Gas Production Values Research Articles

The effects of catfish oil supplementation as unsaturated fatty acid source on Bali cow gas production kinetics, dry matter digestibility, and organic matter digestibility in vitro

The purpose of this study was to investigate the effects of catfish oil (CFO) supplementation on gas production kinetics, dry matter (IVDMD), and organic matter digestibility in vitro (IVOMD) with Bali cow rumen fluid. The design of this study was a completely randomized design with 5 treatment consist of T0 (control diet: Pennisetum purpupoides (60): wheat pollard (30): soybean meal (10)), T1 (T0 + 2% DM CFO), T2 (T0 + 4% DM CFO), T3 (T0 + 6% DM CFO), T4 (T0 + 8% DM CFO) and 3 replication. Gas production technique described by Menke and Steingass was used in this study with 48 hours of incubation time. Gas production kinetics was analyzed by Fit Curve application. The result showed that CFO supplementation did not change the value of gas production, a fraction value, b fraction value, gas production rate (c value), IVDMD, and IVOMD, but the increasing supplementation at the level of 8% decreased (P<0.05) gas production, b value, IVDMD, and IVOMD. It could be concluded that catfish oil supplementation as unsaturated fatty acid source at the level of 6% DM in the Bali cow diet did not give a negative effect on rumen substrates degradation.

Determination of Feed Values of Different Physical Processed Common Vetch Seed (Vicia Sativa) by in Vitro Gas Production Technique

In this study, in vitro gas production values, gas production parameters (a, b, a+b and c) and organic matter digestibilities (OMD), metabolizable energy (ME), net energy lactation (NEL) contents, chemical compositions and feed values of different physical processed (raw, soaked, boiled and roasted) common vetch seeds (Vicia sativa) were determined by in vitro gas production technique. Rumen fluid, used in this study, was obtained by probe from one Holstein bull (seven years old, average live weight= 650 kg) raised at Research and Application Farm of Agricultural Faculty Atatürk University. Raw and treated common vetch seeds were incubated for 2, 4, 6, 8, 12, 24, 48, 72 ve 96 hours for the determination of in vitro gas production values and gas production parameters in rumen fluid. It was observed significant differences among all of the common vetch seeds in terms of chemical composition (DM, CA, OM, CP, EE, NDF, ADF, ADL) values (P

Techno-economic evaluation of biogas production from food waste via anaerobic digestion

Food waste is a major constituent in municipal solid wastes and its accumulation or disposal of in landfills is problematic, causing environmental issues. Herein, a techno-economic study is carried out on the potential of biogas production from different types of food waste generated locally. The biogas production tests were at two-time sets; 24-h and 21-day intervals and results showed a good correlation between those two-time sets. Thus, we propose to use the 24-h time set to evaluate feedstock fermentation capacity that is intended for longer periods. Our approach could potentially be applied within industry as the 24-h test can give a good indication of the potential substrate gas production as a quick test that saves time, with minimal effort required. Furthermore, polynomial models were used to predict the production of total gas and methane during the fermentation periods, which showed good matching between the theoretical and practical values with a coefficient of determination R2 = 0.99. At day 21, the accumulative gas production value from mixed food waste samples was 1550 mL per 1 g of dry matter. An economic evaluation was conducted and showed that the case study breaks-even at $0.2944 per cubic metre. Any prices above this rate yield a positive net present value (NPV); at $0.39/m3 a discounted payback period of six years and a positive NPV of $3108 were calculated. If waste management fee savings are to be incorporated, the total savings would be higher, increasing annual cash flows and enhancing financial results. This economic evaluation serves as a preliminary guide to assess the economic feasibility based on the fluctuating value of methane when producing biogas from food waste via anaerobic digestion, thus could help biogas project developers investigate similar scale scenarios .

