Dry Digestibility Research Articles

Effects of woody biochar on dry thermophilic anaerobic digestion of organic fraction of municipal solid waste

This study presents the results of semi-pilot scale anaerobic digestion tests conducted under dry thermophilic conditions with the addition of biochar (6% on fresh mass basis of inoculum), derived from an industrial gasification plant, for determining biogas and biomethane production from organic fraction of municipal solid waste. By using two types of inocula (from a full-scale dry anaerobic digestion plant and from lab-scale biomethanation tests), the obtained experimental results did not show significant increase in methane yield related to the presence of biochar (330.40 NL CH4 kgVS−1 using plant inoculum; 335.41 NL CH4 kgVS−1 using plant inoculum with biochar, 311.78 NL CH4 kgVS−1 using lab-inoculum and 366.43 NL CH4 kgVS−1 using lab-inoculum with biochar), but led to significant changes in the microbial community composition. These results are likely related with the specific biochar physical-chemical features and low adsorption potential.Resulting digestate quality was also investigated: biochar-enriched digestates were characterized by increased biological stability (809 ± 264 mg O2 kgVS−1 h−1 vs. 554 ± 76 mg O2 kgVS−1 h−1 for biochar-free and biochar-enriched digestates, respectively), lower heavy metals concentrations (with the exception of Cd), but higher polycyclic aromatic hydrocarbons content, with a reported maximum concentration of 8.9 mgPAH kgTS−1 for biochar-enriched digestate derived from AD test with lab-inoculum, which could trigger non-compliance with regulation limits for agricultural reuse of digestates. However, phytotoxicity assessments showed a decreased toxicity of biochar-containing digestates when compared to biochar-free digestates.

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.

Anaerobic Digestion of Napier Grass (Pennisetum purpureum) in Two-Phase Dry Digestion System Versus Wet Digestion System

Napier grass (Pennisetum purpureum) is a high yield tropical grass with great potential for anaerobic digestion. Two-phase anaerobic dry digestion (TADD), considered an alternative for anaerobic wet digestion system (AWD) with only front-end leach bed reactor (LBR), is added to existing liquid digester, was tested under different leachate circulations, and was compared with AWD. Leachate circulation frequency in LBR was found to highly influence hydrolysis rate and hence improved overall digestibility of the grass fiber. Additional methane yield of 32.5% was achieved when leachate circulation increased from 1 to 4 times per day and diminished to merely 13.7% more at continuous circulation. A shift in methane generation from leachate digester to LBR as digestion time progressed and important biochemical characteristics were discussed. In AWD, operation at an organic loading of 4 kgVS/m3 d gave the highest methane yield at 145.2 m3/tondry, which is 2.3 times higher than TADD due to an advantage in mass transfer in a total wet environment. This work had advanced our understandings on phase separation in anaerobic digestion system and the key methanation performance among dry and wet digestions of the prototypical lignocellulosic biomass.

Effect of high temperature on gametogenesis of the sea urchin Strongylocentrotus intermedius in the Sea of Japan, northern Hokkaido, Japan

A long-term (1987 to 2011) monitoring survey of recruitment of Strongylocentrotus intermedius juveniles in the Rebun Island in the Sea of Japan of northern Hokkaido revealed a significant negative correlation between juvenile density and water temperature, at times of the year when adults have growing and mature gonads. It is possible that high temperature has a negative impact on gametogenesis of S. intermedius. We investigated digestion, somatic and gonad growth, and gonad development of adult S. intermedius from the Rebun Island from June to September 2011. Experimental temperature treatments were: monthly average (CT, 11.2–19.9 °C), high (HT, 13.4–22.7 °C), and low (LT, 10.5–18.2 °C). These temperatures represent the temperature range of the last 30 years in the island. At the highest temperature in late August, digested kelp dry matter in HT was lower than in LT. Body weight in CT and LT increased significantly during the experiment. Testicular development in CT and LT progressed to the spent stage in late September, but remained at the partly spawned stage in HT. Ovaries in CT and LT developed to the premature, partly spawned, or the spent stage, from early to late September, a time when ovarian development in HT progressed from the premature to the partly spawned stages, although some ovaries retained the growing stage, indicating that oogenesis was suppressed. In CT and LT, oocyte area increased significantly from early to late August, when ovaries developed from the growing to the premature stages, due to initiation of oogenesis. In contrast, in late July, oocyte area in HT was significantly larger in CT and LT, which might be due to increased digested kelp dry matter and digestibility, which enable resources to accumulate for gametogenesis at <20 °C. Oocyte area in HT was significantly smaller in late August and in early September, reflecting delayed ovarian development, but it rapidly increased from early to late September, when kelp digestibility increased, possibly due to decreased temperature, which enables animals to compensate for delayed oocyte growth leading to oogenesis. Low gonad growth in HT, and delayed maturation and spawning would be the causal factor of decreased juvenile recruitment.

