1,354,779 research outputs found
Alpine pasture plant species affect in vitro rumen methane production and kinetics
No full textThis study aimed to evaluate the influence of different plant species widespread in alpine pastures on in vitro rumen fermentation parameters and methane kinetic production. A total of 11 plant species were sampled at the beginning of the grazing season and used as substrates in an in vitro batch fermentation system. After 24h of fermentation, plants affected volatile fatty acids profiles, ammonia yield, and dry matter (DM) digestibilities. Carum carvi, Ranunculus. acris and Festuca rubra showed the highest total production of methane per unit of digested DM while Potentilla erecta was the species that produced less methane. In terms of methane as a percentage of the total gas, F. rubra had the highest value (28.9%) while R. acris had the lowest (24.2%). Total gas and methane production were monitored continuously and the percentage of methane in total gas was fitted with the Gompertz model. Plants differed significantly (p 0.9). The two grasses (F. rubra and Poa alpina) together with Hypericum maculatum showed an opposite behaviour with low values in MFR, A and a longer TMFR. The results of the methane production kinetics allow for an in-depth evaluation of plant species, adding further information to those registered at the end of fermentation
A new equipment for continuous measurement of methane production in a batch in vitro rumen system
No full textA new rumen batch fermentation system that allows continuous measures of total gas (GP) and methane production (MP) was tested. The fermentation system is composed of glass bottles connected to gas counters (Ritter Apparatebau GmbH & Co. KG) and an infrared gas analyser that measures the methane concentration. The system allows direct and continuous measurement of GP and MP for accurate kinetic studies. The aim of the work was to test the rumen fermentation system and compare the GP and MP kinetics obtained. Barley meal (BM), alfalfa hay (AH), corn silage (CS), and soya bean hulls (SH) were used as substrates in four consecutive fermentation runs. Cumulative volumes of GP and MP and the percentage of methane on total GP were recorded continuously until 48 h and average values at 1 h intervals were fitted with an exponential model with a lag phase reaching a good fit (R2 > 0.992). GP and MP reached the highest plateau levels for SH (1836 and 370 ml, respectively; p < 0.01) and the lowest for AH (1000 and 233 ml, respectively). The remaining substrates showed intermediate values. MP kinetics showed a discrete lag phase (from 0.09 to 1.12 h), whereas it was equal to zero for the total GP (except for SH). The methane concentration in gas flowing increased rapidly at the beginning of fermentation (from 0.35 to 0.95 h−1) and reached a plateau after approximately 8–12 h. In conclusion, the rumen fermentation system evaluated generates methane data comparable to those reported in the literature and allows simple continuous measurement of methane release throughout fermentation
A meta-analysis on the relationship between rumen fermentation parameters and protozoa counts in in vitro batch experiments
No full textPresent meta-analysis examines recent in vitro rumen batch experiments where a significant change in the protozoa population was measured after the additions of different substances thought to modify in vitro rumen metabolism. The aim is to study how protozoa number is relating to methane yield and rumen fermentation parameters. Approximately 80 % of the 46 trials from the selected 27 papers (for a total of 201 dietary treatments) tested plant-derived substances, either alone or in mixtures, and 24 trials used rumen fluid from cattle and 22 from sheep. In vitro fermentations with sheep fluid used slightly larger bottles (113 vs 94 mL, P < 0.05), but the inoculum volume, substrate amount, and fermentation duration (38.2 mL, 328.9 mg, and 32.3 h on average, respectively) did not differ (P > 0.05). Only ammonia concentration in cattle fluids was higher compared to sheep (274.2 vs 137.3 mg/L, P < 0.01). Within each trial, we calculated the percentage variation of protozoa compared to control bottles and the majority of the experimental treatments reduced the number of protozoa, by an average of-27.5 %. The relationship between fermentation parameters and variations of pro-tozoa was studied by linear regressions, adjusted for trial effect. In general, protozoa variation in fermentation liquids did not affect total gas production or the sum of volatile fatty acids con-centration. Contrarily, a decrease in protozoa numbers was associated with a significant decrease in methane production, both in absolute terms (R2 = 0.604) and as a proportion of total gas (R2 = 0.528). In terms of individual volatile fatty acids, there was a slight decrease in acetate (R2 = 0.298), an increase in propionate (R2 = 0.388), resulting in a decrease in the acetate: propionate ratio (R2 = 0.379), and no effect of the protozoa on butyrate. Finally, there appeared to be a positive relationship (R2 = 0.580) between protozoa counts and NH3 concentration. In conclusion, rumen protozoa counts of in vitro batch systems are positively associated with methane and ammonia yields, as found in vivo, and this regression study predicts that the com-plete removal of protozoa results in a reduction of about 25 % and 36 % of total ammonia and methane yields, respectively. Batch fermentation systems appear to be appropriate for testing substances that can modulate protozoa counts and related fermentative characteristics
Rumen fermentation parameters and papillae development in Simmental growing bulls with divergent residual feed intake
