Plant extracts to manipulate rumen fermentation

Efficacy of Salvia officinalis Shrub as a Sustainable Feed Additive for Reducing Ruminal Methane Production and Enhancing Fermentation in Ruminants

The objective of this study was to evaluate the effects of the inclusion of dried Salvia officinalis (SO) shrub leaves on nutrient degradability, ruminal in vitro fermentation, gas production (GP), methane (CH4), and carbon dioxide (CO2) productions. Dried and ground SO shrub leaves were included at 0% (control), 0.5%, 1%, 1.5%, and 2% DM of a diet consisting of (per kg DM) 500 g concentrate feed mixture, 400 g berseem hay, and 100 g rice straw. The diet was incubated for 48 h. The asymptotic GP and the rate of GP changed linearly and quadratically (p < 0.01), with the highest GP observed at 1% inclusion of SO and then decreasing thereafter with greater inclusion (i.e., 1.5% and 2%), while CH4 production and its rate decreased linearly (p < 0.01) with all levels of SO inclusion. A linear increase in CO2 production and its rate was also found with an increasing level of SO inclusion in the diet (p < 0.05). Furthermore, the degradability of DM, NDF, and the concentration of total short-chain fatty acids and acetate changed linearly and quadratically, with the greatest being found at 1% SO inclusion and then steadily declining after (p < 0.01) with the 1.5% and 2% inclusion levels. Meanwhile, the propionate, NH3-N, and microbial crude protein levels showed similar trends, with the plateau found at 1% inclusion of SO, where there was no change in butyrate concentration. Moreover, the pH, metabolizable energy, and partitioning factor (PF24) also changed linearly and quadratically (p < 0.05), where the pH and PF24 were considerably reduced and ME increased with a 1% inclusion of SO (p < 0.05). In summary, SO at 1% inclusion in the diet showed the potential to improve gas production kinetics, nutrient degradability, and the ruminal fermentation profile, with a more significant reduction in ruminal CH4 production suggesting that SO at 1% could be included in the ruminant diet to reduce their carbon footprint and increase the production performance.

Immunomodulatory Role of Rosmarinus officinalis L., Mentha x piperita L., and Lavandula angustifolia L. Essential Oils in Sheep Peripheral Blood Mononuclear Cells

Recently, the uses of essential oils (EOs) as rumen modifiers, anti-inflammatory agents, and antioxidants were demonstrated in livestock. In the present study, the role of Mentha x piperita L. (MEO), Rosmarinus officinalis L. (REO), and Lavandula angustifolia L. (LEO) EOs in an in vitro sheep model of inflammation was investigated. With this aim, peripheral blood mononuclear cells (PBMCs) were treated with incremental concentrations (3, 5, 7, and 10%) of each EO to test their effects on cell viability and proliferation and on interleukin (IL)-6, IL-10, and IL-8 secretion. The PBMCs were stimulated by Concanavalin A (ConA) alone or in combination with lipopolysaccharide (LPS) mitogen. The positive and negative controls were represented by PBMCs in the presence or absence, respectively, of mitogens only. The cell viability and proliferation were determined by XTT and BrdU assays, while the cytokines were analyzed by ELISA. The EO treatments did not affect the viability; on the contrary, the PBMC proliferation increased in presence of all the EOs tested, according to the different percentages and mitogens used. The IL-10 secretion was higher in both the REO and the LEO tested at 3% than in the positive control; furthermore, the IL-8 level was influenced differently by the various EOs. The present data demonstrate that EOs may modulate the immune response activated by inflammation.

Effect of red osier dogwood extract on in vitro gas production, dry matter digestibility, and fermentation characteristics of forage-based diet or grain-based diet

This in vitro batch culture study investigated the effects of red osier dogwood (ROD) extract supplementation on gas production (GP), dry matter disappearance (DMD), and fermentation characteristics in high forage (HF) and high grain (HG) diets with varying media pH level. The experiment was a factorial arrangement of treatments in a completely randomized design with 2 media pH (5.8 and 6.5) × 4 dose rates of ROD extract (0, 1, 3, and 5% of DM substrate). An additional treatment of monensin was added as a positive control for each pH level. The HF substrate consisted of 400 and 600 g/kg DM barley-based concentrate and barley silage, respectively, while the HG substrate contained 100 and 900 g/kg DM barley silage and barley-based concentrate, respectively. Treatments were incubated for 24 h with GP, DMD and fermentation parameters determined. No interaction was detected between the media pH level and ROD extract dose rate on GP, DMD and most of the fermentation parameters. The GP, DMD, and total volatile fatty acid (VFA) concentration were greater (P = 0.01) with media pH of 6.5 in both HF and HG diets. The GP were not affected by increasing ROD dose rate, except that GP linearly decreased in the HF (P = 0.04) and HG (P = 0.01) diets at 24 h; the DMD tended to linearly decrease at pH 6.5 (P = 0.06) for both HF and HG diets and at pH 5.8 (P = 0.02) for the HG diet. Adding ROD extract to the HF and HG diets linearly (P = 0.01) increased the acetate molar proportion at high or low media pH and consequently, the acetate to propionate (A:P) ratio linearly (P ≤ 0.04) increased. Supplementation of ROD extract to the HF diet linearly (P = 0.04) decreased the molar proportion of propionate at pH 6.5 (interaction between pH and ROD extract; P = 0.05), but had no effect on propionate proportion when added to the HG diet. Moreover, the proportion of branched-chain fatty acids linearly (P = 0.03) decreased with ROD extract supplementation at low pH (interaction, P < 0.05) for HF diet and linearly decreased (P = 0.05) at pH 6.5 for HG diet (interaction, P < 0.05). The NH3-N concentration was not affected by ROD supplementation in the HF diet but it linearly (P = 0.01) decreased with increasing dose rate in the HG diet. Methane concentration tended to linearly (P = 0.06) increase with ROD extract supplementation at high pH for HF diet and linearly increased at pH 5.8 (P = 0.06) and pH 6.5 (P = 0.02) for HG diet. These results indicate that the decreased DMD and increased A:P ratio observed with addition of ROD extract may be beneficial to HG-fed cattle to reduce the risk of rumen acidosis without negatively impacting fiber digestion.

Effect of nutmeg essential oil (Myristica fragrans Houtt.) on methane production, rumen fermentation, and nutrient digestibility in vitro

The study evaluated the effect of adding of nutmeg (Myristica fragrans Houtt.) essential oil (NEO) as a feed additive on methane production, rumen fermentation parameters, rumen enzyme activity, and nutrient digestibility in vitro. This study was divided into three treatments based on the level of NEO addition, which included 0 µL/L (T0), 100 µL/L (T1), and 200 µL/L (T2). The feed substrate composition consisted of king grass as forage and concentrate in a 60:40 ratio. Feed fermentation was conducted using the Menke and Steingass gas production and two-step Tilley and Terry in-vitro digestibility technique. The data obtained from the study were analyzed using one-way ANOVA and if there were differences between means, they were further assessed using DMRT. The results showed that T2 treatment significantly decreased (P < 0.05) ammonia (NH3) levels, total VFA, acetate, propionate, butyrate, and microbial protein (P < 0.05). Methane production and the activity of rumen protease enzyme significantly decreased (P < 0.05) at T1 and T2 treatment. The T2 treatment significantly reduced (P < 0.05) protein digestibility (IVCPD) at 48 h, while IVCPD at 96 h significantly increased (P < 0.05). On the other hand, the addition of nutmeg essential oil did not effect the activity of the amylase, carboxymethyl cellulase, and β-glucosidase enzymes, as well as the in-vitro digestibility of dry matter (IVDMD), crude fiber (IVCFD), and organic matter (IVOMD). The conclusion drawn from this study is that the optimum level for NEO is 200 µL/L, which can reduce methane production and increase crude protein digestibility at 96 h without any negative effect on rumen fermentation and nutrient digestibility.