Value of the dry ingredients and digestibility of Organic Goat nuts with the granting of Silage Rations of vegetable Trash and leaves Gliricidia (Gliricidia sepium)

This research aims to know the effect of vegetable silage ration feeding trash and leaves (Gliricidia sepium) gliricidia against the value of the dry ingredients and digestibility of organic livestock goat nuts. This study used a Randomized Design Group with 3 treatments and 3 replicates (blocks/groups) each of Deuteronomy includes 3 goats nuts. R1 is the treatment of gliricidia ad libitum leaves, vegetable waste and silage R1 leaves gliricidia (30%: 70%) and vegetable waste and silage R2 leaves gliricidia (70%: 30%). The observed variables are the values of the digestibility of dry ingredients and the digestibility of organic matter. The results showed that the treatment of vegetable waste silage given does not affect real (P0,05 &gt;) against the consumption of dry ingredients of vegetable leaf litter silage ration gliricidia as a whole. The results showed equivalent value the digestibility of the ration dry ingredients of highest to lowest (%) respectively is R2 (80.7%), R1 (75,3%), and the Ro(71.3). While the addition of vegetable waste in silage ration leaves gliricidia does not affect real (P0,05&gt;) against the value of the digestibility of organic matter. It can be concluded that the provision of rations of vegetable trash and leaves silage gliricidia (Gliricidia sepium) do not affect the real value of the dry ingredients and digestibility of organic livestock goat nuts.

Taloženje silicijum-dioksida u hidrometalurškim procesima

Introduction/purpose: Dissolution of nonferrous metals from oxidic ores such as laterite, high silicon bauxite and eudialyte during acidic treatment was connected with silica gel formation. Methods: Familiarity with behavior of silica in hydrometallugical processes such as dissolution at atmospheric and high pressure, precipitation, neutralization and filtration is most important for the recovery of metals from water solution. Results: Gel formation was avoided using dry digestion and a carbonation process of olivine under high pressure in an autoclave. Conclusion: Fine silica was prepared from olivine in water solution at 175°C and 120 bar for 4 hours in an autoclave using some additives such as sodium bicarbonate and oxalic acid.

Contaminación por mercurio en árboles de carpes (Carpinus betulus) en espacios verdes en el área del parque industrial (Irán)

El mercurio es un metal tóxico que puede acumularse en los órganos de las plantas en grandes cantidades ocasionando toxicidad a los humanos. Carpinus betulus es una especies de los bosques mixtos hircanos del Caspio. En esta investigación, se estudió la cantidad de mercurio que pueden absorber los árboles de carpes del ambiente. Veinticinco árboles fueron seleccionados al azar, las distancias entre árboles fueron de 10 a 15 m en un parque industrial en el norte de Irán. De cada árbol seleccionado, se cosecharon 15 g de hojas y 15 g de raíz con tijeras hortícolas, y 15 g de tierra a partir de 30 cm de profundidad. Se seleccionaron cuatro estaciones cerca de la fábrica de acero. Se seleccionó una estación de control ubicada a 2 km de la fábrica de acero y se ubicaron tres estaciones cerca de la fábrica de acero. Las muestras de hojas, tierra y raíces se prepararon y codificaron, se colocan en sobres de papel y se transfirieron al laboratorio. La cantidad de mercurio en las muestras de plantas se preparó mediante digestión en seco con espectroscopía de absorción atómica. Para comparar el efecto de la concentración de mercurio en la hoja y la raíz, se utilizó la prueba de Tukey. La concentración promedio de mercurio en el suelo fue de 0.96 mg/kg, en la raíz 0.551 mg/kg y en la hoja 0.28 mg/kg. Se observó que con el aumento de mercurio la cantidad de clorofila en la hoja disminuye. Se puede concluir que la cantidad de acumulación de metales mercurio en el árbol Carpinus betulus es adecuada para absorber la contaminación del mercurio de la contaminación del suelo.

