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The use of food additives such as antibiotics is a useful tool in reducing energy loss (methane) and nitrogen (ammonia). However, the use of antibiotics in animal feed has been banned in the EU since January 2006 due to their residual risk in milk and meat and its subsequent effects on human health (Aminipour et al. 2017). Essential oils of herbals are used because of their antimicrobial effect against bacteria, protozoa and fungi, their ability to manipulate rumen fermentation, and their potential to reduce methane production in ruminant diets (Gunal et al. 2017). The results of research show that peppermint essential oil reduces methane, ammonia nitrogen concentration, number of protozoa and changes the molar ratio of short-chain fatty acids (Ahmad et al. 2014). Some experiments show that thyme essential oil reduces the production of gas (Roy et al. 2015), methane (Baraz et al. 2018). Although there is useful information about the effects of peppermint, thyme and rosemary essential oils on their positive effect on rumen fermentation, a study examining the effect of a mixture of these essential oils is not available. Therefore, this study was conducted to evaluate the effect of different doses of three mixes of peppermint, thyme and rosemary essential oils (6, 12 and 18 µl) on in vitro gas production parameters.

The essential oils were mixed in three levels of 150, 300, 450 µl, with three different ratio including A=(1: 3: 2), B=(2: 1: 3) and C=(3: 2: 1); thereafter, the effect of different doses (6, 12, 18 μl) of these three combinations on fermentation parameters was studied. Rumen fluid was obtained from three sheep before morning feeding via rumen fistula. The effect of the mixture of essential oils on gas production and kinetics of gas production was investigated by incubating 125 mg of each sample at 2, 4, 6, 8, 12, 24, 36, 48, 72 and 96 hours. Also, in another experiment, by incubating the samples for 24 hours, gas production and methane production were estimated. Also, different mixtures were compared in terms of their effect on reducing the amount of methane production.

Adding a mixture of essential oils in different doses reduced gas production compared to the control group (P<0.05). Comparison of the three mixtures of essential oils tested showed that during the incubation period of 2 to 12 hours, mixtures B and C showed a decreasing trend in gas production, meanwhile mixture C had the lowest value compared to the other two mixtures (P<0.05). There was no significant difference between mixtures A and B during 24 to 48 hours of incubation, but mixture C showed the lowest value compared to the other two mixtures (P<0.05). At 72 to 96 hours of incubation, mixtures A, B and C did not show significant differences in gas production (P<0.05). The results of this experiment showed that mixture C caused a further reduction in gas production than other mixtures. Decreased gas production can be related to a decrease in the fermentation activities of microorganisms and a decrease in dry matter digestibility (Tan et al. 2011). On the other hand, reduction in gas production by essential oils may indicate more efficient use of energy due to inhibition of energy loss in the form of methane (Aminipour et al. 2017). In the present experiment, different doses of essential oil mixtures reduced gas production, so that at 2 to 96 hours of incubation, doses of 6 and 12 did not differ significantly in terms of gas production (P <0.05); but the level of 18 µl compared to other doses showed a significant decrease in gas production (P <0.05). The mixture of essential oils at the level of 6 μl showed that mixture A, which contained the highest amount of thyme and rosemary essential oils, had no effect on gas production during incubation compared to control, while mixture C, which contained higher amounts of peppermint and Thyme essential oils had the greatest impact on gas production. The gas production potential (B) was not significantly different between the three mixtures (P>0.05), although numerically it was the lowest in mixture C (19.53 versus 11.82). Gas production rate (c) had a similar trend so that despite the lack of significant differences between the three mixtures (P>0.05), numerically C mixture showed the lowest value in terms of this parameter. A decreasing trend in methane production at the level of 18 μl of essential oil of a mixture of three herbals was observed, so that in mixture B was the lowest value compared to the control group (P <0.05). Essential oils may directly inhibit the growth and activity of methanogenic microbes, or indirectly by reducing the number of methanogen-related protozoa (Gonal et al. 2017) or by indirect reduction in some processes of methanogenic microbial metabolism (Cobellis et al. 2015) affect methane production.Due to the fact that the proportion of two thirds of mixture B is peppermint essential oil, the percentage of methane production in mixture B compared to the control showed a significant decrease. It has been reported that the decrease in methane production may be due to the reduction of total protozoan by menthol as the main active ingredient of peppermint essential oil (Roy et al. 2015).