Linkages between rumen microbiome, host, and environment in yaks, and their implications for understanding animal production and management

Livestock on the Qinghai-Tibetan Plateau is of great importance for the livelihood of the local inhabitants and the ecosystem of the plateau. The natural, harsh environment has shaped the adaptations of local livestock while providing them with requisite eco-services. Over time, unique genes and metabolic mechanisms (nitrogen and energy) have evolved which enabled the yaks to adapt morphologically and physiologically to the Qinghai-Tibetan Plateau. The rumen microbiota has also co-evolved with the host and contributed to the host's adaptation to the environment. Understanding the complex linkages between the rumen microbiota, the host, and the environment is essential to optimizing the rumen function to meet the growing demands for animal products while minimizing the environmental impact of ruminant production. However, little is known about the mechanisms of host-rumen microbiome-environment linkages and how they ultimately benefit the animal in adapting to the environment. In this review, we pieced together the yak's adaptation to the Qinghai-Tibetan Plateau ecosystem by summarizing the natural selection and nutritional features of yaks and integrating the key aspects of its rumen microbiome with the host metabolic efficiency and homeostasis. We found that this homeostasis results in higher feed digestibility, higher rumen microbial protein production, higher short-chain fatty acid (SCFA) concentrations, and lower methane emissions in yaks when compared with other low-altitude ruminants. The rumen microbiome forms a multi-synergistic relationship among the rumen microbiota services, their communities, genes, and enzymes. The rumen microbial proteins and SCFAs act as precursors that directly impact the milk composition or adipose accumulation, improving the milk or meat quality, resulting in a higher protein and fat content in yak milk and a higher percentage of protein and abundant fatty acids in yak meat when compared to dairy cow or cattle. The hierarchical interactions between the climate, forage, rumen microorganisms, and host genes have reshaped the animal's survival and performance. In this review, an integrating and interactive understanding of the host-rumen microbiome environment was established. The understanding of these concepts is valuable for agriculture and our environment. It also contributes to a better understanding of microbial ecology and evolution in anaerobic ecosystems and the host-environment linkages to improve animal production.

Influence of direct-fed microbial blend and Ferula elaeochytris on in vitro rumen fermentation pattern and degradability during simulated ruminal acidosis

Introduction

The use of probiotics and phytobiotics has attracted interest because of their protective effect against acidosis. Ferula elaeochytris (FE) is considered a good source of bioactive compounds, mainly monoterpene α-pinene. This study aimed to investigate the effect of a direct-fed microbial blend (Pro) and FE on rumen fermentation parameters in vitro under normal and acidosis conditions.

Material and Methods

An in vitro experiment using the Hohenheimer Futterwerttest (HFT) gas production system was conducted. An acidosis challenge was made to compare the effectiveness of the probiotics blend and FE extract on ruminal pH regulation. To generate different ruminal fermentation parameters, the design of the trial considered the 2 additives (Pro and FE) × 6 incubation times (2, 4, 8, 12, 24 and 48 h) × 2 conditions (acidosis and normal) × 2 incubation runs for each feedstuff (barley, alfalfa and straw).

Results

An acidosis challenge was successfully induced. The Pro and FE additives had no impact on the observed rumen fermentation parameters such as volatile fatty acid concentration or ammonia (P = 0.001). The acidosis condition decreased total in vitro degradability (IVD) by 3.5% and 21.9% for barley and straw, respectively (P < 0.001). The additives had different significant effects on the IVD of nutrients during both normal and acidosis conditions. In alfalfa samples, FE supplementation significantly decreased the IVD of all observed nutrients under the ruminal acidosis condition, although it had no effect during the normal condition.

Conclusion

An acidosis challenge was successfully induced and the effect of additives was varied on fermentation parameters and rumen degradability of different feeds either under normal or acidosis conditions.

Effects of Essential Oil Blends on In Vitro Apparent and Truly Degradable Dry Matter, Efficiency of Microbial Production, Total Short-Chain Fatty Acids and Greenhouse Gas Emissions of Two Dairy Cow Diets

The current study evaluated nine essential oil blends (EOBs) for their effects on ruminal in vitro dry matter digestibility (IVDMD), efficiency of microbial production, total short-chain fatty acid concentration (SCFA), total gas, and greenhouse gas (GHG) emissions using two dietary substrates (high forage and high concentrate). The study was arranged as a 2 × 2 × 9 + 1 factorial design to evaluate the effects of the nine EOBs on the two dietary substrates at two time points (6 and 24 h). The inclusion levels of the EOBs were 0 µL (control) and 100 µL with three laboratory replicates. Substrate × EOBs × time interactions were not significant (p > 0.05) for total gas and greenhouse gas emissions. The inclusion of EOBs in the diets resulted in a reduction (p < 0.001) in GHG emissions, except for EOB1 and EOB8 in the high concentrate diet at 6 h and for EOB8 in the high forage diet at 24 h of incubation. Diet type had no effect on apparent IVDMD (IVADMD) whereas the inclusion of EOBs reduced (p < 0.05) IVADMD with higher values noted for the control treatment. The efficiency of microbial production was greater (p < 0.001) for EOB treatments except for EOB1 inclusion in the high forage diet. The inclusion of EOBs affected (p < 0.001) the total and molar proportion of volatile fatty acid concentrations. Overall, the inclusion of the EOBs modified the rumen function resulting in improved efficiency of microbial production. Both the apparent and truly degraded DM was reduced in the EOB treatments. The inclusion of EOBs also resulted in reduced GHG emissions in both diets, except for EOB8 in the high forage diet which was slightly higher than the control treatment.

Advances in Pasture Management and Animal Nutrition to Optimize Beef Cattle Production in Grazing Systems

The increasing demand of meat requires the adoption of sustainable intensification livestock systems, applying nutritional strategies to reduce any negative contribution from beef cattle to global warming and, at the same time, to increase animal performance and productive efficiency. The pasture management practices and feed supplementation, mainly using non-edible feed with less costs, could minimize environmental and social impacts, resulting in higher productivity with less inputs utilization. Tropical grass submitted to grazing management according to plant height present high soluble protein and low levels of indigestible neutral detergent fiber contents. Energy or rumen undegradable protein supplementation, associated to alternative additives to antibiotics effects, such as probiotics, tannin, essential oils and saponin, can help to fully exploit the animal genetic potential and nutrient utilization efficiency, which decreases greenhouse gases emissions and improves animal performance. Hence, more information about these tools can make the livestock systems in tropical pasture more efficient and eco-friendlier.

Oregano Essential Oils Promote Rumen Digestive Ability by Modulating Epithelial Development and Microbiota Composition in Beef Cattle

This study aimed to explore the effects of oregano essential oils (OEO) on the rumen digestive ability using multi-omics sequencing techniques. Twenty-seven castrated Pingliang red cattle were randomly separated into three groups (3 cattle/pen; n = 9) and fed on a daily basal diet supplemented with 0 (Con group), 130 mg (L group), and 260 mg (H group) OEO. The finishing trial lasted for 390 days, and all cattle were slaughtered to collect rumen tissue and content samples. We found that the rumen papillae length in the H group was higher than in the Con group. Amylase concentrations were decreased in the H group than the Con group, whereas the β-glucosidase and cellulase concentrations increased. Compared to the Con group, the relative abundance of propionate and butyrate in the H group was significantly higher. Higher relative abundance of Parabacteroides distasonis and Bacteroides thetaiotaomicron were observed with increasing OEO concentration. The function of rumen microbiota was enriched in the GH43_17 family, mainly encoding xylanase. Besides, metabolites, including heparin, pantetheine, sorbic acid, aspirin, and farnesene concentrations increased with increasing OEO dose. A positive correlation was observed between Parabacteroides distasonis, Bacteroides thetaiotaomicron, and β-glucosidase, cellulase and propionate. The abundance of Parabacteroides distasonis and Parabacteroides_sp._CAG:409 were positively correlated with sorbic acid and farnesene. In summary, OEO supplementation increased the rumen digestive ability by modulating epithelial development and microbiota composition in beef cattle. This study provides a comprehensive insight into the OEO application as an alternative strategy to improve ruminant health production.

