Chemical composition of rumen microbial fraction and fermentation parameters as affected by tannins and saponins using an in vitro rumen fermentation system

Effects of Caragana korshinskii tannin on fermentation, methane emission, community of methanogens, and metabolome of rumen in sheep

The purpose of this research was to investigate the impact of dietary supplementation of Caragana korshinskii tannin (CKT) on rumen fermentation, methane emission, methanogen community and metabolome in rumen of sheep. A total of 15 crossbred sheep of the Dumont breed with similar body conditions, were divided into three groups (n = 5), which were fed with CKT addition at 0, 2 and 4%/kg DM. The study spanned a total of 74 days, with a 14-day period dedicated to adaptation and a subsequent 60-day period for conducting treatments. The results indicated that the levels of ammonia nitrogen (NH3-N) and acetate were reduced (p < 0.05) in rumen sheep fed with 2 and 4% CKT; The crude protein (CP) digestibility of sheep in 2 and 4% CKT groups was decreased(p < 0.05); while the neutral detergent fiber (NDF) digestibility was increased (p < 0.05) in 4% CKT group. Furthermore, the supplementation of CKT resulted in a decrease (p < 0.05) in daily CH4 emissions from sheep by reducing the richness and diversity of ruminal methanogens community, meanwhile decreasing (p < 0.05) concentrations of tyramine that contribute to methane synthesis and increasing (p < 0.05) concentrations of N-methy-L-glutamic acid that do not contribute to CH4 synthesis. However, CH4 production of DMI, OMI, NDFI and metabolic weight did not differ significantly across the various treatments. To sum up, the addition of 4% CKT appeared to be a viable approach for reducing CH4 emissions from sheep without no negative effects. These findings suggest that CKT hold promise in mitigating methane emissions of ruminant. Further investigation is required to evaluate it effectiveness in practical feeding strategies for livestock.

Assessing the In Vitro and In Vivo Effect of Supplementation with a Garlic (Allium sativum) and Oregano (Origanum vulgare) Essential Oil Mixture on Digestibility in West African Sheep

This study assessed the impact of a mixture of garlic (Allium sativum) and oregano (Origanum vulgare) essential oils (EOGOs) on in vitro dry matter digestibility (IVDMD) and in vivo apparent nutrient digestibility. Different EOGO inclusion levels were evaluated to assess the dose response and potential effects of the mixture. Three EOGO inclusion levels (0.5, 0.75, and 1 mL/kg of incubated dry matter) were evaluated in vitro, while four treatments (0.5, 0.75, and 1 mL/day of EOGO and a control group) were tested in vivo on 12 West African sheep. A randomized controlled trial was conducted using a 4 × 4 design. Blood parameters (glucose, blood urea nitrogen, and β-hydroxybutyrate) were measured to observe the effect of EOGO on the metabolism. The results showed that the inclusion of EOGO significantly enhanced IVDMD at low levels (p < 0.052) compared with the highest levels in treatments containing 0.5 and 0.75 mL/kg of EOGO dry matter. A higher intake of dry matter (DM), crude protein (CP), and neutral detergent fiber (NDF) (p < 0.05) was observed in the in vivo diets with the inclusion of EOGO. In terms of in vivo apparent digestibility, significant differences were found among treatments in the digestibility coefficients of DM, CP, and NDF. EOGO inclusion increased the digestibility of DM. CP digestibility displayed a cubic effect (p < 0.038), with the lowest values of digestibility observed at 1 mL EOGO inclusion. Additionally, NDF digestibility showed a cubic effect (p < 0.012), with the highest value obtained at 0.75 mL of EOGO inclusion. The inclusion levels above 0.75 mL EOGO showed a cubic effect, which indicates that higher concentrations of EOGO may not be beneficial for the digestibility of CP and NDF. Although no significant difference was observed in total digestible nutrients, a linear trend was observed (p < 0.059). EOGO improved the intake of DM, CP, and NDF. EOGO supplementation improved the digestibility of DM and NDF, with optimal levels observed at 0.5 mL/day. No significant effects were observed in the blood parameters. These results suggest that EOGO has the potential as an additive in ruminal nutrition to improve food digestibility and serve as an alternative to antibiotic additives. The use of EOGO potentially improves fiber digestion and may reduce the use of antibiotics in livestock production. Garlic (A. sativum) and oregano (O. vulgare) essential oils effectively modulated fiber digestibility at 0.75 mL/day. Garlic (A. sativum) and oregano (O. vulgare) essential oils have the potential to improve digestibility at low inclusion levels and serve as an alternative to antibiotic additives. The effectiveness of essential oils is greater in a mixture and at lower doses.