The results of this study showed that in the gas production test at 2 to 96 hours, all three levels of 6, 12 and 18 microliters significantly reduced gas production at all incubation times, even 24 hours, so At the level of 18 microliters, the largest decrease in gas production was observed. Of the three mixtures used, mixture B showed the greatest effect in reducing methane production. Therefore, a dose of 18 μl with a decrease in total gas production and mixture B with a dose of 18 μl with a decrease in methane production has the potential to change ruminal fermentation.

In order to investigate the effect of licorice extract (LE) on growth performance, fermentation parameters, and rumen protozoan population in fattening lambs, 28 male lambs weighing 36.45 ± 1.75 kg in a completely randomized design with four treatments and seven replicates were used. Experimental treatmeشnts included: control, basic diet without licorice extract, and treatments one to three included basic diet plus five, 10 and 25 mg of LE per kilogram of DM. The ratio of forage to concentrate was 30:70, which was given to the animals as per their appetite. Adding 25 mg of the extract to the diet increased the daily gain and improved the feed conversion ratio (P<0.05). The pH of rumen fluid and gas production increased at the level of 25 mg of extract (P<0.05). Methane production was not affected by adding LE to the diet. The changes in metabolizable energy, degraded organic matter and concentration of volatile fatty acids in diets containing 5 and 25 mg of LE were more than other groups (P<0.05). The total population of protozoa as well as the number of Entodinia decreased by feeding diets containing LE (P<0.05) but the number of Isotrichida increased, significantly. Based on the results of this research, adding 25 mg/kg of licorice extract to the diet improves the rumen metabolism and the performance of fattening lambs, but it had no effect on the amount of energy loss in the form of methane.

Pastures provide an important part of ruminant fodder needs, and farmers store some pasture plants to use in winter-feeding of livestock. Therefore, having enough information about the nutritional value of such plants can help to optimize their consumption in animal feeding. Completing the information on the good-quality plants adapted to different environments will help to use and develop these valuable resources in a better way. In addition, it may be possible to improve rumen fermentation by aromatic pasture plants. Adiantum capillus-veneris (Adiantum) and Salvia officinalis L. (Salvia) are valuable genetic resources in pastures that are also used in livestock feeding. Due to the presence of plant secondary metabolites, they may improve rumen fermentation. However, there is little information on the nutritional value of Adiantum. Some information is available on the chemical composition of Salvia species (especially the leaves) and the effect of its essential oil on the rumen, but data on the use of the whole plant as forage are limited. Therefore, this study aimed to assess the nutritional value of Adiantum and Salvia compared to alfalfa, and the effect of including different levels of them in the diet on in vitro ruminal fermentation variables and digestibility.
The experimental pasture plants (Adiantum and Salvia) were obtained in July, after flowering, from the pasture of Safrin village located in the rural district of Rajaeedasht in western Alamut (Qazvin, Iran). In experiment I, the chemical composition of the fodders was determined by the standard methods, considering alfalfa as the control forage. In experiment II, the effect of different dietary levels of the fodders was assessed using in vitro gas production technique with five treatments including 1. A diet without the rangeland plants (control diet), 2. A diet containing 15% of Adiantum, 3. A diet containing 30% of Adiantum, 4. A diet containing 15% of Salvia, and 5. A diet containing 30% of Salvia (on a DM basis). The in vitro digestibility, fermentation variables, microbial biomass production (MBP), total antioxidant power (TAP), protozoa numbers, and methane production were determined. The gas test was performed in three replicates and two runs, and data were analyzed using the GLM procedure of SAS.
According to the results of experiment I, Adiantum and Salvia had higher ash compared to alfalfa (P<0.05). The crude protein and digestibility of Adiantum were lower than Salvia and alfalfa (P<0.05). The lower digestibility of Adiantum could be due to its higher lignin and ash and the lower crude protein concentration. Therefore, when consuming Adiantum in diets of high-productive ruminants, it is necessary to pay more attention to the use of energy supplements. Compared to alfalfa, the in vitro fermentation of Adiantum and Salvia resulted in higher in vitro ruminal MBP and TAP and lower ammonia-N and protozoa population (P<0.05), due to the presence of plant secondary metabolites such as phenolics, tannins, flavonoids, anthocyanins, and terpenes. The results of experiment II showed that the inclusion of Adiantum and Salvia in the diet had no significant (P>0.05) effect on in vitro gas production, organic matter digestibility, and metabolizable energy. Dietary use of Salvia, however, enhanced truly degraded substrate (P<0.05). Sometimes, high amounts of secondary metabolites in plants may have negative effects on the rumen but the amounts of metabolites in the pasture plants used in this study were not so high as to hurt rumen microbes and digestion. Dietary inclusion of Adiantum and Salvia improved in vitro TAP and decreased protozoa population, methane production, and acetate to propionate ratio (P<0.05). The lowest methane production was observed for the diets containing Salvia. The positive effect of the rangeland plants on in vitro TAP was because both plants contain significant amounts of various secondary metabolites (such as phenolic compounds, flavonoids, and terpenes) that are known to be favorable and high-capacity antioxidants. These plant metabolites can remove free radicals, bind transition metals (such as free iron), remove active oxygen from the environment, induce antioxidant enzymes, and reduce and moderate the conditions of oxidative stress and destruction. The reduction of methane release using Adiantum and Salvia in the diet was probably related to the fact that plant secondary metabolites destruct the protozoa or interfere with their metabolic pathways. In addition, they may inhibit methanogenic and hydrogen-consuming bacteria or hydrogen-producing Gram-positive bacteria. The dietary addition of Adiantum and Salvia improved in vitro ruminal MBP and decreased the ammonia-N concentration (P<0.05) compared to the control diet. The result could be due to the reduction of the protozoa population, causing a decrease in nitrogen recycling in the rumen and a decrease in bacteria predation. The formation of phenolic-protein complexes can also be another possible reason for reducing protein breakdown and ammonia concentration. Moreover, as rumen protozoa are reduced, the bacteria will have fewer natural predators and their population (reflected in the higher MBP) will increase, improving the degradation of feed ingredients. The inclusion of Adiantum and Salvia in the diet did not affect in vitro pH, total volatile fatty acids, and partitioning factor (P>0.05).
It is possible to include whole plants of Adiantum and Salvia in the diet, up to 30% DM, without adverse effects on digestibility. It also improves diet efficiency by increasing in vitro ruminal MBP and TAP and reducing methane and ammonia production.