The Use of Coffee Husk as Napier Grass Substitution and Its Effect on Madura Cattle Performance

This research aimed to evaluate the performance of fattened madura cattle fed on coffee husk as a source of fibre to substitute grasses. Twenty Madura steers aged approximately 1.5 to 2.0 years with initial weight of 165-190 kg were divided randomly into four different experimental diets, namely R0= 90% concentrates +0% coffee husk +10% napier grass, R1= 90 % concentrates +3.33% coffee husk +6.67% napier grass, R2 = 90% concentrate +10% 6.67% coffee husk +3.33% napier grass, R3 = 90% concentrates 90% + 10% coffee husk +0% napier grass. The feed was given at 3% body weight of dry mater. The cows were kept in individual pen for two months. Variables measured were dry mater intake, feed efficiency, average daily gain (ADG), digestibility of feed and income over feed cost. Data obtained were analyzed using analysis of variance based on randomized block design followed by Duncan’s multiple range test. Results showed that dry matter intake, ADG, feed efficiency and feed digestibility of cattle on each treatment of the feed were not significantly different (P &gt; 0.05). Average of dry matter intake and daily gain for R0, R1, R2, and R3 were 6.01, 5.84, 5.73 and 5.62 kg/head/day and 0.88, 0.87, 0.84 and 0.93 kg/head/day respectively. While the average of feed efficiency and DM digestibility for R0, R1, R2, and R3 were 14.64, 14.89, 14.65 and 16.54 % and 84.82, 84.37, 83.47 and 83.30 %, respectively. It is concluded that the used of 10% coffee husk as a source of fibre for substitution of napier grass can be used without negative effect on madura’s cattle performances and tend to give higher values of IOFC on fattening program.

Dry batch anaerobic digestion of food waste in a box-type reactor system: Inoculum preparation and reactor performance

Abstract A box-type reactor system with liquid inoculum has been studied for the dry anaerobic digestion of food waste. The food waste was processed without any pre-treatment to remove physical impurities, neither water addition to dilute and slurry the feedstock. The experiment was carried out with inoculum to substrate ratios of 1:1 (w/w) and 0.08:1 (VS basis). Previous acclimation of liquid inoculum enhanced the process, assuring a fast start up of the box digester and preventing from process failure by volatile fatty acids accumulation. The percolate recirculation strategy was shown to have a relevant effect on the progress of the process. The results suggest that the process can be optimized by providing low percolate recirculation rate during the start-up of the box digester followed by an increase in the percolate recirculation rate when volatile fatty acids decrease and methane content in the biogas increases. The methane yield obtained in the box digester from the food waste was in the range 460–477 L CH4 kg−1 VS, being the VS removal efficiency between 91.1 and 91.4%. Globally, the process operated at an organic loading rate of 2.5 kg VS m−3 d−1 and yielded a volumetric methane production rate of 1.0 m3 CH4 m3 d−1. These results show the high potential of food waste for its conversion in renewable energy by using the dry batch anaerobic technology.

Preparation of a new high-performance calcium-based desulfurizer using a steam jet mill

Dry flue gas desulfurization is an increasingly attractive technique in SO2 emission control. However, the low efficiency in dry desulphurization is the bottleneck of this technology. To find a high-performance desulfurizer is an urgent task. This research utilized a steam jet mill digestion to prepare a desulfurizer at steam temperature of 220 ℃ and pressure of 0.45 MPa, and compared this product with the conventional digestion desulfurizer. Our results show that the digestion in steam jet mill can transform all the calcium oxide into calcium hydroxide. The calcium hydroxide had good fluidity and with honeycomb morphological characteristics. The experiments of dry flue gas desulfurization demonstrated that under the relative humidity of 15, 30 and 45%, the total dead times were 340, 640 and 720 min, the working time for keeping a 100% desulfurization efficiency were 120, 420 and 580 min, and the total sulfur fixation were 124.05, 274.58 and 332.09 mg. Compared with the desulfurizer by conventional dry digestion, the desulfurizer prepared in this research had a significantly superior performance. This experiment provides a new method for high-performance desulfurizer via quicklime digestion, which is an important step in pushing forward the application of dry flue gas desulfurization.

