Influence of foliage from African multipurpose trees on activity of rumen protozoa and bacteria

Fennel seeds dietary inclusion as a sustainable approach to reduce methane production and improve nutrient utilization and ruminal fermentation

Ruminants are considered a major producer of methane (CH4 ). Therefore, the present study aimed to determine the ability of dry fennel seeds to affect in vitro gas production and fermentation. Fennel seeds were included at 0% (Control), 0.5%, 1%, 1.5%, and 2% DM of a diet containing per kg DM: 500 g concentrate feed mixture, 400 g berseem hay, and 100 g of rice straw. The incubations lasted 48 h. Fennel seeds increased (P < 0.001) the asymptotic gas production and decreased its rate, while decreasing the production and proportion of CH4 (P < 0.05) and increased its rate. Moreover, fennel seed increased DM and neutral detergent fiber (P < 0.01) degradability, and increased total production of short-chain fatty acids, acetate, and propionate (P < 0.05). Compared to the control, fennel seeds increased (P < 0.01) metabolizable energy, partitioning factor, and microbial crude protein production. Overall, fennel seeds can be included up to 2% DM in ruminant diets as an environmentally friendly product in animal farming due to its ability to improve feed utilization, ruminal fermentation and while reducing CH4 production.

Anti-methanogenic potential of seaweeds and seaweed-derived compounds in ruminant feed: current perspectives, risks and future prospects

With methane emissions from ruminant agriculture contributing 17% of total methane emissions worldwide, there is increasing urgency to develop strategies to reduce greenhouse gas emissions in this sector. One of the proposed strategies is ruminant feed intervention studies focused on the inclusion of anti-methanogenic compounds which are those capable of interacting with the rumen microbiome, reducing the capacity of ruminal microorganisms to produce methane. Recently, seaweeds have been investigated for their ability to reduce methane in ruminants in vitro and in vivo, with the greatest methane abatement reported when using the red seaweed Asparagopsis taxiformis (attributed to the bromoform content of this species). From the literature analysis in this study, levels of up to 99% reduction in ruminant methane emissions have been reported from inclusion of this seaweed in animal feed, although further in vivo and microbiome studies are required to confirm these results as other reports showed no effect on methane emission resulting from the inclusion of seaweed to basal feed. This review explores the current state of research aiming to integrate seaweeds as anti-methanogenic feed additives, as well as examining the specific bioactive compounds within seaweeds that are likely to be related to these effects. The effects of the inclusion of seaweeds on the ruminal microbiome are also reviewed, as well as the future challenges when considering the large-scale inclusion of seaweeds into ruminant diets as anti-methanogenic agents.

Tropical tree foliage supplementation in ruminants improves rumen fermentation and the bacterial profile and decreases methane production

The main of this study was to evaluate the effect of supplementation of tropical tree foliage in ruminant diets on the in vitro fermentation, bacterial population, volatile fatty acids (VFAs), and enteric CH4 production. Seven experimental diets were evaluated: a control treatment of Pennisetum purpureum (T7) and six treatments of P. purpureum supplemented (30%) with the foliage of Neomillspaughia emargiata (T1), Tabernaemontana amygdalifolia (T2), Caesalpinia gaumeri (T3), Piscidia piscipula (T4), Leucaena leucocephala (T5), and Havardia albicans (T6). The T2, T7, and T5 treatments had the highest (p < 0.05) digestibility of dry matter. Overall, supplementation increased (p < 0.05) the concentrations of propionic and butyric acid and decreased acetic acid. Methanogenic bacteria decreased (p < 0.05) in T1, T2, T5, and T6. Ruminococcus albus decreased in T1, T2, T3, and T5 and Selenomonas ruminiantum increased in T3. Fibrobacter succinogenes increased, except in T5. Methane production decreased (p < 0.05) in T1, T4, T5, and T6. The supplementation with Leucaena leucocephala, Tabernaemontana amygdalifolia, Neomillspaughia emargiata, Piscidia piscipula, Havardia albicans, and Caesalpinia gaumeri is a potential alternative nutritional strategy for ruminants that results in positive changes in VFAs profile, a decrease on CH4 production and methanogenic bacteria, and changes on fibrolytic and non-fibrolytic bacteria composition.HIGHLIGHTSTropical tree foliage supplementation increased propionic and butyric acid and decreased acetic acid concentrations.Fibrolytic, non-fibrolytic, and Methanogenic bacteria were selectively modulated with the supplementation of tropical tree foliage.The enteric methane (CH4) production decreased with the supplementation of tree foliage.The supplementation of Tabernaemontana amygdalifolia and Leucaena leucocephala had the highest digestibility and is a potential alternative nutritional strategy for ruminants.