This study aimed to investigate the effect of reducing the dietary level of crude protein (CP) and inclusion of extruded soybean meal (SBM) and canola meal (CM) on blood and ruminal parameters, the population of methanogens, and hyper-ammonia producing bacteria (HAB) of feedlot calves. To this purpose, 36 male calves were used in a completely randomized experimental design with six treatments and six replicates. Experimental treatments included: 1) Control (CP=15%, SBM (15SBM)), 2) SBM (CP=13%, 13SBM), 3) Extruded SBM (CP=13%, EXSBM), 4) CM (CP=13%, 13CM), 5) Extruded CM (CP=13%, EXCM), and 6) Fish meal (CP=13%, FM). Concentrations of albumin, total protein, creatinine, and blood urea nitrogen in experimental treatments decreased compared to 15SBM (P>0.05). The highest values of ruminal ammonia and acetate and the lowest amounts of propionate and volatile fatty acids (VFA) were observed in the 15SBM (P<0.05). The minimum ruminal HAB population was observed in EXSBM and EXCM and then in 13SBM, 13CM and FM and was maximum in 15SBM (P<0.05). Also, treatments fed EXSBM and EXCM had a smaller methanogens population than the control group (P<0.05). Based on the results obtained, decreasing dietary CP level and processing of extrusion for SBM and CM decreased HAB population, rumen ammonium, and blood urea concentration. Furthermore, extrusion declined methanogens bacteria population and acetate to propionate ratio and increased total VFA concentrations which can be considered as an indication of the rumen improvement in fermentation efficiency index.

This study was carried out to investigate the effects of different levels of pistachio by-product biochar (PBPB) on cumulative gas production, gas production parameters, short chain fatty acids, digestibility, methane and ammonia production and volatile fatty acids in an in vitro batch fermentation system. The study was carried out in a completely randomized design with four treatments and three replications. Four levels of PBPB including 0, 0.5, 1 and 1.5 % was added to the experimental diets with ratio 60% forage to 40% concentrate. All samples were incubated in three replications using buffered ruminal fluid collected from 4 Kermanian sheep. Result indicated that inclusion of biochar to experimental diet had no significant effect on cumulative gas production after 24 and 96 h of incubation, short chain fatty acids, protozoa population and volatile fatty acids. Inclusion of PBPB to the diet significantly increased pH (P<0.01) compared to control treatment . Concentrations of ammonia (P<0.05) and methane (P<0.01) significantly decreased at 1 and 1.5% of PBPB compared to control. In general, these findings indicated that the use of PBPB can have had a great potential to decrease methane mitigation and ammonia concentrations and improving of rumen fermentation