Dose-response effects of the Savory (Satureja khuzistanica) essential oil and extract on rumen fermentation characteristics, microbial protein synthesis and methane production in vitro

The objective of the present study was to investigate dose-response effects of the essential oil (EO) and dry extract (EX) of Satureja khuzistanica (SK) on in vitro gas production kinetics, rumen fermentation, ruminal methanogenesis and microbial protein synthesis. So, EO and EX were tested at 0 (as control); 150 (low dose); 300, 450 (intermediate doses) and 600 mg/L (high dose). The gas produced over 24 h of incubation (GP24) decreased linearly with both EO and EX dosages (P<0.01). In vitro methane production was reduced by both EO (14–69%, depending on the included dose) and EX (7–58%). Microbial protein (MP) as well as the efficiency of microbial protein synthesis (EMPS) were improved by EO (18.8–49.8% and 20.4–61.5% for MP and EMPS, respectively) and to a lesser extent by EX (8.3–25.7% and 4.6–24.2% for MP and EMPS, respectively). Ammonia concentration was dropped in linear and quadratic manners with EO (P<0.05), and linearly with EX dosages (P<0.01). EO and EX exhibited depressive effects (in linear and quadratic (P<0.05), and linear manners (P<0.01), respectively) on total protozoa count. A mixed linear and quadratic effect was observed from both EO and EX on total VFA concentration (P<0.01). Total VFA concentration increased at 300 mg/L of EX, but decreased at high dose of both EO and EX. The acetate proportion increased with EO intermediate and high dosages, but it decreased at the expense of propionate at low and intermediate doses of EX. In total, these findings confirmed previous research on the great capacity of plant-based feed additives in positively modulating rumen fermentation that their effects may vary depending on the used doses. Specifically, these results suggest that EO and EX have high potentials to improve rumen functions at intermediate doses, which needs to be confirmed by in vivo experiments.

Partial replacement of forage and concentrate with pomegranate pulp (peel and seed) silage and pomegranate seed pulp in Mehraban fattening lambs: effect on performance and carcass characteristics

The aim of this study was to evaluate the effects of partial replacement of forage and concentrate with pomegranate pulp silage (PPS) and dried pomegranate seed pulp (PSP) on performance, dry matter intake (DMI), and carcass characteristics of fattening Mehraban lambs. Twenty-four male lambs (mean body weight 27.0 ± 3.5 kg) were fed with three isonitrogenous and isoenergetic diets (n = 8 per diet), consisting of a control diet, a PPS diet containing 27.2% pomegranate pulp silage, and a PSP diet containing 31.4% dried pomegranate seed pulp. The experimental diets were fed ad libitum as total mixed rations for 65-day fattening period, on two meals per day, and then the growth performance, feed intake, and carcass characteristics were determined. The initial BW, final BW, average daily gain (ADG), and feed conversion ratio (FCR) were not different among the experimental diets. The amount of DMI in PSP diet was higher than that in the control diet (P = 0.023) but was not different between the control and PPS diets. There was no significant difference among diets for carcass characteristics. Using PPS and PSP in the diets decreased (P < 0.05) the kidney fat, but had no impact on the heart, liver, kidneys, spleen, and lungs. The results showed that PPS and PSP could be used to replace part of the diet for fattening lambs, while decreasing the dietary cost without having any negative effects on animal performance.

Supplementation of fruit peel pellet containing phytonutrients to manipulate rumen pH, fermentation efficiency, nutrient digestibility and microbial protein synthesis

BACKGROUND

Phytonutrient pellet, a new rumen enhancer, was formulated from various tropical fruit peels containing phytonutrients (condensed tannins and saponins) and named MARABAC. To substantiate the MARABAC supplementation effect, it was supplemented with low and high levels of concentrate supplementation in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement using beef cattle. Based on this investigation, interesting findings were highlighted and are reported herein.

RESULTS

The high level of concentrate supplementation (HCS) reduced rumen pH remarkably, but was buffered and enhanced by MARABAC supplementation. Rumen pH was reduced to 5.74 at 8 h, post feeding upon receiving HCS, and was buffered back to 6.19 with MARABAC supplementation. The supplementation exhibited an additional pronounced (P < 0.01) effect on improving nutrient digestibility and efficiency of microbial nitrogen supply, mitigating rumen methane production and reducing protozoal population. Rumen and fermentation end-products, especially propionate production, were enhanced (P < 0.05), while rumen methane production was subsequently mitigated (P < 0.01).

CONCLUSION

MARABAC is a new promising dietary rumen enhancer for future replacement of chemicals and antibiotics used to enhance the rumen fermentation. Nevertheless, more in vivo feeding trials should be further conducted to elucidate the insight impacts. © 2021 Society of Chemical Industry.

Effects of dietary inclusion of Moringa oleifera leaf meal on nutrient digestibility, rumen fermentation, ruminal enzyme activities and growth performance of buffalo calves

This study was conducted to investigate the impact of dietary inclusion of Moringa oleifera leaf meal (MLM) as a substitution for soybean meal on nutrient digestibility, rumen fermentation, rumen enzyme activity, blood metabolites, growth-related hormones, and growth performance of buffalo calves. Thirty buffalo calves eight to nine months of age with an average body weight of approximately 153.7 ± 0.97 kg were randomly distributed through three dietary treatments (ten calves/treatment). MLM inclusion rates were 15% (M15) and 20% (M20), replacing soybean meal by 50 and 75% in the concentrate mixture, respectively. The results indicated that, digestibility of dry matter, organic matter (OM), and crude fiber (CF) increased significantly (p < 0.05) with MLM inclusion, while the digestibility of crude protein (CP) and ether extract (EE) reduced significantly (p < 0.05) with MLM addition. Dietary supplementation with MLM significantly affected (p < 0.001) rumen fermentation by reducing ruminal enzymes, ruminal ammonia-N, total protozoa, and acetate/propionate ratio and increasing acetic, propionic, and butyric acids and total volatile fatty acid concentrations (p < 0.001). Furthermore, dietary inclusion of 15% MLM significantly improved (p < 0.001) final body weight, dry matter intake of feed, daily weight gain, feed conversion efficiency, blood metabolites, and plasma insulin growth factor-I (IGF-I). It can be concluded that MLM is a multi-purpose protein supplement that provides some nutritional and therapeutic advantages when replacing 50% of soybean meal. Dietary supplementation of 15% MLM improved rumen fermentation, growth performance, blood metabolites, plasma IGF-I and mitigated ammonia and methane without any adverse effects in growing buffalo calves.

Sustainable impact of pulp and leaves of Glycyrrhiza glabra to enhance ruminal biofermentability, protozoa population, and biogas production in sheep

The aim of this study was to evaluate the effect of pulp and leaves of Glycyrrhiza glabra to reduce the ruminal biogas production in sheep. Five experimental diets of two levels of Glycyrrhiza glabra pulp (GGP) and Glycyrrhiza glabra leaves (GGL) at 150 and 300 g/kg dry matter (DM) were assessed for biogas production and fermentation parameters. Diets were control (diet without GGP or GGL), GGP15 (diet contains GGP at 150 g/kg DM), GGP30 (diet contains GGP at 300 g/kg DM), GGL15 (diet contains GGL at 150 g/kg DM), and GGL30 (diet contains GGL at 300 g/kg DM). Inclusion of 150 and 300 g/kg GGP and 300 g/kg GGL decreased (P < 0.0001) asymptotic biogas production (A), fermentation rate (μ), biogas production at 24 h of incubation (GP24), apparent degraded substrate (ADS), in vitro organic matter disappearance (OMD), and metabolizable energy (ME). Microbial protein biomass (MP) was improved (P = 0.003) by GGP15, GGL15, and GGL30 versus control. Total VFAs (P = 0.003), acetate (P = 0.009), and butyrate (P = 0.002), CH4 (mmol and mL/g OMD), CO2 (mmol and mL/g OMD) (P = 0.0003 and P = 0.0002, respectively), were decreased in GGP15, GGP30, and GGL30 diets versus control. Acetate to propionate ratio (Ac/Pr) was decreased (P = 0.038) in GGL30 diet compared to other diets. Replacing GGP and GGL with alfalfa reduced NH3-N concentration (P = 0.022), total protozoa (P < 0.0001), Isotricha spp. (P = 0.047), Dasytricha spp. (P = 0.067), subfamilies of Entodiniinae (P < 0.0001), and Diplodiniinae (P = 0.06). Results suggested that inclusion of dietary GGL at 150 g/kg dry matter positively modified some rumen parameters such as microbial protein production, protozoa population, and NH3-N concentration, which may be useful economically in ruminant animals and decreasing of environmental pollution.