Determination of the in vitro digestibility and nutrient content of commercial premium extruded foods with different types of protein content for adult dogs

The purpose of this study was to compare the in vitro digestibility levels and chemical compositions of commercial extruded dry-type adult dog foods with different types of protein contents [fish meat (F-dog foods) (n = 7), lamb meat (L-dog foods) (n = 9), or poultry meat (P-dog foods) (n = 8)]. The in vitro digestion values of premium commercial dog foods were examined at three stages: gastric digestion, small intestine digestion and large intestine digestion/fermentation. The metabolisable energy (ME), crude protein (CP), starch, diethyl ether extract (EE) and ash contents and the in vitro cumulative gas production values of all the premium dog foods differed significantly among the commercial brands in the same category (F-, L- or P-dog foods) (P &amp;lt; 0.05). The crude fibre (CF) and the CP/1 000 kcal ME values of the F- and P-dog foods demonstrated a significant difference among the commercial brands (P &amp;lt; 0.05). The organic matter disappearance (OMd) values of the L-dog foods showed a significant difference among the commercial brands (P &amp;lt; 0.05); but the OMd values of the F- and P-dog foods did not differ among the commercial brands (P &amp;gt; 0.05). The average values of the OMd for the F-dog foods were more rapid than the average for the L- and P-dog foods, in the evaluation of all the foods (P = 0.001). Besides, the price of the L-dog foods was positively correlated with the OMd and CP of the L-dog foods; however, it was negatively correlated with the NFE (nitrogen free extract) and CHO (total carbohydrates) of the L-dog foods (P &amp;lt; 0.05). The CP values of the L-dog foods were positively correlated with the OMd values (P &amp;lt; 0.05). Although price is an important determinant of food quality in the L-dog foods, it is not in the F- and P-dog foods. In the general evaluation of all the dog foods, there was no correlation among the food price and the digestibility and the nutrient content for all of the premium dog foods. The present study indicated that the energy, nutrient matter and digestibility of premium dog foods changed with the change in the variety and the amount of the feedstuffs. The digestibility of the dog foods with the fish meat were higher than those of the other dog foods. The amount of protein that an adult dog will receive with 1 000 kcal of DM (dry matter) consumption of premium dog foods with fish meat and chicken meat, varied among the brands. This point showed the need to pay attention to the food consumption amount of the dogs and the energy-protein balance in their diets, especially dog foods with fish meat and chicken meat.

Overload type and optimization of meadow carrying capacity in Maqin County in the Three-River Source Region, China

Alpine meadows, comprising the main ecosystem of the Three-River Source Region, play an important role in the economic development of western pastoral areas. To determine whether the grazing level was too intense or the nutrient-carrying capacity of the meadows was overloaded, and to offer solutions in Maqin County, Qinghai Province, China, the meadows carrying capacity was determined by combining grass-yield and nutrients data for different seasons across different meadows. The results showed that the levels of crude protein (CP), ether extract (EE), ash, soluble sugars (SS), gas production, and energy value of forage in the summer–autumn grazing meadows were higher than those of the winter–spring meadows. Neutral detergent fiber (NDF) and acid detergent fiber (ADF) of forage in the summer–autumn grazing meadows were lower than those of the winter–spring meadows. We found that no pastures were overloaded with metabolizable energy (ME) for the whole year but digestible crude protein (DCP) was overloaded in winter–spring. And there were differences in the amount carrying capacity (forage yield) of seasonal grazing meadows for the different herds, the overload types were annual overloading (herd A), overloaded in summer–autumn (herd B), overloaded in winter–spring (herd C), and not overloaded (herd D). Compared with the previous grazing mode, theoretical carrying capacity, DCP carrying capacity, and ME carrying capacity of herd A increased by 20, 19, and 27 sheep units, respectively, after optimization; herd B: 36, 31, and 45 sheep units, respectively; herd C: 28, 23, and 44 sheep units, respectively; and herd D: 43, 40, and 61 sheep units, respectively. In the Three-River Source Region and similar alpine pastoral areas, the grassland-livestock structure should be optimized to improve grassland vegetation status and increase the theoretical carrying capacity.

Agronomic and qualitative characterization of multi-cut berseem clover (Trifolium alexandrinum L.) cultivars.