The methane production from ruminant production system was estimated to reach 250-500 L per animal per day which has been reported to contribute up to 8-10 % of global warming during the next 50-100 years. The aim of this study was to investigate the correlation among methane emission (predicted by volatile fatty acids) with milk production traits, its components and breeding values (BV) of these traits in Iranian Holstein cattle. The rumen digesta was obtained from 150 cattle through stomach tubing and this population divided into 2 groups with 75 cattle in each (the groups have different milk production BV). Data were analyzed by R.3.3.0. The results showed that methane emission per unit of milk and fat were different in the two groups (P<0.0001). Also, the BVs of milk production, fat and protein traits and daily production of milk, fat and protein had weak to moderate negative correlation with methane emission per unit(P<0.05). The highest correlation was observed between daily production of fat with methane emission per unit of fat (-0.79) as well as daily milk production with methane emission per unit of milk (-0.62). These results showed that methane emission may be reduced by indirect selection per generation for the traits had a high correlation with the gas (daily production of milk and fat).

This study was conducted to evaluate the effect of different doses of fennel essential oil (100, 250, 500, 750 and 1000 µg) on in vitro gas production parameters and protozoa population using goat rumen fluid. Rumen fluid was obtained from six Markhoz goats before morning feeding via esophageal tube. Gas production during 96 hours of incubation was recorded. The effect of essential oil on total protozoa and different genus was investigated. Also, gas production after 24h, methane production and some of the other in vitro ruminal parameters were determined. Gas production potential (B) and fermentation rate (c) were decreased by inclusion of the essential oil (P<0.0001), while lag phase in low doses of the essential oil increased (P=0.004). The pH did not alter due to the additionof the essential oil, but ammonia nitrogen and total volatile fatty acids were declined at doses of 750 and 1000 µg of the essential oil. Gas 24h, methane production, in vitro organic matter digestibility and metabolizable energy decreased, while partitioning factor, microbial mass and its efficiency increased by adding the essential oil (P<0.0001). Adding fennel essential oil into fermentation media decreased total protozoa number and Entodinium spp and Isotricha spp (P<0.0001), but it had no effect on Diplodiniinae and Ophryoscolecinae populations. The results showed that the fennel essential oil may have selective antiprotozoal effect on Entodinium spp and Isotricha spp., and it has a good potential to change rumen fermentation by decreasing methane production, ammonia concentration and increasing the partitioning factor.

Two experiments were conducted to assess the addition of pistachio by-product biochar (PBB) to lactatingewes’ diet. In first experiment, the effects of the addition of different levels (0, 0.5, 1 and 1.5% diet on dry matter basis, DM) of PBB on rumen fermentation parameters after 24h of incubation were investigated in a completely randomized design with four treatments and three replications. Second experiment was designed to evaluate effect of feeding selected level ofPBB on performance and nutrient digestibility of 8 lactatingKermanian ewes in a Latin square change-over designwith two 21-day periods. Methane production and ammonia-N concentrations decreased linearly (P<0.01), and pH increased linearly (P<0.01) as the dietary level of PBB raised. With the addition of 1% PBB to the lactating ewes’ diet, milk yield, blood glucose, digestibility of DM increased(P<0.05) and blood urea nitrogen (BUN) decreased (P<0.05)compared to control group.In general, adding 1% of PBB to lactatingewes’ diet can improve milk yield and digestibility of DM.

Extract of Scrophularia striata (ES) was tested as a feed additive for improving the efficiency of ruminal degradation of nutrients, concentration of total phenolic and flavonoid compounds and antioxidant activity using the rumen simulation technique (RUSITEC). Twelve fermentation units (vessels) were set up for 2 experimental runs each lasting 10 d wherein the last 5 days served for sampling. Treated vessels were supplied with no additive (Control), 10 mg/d monensin (Monensin), and 480 and 960 mg/d of ES, respectively. Both levels of ES and monensin decreased methane production expressed per gram nutrients degraded (P<0.05). Production of total volatile fatty acid per gram DM and organic matter degraded was higher in ES treatments in comparison with control and Monensin (P<0.05). The ammonia production expressed per gram CP degraded was lower than control only in the high level of ES supplementation (P<0.05). The latter treatment also resulted in the highest concentration of total flavonoid, phenol lic compounds and antioxidant activity compared to other treatments (P<0.05). Based on the present results, ES could be considered as an alternative to antibiotic for improving the efficiency of degradation, increasing ruminal antioxidant activity and decreasing methane production.