Lemongrass supplementation to Farafra ewes improved feed utilization, lactational performance and milk nutritive value in the subtropics

Application of phytogenic feed additives in livestock production is a sustainable practice and the search for more phytogenic options continues. This study was conducted to investigate the impact of lemongrass supplementation on nutrient utilization, rumen fermentation and milk production and composition. Thirty gestating Farafra ewes were randomly assigned to three experimental treatments of control (without a supplement), or with the supplementation of 5 g (LEM5 treatment), or 10 g of lemongrass/ewe/d (LEM10 treatment) for 12 weeks. Lemongrass supplementation at both doses did not influence ( p > 0.05) nutrient intake, but improved nutrient digestibility (p < 0.05). Furthermore, LEM5 and LEM10 treatments improved (p ≤ 0.001) ruminal total volatile fatty acids, acetate and propionate. Blood glucose was increased (p < 0.05) and cholesterol was decreased in ewes supplemented with lemongrass at both doses. Milk yield, energy corrected milk yield, and milk component were improved (p ≤ 0.001) in ewes supplemented with lemongrass at 5 and 10 g while the feed efficiency was decreased. Lemongrass supplementation at both doses increased (p = 0.040) the proportion of milk total conjugated linoleic acid without affecting other milk fatty acids. In most of the parameters evaluated, there was no significant difference between LEM5 and LEM10. Therefore, lemongrass supplementation at 5 g/ewe/d can be used in dairy production with positive impacts.

Reducing enteric methane production from buffalo (Bubalus bubalis) by garlic oil supplementation in in vitro rumen fermentation system

Enteric methane production contributes significantly to the greenhouse gas emission globally. Although, buffaloes are integral part of livestock production in Asian countries, contributing milk, meat and draft power, the contribution of enteric methane to environmental pollution attracts attention. The present study investigated the efficacy of garlic (Allium sativum) oil in reducing enteric methane production from buffaloes (Bubalus bubalis) by in vitro rumen fermentation. Garlic oil (GOL) was tested at four concentrations [0 (Control), 33.33 µl (GOL-1), 83.33 µl (GOL-2) and 166.66 µl (GOL-3) per litre of buffered rumen fluid] in 100-ml graduated glass syringes and incubated at 39℃ for 24 h for in vitro rumen fermentation study. Supplementation of GOL-1 increased (p < 0.05) total gas production in comparison with GOL-3; however, it remained comparable (p > 0.05) with control and GOL-2. Graded doses of garlic oil inclusions reduced (p < 0.001) methane concentration (%) in total gas and total methane production (ml/g DM), irrespective of concentrations. The feed degradability, volatile fatty acids and microbial biomass production (MBP) were not affected (p > 0.05) by GOL-1, but these tended to decrease in GOL-2 with marked reduction (p < 0.01) in GOL-3. The decrease (p < 0.01) in NH3–N concentration in fermentation fluid in the presence of garlic oil, irrespective of concentration, suggests reduced deamination by inhibiting rumen proteolytic bacterial population. The activities of ruminal fibrolytic enzymes (CMCase, xylanase, β-glucosidase, acetyl esterase) were not affected by lower dose (GOL-1) of garlic oil; however, reduction (p < 0.05) of these enzymes activity in rumen liquor was evident at higher doses (GOL-2 and GOL-3) of supplementation. This study shows positive impact of garlic oil supplementation at low dose (33.33 µl/l of rumen fluid) in reducing enteric methane production, thereby, abatement of environmental pollution without affecting feed digestibility.

Strategic supplementation of Flemingia silage to enhance rumen fermentation efficiency, microbial protein synthesis and methane mitigation in beef cattle

Background

Good quality protein as an on-farm feed resource has been in great demand to support the productivity of ruminants. A digestion trial using beef cattle crossbreds was conducted to assess the four dietary treatments of Flemingia macrophylla silage (FMS) supplementation at 0, 0.2, 0.4 and 0.6 kg dry matter (DM)/day in a 4 × 4 Latin square design. Feed DM intakes were measured during the 14 days and sample of feeds, feces, urine, as well as rumen fluid and blood were collected during the 7 days while the animals were on metabolism crates.

Results

Based on this experiment strategic supplementation of FMS increased (P < 0.05) nutrients digestibility (organic matter, crude protein, and acid detergent fiber) enhanced rumen total volatile fatty acid production especially propionic acid (C₃), C₂:C₃ ratio while, remarkably promoted the microbial protein synthesis (MPS) by increasing N-balance and retention of purine derivatives.

Conclusions

Under this experiment, the results revealed the potential use of FMS as a good-quality feed to improve nutrients digestibility, rumen fermentation, microbial protein synthesis, and to mitigate methane production. FMS supplementation at 0.6 kg DM/day exhibited the best result.

Phytogenic Additives Can Modulate Rumen Microbiome to Mediate Fermentation Kinetics and Methanogenesis Through Exploiting Diet-Microbe Interaction

Ruminants inhabit the consortia of gut microbes that play a critical functional role in their maintenance and nourishment by enabling them to use cellulosic and non-cellulosic feed material. These gut microbes perform major physiological activities, including digestion and metabolism of dietary components, to derive energy to meet major protein (65-85%) and energy (ca 80%) requirements of the host. Owing to their contribution to digestive physiology, rumen microbes are considered one of the crucial factors affecting feed conversion efficiency in ruminants. Any change in the rumen microbiome has an imperative effect on animal physiology. Ruminal microbes are fundamentally anaerobic and produce various compounds during rumen fermentation, which are directly used by the host or other microbes. Methane (CH4) is produced by methanogens through utilizing metabolic hydrogen during rumen fermentation. Maximizing the flow of metabolic hydrogen in the rumen away from CH4 and toward volatile fatty acids (VFA) would increase the efficiency of ruminant production and decrease its environmental impact. Understanding of microbial diversity and rumen dynamics is not only crucial for the optimization of host efficiency but also required to mediate emission of greenhouse gases (GHGs) from ruminants. There are various strategies to modulate the rumen microbiome, mainly including dietary interventions and the use of different feed additives. Phytogenic feed additives, mainly plant secondary compounds, have been shown to modulate rumen microflora and change rumen fermentation dynamics leading to enhanced animal performance. Many in vitro and in vivo studies aimed to evaluate the use of plant secondary metabolites in ruminants have been conducted using different plants or their extract or essential oils. This review specifically aims to provide insights into dietary interactions of rumen microbes and their subsequent consequences on rumen fermentation. Moreover, a comprehensive overview of the modulation of rumen microbiome by using phytogenic compounds (essential oils, saponins, and tannins) for manipulating rumen dynamics to mediate CH4 emanation from livestock is presented. We have also discussed the pros and cons of each strategy along with future prospective of dietary modulation of rumen microbiome to improve the performance of ruminants while decreasing GHG emissions.

Role of Secondary Plant Metabolites on Enteric Methane Mitigation in Ruminants

The rumen microbiome plays a fundamental role in all ruminant species, it is involved in health, nutrient utilization, detoxification, and methane emissions. Methane is a greenhouse gas which is eructated in large volumes by ruminants grazing extensive grasslands in the tropical regions of the world. Enteric methane is the largest contributor to the emissions of greenhouse gases originating from animal agriculture. A large variety of plants containing secondary metabolites [essential oils (terpenoids), tannins, saponins, and flavonoids] have been evaluated as cattle feedstuffs and changes in volatile fatty acid proportions and methane synthesis in the rumen have been assessed. Alterations to the rumen microbiome may lead to changes in diversity, composition, and structure of the methanogen community. Legumes containing condensed tannins such as Leucaena leucocephala have shown a good methane mitigating effect when fed at levels of up to 30–35% of ration dry matter in cattle as a result of the effect of condensed tannins on rumen bacteria and methanogens. It has been shown that saponins disrupt the membrane of rumen protozoa, thus decreasing the numbers of both protozoa and methanogenic archaea. Trials carried out with cattle housed in respiration chambers have demonstrated the enteric methane mitigation effect in cattle and sheep of tropical legumes such as Enterolobium cyclocarpum and Samanea saman which contain saponins. Essential oils are volatile constituents of terpenoid or non-terpenoid origin which impair energy metabolism of archaea and have shown reductions of up to 26% in enteric methane emissions in ruminants. There is emerging evidence showing the potential of flavonoids as methane mitigating compounds, but more work is required in vivo to confirm preliminary findings. From the information hereby presented, it is clear that plant secondary metabolites can be a rational approach to modulate the rumen microbiome and modify its function, some species of rumen microbes improve protein and fiber degradation and reduce feed energy loss as methane in ruminants fed tropical plant species.