Berseem clover is the main forage crop grown in Mediterranean regions. There are plenty of cultivars that possess variability in their productivity and quality among the different cuts. Therefore, accurate agronomic and qualitative characterization is crucial for selecting the most promising cultivars for breeding and feeding purposes. In the present study, the agronomic characteristics, ruminal degradability and fermentation measures of five cuts of the five most prominent Egyptian beseem clover cultivars (Helaly, Serw, Giza6, Gemmeza1 and Sakha4) were evaluated. The Giza6 cultivar produced a significantly higher fresh yield and high whole plant dry matter content on the 3rd cut. Giza6 was among the superior cultivars in crude protein content and had the highest values of gas production at the 3rd cut, and ruminal degraded acid detergent fiber and propionate concentrations at the 2nd cut, at the same time as presenting the lowest ammonia concentrations at the 3rd and 5th cuts. Overall, the 3rd cut produced significantly higher fresh yield across all cultivars, except for Sakha4. The 3rd cut also produced a higher leaf to stem ratio compared to the 4th and 5th cuts. The 1st three cuts had higher degraded neutral detergent fiber than the 4th and 5th cuts. The 1st cut was characterized by low propionate concentration in the Helaly and Gemmeza1 cultivars compared to the other cuts. Expanded production of the high-yielding, high-quality cultivar Giza6 is recommended. When harvesting, three cuts is optimal for berseem clover cultivation for breeding and feeding programs. © 2020 Society of Chemical Industry.

Comparison of anaerobic digestion technologies: An Italian case study

The present study focused on a comparison of two technologies applied in the mesophilic anaerobic digestion, namely a conventional wet one and a dry batch one. The considered substrate was the source sorted organic fraction of municipal solid waste (SS-OFMSW) and the input flow rate, for the study case, was 35,000 Mg/year. The analysed systems included the pre-treatment of the SS-OFMSW, anaerobic digestion, upgrading of biogas to biomethane and aerobic post-treatment for the purpose of obtaining compost. The comparison was made by the calculation of three indicators: net present value, total primary energy and CO2 equivalent emissions, with the aim of providing elements for choosing the most appropriate technology for the specific case. The results obtained demonstrated the finding of worse values by the total primary energy indicator for the dry batch technology, providing a saving of approx. 21% lower compared to the wet one. In terms of CO2 equivalent emissions, the dry batch anaerobic digestion technology provided a better indicator than the wet anaerobic digestion system. Sensitivity analysis revealed the finding of an opposite result only when high specific gas production values were assumed for wet anaerobic digestion, and low specific gas production values for the dry batch technology.From an economic perspective, the results indicated a preference for the dry batch technology due to a higher net present value and a shorter period of return of the investment. This finding was also confirmed by a Monte Carlo uncertainty analysis, showing how the dry batch system featured a 90% of possibility of achieving a higher economically sustainability versus the wet technology.

An investigation of long range reliance on shale oil and shale gas production in the U.S. market

Despite the rising profiles of both shale oil and shale gas plays in the U.S. and the importance of testing for their persistence, no study has examined the persistence of the availability of shale oil and shale gas plays in the country. This paper focuses on the analysis of shale oil and shale gas production using long range dependence techniques in the U.S. for the period, January 2000 to April 2019. The empirical findings illustrate that the series examined are highly persistent, finding very little evidence of mean reverting patterns. Among the implications of the results, which are discussed in the paper, is that there is a hysteresis in shale oil and gas production in U.S., and therefore shocks resulting from new government policies relating to shale oil and gas in U.S. will have lasting impacts on their production. Besides, it will not be feasible to use forecasting as a basic instrument for unconventional energy sources as the previous values of shale oil and gas production cannot be utilised to accurately forecast their subsequent values.