Effects of ethanol and acetone extracts of Glycyrrhiza glabra at six levels (0, 50, 100, 200,300 or 500 µl) were evaluated on gas production process, ruminal fermentation and protozoa population in Markhoz goat. The gas production was conducted by alfalfa substrate using compiled randomized design with five replications in each treatment. The fermentation parameters, methane, partitioning factor (PF) and volatile fatty acids (VFA) were recorded. The gas production in 24 h was increased in all levels of both extracts (P˂0.01). The methane production decreased in ethanol extract (P˂ 0.05) however, it was increased by acetone extract at level of 300 and 500 µl (P˂0.01). The organic matter degradability was improved by addition of both extracts (P˂0.01). The Ammonia was declined by ethanol extract (P˂ 0.01). The PF and microbial mass production were decreased by inclusion of both extract, however the VFA and metabolizable energy were enhanced at all levels of both extracts (P˂0.01). All subfamily (except Diplodiniinae)and total protozoa population were decreased by both extracts. It can be concluded that ethanol and acetone extracts of Glycyrrhiza glabra has the potential to improve degradability and were decreased methane production and protozoa population of goat rumen.

This review aimed to collect and summarize all available current evidence of the effects of pistachio by-product (PBP) on rumen fermentation and biohydrogenation, microbial protein synthesis, methane emission, physiological parameters and blood metabolites in ruminants. The results showed that the concentration of NH3-N and efficiency of microbial nitrogen synthesis in the rumen decreased in PBP supplemented diets, although the PBP diets had lower microbial protein synthesiscompared to the control groups. By increasing PBP supplementation the concentrations of total volatile fatty acids and the total population of the rumen bacteria in the rumen were reduced in some experiments. Some studies suggest that the use of PBP can be a useful strategy for increasing the CLA content of milk fat in Saanen dairy goats. This by-product is effective in reducing methane emissions from livestock. In general, PBP can be used in ruminant diets at inclusion levels up to 300 g/kg, or more without interfering with performance, ruminal fermentation, blood metabolites, hematological parameters, and kidney and liver function.

Iran in addition to the emergence of pomegranate and its natural habitat, the number of varieties and is the largest producer of pomegranate in the world. Pomegranate peels comprising almost 26–30% of total fruit weight; in recent years the biological activity of pomegranate peel polyphenols has become a subject of interest among many researchers and consumers. Tannins effects on rumen methanogens and protozoa was proven, as well as the effect of that on gas production kinetic and rumen fermentation according to the type of vegetation is varies. Thus the objective of this study was to determine the chemical composition, polyphenolic components, in vitro apparently and truly degraded dry matter, methane production, the number of protozoa of three pomegranate peels (Torsh Jangali Gorgan, malas Behshahr and Shirin kolbad) varieties.
Varieties collected during harvested season (autumn) from different region of Golestan province and dried. The study was carried out in a completely randomized design with tree treatment and four replicates. After an initial gas test to evaluate 96 h gas production profiles of pomegranate peels, the time to half maximal gas production was calculated and a second incubation conducted with fermentation stopped at substrate specific half time (t ½) and 24 h for each substrate. True DM degradability was measured from incubated residues and combined with gas volume to estimate the partitioning factor (PF).
Highest CP in Shirin Kolbad and highest EE and ADF in Torsh Jangali Gorgan varieties were observed. Total Phenol composition in Torsh Jangali Gorgan variety with 8.91% and total tannin in malas Behshahr variety with 8.06% were high than Other varieties. Shirin kolbad pomegranate peel had greater in vitro apparently and truly degraded dry matter, microbial protein, and short chain fatty acids (respectively 0.347, 0.590 (mg), 500.79 (g/kg DM), and 0.9 (mmol) in 24 h incubation (P The results of this study showed that pomegranate peel is an important agro-based by-product that is produced in Iran and because of having phenolic components and tannins has antimicrobial activity against microorganisms that produced methane as well as protozoa, that, three varieties of this pomegranate peel can be used for modulating rumen fermentation and methane reduction.