Effects of supplementation levels of Allium fistulosum L. extract on in vitro ruminal fermentation characteristics and methane emission

BACKGROUND

Ruminants release the majority of agricultural methane, an important greenhouse gas. Different feeds and additives are used to reduce emissions, but each has its drawbacks. This experiment was conducted to determine the effects of Allium fistulosum L. (A. fistulosum) extract on in vitro ruminal fermentation characteristics, and on methane emission.

METHODS

Rumen fluid was taken from two cannulated rumen Hanwoo cow (with mean initial body weight 450 ± 30 kg, standard deviation = 30). Rumen fluid and McDougall's buffer (1:2; 15 mL) were dispensed anaerobically into 50 mL serum bottles containing 300 mg (DM basis) of timothy substrate and A. fistulosum extracts (based on timothy substrate; 0%, 1%, 3%, 5%, 7%, or 9%). This experiment followed a completely randomized design performed in triplicate, using 126 individual serum bottles (six treatments × seven incubation times × three replicates).

RESULTS

Dry matter degradability was not significantly affected (p-value > 0.05) by any A. fistulosum treatment other than 1% extract at 24 h incubation. Methane emission linearly decreased A. fistulosum extract concentration increased at 12 and 24 h incubation (p-value < 0.0001; p-value = 0.0003, respectively). Acetate concentration linearly decreased (p-value = 0.003) as A. fistulosum extract concentration increased at 12 h incubation. Methanogenic archaea abundance tendency decreased (p-value = 0.055) in the 1%, 7%, and 9% A. fistulosum extract groups compared to that in the 0% group, and quadratically decreased (p-value < 0.0001) as A. fistulosum extract concentration increased at 24 h incubation.

CONCLUSION

A. fistulosum extract had no apparent effect on ruminal fermentation characteristics or dry matter degradability. However, it reduced methane emission and methanogenic archaea abundance.

Review: Strategies for enteric methane mitigation in cattle fed tropical forages

Methane (CH4) is a greenhouse gas (GHG) produced and released by eructation to the atmosphere in large volumes by ruminants. Enteric CH4 contributes significantly to global GHG emissions arising from animal agriculture. It has been contended that tropical grasses produce higher emissions of enteric CH4 than temperate grasses, when they are fed to ruminants. A number of experiments have been performed in respiration chambers and head-boxes to assess the enteric CH4 mitigation potential of foliage and pods of tropical plants, as well as nitrates (NO3-) and vegetable oils in practical rations for cattle. On the basis of individual determinations of enteric CH4 carried out in respiration chambers, the average CH4 yield for cattle fed low-quality tropical grasses (>70% ration DM) was 17.0 g CH4/kg DM intake. Results showed that when foliage and ground pods of tropical trees and shrubs were incorporated in cattle rations, methane yield (g CH4/kg DM intake) was decreased by 10% to 25%, depending on plant species and level of intake of the ration. Incorporation of nitrates and vegetable oils in the ration decreased enteric CH4 yield by ∼6% to ∼20%, respectively. Condensed tannins, saponins and starch contained in foliages, pods and seeds of tropical trees and shrubs, as well as nitrates and vegetable oils, can be fed to cattle to mitigate enteric CH4 emissions under smallholder conditions. Strategies for enteric CH4 mitigation in cattle grazing low-quality tropical forages can effectively increase productivity while decreasing enteric CH4 emissions in absolute terms and per unit of product (e.g. meat, milk), thus reducing the contribution of ruminants to GHG emissions and therefore to climate change.

Not all saponins have a greater antiprotozoal activity than their related sapogenins

The antiprotozoal effect of saponins varies according to both the structure of the sapogenin and the composition and linkage of the sugar moieties to the sapogenin. The effect of saponins on protozoa has been considered to be transient as it was thought that when saponins were deglycosilated to sapogenins in the rumen they became inactive; however, no studies have yet evaluated the antiprotozoal effect of sapogenins compared to their related saponins. The aims of this study were to evaluate the antiprotozoal effect of eighteen commercially available triterpenoid and steroid saponins and sapogenins in vitro, to investigate the effect of variations in the sugar moiety of related saponins and to compare different sapogenins bearing identical sugar moieties. Our results show that antiprotozoal activity is not an inherent feature of all saponins and that small variations in the structure of a compound can have a significant influence on their biological activity. Some sapogenins (20(S)-protopanaxatriol, asiatic acid and madecassic acid) inhibited protozoa activity to a greater extent than their corresponding saponins (Re and Rh₁ and asiaticoside and madecassoside), thus the original hypothesis that the transient nature of the antiprotozoal action of saponins is due to the deglycosilation of saponins needs to be revisited.

Effects of Lonicera japonica extract on performance, blood biomarkers of inflammation and oxidative stress during perinatal period in dairy cows

Objective

An experiment was conducted to evaluate the effects of Lonicera japonica extract (LJE) on milk production, rumen fermentation and blood biomarkers of energy metabolism, inflammation and oxidative stress during the perinatal period of Holstein dairy cows.

Methods

Eighteen Holstein dairy cows were used in a complete randomized design experiment with 3 dietary treatments and 6 cows per treatment. All cows received the same basal total mixed ration (TMR) including a prepartal diet (1.35 Mcal of net energy for lactation [NE_L]/kg of dry matter [DM], 13.23% crude protein [CP]) from −60 d to calving and a postpartal diet (1.61 Mcal of NE_L/kg of DM, 17.39% CP) from calving to 30 days in milk (DIM). The 3 dietary treatments were TMR supplemented with LJE at 0 (control), 1 and 2 g/kg DM, respectively. LJE was offered from 21 d before calving to 30 DIM. Dry matter intake (DMI) and milk production were measured daily after calving. Milk and rumen fluid samples were collected on 29 and 30 d after calving. On −10, 4, 14, and 30 d relative to calving, blood samples were collected to analyze the biomarkers of energy metabolism, inflammation and oxidative stress.

Results

Compared with control diet, LJE supplementation at 1 and 2 g/kg DM increased DMI, milk yield and reduced milk somatic cell count. LJE supplementation also decreased the concentrations of blood biomarkers of pro-inflammation (interleukin-1β [IL-1β], IL-6, and haptoglobin), energy metabolism (nonesterified fatty acid and β-hydroxybutyric acid) and oxidative stress (reactive oxygen metabolites), meanwhile increased the total antioxidant capacity and superoxide dismutase concentrations in blood. No differences were observed in rumen pH, volatile fatty acid, and ammonia-N (NH₃-N) concentrations between LJE supplemented diets and the control diet.

Conclusion

Supplementation with 1 and 2 g LJE/kg DM could increase DMI, improve lactation performance, and enhance anti-inflammatory and antioxidant capacities of dairy cows during perinatal period.

Repeated inoculation with fresh rumen fluid before or during weaning modulates the microbiota composition and co-occurrence of the rumen and colon of lambs

Background

Many recent studies have gravitated towards manipulating the gastrointestinal (GI) microbiome of livestock to improve host nutrition and health using dietary interventions. Few studies, however, have evaluated if inoculation with rumen fluid could effectively reprogram the development of GI microbiota. We hypothesized that inoculation with rumen fluid at an early age could modulate the development of GI microbiota because of its low colonization resistance.

Results

In this study, we tested the above hypothesis using young lambs as a model. Young lambs were orally inoculated repeatedly (four times before or twice during gradual weaning) with the rumen fluid collected from adult sheep. The oral inoculation did not significantly affect starter intake, growth performance, or ruminal fermentation. Based on sequencing analysis of 16S rRNA gene amplicons, however, the inoculation (both before and during weaning) affected the assemblage of the rumen microbiota, increasing or enabling some bacterial taxa to colonize the rumen. These included operational taxonomic units (OTUs) belonging to Moryella, Acetitomaculum, Tyzzerella 4, Succiniclasticum, Prevotella 1, Lachnospiraceae, Christensenellaceae R-7 group, Family XIII AD3011, and Bacteroidales S24–7 corresponding to inoculation before weaning; and OTUs belonging to Succiniclasticum, Prevotellaceae UCG-003, Erysipelotrichaceae UCG-004, Prevotella 1, Bacteroidales S24–7 gut group uncultured bacterium, and candidate Family XIII AD3011 corresponding to inoculation during weaning. Compared to the inoculation during weaning, the inoculation before weaning resulted in more co-occurrences of OTUs that were exclusively predominant in the inoculum. However, inoculation during weaning appeared to have more impacts on the colonic microbiota than the inoculation before weaning. Considerable successions in the microbial colonization of the GI tracts accompanied the transition from liquid feed to solid feed during weaning.