Castanea sativa Mill. Leaf: UHPLC-HR MS/MS Analysis and Effects on In Vitro Rumen Fermentation and Methanogenesis

Castanea sativa Mill. (Fagaceae) is a deciduous tree grown for its wood and edible fruits. Chestnut processing produces residues (burs, shells, and leaves) exploitable for their diversity in bioactive compounds in animal nutrition. In fact, plant-specialized metabolites likely act as rumen modifiers. Thus, the recovery of residual plant parts as feed ingredients is an evaluable strategy. In this context, European chestnut leaves from northern Germany have been investigated, proving to be a good source of flavonoids as well as gallo- and ellagitannins. To this purpose, an alcoholic extract was obtained and an untargeted profiling carried out, mainly by means of ultra-high-performance liquid chromatography/high-resolution tandem mass spectrometry (UHPLC-HR MS/MS) techniques. To better unravel the polyphenol constituents, fractionation strategies were employed to obtain a lipophilic fraction and a polar one. This latter was highly responsive to total phenolic and flavonoid content analyses, as well as to antiradical (DPPH^● and ABTS^+●) and reducing activity (PFRAP) assays. The effect of the alcoholic extract and its fractions on rumen liquor was also evaluated in vitro in terms of fermentative parameter changes and impact on methanogenesis. The data acquired confirm that chestnut leaf extract and the fractions therefrom promote an increase in total volatile fatty acids, while decreasing acetate/propionate ratio and CH₄ production.

In Vitro Rumen Fermentation and Post-Ruminal Digestibility of Sorghum-Soybean Forage as Affected by Ensiling Length, Storage Temperature, and Its Interactions with Crude Protein Levels

The study aimed to evaluate the effects of ensiling length, storage temperature, and its interaction with crude protein (CP) levels in sorghum−soybean forage mixtures on in vitro rumen fermentation and post-ruminal digestibility of nutrients. The dietary treatments consisted of fresh forages (d 0) and silages of sorghum and soybean stored indoors or outdoors for 75 and 180 d with additional ingredients to make two dietary CP levels, 90 and 130 g/kg dry matter (DM) and a forage-to-concentrate ratio of 80 to 20. An in vitro procedure was conducted using the ANKOM RF technique to study rumen fermentation. The dietary treatments were incubated in duplicate for 8 and 24 h in three runs. After each incubation time, in vitro rumen fermentation parameters were measured, and the protozoa population was counted using a microscope. Post-ruminal digestibility was determined using the pepsin and pancreatic solubility procedure. Cumulative gas production (GP) increased quadratically with ensiling length (8 h, p < 0.01; 24 h, p = 0.02), and the GP differed between CP levels at both incubation times (p < 0.01). However, total short-chain fatty acid (SCFA) concentrations in rumen inoculum increased quadratically with ensiling length (p < 0.01; for both incubation times), and interaction between ensiling length and CP levels was observed in proportions of acetate and propionate after 24 h of incubation (p < 0.01; for both incubation times). Similarly, an interaction between ensiling length and CP levels was found in the proportion of valerate after 24 h of incubation (p < 0.01). There was a quadratic response to ensiling length in the NH4−N concentration after 8 h (p < 0.01) and 24 h (p < 0.05), and the CP level also differed (p < 0.01) at both incubation times. The ciliate protozoa count after 24 h was higher in low CP diets than in high CP diets (p = 0.04). The amount of CP in the undegraded substrate at both incubation times differed between CP levels (p < 0.01; for both incubation times). An interaction effect between ensiling length and storage temperature after 8 h (p = 0.02) and 24 h (p < 0.01) was observed for intestinal CP digestibility. The effect of CP levels on intestinal CP digestibility differed after 8 h (p < 0.01) and 24 h (p < 0.01). In conclusion, increasing ensiling length beyond 75 d reduced CP digestibility, and additional CP inclusion did not ameliorate this.