In this expriment, the effect of different levels of Ziziphus zizyphus(ZZ) (0, 30 or 60 mg) on fermentation parameters, total protozoa population and three sub family of protozoa Entodiniinae, Ophryscolecinae, Diplodiniinae and family of Isotrichdaeandmethane gas production was assessed using in vitro method and a completely randomized design. The rate of gas production for the insoluble fraction (c) (P˂0.01) was decreased but (P˂0.01) fermentation potential (a) at 30 and 60 mg ZZ by was improved 3 and 6 percent respectively. Cumulative gas production at 24h was not significantly different among treatments; however methane production was decreased (P˂0.05). Ammonia nitrogen also was linearly decreased (P˂0.01) by 20.85 and 43.85 percent, respectively. Incorporation of 60 mg ZZ to the basal diet decreased acetate (P˂0.05) and increased propionate (P˂0.05) and ratio of acetate to propionate was decreased (P˂0.01) from 2.6 to 2.2. Total protozoa population (P˂0.01) and Entodinium count was decreased (P˂0.05). However Ophryscolexs numberincreased (P˂0.05). Based on this study, it is suggested that supplementation of ZZ could improve in vitro ruminal fluid fermentation in terms of potential extent of gas production (6%), reduction of methane losses (17.4%), NH3-N concentration (43.8%), acetate to propionate ratio (0.2 ratio) and protozoal population.

The effect of three levels of eucalyptus leaf (0، 28. 65 or 57. 37mg/200mg substrate)، which were either oven، freeze or air dried on in vitro ruminal fermentation characteristics was assessed. The studied parameters were in vitro gas production (IVGP)، methane production، ammonia (NH3-N) concentration، in vitro organic matter degradability، partitioning factor (PF) (ratio of substrate truly degraded to gas volume produced at 24 h of incubation) and total volatile fatty acids (VFAs) concentration. Three subfamily of Entodiniinae، Ophryscolecinae، Diplodiniinae and family of Isotrichdaewere، also، identified and enumerated. Methods of air (L effect; P<0. 01) and freeze drying (Q effect; P<0. 05) have decreased the concentration of VFAs. However، oven drying method has increased propionic acid concentration (L effect; P<0. 01). Adding eucalyptus leaf has significantly decreased gas production from insoluble fraction (b) (L effect; P<0. 01)، IVGP at 24، 54 h (L and Q effect; P<0. 01)، methane production (L effect; P<0. 05)، NH3-N concentration (L effect; P<0. 01) and total VFAs (L effect; P<0. 01). However، such additive has improved PF (L effect; P<0. 01) only at 57. 31 level. Moreover، the inclusion of eucalyptus has significantly decreased total protozoa population (P<0. 01)، Entoodiniinae subfamily (P<0. 01) and Isotrichdae family (P<0. 05). The results suggest that eucalyptus leaves has positively manipulated in vitro ruminal fermentation، and oven dried method was more effective than two other methods.

The objective of this meta-analysis was to compare effects of chemical methanogenic inhibitors on fermentation parameters in ruminal batch cultures. Nine published in vitro studies including 26 treatment means in which 2-Bromoethane sulfonate, Bromochloromethane and 9,10-Anthraquinone were used as methanogens inhibitor compared in amount of CH4, H2, total volatile fatty acid, actate, propionate and butyrate production. The results showed that all chemical inhibitors reduced methane production significantly (-2.64±0.290) and 2-Bromoethanesulfonate was the most effective inhibitor. The inhibitors had a significant negative effect on acetate production (-1.48±0.255), and positive effect on molar proportions of propionate (+0.94±0.309) and butyrate (+0.69±0.125). The reduction in acetate production was not compensated by increase in propionate and butyrate production, therefore total VFA production reduced (-0.42±0.180) significantly. The inhibitors increased H2 production (+2.31±0.540) significantly and it was less than the predicted amount by stoichiometry equation. It was concluded that although the applied methanogens inhibitors were successful in reducing methane emission, but less VFA recorded and energy lost in form of H2 was significant in batch culture systems.