Conclusions

Repeated rumen fluid inoculation during early life can modulate the establishment of the microbiota in both the rumen and the colon and co-occurrence of some bacteria. Oral inoculation with rumen microbiota may be a useful approach to redirect the development of the microbiota in both the rumen and colon.

Effects of oregano essential oil on in vitro ruminal fermentation, methane production, and ruminal microbial community

Different inclusion rates of oregano essential oil (OEO) were investigated for their effects on ruminal in vitro fermentation parameters, total gas, methane production, and bacterial communities. Treatments were (1) control, 0 mg/L of OEO (CON); 13 mg/L (OEO1); 52 mg/L (OEO2); 91 mg/L (OEO3); and 130 mg/L (OEO4), each incubated with 150 mL of buffered rumen fluid and 1,200 mg of substrate for 24 h using the Ankom in vitro gas production system (Ankom Technology Corp., Fairport, NY). Treatment responses were statistically analyzed using polynomial contrasts. Digestibility of DM, NDF, and ADF increased quadratically with increasing OEO inclusion rates. Digestibility of DM and NDF were highest for OEO2, whereas ADF digestibility was highest for OEO3, compared with CON, with the remaining treatments being intermediate and similar. Ammonia nitrogen concentrations decreased from CON at a quadratic rate with increasing OEO inclusion rates, and OEO2 had the lowest concentration compared with the other groups. Total VFA, acetate, propionate, butyrate, valerate, and isovalerate concentrations linearly decreased with increasing OEO inclusion rates. Total gas production levels by CON and OEO4 were greater than those of OEO1, OEO2, and OEO3 in a quadratic response, and methane production linearly decreased from CON, compared with OEO4, at a decreasing rate with OEO inclusion rates. As determined by 16S rRNA sequencing, the α biodiversity of ruminal bacteria was similar among OEO inclusion rates. Increasing OEO inclusion rates linearly increased the relative abundance of Prevotella and Dialister bacteria. Several bacteria demonstrated different polynomial responses, whereas several bacteria were similar among increasing OEO inclusion rates. These results suggested that OEO supplementation can modify ruminal fermentation to alter VFA concentrations and reduce methane emissions by extensively altering the ruminal bacterial community, suggesting an optimal feeding rate for future animal studies of approximately 52 mg/L for mature ruminants.

Methane emissions from sheep fed Eragrostis curvula hay substituted with Lespedeza cuneata

Context Reducing emissions of greenhouse gases from livestock production systems is a global research priority. Forages that contain condensed tannins, such as the perennial legume Lespedeza cuneata, may help to reduce ruminant methane (CH4) emissions. Aims The objective of this study was to investigate the effect of feeding different levels of L. cuneata hay on feed intake and enteric CH4 emissions of sheep fed a basal diet of subtropical Eragrostis curvula hay. Methods Four adult ruminally cannulated Dohne Merino wethers with initial bodyweight of 65.5 ± 3.5 kg were used in the experiment in a 4 × 4 Latin square design. The four experimental treatments were E. curvula hay substituted with 0%, 30%, 60% and 90% L. cuneata hay. Each of four experimental periods lasted 27 days, which consisted of a 14-day adaptation period, a 7-day digestibility trial, and a 6-day CH4-measurement period. During the 6-day CH4-measurement period, CH4 emissions were measured continuously over a 24-h period by using an open circuit respiration system. Key results Dry matter intake (DMI, g/kg W0.75) was higher (P &lt; 0.05) for sheep receiving 60% and 90% L. cuneata than 0% and 30% L. cuneata (77.33 and 84.67 g/kg W0.75 vs 62.96 and 62.71 g/kg W0.75). The increase in DMI corresponded with a linear increase in DM digestibility of the experimental treatments from 38% to 45% as the level of L. cuneata substitution increased. Methane yield was not influenced (P &gt; 0.05) by 30% inclusion of L. cuneata (17.6 g CH4/kg DMI) but decreased (P &lt; 0.05) as the inclusion level increased to 60% and 90% (13.8 and 14.3 g CH4/kg DMI). Conclusions Inclusion of L. cuneata hay in a diet based on E. curvula hay improved diet digestibility, and led to increased concentrations of crude protein, neutral detergent fibre and non-fibre carbohydrates. Substituting E. curvula hay with 60% L. cuneata on a DM basis resulted in the greatest reduction in CH4 yield of 21.4% compared with a diet of 100% E. curvula. Implications The results suggest that L. cuneata has the potential to reduce CH4 yield and possibly increase production from sheep by improving diet DM digestibility and through improved DMI.

Evaluating Strategies to Reduce Ruminal Protozoa and Their Impacts on Nutrient Utilization and Animal Performance in Ruminants - A Meta-Analysis

Several studies have evaluated the effects of complete or partial ruminal protozoa (RP) inhibition; however, to this date, no practical suppressant has been identified and used in large scale. This meta-analysis quantitatively evaluates the effectiveness of multiple strategies on inhibiting RP numbers and their influence on ruminal fermentation and animal performance. This study compared 66 peer-reviewed articles (16 manuscripts for complete and 50 manuscripts for partial RP inhibition that used supplemental phytochemicals and lipids, published from 2000 to 2018, to inhibit RP in vivo. Data were structured to allow a meta-analytical evaluation of differences in response to different treatments (complete RP inhibition, phytochemicals, and lipids). Data were analyzed using mixed models with the random effect of experiment and weighted by the inverse of pooled standard error of the mean (SEM) squared. Supplemental phytochemicals and LCFA had no effects on inhibiting RP numbers; however, supplemental MCFA had a potent antiprotozoal effect. Both complete and partial RP (supplemental phytochemicals and lipids) inhibition decreased methane production, total tract digestibility of OM and NDF, and ruminal NH₃-N concentration and increased propionate molar proportion. Methane production, molar proportions of acetate and propionate, total tract NDF digestibility were affected by the interaction of treatment (supplemental phytochemicals and lipids) and RP numbers. Supplemental phytochemicals and lipids can be effective in reducing methane production when RP numbers is below 7 Log₁₀ cells/mL, especially by supplemental saponins, tannins, and MCFA. In terms of animal performance, supplemental tannins could be recommended to control methane emissions without affecting animal performance. However, their negative effects on total tract digestibility could be a drawback when feeding tannins to ruminants. The negative effects of supplemental lipids on milk fat composition should be considered when feeding lipids to ruminants. In conclusion, ruminal protozoa play important roles on methanogenesis, fiber digestion, and ruminal NH₃-N concentration, regardless of experimental diets and conditions; supplemental phytochemicals and lipids can be effective on reducing methane production when RP numbers is below 7 Log10 cells/mL. Among these partial RP inhibition strategies, supplemental tannins could be recommended to control methane production.