Phytonutrients in Red Amaranth (Amaranthus cruentus, L.) and Feed Ratios Enhanced Rumen Fermentation Dynamics, Suppress Protozoal Population, and Methane Production

The search for alternative modifiers of rumen fermentation to improve the production efficiency of livestock production is highly essential. This in vitro fermentation experiment was conducted using a factorial arrangement of two ratios of roughage to concentrate and seven levels of red amaranth (Amaranthus cruentus L.) leaf powder (RALP) as a percentage of total substrate in a completely randomized design (CRD). There were two factors: factor A was two ratios of roughage (R) to concentrate (C) at 60:40 and 40:60 and factor B was levels of RALP supplementation at 0, 2, 4, 6, 8, 10, and 12% dry matter (DM) of total dietary substrate. The results revealed that a R:C ratio at 40:60 increased rumen fermentation and reduced methane production (p &lt; 0.05). The RALP incorporation as a feed additive was highly promising in enhancing propionate (C3) concentration, reducing acetate (C2) to (C3) ratio, and the protozoal population, while mitigating methane (CH4) production. Furthermore, DM degradation percentages were remarkably enhanced by increasing the RALP levels and R:C ratio at 40:60. In conclusion, plants rich in phytonutrients and minerals such as RALP and the lower R:C ratio showed a promising role in modulating rumen fermentation, mitigating methane production, as well as increasing substrate DM degradability.

Gut Microbiota and Their Role in Health and Metabolic Disease of Dairy Cow

Ruminants are mostly herbivorous animals that employ rumen fermentation for the digestion of feed materials, including dairy cows. Ruminants consume plant fibre as their regular diet, but lack the machinery for their digestion. For this reason, ruminants maintain a symbiotic relation with microorganisms that are capable of producing enzymes to degrade plant polymers. Various species of microflora including bacteria, protozoa, fungi, archaea, and bacteriophages are hosted at distinct concentrations for accomplishing complete digestion. The ingested feed is digested at a defined stratum. The polysaccharic plant fibrils are degraded by cellulolytic bacteria, and the substrate formed is acted upon by other bacteria. This sequential degradative mechanism forms the base of complete digestion as well as harvesting energy from the ingested feed. The composition of microbiota readily gets tuned to the changes in the feed habits of the dairy cow. The overall energy production as well as digestion is decided by the intactness of the resident communal flora. Disturbances in the homogeneity gastrointestinal microflora has severe effects on the digestive system and various other organs. This disharmony in communal relationship also causes various metabolic disorders. The dominance of methanogens sometimes lead to bloating, and high sugar feed culminates in ruminal acidosis. Likewise, disruptive microfloral constitution also ignites reticuloperitonitis, ulcers, diarrhoea, etc. The role of symbiotic microflora in the occurrence and progress of a few important metabolic diseases are discussed in this review. Future studies in multiomics provides platform to determine the physiological and phenotypical upgradation of dairy cow for milk production.

Influence of Supplementing Sesbania grandiflora Pod Meal at Two Dietary Crude Protein Levels on Feed Intake, Fermentation Characteristics, and Methane Mitigation in Thai Purebred Beef Cattle

