References of "Blaise, Yannick"
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See detailEffects of new potential prebiotics on Salmonella Thyphimurium in pigs
Tran, Thi Hanh Tham; Everaert, Nadia ULg; Boudry, Christelle et al

Conference (2016, April 15)

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See detailLINKING CATTLE GRAZING BEHAVIOR TO METHANE AND CARBON DIOXIDE DYNAMICS
Blaise, Yannick ULg; Lebeau, Frédéric ULg; Andriamandroso, Andriamasinoro ULg et al

in Communications in Agricultural and Applied Biological Sciences (2016, February), 81(1), 107-112

Various methods are presently used to measure methane (CH4) emissions of ruminants on pasture. Those measurements are essential to evaluate nutritional strategies to mitigate enteric CH4 emissions as well ... [more ▼]

Various methods are presently used to measure methane (CH4) emissions of ruminants on pasture. Those measurements are essential to evaluate nutritional strategies to mitigate enteric CH4 emissions as well as addressing the selection of low producing individuals. On pasture and in the barn, variations in CH4 emissions are observed depending on the time of the day. However, no studies have been made to link these diurnal fluctuations to behavioural phases, especially on pasture. The aim of this study was to understand the individual dynamics of CH4 production and their links to the grazing behaviour. For this purpose, a new tool was specifically developed. Five red-pied dry cows were equipped with infrared CH4 and carbon dioxide (CO2) sensors measuring concentrations in the exhaled air at 4 Hz. The animals were equipped with a heart rate belt (HR) and motion sensors to detect their feeding behaviours (grazing vs. rumination) for periods of 8 h/d. Wind speed (WS) was also monitor to verify interference with sampled gas concentrations. Results showed that using the CH4:CO2 ratio reduced the interference with WS that was observed on raw CH4 and CO2 concentration signals. CH4:CO2 ratio average over 5 min periods indicated that CH4 emissions were lower during grazing than rumination (P<0.01). The eructation frequency during grazing (0.48 eructation/min, P<0.01) was also lower than during rumination (0.65 eructation/min). HR was higher during grazing that rumination. Because HR is usually linked to metabolic CO2 production intensity, hence influencing the denominator of the CH4:CO2 ratio, further investigation should focus on the quantification of changes in fermentative and metabolic CO2 emissions along the day to estimate total CH4 production more accurately and the relationship between CH4 emissions patterns and post-feeding times. [less ▲]

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See detailHigh rate monitoring CH4 production dynamics and their link with behavioral phases in cattle
Blaise, Yannick ULg; Lebeau, Frédéric ULg; Andriamandroso, Andriamasinoro ULg et al

in EAAP – 67 th Annual Meeting, Belfast 2016 (2016)

Microbial fermentation in the rumen produces methane (CH4) which is a loss of energy for ruminants and also contributes to global warming. While the respiration chamber is the standard reference for CH4 ... [more ▼]

Microbial fermentation in the rumen produces methane (CH4) which is a loss of energy for ruminants and also contributes to global warming. While the respiration chamber is the standard reference for CH4 emissions quantification, daily CH4 production dynamics can be measured only by steps of 30 min and measurements on pasture are impossible. The alternative method using SF6 as tracer gas can be applied for grazing animals but provides average CH4 production values over at least several hours, making it impossible to measure short term dynamics of rumen CH4 production with changing animal behavior along the day. Newly developed methods using CO2 as internal tracer gas extrapolate CH4 emissions from few short measurements. However, both CO2 and CH4 emissions fluctuate during the day depending on the behavior and the post-feeding times questioning the validity of this method. Therefore, an innovative device was developed to monitor at a high rate CH4 and CO2 emission dynamics in order to investigate the link between CH4 dynamics and the animal behavior on pasture. Preliminary results showed the ability of the device to record differences in CH4:CO2 ratios and eructation frequencies according to the individual and the behavior. Results from complementary experiments in barn with animals fed contrasting diets regarding CH4 production (with and without linseed) and on pasture with different forage allowance will be presented in order to highlight how post-feeding time and grazing behavior impact CO2 and CH4 emission dynamics along the day. [less ▲]

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See detailA mucin-enriched fermentation model to assess prebiotic potential of new indigestible carbohydrates
Boudry, Christelle ULg; Tran, Thi Hanh Tham ULg; Blaise, Yannick ULg et al

in 64th Annual Meeting of the European Federation of Animal Science (2013, August 29)

Screening the prebiotic potential of novel indigestible carbohydrates (ICH) is a challenge for feed and food industry and in vitro models are increasingly used for such purposes. Recently extracellular ... [more ▼]