Effects of 3-nitrooxypropanol on rumen fermentation, lactational performance, and resumption of ovarian cyclicity in dairy cows

This study examined the effect of 3-nitrooxypropanol (3-NOP), a substance under investigation, on enteric methane (CH₄) emission, rumen fermentation, lactational performance, sensory properties of milk, and the resumption of ovarian cyclicity in early-lactation dairy cows. Fifty-six multi- and primiparous Holstein cows, including 8 that were rumen cannulated, were used in a 15-wk randomized complete block design experiment. Cows were blocked based on parity and previous lactation milk yield (MY) or predicted MY, and within each block were randomly assigned to one of 2 treatments: (1) control (CON), administered no 3-NOP, or (2) 3-NOP applied at 60 mg/kg of feed dry matter (3-NOP). Enteric CH₄ emission was measured during experimental wk 2, 6, 9, and 15, using the GreenFeed system. Dry matter intake (DMI) and MY data were collected daily throughout the experiment, and milk composition samples were collected 7 times during the experiment. Milk samples were collected from 14 to 60 (±2) d after calving, 3 d per week, and assayed for progesterone concentration to determine resumption of ovarian activity. Compared with CON, 3-NOP decreased daily CH₄ emission by 26%, CH₄ yield (CH₄ per kg of DMI) by 21%, and CH₄ emission intensity [CH₄ per kg of MY or energy-corrected milk (ECM)] by 25%. Enteric emission of carbon dioxide was decreased by 5%, and hydrogen emission was increased 48-fold by 3-NOP. Inclusion of 3-NOP decreased concentration of total volatile fatty acids (by 9.3%) and acetate but increased butyrate molar proportion, ethanol, and formate concentrations in ruminal fluid. Dry matter intake was lower for 3-NOP compared with CON, but DMI expressed as a percentage of body weight was not different between treatments. Treatment had no effect on milk and ECM, body weight change, or body condition score. Milk composition and milk fat and protein yields were not affected by treatment, except that concentrations of short-chain fatty acids in milk were increased by 3-NOP. Nutrient digestibility and blood metabolites and hormones were not affected by 3-NOP, except that insulin was decreased by 3-NOP. There was no effect of 3-NOP on postpartum resumption of ovarian activity, including days to first and second luteal phases, length of first and second luteal phases, and interval from first to second luteal phase. Sensory properties of milk from cows fed 3-NOP and cheese made from that milk were not affected by treatment. In this experiment, 3-NOP decreased daily enteric CH₄ emission, emission yield, and emission intensity, improved feed efficiency, and did not affect lactational performance or onset of ovarian activity in early-lactation dairy cows.

Effects of oregano essential oil on the ruminal pH and microbial population of sheep

Oregano essential oil (OEO), which has antimicrobial properties, may be used for altering the ruminal pH and microbial populations of sheep, as observed by the altered volatile fatty acid patterns. To further elucidate the effects of OEO on ruminal pH and microbial populations of sheep, 3 German merino sheep × local sheep crossbred rams with permanent ruminal fistulas were randomly assigned to a 3 × 3 Latin square design with 12-d periods. The treatments were as follows: control (CON); OEO4: OEO supplied at 4 g•d-1; and OEO7: OEO supplied at 7 g•d-1. Starting on day 11, rumen fluid was collected at 0 h, and at 4, 8, 12, 24 and 48 h after supplying OEO, and then pH values of rumen fluid were immediately measured. The abundance of microbial populations was determined by using qPCR. The ruminal pH values were similar among the sheep from all treatments. The abundance of ruminal fungi was higher for the sheep supplied OEO7 compared with the sheep supplied CON and OEO4, especially at 4 and 12 h. The abundance of ruminal protozoa decreased with supplied OEO, indicating that OEO could inhibit the protozoa. The abundance of the total ruminal bacteria was similar for the sheep from all treatments, but R. flavefaciens, R. albus and F. succinogenes increased in the sheep supplied OEO4 compared with those in the sheep supplied CON, however, the sheep supplied OEO7 had higher abundances of R. flavefaciens than the sheep supplied CON. These results demonstrated that supplying OEO to sheep did not affect the ruminal pH but could shift the rumen microbial population to one with less protozoa. Supplying OEO can preferentially enhance the growth of certain rumen microbial populations, but the shifts were influenced by the supply rate. Therefore, supplying low amount (i.e. 4 g•d-1) of OEO could have positive effects on ruminal microbial populations, whereas supplying elevated doses of OEO could be detrimental to those same ruminal microbial populations.

Effects of Moringa oleifera leaf extract on ruminal methane and carbon dioxide production and fermentation kinetics in a steer model

Ruminal fermentation produces greenhouse gases involved in global warming. Therefore, the effect of nutrient combinations on methane, carbon dioxide, and biogas production as well as ruminal fermentation kinetics was evaluated in in vitro studies. In total mixed rations, dietary corn grain was partially replaced by two levels of soybean hulls (a highly reusable residue), and a Moringa oleifera extract (a natural extract) at three concentration levels was added. Higher levels of both soybean hulls and M. oleifera extract delayed the initiation of methane production and resulted in a lower methane and carbon dioxide production. Thus, total biogas production was also lower. Replacement of corn grain by soybean hulls tended to lower methane production rates and asymptotic carbon dioxide production, and a delay in biogas and methane formation was observed. Asymptotic biogas and carbon dioxide production, however, were increased. The presence of M. oleifera extract tended to delay methane formation and to decrease methane production rate as well as asymptotic methane production. Higher M. oleifera extract levels decreased asymptotic biogas production with the control and the highest soybean hull levels. In the presence of M. oleifera extract, asymptotic carbon dioxide production was shown to be quadratically increased with the control and lowest soybean hull levels, but quadratically decreased with the highest soybean hull level. With the exception of fermentation pH, the interaction of substrate type and M. oleifera extract level was shown to have an effect on all fermentation parameters. Most fermentation parameters were shown to be higher when replacing corn grain by soybean hulls, including fermentation pH. Thus, the conclusion could be drawn that corn grain replacement by soybean hulls (an agricultural residue) in the presence of M. oleifera extract (a sparing leaf product) could ameliorate greenhouse gas emissions and improve digestion.

Effect of cinnamaldehyde on feed intake, rumen fermentation, and nutrient digestibility, in lactating dairy cows1

The objective of this study was to evaluate the effect of cinnamaldehyde, on feed intake, rumen fermentation, nutrient digestibility, milk yield, and components in lactating dairy cows. Six lactating Holstein dairy cows (3 ruminally cannulated and 3 noncannulated) averaging 263 ± 41 d in milk (DIM) and 754 ± 45 kg of BW at the beginning of the study were used. Cows were randomly assigned to 1 of 3 treatments in a replicated 3 × 3 Latin square design with 19 d periods (14 d for diet adaptation and 5 d for sample collection). Treatments were 0, 2, or 4 mg/kg of BW of cinnamaldehyde. Cinnamaldehyde was mixed with 40 g of corn meal and top-dressed onto the total mixed ration (TMR). Diet was fed as a TMR and contained 37% corn silage, 18.5% mixed-mostly grass silage, 24.5% energy supplement, 16.5% protein supplement, and 3.5% vitamin and mineral mix on a DM basis. The dietary nutrient composition averaged 15.1% CP, 37.8% NDF, and 24.7% ADF. Cows were fed and milked twice daily. No differences were observed for DMI (mean = 24.6 kg/d), milk yield (mean = 28.4 kg/d), 3.5% fat-corrected milk (FCM; mean = 30.6 kg/d), and 3.5% energy-corrected milk (ECM; mean = 30.7 kg/d). The dose of cinnamaldehyde did not have any effect on milk components, rumen fermentation, or pH. There were no differences in nutrient digestibility, but there was a trend for a quadratic effect for DM digestibility (P = 0.09): 74.4%, 76.3%, and 73.7% for treatments 0, 2, and 4 mg/kg of BW of cinnamaldehyde, respectively. A linear effect (P = 0.02) and a quadratic effect (P < 0.02) observed for urinary urea N and a quadratic effect (P = 0.03) for allantoin and total purine derivatives with the 2 mg/kg treatment being the lesser value. These data suggest that cinnamaldehyde at these dosages may have an antimicrobial effect in the rumen as suggested by a lesser concentration of urinary total purine derivatives. Overall, supplementing lactating dairy cows with cinnamaldehyde had no effect on feed intake, milk yield, or milk components. However, it appears that cinnamaldehyde has a negative effect on rumen microbial protein synthesis as suggested by the reduced concentration of urinary purine derivatives.

Slight changes in the chemical structure of haemanthamine greatly influence the effect of the derivatives on rumen fermentation in vitro

Although the potential of plants extracts to improve feed efficiency and animal productivity and decrease methane emissions by enteric fermentation has been shown, the information available is often contradictory which has been attributed to differences in the complex mixture of bioactive compounds and their interactions. Understanding the degree to which structural features in a compound may affect the biological activity of an extract is essential. We hypothesised that relative small variations in the structure of a compound can have a significant influence on the ability of the derivatives to alter fermentation in the rumen. Nine compounds were synthetized from the natural alkaloid haemanthamine and tested in vitro for their effects on rumen protozoa and fermentation parameters. Our results showed that simple esterifications of haemanthamine or its derivative dihydrohaemanthamine with acetate, butyrate, pivalate or hexanoate led to compounds that differed in their effects on rumen fermentation.