The aim of the study was to evaluate the effect of crude protein (CP) levels in concentrate and Sesbania grandiflora pod meal (SG) supplementation on feed intake, rumen fermentation, and methane (CH₄) mitigation in Thai purebred beef cattle. Four cattle with 100 ± 5.0 kg body weight were used in this study. A 2 × 2 factorial experiment in a 4 × 4 Latin square design was conducted, in which factor A was the CP levels in concentrate of 14% and 16% of dry matter (DM) and factor B was the supplement levels of SG at 0.4% and 0.6% DM intake, respectively. The results showed that the CP content in concentrate and SG supplementation had no interaction effect on intake, digestibility, ruminal ecologies, ruminal fermentation products, and nitrogen utilization. Increasing CP content to 16% significantly (p < 0.05) increased the ruminal ammonia nitrogen (NH₃-N), nitrogen (N) intake, N absorption, and N retention. SG supplementation significantly (p < 0.05) decreased CP digestibility, NH₃-N, blood urea nitrogen, and protozoa. In addition, SG significantly decreased acetate (C2), acetate to propionate ratio, methane, and fecal N excretion, while it significantly increased total volatile fatty acids (VFAs) and propionate (C3) concentration. In conclusion, SG could mitigate methane emission and enhance nitrogen utilization.

Ensiling of total mixed ration containing persimmon peel: Evaluation of chemical composition and in vitro rumen fermentation profiles

The effects of inclusion of persimmon peel (PP) in total mixed ration (TMR) silage on its nutrient composition, tannin content, and in vitro ruminal fermentation were studied. Four types of TMR silages containing 0, 50, 100, and 150 g/kg of PP on a dry matter basis were prepared. The dietary contents of non‐fiber carbohydrate (NFC) decreased, while soluble protein fraction increased after ensiling of the TMR. In the TMR silages, the content of insoluble tannin increased (p < .05) with increasing PP level. The fraction of soluble protein decreased linearly (p < .01), while that of neutral detergent insoluble protein increased linearly (p < .01) with increasing the PP level in the TMR silages. The total gas and methane yields from the in vitro rumen fermentation of the TMR silages were lower (p < .01) than those of pre‐ensiled TMR and declined linearly (p < .01) with increasing PP level. These results indicate that adding PP to TMR silage may resist the breakdown of dietary protein during the ensiling process, although the ruminal fermentability of TMR possibly decreased after ensiling due to the loss of NFC.

Effects of Black Wattle (Acacia mearnsii) Condensed Tannins on Intake, Protozoa Population, Ruminal Fermentation, and Nutrient Digestibility in Jersey Steers

Simple Summary

Condensed tannins are plant secondary compounds that can modulate ruminal fermentation by binding to proteins, reducing their ruminal degradation, and also reduce ruminal protozoa, which may improve the efficiency of nitrogen utilization. In this study, we tested increasing levels (0, 5, 10, 15, and 20 g/kg of diet dry matter) of Acacia mearnsii condensed tannins in the diets of Jersey steers. Condensed tannins did not affect intake and ruminal protozoa population, but reduced protein digestibility and decreased ruminal pH and acetate proportion. Overall, the tested doses of condensed tannins extract did not improve ruminal fermentation and nutrient digestibility.

Abstract

The objective of this study was to evaluate the effect of inclusion of condensed tannins (CT) from black wattle (Acacia mearnsii) on feed intake, ruminal protozoa population, ruminal fermentation, and nutrient digestibility in Jersey steers. Five ruminally-cannulated steers were used in a 5 × 5 Latin square design, with five periods of 20 days each (14 days for diet adaptation and six days for sample collection per period). Treatments were composed of dietary inclusion levels of condensed tannins at 0, 5, 10, 15, and 20 g/kg of diet dry matter. Intakes of dry matter, organic matter, ether extract, crude protein, neutral detergent fiber, and total digestible nutrients were not affected by condensed tannins. The ruminal pH was reduced linearly with tannin levels. Ruminal ammonia nitrogen concentration was not affected by tannins. Tannins reduced the molar proportion of acetate and did not affect the ruminal protozoal population, which might be related to the low doses used. Digestibilities of dry matter, organic matter, and neutral detergent fiber were not altered; however, there was a linear reduction in crude protein digestibility. Based on these results, CT extracts from black wattle are not recommended for improving nutrient utilization in steers at the tested levels.