PSXII-18 The influence of molybdenum in drinking water or feed on apparent absorption and retention of molybdenum and copper in beef steers

Abstract Twelve Angus steers (BW 694.1 ± 47.4 kg) fitted ruminal cannulae were used to examine the effect of molybdenum (Mo) supplemented in drinking water or feed on apparent absorption and retention of Mo and copper (Cu). Steers were fed a low-quality grass hay diet (DM basis: 6.5% CP; 0.13% S, 3.4 mg Cu/kg, 2.4 mg Mo/kg) for 14 d. Steers were then housed in individual metabolism stalls for 3 d to determine DMI. Steers were then blocked by BW and DMI and randomly assigned within block to one of three treatments (n = 4 steers per treatment). Treatments consisted of: 1) Control (no supplemental Mo); 2) 5.0 mg Mo/kg DM from sodium molybdate dihydrate (Mo-diet), and 3) 1.5 mg Mo/l from sodium molybdate dihydrate delivered in the drinking water (Mo-water). After the 3d DMI determination period, total fecal and urine output was collected for 5 d. Dry matter intake and DM digestibility were similar across treatments. Data were analyzed using a mixed effects model (PROC MIXED, SAS) for a completely randomized block design. Apparent absorption of Cu was greater (P &amp;lt; 0.05) in Control and Mo-water steers when compared to Mo-diet steers. Apparent retention of Cu was greater (P &amp;lt; 0.05) in Control steers when compared to Mo-diet steers. Steers receiving Mo-water had a similar apparent retention of Cu when compared to Control and Mo-diet steers. By design, treatment was a significant (P &amp;lt; 0.01) source of variation for Mo intake. Control steers had lesser (P &amp;lt; 0.05) Mo intake when compared to Mo-diet and Mo-water supplemented steers. Apparent absorption and retention of Mo were greater (P &amp;lt; 0.05) in Mo-diet steers compared to Control and Mo-water steers. These data indicate that Mo metabolism and apparent absorption of Cu are different when Mo is supplemented in water relative to feed.

Effect of Substrate Characteristics and Process Fluid Percolation on Dry Anaerobic Digestion Processes

AbstractThe dry anaerobic batch digestion process is an organic waste treatment technology most appropriate for the treatment of stackable (non‐free‐flowing) dry organic waste materials. The effect of the process fluid percolation and substrate permeability on methane production of organic household waste was investigated in anaerobic dry digestion trials at pilot scale. The container system consisted of two percolation digesters and a fixed‐bed methane digester. The experimental results indicate that material compaction occurs during the digestion process and can have a negative effect on substrate permeability. Structure material addition reduced material compaction and as a result increased the substrate permeability.

Use of Cold-Pressed Sunflower Cake in the Concentrate as a Low-Input Local Strategy to Modify the Milk Fatty Acid Profile of Dairy Cows.

Simple SummaryConsumers demand healthier dairy products. Supplementing plant lipids, rich in poliunsaturated fatty acids, results in improved milk fatty acid profile, but these oils could enter into competition with human food needs and compromise animal performance. The aim of this study was to test the feasibility of formulating cold-pressed sunflower cake (CPSC, high-fat by-product) in a dairy cows’ concentrate to improve milk fatty acid profile. Cold-pressed sunflower cake increased total trans-mono unsaturated fatty acids (21%), total conjugated linoleic acid (31%), and polyunsaturated fatty acids to saturated fatty acids ratio (18%), but did not affect milk production, digestibility, intake, and milk composition. However, reduced fat yield (9%) and fat corrected milk (7%) were observed. Feeding CPSC improved overall acceptability of milk by improving flavor. In conclusion, CPSC could modify milk FA profile without observing a detrimental effect on digestibility, production performance, or milk acceptance. Adopting feeding systems based on the use of cheaper and local alternative feedstuffs rich in polyunsaturated fatty acids would represent a good strategy to change milk fatty acid profile and contribute the promotion of low-input production systems.Cold-pressed sunflower cake (CPSC) is a cheap by-product of oil-manufacturing. Supplementing diets with CPSC, rich in fat and linoleic acid, could be an effective tool for increasing healthy fatty acids (FA) in milk. To test this hypothesis, 10 cows were used in a crossover design with two experimental diets fed during two 63-day periods. Cows’ milk production was recorded and samples were taken for fat, protein, lactose, and for FA composition analysis. Dry matter intake (DMI) and dry matter apparent digestibility (DMD) were estimated using two markers. Milk acceptance test was carried out. CPSC decreased milk C12:0 (10%, p = 0.023) and C16:0 (5%, p = 0.035) and increased C18:1 cis-12 (37%, p = 0.006), C18:1 trans-11 (32%, p = 0.005), C18:2 cis-9 cis-12 (13%, p = 0.004), and cis-9 trans-11 CLA (35%, p = 0.004). CPSC increased total trans-monounsaturated FA (21%, p = 0.003), total CLA (31%, p = 0.007), and PUFA:SFA ratio (18%, p = 0.006). CPSC did not affect milk production, DMD, DMI and milk composition, but reduced fat yield (9%, p = 0.013) and FCM (7%, p = 0.013). CPSC improved milk overall acceptability. In conclusion, CPSC could modify milk FA profile without a detrimental effect on digestibility, production performance, or milk acceptance.

