower ultimate strength, but higher failure strain at 2100 °C due to the weak Fibre/matrix interface that resulted in Fibre-dominated composite behaviour.
-
rapid spark plasma sintering to produce dense uhtcs reinforced with undamaged carbon Fibres
Materials & Design, 2017Co-Authors: Luca Zoli, Antonio Vinci, Michael J. Reece, Diletta Sciti, Laura Silvestroni, Salvatore GrassoAbstract:Abstract Short Fibre reinforced ceramic composites, based on ZrB2 with a carbon Fibre content of 45 vol%, were produced by ball-milling and rapid Spark Plasma Sintering (SPS) at 1800–2300 °C by varying the holding times. Careful control of the sintering parameters, such as the heating rate, dwell temperature and holding time are required to produce a fully dense matrix and avoid Fibre Degradation. The sintered materials were characterized in terms of relative density, morphology of the Fibres and microstructural features of the matrix. The final residual porosity ranged from 16 to 3 vol%. The carbon Fibres maintained their original morphology and the matrix consisted of ZrB2, SiC and ZrC phases. In spite of the good adhesion between the Fibre surface and the matrix promoted by SPS processing, extensive Fibre pull-out was observed in the fracture surfaces of all of the composites sintered at or below 1900 °C.
Pascale Mosoni - One of the best experts on this subject based on the ideXlab platform.
-
live yeasts enhance Fibre Degradation in the cow rumen through an increase in plant substrate colonization by fibrolytic bacteria and fungi
Journal of Applied Microbiology, 2016Co-Authors: Frederique Chaucheyrasdurand, A. Ameilbonne, A. Bichat, Faisury Ossa, Pascale Mosoni, Evelyne ForanoAbstract:AimsTo monitor the effect of a live yeast additive on feedstuff colonization by targeted fibrolytic micro-organisms and Fibre Degradation in the cow rumen. Methods and ResultsAbundance of adhering fibrolytic bacteria and fungi on feedstuffs incubated in sacco in the cow rumen was quantified by qPCR and neutral detergent Fibre (NDF) Degradation was measured. Saccharomyces cerevisiae I-1077 (SC) increased the abundance of Fibre-associated Fibrobacter succinogenes on wheat bran (WB) and that of Ruminococcus flavefaciens on alfalfa hay (AH) and wheat silage (WS). The greatest effect was observed on the abundance of Butyrivibrio fibrisolvens on AH and soya hulls (SH) (P<0001). Fungal biomass increased on AH, SH, WS and WB in the presence of SC. NDF Degradation of AH and SH was improved (P<005) with SC supplementation. ConclusionsLive yeasts enhanced microbial colonization of fibrous materials, the degree of enhancement depended on their nature and composition. As an effect on rumen pH was not likely to be solely involved, the underlying mechanisms could involve nutrient supply or oxygen scavenging by the live yeast cells. Significance and Impact of the StudyDistribution of this microbial additive could be an interesting tool to increase Fibre digestion in the rumen and thereby improve cow feed efficiency.
-
Live yeasts enhance Fibre Degradation in the cow rumen through an increase in plant substrate colonization by fibrolytic bacteria and fungi
Journal of Applied Microbiology, 2016Co-Authors: F. Chaucheyras-durand, A. Ameilbonne, A. Bichat, Faisury Ossa, Pascale Mosoni, Evelyne ForanoAbstract:AIMS: To monitor the effect of a live yeast additive on feedstuff colonisation by targeted fibrolytic microorganisms and Fibre Degradation in the cow rumen.\n\nMETHODS AND RESULTS: Abundance of adhering fibrolytic bacteria and fungi on feedstuffs incubated in sacco in the cow rumen was quantified by qPCR and neutral detergent Fibre (NDF) Degradation was measured. Saccharomyces cerevisiae I-1077 (SC) increased the abundance of Fibre-associated Fibrobacter succinogenes on wheat bran (WB) and that of Ruminococcus flavefaciens on alfalfa hay (AH) and wheat silage (WS). The greatest effect was observed on the abundance of Butyrivibrio fibrisolvens on AH and soya hulls (SH) (P
-
methionine analogues hmb and hmbi increase the abundance of cellulolytic bacterial representatives in the rumen of cattle with no direct effects on Fibre Degradation
Animal Feed Science and Technology, 2013Co-Authors: C Martin, Evelyne Forano, C. Mirande, D P Morgavi, Estelle Devillard, Pascale MosoniAbstract:Abstract Supplementation of diets for ruminants with methionine analogues such as 2-hydroxy-4-(methylthio) butanoic acid (HMB) and its isopropyl ester (HMBi) positively affect milk composition and yield, potentially partly through ruminal actions. Our objective was to investigate effects of HMB and HMBi on the rumen microbial ecosystem, with special emphasis on fibrolytic activities and fibrolytic microorganisms. Six ruminally cannulated Holstein dry cows were randomly assigned to three treatments in a 3 × 3 Latin square design with two cows per cell. Cows were fed twice a day at 7.5 kg/d dry matter (DM) intake with a control diet based on hay and wheat (50/50 on a DM basis) supplemented or not with HMB (Rhodimet ® AT88, Adisseo at 1.25 g/kg DM intake) or HMBi (MetaSmart™, Adisseo, at 2.50 g/kg DM intake). Substrate degradability ( i.e. , corn grain, corn silage) was evaluated by in sacco incubation and effective degradability measurements of DM, crude protein, starch and neutral detergent Fibre. Fermentation products ( i.e. , volatile fatty acids (VFAs), ammonia, lactate) and fibrolytic enzyme activities ( i.e. , carboxymethylcellulase (CMCase), xylanase) were analyzed in rumen content samples before (−1 h) and after (+3 h) feeding. Protozoal populations were counted by microscopy. Abundances in total and fibrolytic bacteria Fibrobacter succinogenes , Ruminococcus flavefaciens and Ruminococcus albus in total rumen contents or adhering to in sacco residues were estimated using quantitative polymerase-chain reaction (qPCR). HMB and HMBi supplementation increased VFA concentrations in the rumen as well as the ruminal abundance of F. succinogenes (P=0.03) and R. flavefaciens (P=0.05), although these increases had no effect on the CMCase and xylanase activities of the rumen contents, nor on in sacco bacterial colonization and Degradation of the two corn substrates. Under our experimental conditions, Met analogues enhanced growth of two cellulolytic bacterial representatives, but did not improve rumen fibrolytic activity.