Gas Production, Digestibility and Efficacy of Stored or Fresh Plant Extracts to Reduce Methane Production on Different Substrates

Simple Summary

Medicinal plants possess the ability to mitigate methane production from ruminants. Long-term stability of these plant extracts are essential qualities to be able to replace other rumen modifiers. After one year of storage, plant secondary metabolites used in this study reduced methane production from low-quality forages, without adverse effects on feed digestibility in vitro.

Abstract

Natural compounds such as plant secondary metabolites (PSM) can be used to replace antibiotic growth promoters as rumen modifiers. In this study, the effectiveness of stored and freshly extracted Aloe vera (AV), Azadirachta indica (AZ), Moringa oleifera (MO), Jatropha curcas (JA), Tithonia diversifolia (TD) and Carica papaya (CP) crude extract and monensin on in vitro gas and methane production, organic matter digestibility (IVOMD) and volatile fatty acids (VFA) were evaluated using a total mixed ration (TMR), lucerne or Eragrostis curvula substrates. Fresh extracts were processed from the same batch of frozen (−20 °C) plant material a few days before the trial while the stored extracts were extracted and stored at 4 °C for 12 months prior to the study. Extraction was done by solubilising 50 g freeze-dried plant material in 500 mL 100% methanol. Four mL of reconstituted 50 mg crude extract per 1000 mL distilled water was added per incubation vial, which already contained 400 mg substrate and in vitro fermentation, and gas production and IVOMD evaluation were carried out using standard procedures. Results showed that storing plant extracts for 12 months did not affect the activity or stability of metabolites present in the crude extracts, as shown by the lack of differences in total gas production (TGP) and methane produced between fresh or stored extracts across the substrates. In the TMR substrate, plant extracts increased IVOMD but did not affect TGP and methane production, whereas monensin did not have any effect. Plant extracts increased IVOMD of Eragrostis substrate and supressed methane production to a greater extent than monensin (p < 0.05). It can be concluded that storing plant extracts for up to 12 months did not compromise their efficacy. In addition, the use of 50 mg/kg of AV, AZ, MO, JA, TD and CP extract to a forage-based diet will reduce methane production while improving feed digestibility.

Effects of the Forage Type and Chop Length of Ramie Silage on the Composition of Ruminal Microbiota in Black Goats

The aim of this study was to investigate the effects of the forage type and chop length of ramie (Boehmeria nivea (L.) Gaud.) silage on rumen fermentation and ruminal microbiota in black goats. Sixteen Liuyang black goats (22.35 ± 2.16 kg) were fed with the roughage of corn silage or ramie silage at chop lengths of 1, 2, or 3 cm. The Chao 1 index and the observed number of microbial species differed significantly between the corn and ramie silage groups (p < 0.05); however, Firmicutes (relative proportion: 34.99-56.68%), Bacteroidetes (27.41-47.73%), and Proteobacteria (1.44-3.92%) were the predominant phyla in both groups. The relative abundance of Verrucomicrobia (0.32-0.82%) was lowest for the 2 and 3 cm chop lengths (p < 0.05) and was negatively correlated with rumen pH and propionic acid concentration (p < 0.05), but positively correlated with the ratio of acetic acid to propionic acid (p < 0.05). The ramie silage fermentation quality was highest for the 1 cm chop length, suggesting that moderate chopping produces optimal quality silage.

Molecular weight of condensed tannins of some tropical feed-leaves and their effect on in vitro gas and methane production