Effects of Ketosis in Dairy Cows on Blood Biochemical Parameters, Milk Yield and Composition, and Digestive Capacity.

IntroductionThis study aimed to characterise the effects of ketosis on milk yield and composition and digestive capacity in transition dairy cows.Material and MethodsSeven ketotic and seven healthy cows were housed in individual stalls for six days. Samples of plasma, milk, refused total mixed ration, and faeces were collected, and the blood biochemical parameters, milk yield and composition, dry matter intake, and faecal dry matter (FDM) production were determined.ResultsCompared with healthy cows, the ketotic cows had significantly higher concentrations of milk fat and citrate, but lower levels of milk protein and lactose. The cows exhibited a need for acid detergent fibre in forage and better digestion of neutral detergent fibre, starch, crude protein, and phosphorus than healthy cows, but more fat and gross energy were excreted in their faeces. Ketotic cows had higher energy-corrected milk yields and lower FDM than healthy cows.ConclusionLower feed intake coinciding with the requirement to maintain high milk production is considered to be the cause of ketosis in dairy cows. Ketotic cows exhibited lower dry matter fat digestion.

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To meet the rising food demand for next generations, soils are needed to stand biological yield and promote animal, plant and human welfare. In this logic, the aim of the study was to determine the effects of different soil uses; (a) successive irrigated rice planting and (b) different soil management practices onto soil chemical properties and nutrient cycling. The study was carried out in areas with dissimilar years of irrigated rice farming, managed with conventional tillage (CT) and minimum cultivation (MC). Having as a reference a native vegetation plot, areas with 2, 4, 9, 14 and 26 years of different management such as conventional tillage or minimum cultivation were evaluated. Soil samplings were performed in the 0 - 0.10, 0.10 - 0.20 and 0.20 - 0.30 m layers. Three sub samples per layer were collected within each replicate and then condensed to the combined sample; straw sampling was also performed. Total nitrogen (TN) and total organic carbon (TOC) were determined by dry digestion in a Vario El III elemental. Highest TOC results were obtained in Ar9 and Ar14 areas in 0-0.10 and 0.10-0.20 m layers; straw production varied from 7.61 to 8.94 Mg ha-1. Ar2 presented higher value in relation to others; nevertheless these variations were not significant. Still, it was observed that the Ar9 and Ar14 areas presented a higher total biomass production (grains and straw) than those found in Ar4, Ar2 and Ar26; so, these variations did not differ. Conversion of native ecosystems to irrigated rice production areas significantly affects soil fertility. Key words: Total organic carbon, soil management, irrigated rice.

Methanogenic activity and microbial communities characteristics in dry and wet anaerobic digestion sludges from swine manure

The metabolic pathways of methanogenesis in anaerobic digestion sludges were investigated by studying the specific methanogenic activity (SMA) and microbial community structure in dry and wet anaerobic digestion sludge (DADS and WADS, respectively). Compared to SMAs in WADS using different substrates, the SMAs in DADS were 15.1% higher (H2/CO2 as the substrate), 34.5% lower (acetate), 45.5% lower (propionate), 19.5% lower (butyrate) and 5.5% lower (glucose). The genus Petrimonas represented 9.5% and 1.4% of the microbial population in DADS and WADS, respectively. The hydrogenotrophic methanogens Methanocorpusculum (48.0%) and Methanobrevibacter (15.3%) were the dominant archaeal genera in the DADS, and the acetotrophic methanogens Methanosaeta (77.0%) was the dominant archaeal genus in the WADS. This study indicated that anaerobic digestion in DADS possibly was affected by the sensitivity of hydrogenotrophic methanogens to hydrogen partial pressure (PH2) and the limited mass transfer of hydrogen, which consequently reduced methane production efficiency and altered the metabolic pathway of glucose degradation and methanogenesis.