Phenological changes in the nutritive value of honey mesquite leaves, pods, and flowers in the Chihuahuan Desert

AbstractHoney mesquite [Prosopis glandulosa (Torr.) glandulosa] is a potential foraging resource in southwestern United States rangelands and in other semi‐arid rangelands. Yet, intake by ruminants is limited. We conducted an in vitro digestion experiment to assess phenological changes in nutrient value and relative digestibility of honey mesquite leaves, pods, and flowers throughout the 2012 growing season. Crude protein (CP) content of leaves decreased (P &lt; .001) during the year, while acid detergent fiber (ADF) and neutral detergent fiber (NDF) increased (P &lt; .05). Crude protein content of pods decreased (P = .009) over time, but we did not detect (P &gt; .10) any phenological changes in ADF or NDF levels during the study. A cubic response was observed with in vitro gas production and Julian date for both leaves and pods (P ≤ .01). Gas production from leaves collected in spring and early summer were lower than during late summer and early fall. Gas production and nutrient content values suggest that concentration of secondary compounds of mesquite leaves may decrease in late summer. Gas production values of mesquite leaves were lowest in early and mid‐summer when CP levels were high and fiber levels were low. Mesquite flowers and pods can be valuable forage resources for cattle. Although mesquite leaves contain nutrients, secondary compounds likely limit intake, especially in late spring and early summer when the CP in mesquite leaves would be most beneficial because quality of herbaceous forages in southwestern United States rangelands at that time is usually low.

Investigating reservoir stresses and strain effects during production from coal bed methane gas reservoir on reservoir properties and gas production – a numerical study

The effects of stresses and strains, occurring in a reservoir, on the cumulative gas production and the petrophysical properties are studied. Existing strain and stress model equations have been used to analyse the coupled effect of matrix shrinkage and cleat compressibility change on reservoir properties. A coal bed methane (CBM) gas reservoir, low permeable and undersaturated, is semi-analytically modelled. A nearly suitable model from among them is eventually proposed to predict the cleat permeability and gas production existing in the field using a dynamic drainage area (DDA) approach. These results vary with the production time. The strain model predicts gas production values and the stress models predict a range of cleat permeability variation values close to field values. Cleat permeability and cleat porosity both affect gas productivity but in the opposite manner. [Received: December 29, 2018; Accepted: May 14, 2019]

Who Benefits from a Resource Boom? Evidence from the Marcellus and Utica Shale Plays

We analyze the impact of the recent energy boom in the Marcellus and Utica shale formations on local labor markets in Ohio, Pennsylvania and West Virginia. Unique to our analysis is the use of origin-destination files (LODES) from the U.S. Census Bureau which provide employment statistics at the census block level based on where jobs are located and where workers live who hold those jobs. The richness of this data enables us to identify cross border mobility of workers as labor demand increases due to greater resource extraction. We find that increases in the value of new oil and gas production significantly increases local employment and average earnings in the county, but that a large fraction of new jobs are filled by workers who reside outside of the county. Specifically, a one standard deviation increase in the value of new oil and gas production per capita in a county-year increases workplace employment by 283 jobs, decreases the fraction of jobs held locally, and increases the flow of workers from counties 25-200 miles away. Furthermore, we find some positive employment spillovers across industries, but these new jobs largely appear to go to non-local residents as well. We do find evidence that the earnings distribution shifts to the right for both local residents and workers who reside outside the county.

Forecasting blast furnace gas production and demand through echo state neural network-based models: Pave the way to off-gas optimized management

The efficient use of resources is a relevant research topic for integrated steelworks. Process off-gases, such as the ones produced during blast furnace operation, are valid substitutes of natural gas, as they are sources of a considerable amount of energy. Currently they are recovered, for instance, by using in hot blast stoves but sometimes part of such gas is flared due to non-optimal management of such resource. In order to exploit the off-gases produced in an integrated steelworks, the interactions between gas producers and users in the whole gas network need to be considered. The paper describes two models exploited by a Decision Support Tool that is under development within a European project. Such models forecast, respectively, the blast furnace gas amount and its heating power by obtaining an error between 1.6 and 6.9% in a time horizon of 2 h and the blast furnace gas demand by hot blast stoves by giving a prediction error between 5.0 and 12.1% in the same time horizon. The forecasted values of blast furnace gas production and main demand allow a continuous optimal planning of the blast furnace gas usage according to its availability and to the needs in the steelworks, by avoiding losses of a valuable secondary resource and related emissions.