Screening the prebiotic potential of novel indigestible carbohydrates (ICH) is a challenge for feed and food industry and in vitro models are increasingly used for such purposes. Recently extracellular binding proteins responsible for the adherence to intestinal mucus were described for several Lactobacillus species. As this genus is known for its beneficial effect on gut health, we enriched the in vitro gas fermentation model with mucin in order to evaluate the prebiotic potential of 5 ICH. Mucin-coated microcosms (MCM) were prepared as described by Van den Abbeele et al. (2012, Microbial Biotechnology, 5, 106-115) and introduced in the fermentation bottles with an inoculum prepared from fresh faeces of 3 sows mixed with a nutritive buffer solution. Fermentation was performed at 39°C, using 200 mg of substrate, 30 ml of inoculum and 6 MCM, yielding approx. 20 mg mucin each, in 140 ml glass bottles. A first study was performed with inulin and cellulose as substrates, with and without mucus in the bottles. A second study was performed with 5 substrates (inulin, IMO, beet pulp POS, cellobiose and gluconate) in presence of mucus. After 8 and 72h, SCFA and the microflora of fermentation broth was analysed as well as the microflora on the MCM. The comparison of the microflora evolution with and without mucus showed a better development of the Lactobacillus in the fermentation broth, mainly in presence of inulin. The development of the Lactobacillus genus allowed the classification of the 5 substrates tested in the second study (Inulin > IMO > Gluconate > Cellobiose > POS)(P < 0.05) which was not possible without mucus (P > 0.05). Inulin and IMO showed also the highest development of Bifidobacteria (P < 0.05) and the highest levels of butyrate production (P < 0.05) compared to the three other substrates, indicating a high prebiotic potential. [less ▲]

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See detailIn vitro determination of prebiotic potential of sugar beet pulp extracted candidates and influence of production method
François, Emmanuelle ULg; Goffin, Dorothée ULg; combo, Agnan Marie-Michelle et al

Poster (2012, June 12)

Various prebiotic hydrolysates were produced starting from sugar beet pulp (SBP) using alternative solution to traditional acidic hydolysis. SBP pectin was first extracted by acid extraction and ethanol ... [more ▼]

Various prebiotic hydrolysates were produced starting from sugar beet pulp (SBP) using alternative solution to traditional acidic hydolysis. SBP pectin was first extracted by acid extraction and ethanol precipitation. Then two technics are used to produced pectic oligosaccharides (POS) : enzymatic hydrolysis (EnzPOS : Rapidase Smart (DSM) ; 50°C ; pH 5) and microwaves-assisted hydrolysis (MW1POS : 104°C/10min/pH 7; MW2POS : 110°C/15min/pH 7). Structural characterization of fractions gave rise to different structural profiles between the four products. Moreover, fermentation parameters obtained in-vitro (A, B, Rmax and Tmax) were also characteristic of the fractions and in favor of a tight relationship between POS structure and POS function. Finally, to avoid solvent use, POS production could be envisaged directly on SBP. Avoiding the step of acidic extraction will allow to meet the green chemistry principles. [less ▲]

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See detailImpact of mixing imperfections on yeast bioreactor performances: Scale-down reactor concept and related experimental tools
Delvigne, Frank ULg; Blaise, Yannick ULg; Destain, Jacqueline ULg et al

in Cerevisia and Biotechnology (2012), 37

A method combining environmental data extracted from the dissolved oxygen profile of a fed-batch bioreactor and a dynamic discrete Markov chain model has been presented in order to give more insight about ... [more ▼]

A method combining environmental data extracted from the dissolved oxygen profile of a fed-batch bioreactor and a dynamic discrete Markov chain model has been presented in order to give more insight about the glucose and dissolved oxygen fluctuations experienced by the microorganisms during cultivation in heterogeneous bioreactor. The fed-batch cultivation of Saccharomyces cerevisiae has been performed in a well-mixed and a partitioned scale-down reactor (SDR). The analysis of the environmental sequences has shown extended time lengths for the glucose availability and depletion sequences in the case of the SDR under a DO-controlled fed-batch culture. The Markov chain model developed in this work is able to capture the stochastic environmental events, i.e. in our case the environmental states experienced by the microorganisms crossing the tubular part of the SDR. The simulation results show clearly an extension of the starvation periods in the case of the culture performed in the SDR. The simulations have been performed at the single cells level allowing future improvements of our model and notably in the context of the population segregation phenomena occurring in fed-batch cultures. As a perspective, flow cytometry has been presented as a high-throughput analytical tool for the investigation of yeast physiology at the single cell level and in process-related conditions. [less ▲]

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