Comparison of Dry Versus Wet Milling to Improve Bioethanol or Methane Recovery from Solid Anaerobic Digestate

Biogas plants for waste treatment valorization are presently experiencing rapid development, especially in the agricultural sector, where large amounts of digestate are being generated. In this study, we investigated the effect of vibro-ball milling (VBM) for 5 and 30 min at a frequency of 20 s−1 on the physicochemical composition and enzymatic hydrolysis (30 U g−1 total solids (TS) of cellulase and endo-1,4-xylanase from Trichoderma longibrachiatum) of dry and wet solid separated digestates from an agricultural biogas plant. We found that VBM of dry solid digestate improved the physical parameters as both the particle size and the crystallinity index (from 27% to 75%) were reduced. By contrast, VBM of wet solid digestate had a minimal effect on the physicochemical parameters. The best results in terms of cellulose and hemicelluloses hydrolysis were noted for 30 min of VBM of dry solid digestate, with hydrolysis yields of 64% and 85% for hemicelluloses and cellulose, respectively. At the condition of 30 min of VBM, bioethanol and methane production on the dry solid separated digestate was investigated. Bioethanol fermentation by simultaneous saccharification and fermentation resulted in an ethanol yield of 98 geth kg−1 TS (corresponding to 90% of the theoretical value) versus 19 geth kg−1 TS for raw solid digestate. Finally, in terms of methane potential, VBM for 30 min lead to an increase of the methane potential of 31% compared to untreated solid digestate.

PREDICTION OF THE APPARENT ILEAL DIGESTIBILITY OF DIETS CONTAINING CARAWAY SEED SIEVING FOR RABBITS BY ITS CHEMICAL COMPONENTS OR BY IN-VITRO ENZYMATIC ANALYSIS AND COMPARED IT WITH IN VIVO DIGESTIBILITY VALUES

The use of multiple-enzymatic in vitro methods has been proven to be a good alternative to chemical analyses to stimulate the digestive processes and to predict energy values with greater precision in rabbits. The basal experimental diet was formulated and pelleted to cover the nutrient requirements of rabbits according to NRC (1977). The experimental groups were classified as the following: R1 fed the basal diet and served as the control group (R1), and control containing 2%, or 4% or 6% caraway seeds sieving (CSS) for R2, R3 and R4, respectively. The prediction equations of the DMD %, GEd% and DE (MJ Kg-1 DM) of diets using in vitro analysis, the highly significant (P<0.01) prediction effect of DMD was recorded with R3 (containing 4% CSS), the values were 76.60% in R3, followed 75.04% in R4 and the lowest value 73.89% in R2 compared with control 72.07%. Predicting nutritional values ​​by analyzing the laboratory in vitro with the chemistry analysis (g / kg) of the dry matter, the higher significant (P<0.01) prediction of DMD% was recorded with R3, the values were 82.04% in R3, 80.37% in R4 and 79.14% in R2 compared with control 75.62%, the estimating GEd%, and. DE (MJ Kg-1DM) increased the prediction ratio for GEd% and DE (MJ / kg DM) using DMDinv and EE with R3, and the values ​​were 82.81% and 14.07(MJ/kg DM) respectively. These values were higher than these predicted by in vitro only DMD in vivo trails were slightly higher values compared with DMD in vitro by 0.54%,0.38, 6.65 and 4.21% for R1, R2, R3, and R4, respectively. The prediction DMSin vivo from the equation in vitro system higher compared with the values DMDinv and values DMDin vivo trials, the values were 79.16%, 81.54 %,80.17%, and 76.28%, for R2, R3, and R4, respectively. Values of nitrogen-corrected apparent metabolizable energy content (AMEn) and its proportion on total gross energy (AMEn/GE%) in the diets CSS were highest values determined by chemical composition results compared with the same values obtained by using in vitro dry matter digestibility results. The highest significant values of AMEn/GE% and AMEn (kcal kg–1 DM) were obtained with R3 they were 76.20 and 3,460 kcal kg–1 DM, respectively. The values highest increased AMEn/GE% determined by using in vitro dry matter digestibility result was recorded with R3 by 9.48%, followed R4 by 6.66%, finally, R 2 by 4.97%, the values of AMEn (kcal kg–1 DM) were 2,903, 2,852 and 2,820, for R3, R4 and R2 compared with R1 control were 2,726. The Prediction apparent ileal digestibility of protein values of In-vitro was given the highest value compared to the digested protein by the digestion experience on rabbits. Results of endogenous protein losses (EPLg / kg DM intake) were lower with diets containing caraway seed sieving compared to the control diet. The values ​​were 29.43, 27.60, 28.65% and R2, R3 and R4, respectively compared to the control 31.64%. Predicting the values of essential and non-essential amino acids by the results of the digested protein obtained from the in vitro enzyme system. A significant increase was recorded with rabbits’ diets containing caraway seed sieve by levels 2 and 4% for R2 and R3, respectively, but a nonsignificant increase recorded with the R4 which contains 6% compared with the control R1. Caraway seed saving containing medicines compounds of total antioxidant 319.77 mg/100g ascorbic acid equivalent, total flavonoids 120.56 m/100g Quercetin equivalent, total phenols 447 mg/100g gallic acid equivalent and carvacrol 3934 g/L. In conclusion, a study of diets containing 4% caraway seeds sieving (CSS) indicated the highest nutritional values. The nutritional values ​​can be predicted through the estimation of in vitro dry matter enzymatic digestibility in rabbit diets.