Evaluation of antibacterial and antioxidant activities of three types of benzoin resin

The benzoin resin is used extensively in traditional medicine for its many reported therapeutic properties. The essential oils of three different types of benzoin resin were extracted using the traditional method in this study. The yield of essential oils of the white, red and gray types of resin was 1.01, 0.92 and 0.54%, respectively. The obtained extracts were tested against two types of pathogenic bacteria, Staphylococcus aureus and Escherichia coli. The tests showed that essential oil of gray type resin is effective against both Escherichia coli (14 mm) and Staphylococcus aureus (11 mm). The antioxidant activity has been also evaluated to compare the efficiency of different type of resin with DPPH· assay. In the DPPH· system, the antioxidant activity of the red resin extract (0.01 μg/mL) was superior to that of the white (27.32 μg/mL) and gray (42.90 μg/mL) extracts, with IC50 values, respectively.

Effect of traditional Chinese medicine compounds on rumen fermentation, methanogenesis and microbial flora in vitro

This study was conducted to investigate the effects of traditional Chinese medicine compounds (TCMC) on rumen fermentation, methane emission and populations of ruminal microbes using an in vitro gas production technique. Cablin patchouli herb (CPH), Atractylodes rhizome (AR), Amur Cork-tree (AC) and Cypsum were mixed with the weight ratios of 1:1:1:0.5 and 1:1:1:1 to make up TCMC1 and TCMC2, respectively. Both TCMC were added at level of 25 g/kg of substrate dry matter. In vitro gas production was recorded and methane concentration was determined at 12 and 24 h of incubation. After 24 h, the incubation was terminated and the inoculants were measured for pH, ammonia nitrogen, volatile fatty acids (VFA). Total deoxyribonucleic acid of ruminal microbes was extracted from the inocula, and populations were determined by a real-time quantitative polymerase chain reaction. Populations of total rumen methanogens, protozoa, total fungi, Ruminococcus albus, Fibrobacter succinogenes and Ruminococcus flavefaciens were expressed as a proportion of total rumen bacterial 16S ribosomal deoxyribonucleic acid. Compared with the control, the 2 TCMC decreased (P ≤ 0.05) total VFA concentration, acetate molar proportion, acetate to propionate ratio, gas and methane productions at 12 and 24 h, hydrogen (H) produced and consumed, and methanogens and total fungi populations, while the 2 TCMC increased (P ≤ 0.05) propionate molar proportion. Traditional Chinese medicine compound 1 also decreased (P ≤ 0.05) R. flavefaciens population. From the present study, it is inferred that there is an effect of the TCMC in suppressing methanogenesis, probably mediated via indirect mode by channeling H₂ utilized for methanogenesis to synthesis of propionate and direct action against the rumen microbes involved in methane formation. In addition, the relative methane reduction potential (RMRP) of TCMC2 was superior to that of TCMC1.

Effect of Eucalyptus globulus leaves extracts on in vitro rumen fermentation, methanogenesis, degradability and protozoa population

The aim of the research was to evaluate the effect of three Eucalyptus globulus extracts rich in phenolic compounds, especially flavonoids, on rumen fermentation, methane (CH4) production, organic matter degradability and protozoa population using an in vitro gas production technique. Four concentrations (0, 50, 75 and 100 mg) of three Eucalyptus extracts (ethyl acetate, n-butanol and aqueous) were added to a diet of ruminants (forage: concentrate ratio 60:40) and incubated at 39°C under anaerobiosis with buffered rumen fluid. After 24 h, the fermentation fluid was analysed for ammonia-N and volatile fatty acids (VFA). Organic matter degradability (OMD) and protozoa were also determined; in vitro gas production was also recorded and CH4 concentration was measured. Compared to the control, CH4 production was significantly lower for ethyl acetate extract (P<0.05), but higher for n-butanol and aqueous extracts. Production of ammonia- N was lower in all Eucalyptus extracts (P<0.05). Propionate production (P<0.05) increased for ethyl acetate and n-butanol extracts, whereas no effect was registered for VFA, for all Eucalyptus extracts. Ethyl acetate extract decreased in vitro OMD (P<0.05), whereas n-butanol and aqueous extracts were comparable to the control. Protozoa population decreased (P<0.05) for all extracts in comparison with the control. Eucalyptus ethyl acetate extract might be promising to be used as a potent anti-methanogenic additive. Moreover, the assessment of the right dosage seems to be important to decrease methane production, without reducing feed nutritional value.

Meta-proteomics of rumen microbiota indicates niche compartmentalisation and functional dominance in a limited number of metabolic pathways between abundant bacteria

The rumen is a complex ecosystem. It is the primary site for microbial fermentation of ingested feed allowing conversion of a low nutritional feed source into high quality meat and milk products. However, digestive inefficiencies lead to production of high amounts of environmental pollutants; methane and nitrogenous waste. These inefficiencies could be overcome by development of forages which better match the requirements of the rumen microbial population. Although challenging, the application of meta-proteomics has potential for a more complete understanding of the rumen ecosystem than sequencing approaches alone. Here, we have implemented a meta-proteomic approach to determine the association between taxonomies of microbial sources of the most abundant proteins in the rumens of forage-fed dairy cows, with taxonomic abundances typical of those previously described by metagenomics. Reproducible proteome profiles were generated from rumen samples. The most highly abundant taxonomic phyla in the proteome were Bacteriodetes, Firmicutes and Proteobacteria, which corresponded with the most abundant taxonomic phyla determined from 16S rRNA studies. Meta-proteome data indicated differentiation between metabolic pathways of the most abundant phyla, which is in agreement with the concept of diversified niches within the rumen microbiota.

Essential oil and monensin affect ruminal fermentation and the protozoal population in continuous culture

The interaction of monensin and essential oil was hypothesized to suppress protozoa and methane production while maintaining normal rumen function. The objective of this study was to determine the effects of feeding monensin (MON) and CinnaGar (CIN, a commercial blend of cinnamaldehyde and garlic oil; Provimi North America, Brookville, OH) on ruminal fermentation characteristics. Continuous culture fermentors (n = 4) were maintained in 4 experimental periods in a 4 × 4 Latin square design. Four dietary treatments were arranged in a 2 × 2 factorial: (1) control diet, 37 g/d of dry matter (40 g/d at ∼92.5% dry matter) of a 50:50 forage:concentrate diet containing no additive; (2) MON at 11 g/909 kg of dry matter; (3) CIN at 0.0043% of dry matter; and (4) a combination of MON and CIN at the levels in (2) and (3). Treatment had no effects on protozoal populations, concentration of NH₃N, total N flow of effluent, production of total volatile fatty acids, or flows of conjugated linoleic acid and total C18 fatty acids. The MON decreased acetate:propionate ratio and biohydrogenation of both total C18 and 18:1 cis-9 but increased protozoal generation time, concentration of peptide, and flow of 18:1 trans-11. The MON tended to decrease protozoal counts in effluent and flow of 18:0 but tended to increase propionate production. The CIN decreased true organic matter digestibility and protozoal N flow of effluent but increased nonammonia, nonmicrobial N flow. The CIN tended to decrease protozoal counts, microbial N flow, and neutral detergent fiber digestibility but tended to increase biohydrogenation of total C18, 18:2, and 18:3. The CIN tended to increase isovalerate production. The MON and CIN tended to interact for increased methane production and bacterial N flow. A second experiment was conducted to determine the effects of MON and CIN on protozoal nitrogen and cell volume in vitro. Four treatments included (1) control (feed only), (2) feed + 0.0043% dry matter CIN, (3) feed + 2.82 μM MON, and (4) feed + CIN + MON at the same levels as in (2) and (3). With no interactions, MON addition decreased percentage of protozoa that were motile and tended to decrease cell volume at 6 h. The CIN did not affect cell count or other indicators of motility or volume at either 3 or 6 h. Under the conditions of our study, we did not detect an additive response for MON and CIN to decrease protozoal counts or methane production. A 3-dimensional method is suggested to better estimate protozoal cell volume.