Choice of optimal technological operation mode of off-shore gas-condensate wells exploited in complicated conditions

The object of research is a new method for the approach to control the optimal technological regime of gas and gas condensate wells. It is noted that in order to optimize the technological regime of the well, by extracting liquid and solid particles, it is necessary to know the minimum value of gas production or gas flow rate, which, in turn, is provided by determining the corresponding value of the bottomhole pressure. To determine the bottomhole pressure at which the well reaches the optimal operating mode, an equation is obtained that has a complex structure with respect to the bottomhole pressure (pressure in the elevator shoe), for the solution of which the graphoanalytical method was used. The proposed method for optimizing the operation of gas and gas condensate wells was tested on the basis of actual data. And it is shown that it is possible to determine the optimal operating mode of gas and gas condensate wells by determining bottomhole pressure values at which liquid and solid particles are transported from the bottom of the wells to the earth's surface. In this case, the initial data for wells (No. 652 and 704) operated on the VII horizon of the Sangachal-Sea-Duvanny-Sea-Khara-Zira (Azerbaijan) field is used to determine their technological regimes. It is shown that it seems possible to increase the productivity of offshore gas and gas condensate wells by changing the design of their lifts and the proposed method allows to extract liquid and solid particles from the trunk to the earth's surface. For each case, the particle deposition rates in the gas medium and the gas flow rate in the elevator shoe were calculated. Judging by the value of the difference in the determined particle deposition rates and gas flow in the elevator shoe, the possibility of the formation of liquid plugs in the well is established. If a situation arises when the gas flow rate does not ensure the extraction of liquid particles on the earth's surface, it is proposed to change the diameters of the lifting pipes.

Steam gasification of oat hull pellets over Ni-based catalysts: Syngas yield and tar reduction

Renewable and clean energy generated from agricultural crops wastes can displace fossil fuels in heating and power generation. The abundant and low-value byproduct from agricultural industries can have a positive impact on the economy and environment of agricultural provinces in Canada and elsewhere. In this work, the effects of catalytic and non-catalytic steam gasification of oat hull pellets on syngas production and tar reduction were evaluated. For non-catalytic gasification, the impacts of temperature, between 650 and 850 °C, and steam-to-biomass ratio, between 0.25 and 0.50, were tested. Higher temperature increased fuel gas production and heating value, and decreased tar and char yields. Similar effects were observed with increasing steam-to-biomass ratio, except for char yield, which was not affected. For catalytic gasification, Ni/Al2O3 catalysts, with and without Ce, were synthesized and characterized. All catalytic gasification experiments were performed in a two-stage fixed bed reactor at 650 °C and catalyst-to-biomass ratio of 0.5. Among unpromoted catalysts, 10% Ni loading showed the lowest tar formation. Furthermore, adding cerium promoter increased metal dispersion, decreased reduction temperature, and lowered coke formation as observed in TGA. Increasing catalyst to biomass ratio from 0.2 to 1 reduced tar formation from 2.3 to 1.3% but had insignificant influence on syngas yield. As compared to non-catalytic process, using Ni-based catalysts improved the efficiency of steam gasification of oat hull pellets by increasing syngas production and decreasing tar formation. Improving the efficiency will make steam gasification a promising method to convert the agricultural wastes to a clean energy.

Comparison of nutritive value between intact and defatted black soldier fly larvae for animal feed

In this study, the possibility black soldier fly (BSF) larvae as a novel feedstuff for animal was investigated. The objective of this study was to compare the nutritive value between intact and defatted BSF larvae for animal feed by means of chemical composition determination and in vitro rumen fermentation technique. The following treatments were tested: intact BSF (T1), BSF low in lipid by mechanical extraction (T2), BSF low in lipid by chemical extraction (T3), and soybean meal (T4). The samples were subjected to proximate analysis, Van Soest’s fiber fraction and cell wall nitrogen determination. The samples were further incubated in vitro with buffered-rumen fluid in four replicates, represented by two incubation units per replicate, and conducted for 48 h at 39°C. Parameters measured in the in vitro evaluation were total gas production and methane emission at regular time point intervals. Other parameters measured after the incubation were dry matter degradation, organic matter degradation, total volatile fatty acid (VFA), ammonia concentration and pH. Data were tested using analysis of variance (ANOVA) and if there was a significant different at P<0.05 then continued with Duncan’s multiple range test. Results revealed that removal of lipid from BSF larvae either by mechanical or chemical extraction increased dry matter degradability (DMD), organic matter degradability (OMD) and total gas production values as compared to intact BSF (P<0.05). However, these values were still lower than those of soybean meal (P<0.05). Concentrations of ammonia and total VFA were similar across all dietary treatments. It can be concluded that removal of lipid from BSF larvae by either mechanical or chemical extraction improves its utilization in the in vitro rumen fermentation system.