The concentration and molecular weights (MW) of condensed tannins (CT) of three locally available tropical plant species leaves which have potential to be used as ruminant feed, and their effects on in vitro gas, including methane, production were investigated. Leaves of three plant species, namely, leucaena (Leucaena leucocephala), cassava (Manihot esculenta, Cranzt), and Siamese neem (Azadirachta indica A.Juss. var. Siamensis Valeton) were used in the present study. CT contents ranged from 1.2% in the leucaena to 5.0% in Siamese neem. The weight-average molecular weights (Mw) of the purified CTs, determined using gel-permeation chromatography, were 3222, 3409 and 3612 Da for leucaena, cassava and Siamese neem respectively. The above values were within the range reported for CTs of various tropical plant species. We know of no published data on MW of CTs from leaves of cassava and Siamese neem and, thus, this research, for the first time, reported the MWs of the above two plant materials. Subsequently, two CT extracts with differing MWs, such as CTs extracted from leaves of Siamese neem and leaves of leucaena, were selected as the representative of high and low MWs of CT respectively, and used for investigation of the effect of the MW of CT on in vitro gas production and fermentation parameters. Supplementation of CTs of a higher MW extracted from leaves of Siamese neem (at 2–6 mg/100 mg DM) significantly inhibited in vitro total gas and methane production, while supplementation of CTs with a lower MW extracted from leaves of leucaena had no effect, except for total gas production at the highest level (6 mg/100 mg DM) of supplementation. Similarly, CT from Siamese neem leaves had a stronger inhibitory effect (P &lt; 0.001) on in vitro volatile fatty acid, acetic acid and butyric acid production. The above results indicated that concentrations and the MW of CT varied among the plant species; in addition, the efficacy of CTs to inhibit ruminal CH4 emission are influenced by their MW.

In vitro microbial protein synthesis, ruminal degradation and post-ruminal digestibility of crude protein of dairy rations containing Quebracho tannin extract

This study evaluated the effects of Quebracho tannin extract (QTE) on in vitro ruminal fermentation, chemical composition of rumen microbes, ruminal degradation and intestinal digestibility of crude protein (iCPd). Three treatments were tested, the control (basal diet without QTE), the basal diet with 15 g QTE/kg dry matter (DM) and the basal diet with 30 g QTE/kg DM. The basal diet contained (g/kg DM): 339 grass silage, 317 maize silage and 344 concentrate. In vitro gas production kinetic was determined using the Hohenheim gas test (Experiment 1). The Ankom RF technique, a batch system with automatic gas pressure recordings, was used to determine in vitro production of short-chain fatty acids (SCFA) and ammonia-nitrogen concentration (NH₃ -N), as well as nitrogen and purine bases content in liquid-associated microbes (LAM) and in a residue of undegraded feed and solid-associated microbes (Feed+SAM) (Experiment 2). Ruminal degradation and iCPd were determined using the nylon bag technique and the mobile nylon bag technique, respectively (Experiment 3). Gas production (Experiment 1), total SCFA and NH₃ -N (Experiment 2) decreased with increasing QTE levels. Microbial mass and composition of LAM were not affected by QTE, but total mass of Feed+SAM linearly increased, likely due to decreased substrate degradation with increasing QTE levels. The total amount of N in microbial mass and undegraded feed after the in vitro incubation increased with increasing QTE levels, suggesting a potential greater N flow from the rumen to the duodenum. In contrast to in vivo studies with the same QTE, no effects were detected on ruminal effective degradability and iCPd, when using the nylon bag techniques. Based on the in vitro procedures, QTE increased the supply of N post-rumen; however, some evidence of a decreased fibre degradation were also observed. Therefore, the benefit of adding QTE to diets of cattle is still questionable.

Fermentation Characteristics and Microbial Diversity of Tropical Grass-legumes Silages

Calliandra calothyrsus preserved in silage is an alternative method for improving the crude protein content of feeds for sustainable ruminant production. The aim of this research was to evaluate the quality of silage which contained different levels of C. calothyrsus by examining the fermentation characteristics and microbial diversity. Silage was made in a completely randomized design consisting of five treatments with three replications i.e.: R0, Pennisetum purpureum 100%; R1, P. purpureum 75%+C. calothyrsus 25%;, R2, P. purpureum 50%+C. calothyrsus 50%; R3, P. purpureum 25%+C. calothyrsus 75%; and R4, C. calothyrsus 100%. All silages were prepared using plastic jar silos (600 g) and incubated at room temperature for 30 days. Silages were analyzed for fermentation characteristics and microbial diversity. Increased levels of C. calothyrsus in silage had a significant effect (p<0.01) on the fermentation characteristics. The microbial diversity index decreased and activity was inhibited with increasing levels of C. calothyrsus. The microbial community indicated that there was a population of Lactobacillus plantarum, L. casei, L. brevis, Lactococcus lactis, Chryseobacterium sp., and uncultured bacteria. The result confirmed that silage with a combination of grass and C. calothyrsus had good fermentation characteristics and microbial communities were dominated by L. plantarum.

