scholarly journals Effects of dilution rate and retention time of concentrate on efficiency of microbial growth, methane production, and ruminal fermentation in Rusitec fermenters

2009 ◽  
Vol 92 (8) ◽  
pp. 3930-3938 ◽  
Author(s):  
M.E. Martínez ◽  
M.J. Ranilla ◽  
S. Ramos ◽  
M.L. Tejido ◽  
M.D. Carro
Animals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1316
Author(s):  
Jairo García-Rodríguez ◽  
Cristina Saro ◽  
Iván Mateos ◽  
Jesús S. González ◽  
María Dolores Carro ◽  
...  

Citrus pulp is a highly abundant by-product of the citrus industry. The aim of this study was to assess the effects of replacing extruded maize (EM; 20% of total diet) by dried citrus pulp (DCP; 20%) in a mixed diet on rumen fermentation and microbial populations in Rusitec fermenters. The two diets contained 50% alfalfa hay and 50% concentrate, and the same protein level. Four Rusitec fermenters were used in a cross-over design with two 13-d incubation runs. After 7-d of diet adaptation, diet disappearance, fermentation parameters, microbial growth, and microbial populations were assessed. Fermenters receiving the DCP showed greater pH values and fiber disappearance (p < 0.001) and lower methane production (p = 0.03) than those fed EM. Replacing EM by DCP caused an increase in the proportions of propionate and butyrate (p < 0.001) and a decrease in acetate (p = 0.04). Microbial growth, bacterial diversity, and the quantity of bacteria and protozoa DNA were not affected by the diet, but the relative abundances of fungi and archaea were greater (p < 0.03) in solid and liquid phases of DCP fermenters, respectively. Results indicate that DCP can substitute EM, promoting a more efficient ruminal fermentation.


2021 ◽  
Vol 2 ◽  
Author(s):  
Friederike Pfau ◽  
Martin Hünerberg ◽  
Karl-Heinz Südekum ◽  
Gerhard Breves ◽  
Marcus Clauss ◽  
...  

This study investigated the impact of carbohydrate source and fluid passage rate (dilution rate) on ruminal fermentation characteristics and microbial crude protein (MCP) formation. Three commonly used feeds (barley grain [BG], beet pulp [BP], and soybean hulls [SBH]), which differ considerably in their carbohydrate composition, were incubated together with a mixture of grass hay and rapeseed meal in two identical Rusitec apparatuses (each 6 vessels). Differences in fluid passage rate were simulated by infusing artificial saliva at two different rates (1.5% [low] and 3.0% [high] of fermenter volume per h). This resulted in six treatments (tested in 3 runs): BGhigh, BGlow, BPhigh, BPlow, SBHhigh and SBHlow. The system was adapted for 7 d, followed by 4 d of sampling. Production of MCP (mg/g degraded organic matter [dOM]; estimated by 15N analysis) was greater with high dilution rate (DL; p &lt; 0.001) and was higher for SBH compared to both BG and BP (p &lt; 0.001). High DL reduced OM degradability (OMD) compared to low DL (p &lt; 0.001), whereas incubation of BG resulted in higher OMD compared to SBH (p &lt; 0.002). Acetate:propionate ratio decreased in response to high DL (p &lt; 0.001). Total gas and methane production (both /d and /g dOM) were lower with high DL (p &lt; 0.001). In our study increasing liquid passage rate showed the potential to increase MCP and decrease methane production simultaneously. Results encourage further studies investigating these effects on the rumen microbial population.


Author(s):  
Haihao Huang ◽  
Malgorzata Szumacher-Strabel ◽  
Amlan Kumar Patra ◽  
Sylwester Ślusarczyk ◽  
Dorota Lechniak ◽  
...  

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 461-461
Author(s):  
Jordan L Cox-O’Neill ◽  
Vivek Fellner ◽  
Alan J Franluebbers ◽  
Deidre D Harmon ◽  
Matt H Poore ◽  
...  

Abstract Ruminant animal performance has been variable in studies grazing annual cool-season grass and brassica monocultures and mixtures. There is little understanding of the fermentation mechanisms causing variation. The aim of this study was to determine apparent dry matter (DM) digestibility, methane, and volatile fatty acid (VFA) concentration from different proportions of cereal rye (Secale cereal; R) and turnip (Brassica rapa L.; T) (0R:100T, 40R:60T, 60R:40T, and 100R:0T) via in vitro batch fermentation. Freeze-dried forage samples from an integrated crop-livestock study was assembled into the four treatments with a 50:50 leaf to root ratio for turnip. Measurements were made following a 48 hr fermentation with 2:1 buffer and ruminal fluid inoculum. Data were analyzed using Mixed Procedure of SAS with batch (replicate) and treatment (main effect) in the model; differences were declared at P ≤ 0.05, with tendencies declared at &gt; 0.05 but &lt; 0.10. Rumen apparent DM digestibility (26.8%; overall mean) was not different among treatments. Methane production was less (P &lt; 0.01) with inclusion of turnip ranging from 774 nmol/ml for 0R:100T to 1416 nmol/ml for 100R:0T. Total VFA production, acetate to propionate ratio, acetate, and valerate were not affected by forage treatments (117 mM, 1.45, 39.84 mol/100 mol, and 7.86 mol/100 mol, respectively; overall mean). Propionate, isobutyrate, and isovalerate concentrations were greater and butyrate concentration less with greater (P &lt; 0.01) proportions of rye in the mixture. No effect of R:T ratio on digestibility or total VFA production along with the observed differences in individual VFA concentration do not explain variable response in grazing animals. Additionally, methane production results indicate that grazing turnips could potentially reduce methane production and thus reduce ruminant livestock’s contribution to greenhouse gas emissions.