Forty-eight Mehraban male lambs each of 6 months of age and 32. 1 ± 3. 9 kg Body Weight (BW) were utilized to study the effects of administration of Echum amoenum Extract (EAE) on plasma metabolites and Methane gas. Following 2 weeks of adaptation and being fed a Total Mixed Ration (TMR) of 60 to 40-ratio concentrate to forage، the lambs were divided by their initial BW into 4 groups of 12 lambs each in a completely randomized design. The control group received only TMR، while the second، third and fourth groups receiving 0. 3، 1. 5 or 3 ml/Kg DM EAE extract for a 90 day experimental period. The Echum amoenum extracts were added to the diet fed to each lamb at the 8:00 h. Blood samples were collected at day 37 (S1) and day 72 (S2) from the jugular vein. The plasma metabolites studied were total protein، albumin، creatinine، Blood Urea Nitrogen (BUN)، glucose، triglyceride as well as cholesterol. The correlation among، and between these metabolites، was also assessed. The results indicated that creatinine، BUN and triglyceride were significantly different from control in day 37 of sampling.

In this trial, the effect of different levels of Echum amoneum (EA) (0.3, 30, 300 or 3000 µl) on in vitro ruminal fermentation characteristics and methane production was assessed. The parameters studied were in vitro Gas Production (IVGP), methane production, ammonia (NH3-N) concentration, in vitro Organic Matter Degradability (IVOMDe), Partitioning Factor (PF) (the ratio of substrate truly degraded to gas volume produced at 24 h of incubation) and total Volatile Fatty Acids (VFAs) concentration. The correlation of methane gas with total protozoa population and three subfamilies of Entodiniinae, Ophryscolecinae, Diplodiniinae and family of Isotrichdae, also, were studied. Gas production from insoluble fraction (b) (linear effect; P<0.01) was significantly (quadratic effect; P<0.01) increased with increasing level of EA. The inclusion of EA at either 300 or 3000µl increased IVGP at hours 24 and 54 (linear effect; P<0.01). However, methane production was reduced (linear effect; P<0.05) by 54, 41 or 43% when EA was added at 3, 30 or 300 µl respectively, without changing the degradability of organic matter. The inclusion of EA extract reduced NH3-N concentration (P<0.01), while PF (quadratic effect; P<0.01) led to an increase. On the other hand, EA addition decreased the concentration of VFAs and acetic acid (P<0.05), but increased the propionic acid (P<0.05). Moreover, the inclusion of EA has shown a significant effect of antiprotozoal activity, and, there is a tendency of total protozoa population, Diplodiniinae, Ophryscolecinae, and Isotrichdae family to decline. The results finally suggest that EA plant is of the potential to positively manipulate in vitro ruminal fermentation.

The aim of the current study was the screening the activity of 23 medicinal plants for decreasing the in Vitro ruminal methane production, as well to and assess sheep ruminal in vitro fermentation parameters. 57.3 mg of each medicinal plants along with 142.7 mg control diet were weighted in 120 ml wheatons in 4 replicates. The samples were incubated using ruminal fluid obtained from 3 castrated male Ghezel sheep with 61.8 kg of body weight and 4 years of age. After 24 h of incubation, total Gas Production (GP), methane production, ammonia content as well as Volatile Fatty Acids (VFA) were assessed. The obtained data were statistically analyzed using a completely randomized design. The results showed that GP from the incubation of Allium hertifolium, Tribulus terrestris L and Foetida ferula-assa increased in comparison with the control treatment (p<0.05). The molar proportion of methane in GP was decline by 20% in treatments containing Allium hertifolium, Elettaria cardamomum Maton, Thymus vulgaris, Nigella sativa, Rosmarinus officinalis, Rheum palmatum, Chamaemelum nobile, Sygium aromaticum and Thea sinensis in comparison with the control treatment (p<0.05). The concentrations of total VFA in treatments containing Zingiber officinale, Nigella sativa, Chamaemelum nobile, Trachyspermum copticum and Thea sinensis were higher than that in control (p<0.05). On the other hand, treatments containing Allium hertifolium, Foetida ferula-assa, Alpinia officinarum, Elettaria cardamomum Maton, Achillea milhemsii, Glycyrrhiza glabra, Rosmarinus officinalis, Pimpinella anisum, Chamaemelum nobile, Hyssopus officinalis and Fumaria officinalis Lan contained lower levels of ammonia concentrations than in the control diet (p<0.05). The results indicated that the treatment containing Allium hertifolium lowered the methane production and ammonia concentration without any negative effect observed on the total gas production.