No full textResidual feed intake (RFI), a widespread index used to measure animal feed efficiency, is influenced by various individual biological factors related to inter-animal variation that need to be assessed. Herein, 30 Simmental bulls, raised under the same farm conditions, were divided on the basis of RFI values into a high efficient group (HE, RFI = − 1.18 ± 0.33 kg DM/d, n = 15) and a low efficient group (LE, RFI = 0.92 ± 0.35 kg DM/d, n = 15). Subsequently, bulls were slaughtered at an average BW of 734 ± 39.4 kg. Their ruminal fermentation traits were analysed immediately after slaughtering and after 24 h of in vitro incubation. Furthermore, ruminal micro-biota composition and ruminal papillae morphology were examined. The LE group exhibited a higher propionate concentration as a percentage of total volatile fatty acids (17.3 vs 16.1%, P = 0.04) in the rumen fluid collected during slaughtering, which was also confirmed after in vitro fermentation (16.6 vs 15.4% respectively for LE and HE, P = 0.01). This phenomenon resulted in a significant alteration in the acetate−to−propionate ratio (A:P) with higher values for the HE group, both after slaughter (4.01 vs 3.66, P = 0.02) and after in vitro incubation (3.78 vs 3.66, P = 0.02). Methane production was similar in both groups either as absolute production (227 vs 218 mL for HE and LE, respectively) or expressed as a percentage of total gas (approximately 22%). Even if significant differences (P < 0.20) in the relative abundance of some bacterial genera were observed for the two RFI groups, no significant variations were observed in the alpha (Shannon index) and beta (Bray–Curtis index) diversity. Considering the papillae morphology, the LE subjects have shown higher length values (6.26 vs 4.90 mm, P < 0.01) while HE subjects have demonstrated higher papillae density (46.4 vs 40.5 n/cm2, P = 0.02). Histo-morphometric analysis did not reveal appreciable modifications in the total papilla thickness, boundaries or surface between the experimental groups. In conclusion, our results contribute to efforts to analyse the factors affecting feed efficiency at the ruminal level. Propionate production, papillae morphology and a few bacterial genera certainly play a role in this regard, although not a decisive one
Green synthesis of Ag nanoparticles using plant metabolites
No full textNano-biotechnology is one of the most promising areas in modern nanoscience and technology. In this
emerging area of research, nanoparticles (NPs) play an important role since the large-scale production and huge numbers
of utilization. Gold and silver nanoparticles are among the most extensively studied nanomaterials, since they show high
stability and low chemical reactivity in comparison to other metals. They are commonly synthesized using toxic chemical
reducing agents able to reduce metal ions into uncharged NPs and/or high energy supplied procedures. The most
commonly used method for the synthesis of NPs requires toxic chemicals like N,N-dimethyl formamide (DMF) or
trisodium citrate, but recently a green technique, based on natural reducing agents, has been suggested to substitute the
nature-unfriendly chemical methods. Many scientific works put in evidence the efficacy of plant extracts to reduce metal
salts into the respective NPs, but this process lacks a clear control of NPs shapes and dimensions, since many different
metabolites present into the extracts could participate to the process. This paper aims to clarify the reducing action of
single pure natural compounds usually present in plant tissues and to obtain a stable and reproducible protocol for NPs
synthesis
Multiple production of W bosons in p p and p A collisions
No full textThe production of equal sign W boson pairs, through single and dou- ble parton collisions, are comparable in magnitude at the LHC. As a consequence of the strong anti-shadowing of MPI in interactions with nuclei, the double scattering contribution is further enhanced in the case of hadron-nucleus collision
Electrogenic bromosulfalein transport in isolated membrane vesicles: implementation in both animal and plant preparations for the study of flavonoid transporters
No full textBromosulfalein is an organic anion dye used in the study of a variety of membrane carriers expressed inanimal tissues and involved in transport of drugs and metabolites. The spectrophotometric assay of electrogenicbromosulfalein transport in membrane vesicles, isolated from various mammalian organs or tissues, enablesto specifically measure the transport activity of bilitranslocase (TCDB 2.A.65.1.1). The latter is a bilirubin- andflavonoid-specific transporter expressed in rat liver, the organ where its function has been better characterized. Thespectrophotometric assay of electrogenic bromosulfalein transport requires minimal volumes of membrane vesicles,is completed within 1 min, and, therefore, is a useful tool to screen the transporter spectrum of potential substrates,by testing them as reversible inhibitors of bromosulfalein transport kinetics. Furthermore, the assay enables tostudy the progress of time-dependent inactivation of bromosulfalein transport, caused by different protein-specificreagents, including specific anti-sequence antibodies. Inactivation can be retarded by the presence of substratesin a concentration-dependent manner, enabling to derive the dissociation constants of the transporter–substratecomplex and thus to gain further insight into the transporter structure–function relationship. This assay, implementedin membrane vesicles isolated from plant organs, has paved the way to the discovery of homologues of bilitranslocasein plants
Ecophysiological response of maize (Zea mays L.) to water stress: remote sensing and upscaling techniques for a more efficient management of water resources in agriculture
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