Water deficit and nitrogen affects yield and feed value of sorghum sudangrass silage

This study was carried out to determine potential effects of water deficit and nitrogen treatments on yield components of sorghum sudangrass and nutritional composition, fermentation, organic matter digestibility, gas-methane production of sorghum sudangrass silage. Plants were grown under combinations of three different irrigation levels (I100: 100, I75: 75 and I50: 50% of depleted water from field capacity) and three different nitrogen doses (N1: 100, N2: 200, N3: 300 kg ha−1). Experiments were conducted in randomized blocks - split plots design for two years in 2013 and 2014. Harvested plants were ensilaged, silage samples were opened after 60 days and relevant analyses were performed on silage samples. Irrigation treatments increased green herbage yield, yield components, acid detergent fiber (ADF), neutral detergent fiber (NDF), dry matter and crude ash and decreased crude protein, gas production and organic matter digestibility. Increasing nitrogen doses increased panicle and leaf ratio, crude protein ratio and green herbage yield and decreased dry matter and pH levels. The greatest ADF, NDF, metabolic energy, gas production and organic matter digestibility values were obtained from 200 kg ha -1 treatment. Current findings revealed that increasing yield but decreasing quality values were observed with increasing irrigation levels. Appropriate nitrogen doses had positive impacts on green herbage yield and feed quality. There were not significant differences between N3 × I100 and N2 × I75 treatments. Therefore, a slight water deficit (I75) and normal nitrogen supply (200 kg ha−1) is recommended for sorghum sudangrass culture without any significant losses in yield and quality parameters.

EVALUATION OF CORN SILAGE FROM DIFFERENT REGIONS IN EGYPT

The main objective of this study was to evaluate different samples of corn silage (Whole corn plant with ears) from different regions in Egypt to determine each sample has the highest nutritive value and nutrients digestibility and therefore reduce the feed cost, increase feed efficiency and probability of lactating dairy farms. Silage samples were collected from different four areas in Egypt; El-Salhya, El-Nobarya, El-Monofia and Ganakles. The study Included three field and laboratory work cores which were; chemical composition, in-vitro and in-situ evaluation studies. The samples were analyzed for its chemical composition, Dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL). The silage samples were evaluated in-vitro and in-situ. In-vitro evaluation was conducted using gas production technic. Gas production (GP) was recorded at 0, 2, 4, 8, 16, 24 and 48 hours of incubation. The organic matter digestibility (OMD), short chain fatty acids (SCFA), and metabolizable energy (ME) were measured. The in-situ experiment, involved nylon bags containing silage samples from different regions were incubated in three fistulated Barki rams for 24h. Samples were taken out at 2, 4, 8, 12 and 24h of incubation. The obtained results indicated that the Ganakles silage ampel recorded the lowest (P<0.01) values of GP within the different times compared to others. The silage from El-Salhya had the highest (P<0.01) values for OMD and SCFA. The DMD of in-situ samples was significantly (P<0.01) increased within the different times of incubation with Al-Salhia silage samples, but the lowest significant values (P<0.01) were recorded with Al-Nobaria silage samples. Depending on invitro and in-situ results for silage type results, in vitro and in-situ for silage type from Al-Salhia area had a best characteristics of good silage and was chosen forever conducting lactation trial.