1994 ◽  
Vol 30 (8) ◽  
pp. 45-54 ◽  
Author(s):  
O. Mizuno ◽  
Y. Y. Li ◽  
T. Noike

The effects of sulfate concentration and COD/S ratio on the anaerobic degradation of butyrate were investigated by using 2.0 L anaerobic chemostat-type reactor at 35°C. The study was conducted over a wide range of the COD/S ratio (1.5 to 148) by varying COD concentrations (2500–10000 mg/L) and sulfate concentrations (68–1667 mg-S/L) in the substrate. The sludge retention time at each COD/S ratio was changed from 5 to 20 days. The interaction between methane producing bacteria (MPB) and sulfate-reducing bacteria (SRB) was evidently influenced by COD/S ratio in the substrate. When COD/S ratio was 6.0 or more, methane production was the predominate reaction and over 80% of the total electron flow was used by MPB. At the COD/S ratio of 1.5, SRB utilzed over 50% of the total electron flow. A large amount of sulfate reduction resulted in not only the decrease of methane production, but also the rapid increase of the bacterial growth. The degradation pathway of butyrate and the composition of bacterial populations in the reactor were also dominated by COD/S ratio. In sulfate depleted condition, butyrate was degraded to methane via acetate and hydrogen by MPB. On the other hand, butyrate was firstly degraded into sulfide and acetate in sulfate rich conditions by SRB, and the produced acetate was then degraded by acetate consuming MPB and SRB. The methanogenesis from acetate was inhibited by the high concentration of sulfide.


1970 ◽  
Vol 46 (3) ◽  
pp. 325-335
Author(s):  
E. Maleki ◽  
G.Y. Meng ◽  
M. Faseleh Jahromi ◽  
R. Jorfi ◽  
A. Khoddami ◽  
...  

The objective of this study was to determine the effect of pomegranate (Punica granatum L.) seed oil (PSO) on gas and methane (CH4) production, ruminal fermentation and microbial populations under in vitro conditions. Three treatments consisting of a control diet containing 10 mg tallow (CON); the control diet with 5 mg PSO + 5 mg tallow (MPSO) and the control diet containing 10 mg PSO (HPSO) were compared. Ten mg of the experimental fat/oil samples were inserted into a gas-tight 100 mL plastic syringe containing 30 mL of an incubation inoculum and 250 mg of a basic substrate of a hay/concentrate (1/1, w/w) mixture. In vitro gas production was recorded over 0, 2, 4, 6, 8, 10, 12 and 24 h of incubation. After 24 hours, incubation was stopped, and methane production, pH, volatile fatty acids (VFAs) and microbial counts were measured in the inoculant. Gas production at 4, 6, 8, 10, 12 and 24 h incubation, metabolizable energy and in vitro organic matter disappearance increased linearly and quadratically as level of PSO increased. Furthermore, the 10 mg PSO (HPSO) decreased CH4 production by 21.0% compared with the control (CON) group. There were no significant differences in total and individual VFA concentrations between different levels of PSO, except for butyric acid. After 24 h of incubation, methanogenesis decreased in the HPSO compared with the MPSO and CON treatments. In addition, total bacteria and protozoa counts increased with rising PSO levels, while population methanogenesis declined significantly. These results suggested that PSO could reduce methane emissions, which might be beneficial to nutrient utilization and growth in ruminants.


2006 ◽  
Vol 53 (8) ◽  
pp. 223-231 ◽  
Author(s):  
T. Paavola ◽  
E. Syväsalo ◽  
J. Rintala

The objective of this study was to compare methane production and characteristics of digested material in anaerobic digestion concepts according to the Animal By-Products Regulation (ABP-Regulation) of the EC (hygienisation of biowaste for 1 hour at 70 °C, particle size &lt;12 mm) and Finnish national regulations (treatment temperature 55 °C, feeding interval 24 h, hydraulic retention time (HRT) 20 d, particle size &lt;40 mm) and with small variations in treatment methods for treating manure and biowaste. Moreover, the survival of three different salmonella bacteria in these processes was studied. Hygienisation of biowaste prior to digestion at 35 °C enhanced methane production by 14–18% compared to similar treatment without hygienisation. The differences in treatment temperature, HRT and hygienisation of biowaste prior to digestion did not significantly affect the characteristics of digested material. The concepts according to the ABP-Regulation and Finnish national regulations were effective in destroying salmonella bacteria to an undetectable level.


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