Meta-analysis on Methane Mitigating Properties of Saponin-rich Sources in the Rumen: Influence of Addition Levels and Plant Sources

Saponins have been considered as promising natural substances for mitigating methane emissions from ruminants. However, studies reported that addition of saponin-rich sources often arrived at contrasting results, i.e. either it decreased methane or it did not. The aim of the present study was to assess ruminal methane emissions through a meta-analytical approach of integrating related studies from published papers which described various levels of different saponin-rich sources being added to ruminant feed. A database was constructed from published literature reporting the addition of saponin-rich sources at various levels and then monitoring ruminal methane emissions in vitro. Accordingly, levels of saponin-rich source additions as well as different saponin sources were specified in the database. Apart from methane, other related rumen fermentation parameters were also included in the database, i.e. organic matter digestibility, gas production, pH, ammonia concentration, short-chain fatty acid profiles and protozoal count. A total of 23 studies comprised of 89 data points met the inclusion criteria. The data obtained were subsequently subjected to a statistical meta-analysis based on mixed model methodology. Accordingly, different studies were treated as random effects whereas levels of saponin-rich source additions or different saponin sources were considered as fixed effects. Model statistics used were p-value and root mean square error. Results showed that an addition of increasing levels of a saponin-rich source decreased methane emission per unit of substrate incubated as well as per unit of total gas produced (p<0.05). There was a decrease in acetate proportion (linear pattern; p<0.001) and an increase in propionate proportion (linear pattern; p<0.001) with increasing levels of saponin. Log protozoal count decreased (p<0.05) at higher saponin levels. Comparing between different saponin-rich sources, all saponin sources, i.e. quillaja, tea and yucca saponins produced less methane per unit of total gas than that of control (p<0.05). Although numerically the order of effectiveness of saponin-rich sources in mitigating methane was yucca>tea>quillaja, statistically they did not differ each other. It can be concluded that methane mitigating properties of saponins in the rumen are level- and source-dependent.

Influence of Albizia lebbeck Saponin and Its Fractions on In Vitro Gas Production Kinetics, Rumen Methanogenesis, and Rumen Fermentation Characteristics

The present study was undertaken to investigate the effect of crude seed powder (CSP) and gross saponins extract (GSE) of seeds of Albizia lebbeck on antimicrobial activity by taking two Gram-positive (Staphylococcus aureus and Bacillus cereus), two Gram-negative (Escherichia coli and Salmonella Typhi) bacteria, and two fungi species (Aspergillus niger and Candida butyric) were taken at 25, 50, 100, 250, and 500 µg levels using agar well diffusion method. Zone of inhibition was increased with increasing of concentration of CSP and saponins which indicates that Gram-negative bacteria (E. coli), Gram-positive bacteria (B. cereus), and A. niger were significantly susceptible to inhibition. Another experiment was conducted to study the effect of GSE and saponins fraction A and B of A. lebbeck supplementation at 6% on DM basis on methane production and other rumen fermentation parameters using in vitro gas production test, by taking three different type diets, that is, high fiber diet (D1, 60R : 40C), medium fiber diet (D2, 50R : 50C), and low fiber diet (D3, 40R : 60C). Significant (P ≤ 0.05) increase was seen in IVDMD, methane production; however ammonia nitrogen concentration decreased as compared to control. The methane production was reduced in a range between 12 and 49% by saponin supplemented diets except in case of GSE in D2. Sap A showed the highest methane reduction per 200 mg of truly digested substrate (TDS) than other treatment groups. Results in relation with quantification of methanogens and protozoa by qPCR indicated the decreasing trend with saponins of A. lebbek in comparison with control except total methanogen quantified using mcr-A based primer.