&lt;b&gt;Chemical-bromatological composition and in vitro ruminal kinetics of sugar cane silage with maniçoba

The objective this study was to evaluate the effect of maniçoba supplementation in sugar cane silage with respect to chemical-bromatological composition and the in vitro degradation kinetics of the silage. This experiment was conducted in a completely randomized design with four treatments (maniçoba levels: 0, 20, 30, and 40%) and six repetitions. Silage samples were analyzed for their chemical-bromatological composition, digestible energy, metabolizable energy, total digestible nutrients, in vitro gas production and degradability parameters. The silage with higher inclusion level had better bromatological composition (p &lt; 0.05) than the silage without maniçoba for CP, NDF, ADF and MM (6.49, 56.64, 38.66 and 4.52% versus 2.21, 70.96, 49.95 and 2.78%). Higher ME content (2.35 MJ kg-1 MS versus 1.85 MJ kg-1 MS), DE (2.87 Mcal kg-1 MS versus 2.25 Mcal kg-1 MS) and TDN (65.16% versus 51.11%), respectively. The highest values for gas production were also observed in silage with added maniçoba due to higher NFC content (34.87%). With an increase in the proportion of maniçoba, there was an increase in the soluble a fraction, b fraction, and thus a higher effective degradability of dry matter (46.56%). The addition of maniçoba improves the nutritive value of sugarcane silage.

Potential of guava leaves for mitigating methane emissions and modulating ruminal fermentation characteristics and nutrient degradability

Guava leaves (Psidium guajava, GL), a high-phenolic- and flavonoid-containing plant resource capable of substituting the high-quality forage, may help in mitigating ruminal methane (CH4) emission without adverse impact on nutrient degradability if supplemented at an appropriate level. In order to test this hypothesis, rumen fermentation, CH4 production, and nutrient degradability of GL either solely or as a substitute of berseem hay (Trifolium alexandrinum, BH) were evaluated in a diet containing 50:50 concentrate to roughage. Five different levels of GL (0, 12.5, 25, 37.5, and 50%) were tested in vitro after 24h incubation using a semi-automated gas production (GP) system. The current findings indicated that merely the presence of GL resulted in significantly lower values for cumulative GP (P < 0.001), CH4 emission (P < 0.05), truly degraded dry matter (TDDM; P < 0.001), truly degraded organic matter (TDOM; P < 0.001), and ammonia nitrogen (NH3-N) concentration (P < 0.001); however, pH (P < 0.001) and partitioning factor (P < 0.001) were higher. The total and individual volatile fatty acid (VFA) concentrations were drastically declined with GL as compared to BH (P < 0.05). A negative linear correlation was recorded between the levels of GL and GP including CH4 production (P < 0.05). The addition of GL up to 25% did not pose any negative effect on both TDDM and TDOM values along with NH3-N concentration. In addition, the inclusion of GL up to 25% did not affect the total or individual VFA concentration. Conclusively, in a medium concentrate diet, use of 25% GL and 25% BH in animal diet could be a promising alternative for mitigating the CH4 production without any deleterious effect on nutrient degradability.

Microbial characterization of five Chinese traditional sourdoughs by high-throughput sequencing and their impact on the quality of potato steamed bread

To improve the quality of potato steamed bread, the microbial diversity of 5 different sourdoughs and their effects on potato steamed bread were studied. The proximate composition analysis differentiated the Chinese traditional sourdough (CTS) with different levels of nutrients and pH (3.82–6.22). High-throughput sequencing revealed the predominant microbes in the five CTSs were Lactobacillus, Pediococcus, and Wickerhamomyces. Similarities of bacterial and fungal compositions were observed within them. The fermentation rheological results suggested CTS1 and CTS3 had higher total gas production value (2355.5 mL and 2249.5 mL respectively) than baker’s yeast. CTSs resulted in various effects on the appearance and texture properties of potato steamed bread with CTS1 showed the highest specific volume (2.38 mL/g) and sensory score (7.43). Wickerhamomyces significantly correlated with the total gas production, hardness, resilience, and lightness of potato steamed bread. The study suggested a potential application of CTSs in fermented potato staple foods.