Overseeding Eastern Gamagrass with Cool‐Season Annual Grasses or Grass–Legume Mixtures

Eastern gamagrass [Tripsacum dactyloides (L.) L.] can serve as an alternative warm‐season perennial forage in the southeastern United States. A 2‐yr study was conducted to evaluate effects of (i) overseeding with cool‐season forages and (ii) N fertilization in the spring on herbage accumulation, nutritive value, and persistence of ‘Highlander’ eastern gamagrass. Overseeding treatments included: control (no overseeding), early‐maturing ‘Florida 401’ rye (Secale cereale L.), mid‐maturity ‘Wrens Abruzzi’ rye, and a mixture of ‘Wrens Abruzzi’ and ‘AU Red Ace’ red clover (Trifolium pratense L.). During late spring, eastern gamagrass was fertilized with either 67 or 135 kg N ha−1 to evaluate growth response following overseeding and differing N input levels. Herbage accumulation (kg dry matter [DM] ha−1) and nutritive value (in vitro dry DM digestibility and crude protein) were measured during the cool‐ and warm‐season production window. Forage canopy cover and botanical composition determinations measured persistence and compositional change during each growing season. Mob‐stocking was implemented every 28 d to simulate rotational grazing. There was no effect of overseeding with cool‐season annual grasses or grass–legume mixtures on seasonal eastern gamagrass herbage accumulation or persistence during the trial. Cool‐season forage herbage accumulation in this study was limited. Spring N fertilization stimulated a rapid growth response in eastern gamagrass, but N‐level effects dissipated as the season progressed. Results indicate that overseeding may be a viable option in eastern gamagrass swards, but given the low level of cool‐season forage production observed in this study, evaluation of additional cool‐season species/blends and economic viability of this system is needed.

A snapshot of microbial community structures in 20 different field-scale anaerobic bioreactors treating food waste

This study aimed to identify significant factors shaping the microbial populations in biogas plants treating food waste (FW). Twenty full-scale anaerobic acidogenic/methanogenic bioreactors, located at 11 FW treatment facilities, were compared to find patterns in their microbial community structures and potential interactions with the process parameters. Temperature, hydraulic retention time, and organic loading rate were design parameters that systematically influenced the microbial communities. The latter two clearly separated the acidogenic and methanogenic bioreactors. Lactobacillus was the dominant (69.7 ± 19.8%) bacteria in the acidogenic reactors, while hydrogen-utilizing methanogens, such as Methanoculleus (65.1 ± 33.5%), were the dominant archaea in most methanogenic digesters. Defluiviitoga was the dominant (82.7 ± 1.4%) bacteria in the thermophilic digesters, but was also the most abundant (33.1–33.6%) bacteria in dry mesophilic digesters. The two bioreactor categories had lower bacterial diversities, and also higher propionate concentrations (>5 g/L in 4 out of 5 cases), which may impose potential risks for the management of such digesters. The current ‘snapshot’ of the microbial communities suggests several bacterial and archaeal taxa as potential indicators of bioreactor categories and/or process variables.