Can a blend of integrated feed additives modulate ruminal fermentation patterns and performance of growing lambs? In vitro and in vivo assessments

Two in vitro and in vivo experiments were accomplished to investigate the impacts of integrated feed additives (IFA, combination of protected fat, lysine, and methionine plus yucca extract, eucalyptus essential oil, and direct-fed microbial) on gas production (GP), ruminal fermentation and degradability parameters and lamb performance, digestibility, and nitrogen balance. In the in vitro experiment, responses of graded doses (0, 25, 50, 75, 100, and 125 g IFA/kg DM) were evaluated. In the in vivo experiment, 15 Barki male lambs (30.43 ± 0.74 kg BW ± SE) were individually allotted in complete randomized design into three treatments (five animal/treatment) as control (basal diet without additive), low dose (50 g/kg DM) and high dose (100 g/kg DM) for 120 days. In vitro results showed that both doses (100 and 125 g/kg DM) quadratically decreased (p < 0.001) GP and ammonia nitrogen (NH-3N) concentration. In vivo experiment revealed that dry matter intake was increased (p = 0.016) with low dose compared to high dose. Inclusion of high dose decreased blood serum glucose concentrations (p > 0.05) and ruminal protozoal populations (p = 0.094) compared with low dose and control diet. Both doses of IFA increased (p < 0.05) serum urea, creatinine, and triglyceride concentrations, while decreased (p < 0.001) ruminal NH3-N concentrations. These results suggested that, although IFA was effective to modify in vitro ruminal fermentation process and feed degradability, such aspects did not improve in vivo performance of growing lambs.

A Review of Effect of Saponins on Ruminal Fermentation, Health and Performance of Ruminants

Saponins are steroid, or triterpene glycoside, compounds found in plants and plant products, mainly legumes. However, some plants containing saponins are toxic. Saponins have both positive and negative roles in animal nutrition. Saponins have been shown to act as membrane-permeabilizing, immunostimulant, hypocholesterolaemic, and defaunating agents in the rumen for the manipulation of ruminal fermentation. Moreover, it has been reported that saponins have impair protein digestion in the gut to interact with cholesterol in the cell membrane, cause cell rupture and selective ruminal protozoa elimination, thus improving N-use efficiency and resulting in a probable increase in ruminant animal performance.

Antibacterial and Antioxidant Properties of Extracts of Yucca Baccata, a Plant of Northwestern Mexico, against Pathogenic Bacteria

Introduction

Bacterial agents and oxidative reactions are involved in health and food preservation issues, and Yucca baccata (Y. baccata) can be a source of compounds with practical applications in both areas, but its investigation remains limited.

Materials and Methods

Butanolic (YBE) and aqueous (YAE) extracts were obtained from the stem of Y. baccata. The total saponin, phenolic, and flavonoid contents were analyzed in the YBE and YAE. The antioxidant capacity of the extracts was determined by the DPPH, TEAC, FRAP, and ORAC assays. Seven Gram-positive and five Gram-negative pathogenic bacteria strains were used to determine the MIC and MBC.

Results

Saponin contents were 30% and 1.81% (w/w) in the YBE and YAE, respectively. The total phenolic and flavonoid contents in the extracts were 29.5 μg GAEmg⁻¹ (2.95%) and 5.58 μg GAEmg⁻¹ (0.56%) in the YBE and 69.92 μg QEmg⁻¹ (7.0%) and 1.65 μg QEmg⁻¹ (0.165%) in the YAE. The antioxidant capacity values of YBE were 29.18 μg TEmg⁻¹, 121.8 μg TEmg⁻¹, 33.41 μg TEmg⁻¹, and 156.84 μg TEmg⁻¹ by the DPPH, TEAC, FRAP, and ORAC assays, respectively. YAE had lower antioxidant values than YBE (P < 0.05). Values of 80 mgmL⁻¹ and 100 mgmL⁻¹ were estimated for MIC and MBC of YBE against the Gram-positive bacteria. Values of 100 mgmL⁻¹ and 120 mgmL⁻¹ for MIC and MBC of YBE were estimated against the Gram-negative bacteria. No MIC and MBC were obtained for YAE.

Conclusion

YBE exhibited higher antioxidant activity than YAE. Apparently, antibacterial properties of the YBE tended to be higher than those of the YAE.

Effects of Anemoside B4 on Diarrhea Incidence, Serum Indices, and Fecal Microbial of Suckling Calves

The study was conducted to evaluate the effects of Anemoside B4 on diarrhea incidence, serum indices, and fecal microbial of suckling calves. Sixty newborn Chinese Holstein calves with similar body weight (43.7 ± 3.9 kg) were randomly divided into four groups with 15 calves each, fed the diet which was supplied 0 (CON), 15 (A1), 30 (A2), and 45 (A3) mg/day of Anemoside B4, respectively. The trial period is 56 days. The blood and fecal samples were collected at 28 and 56 days of age. Results show that during the whole trial period, the diarrhea incidence in Group A1, A2, and A3 was significantly lower than that in Group CON (p < 0.05). Compared with the Group CON, Anemoside B4 supplementation significantly decreased the contents of serum D-lactic acid and diamine oxidase at 28-day-old (p < 0.05). At 56-day-old, the content of serum D-lactic acid in Group A3 tended to be higher (0.05 < p < 0.01), and the content of serum diamine oxidase in Group A3 increased significantly, in comparison with Group CON (p < 0.05). Group A3 increased the level of Chao1 and Simpson indices at 28-day-old (0.05 < p < 0.01), and Chao1, Observed_species, Shannon, and Simpson indices at 56-day-old (p < 0.05), in comparison to Group CON. Compared with Group CON, 45 mg / day Anemoside B4 supplementation significantly increased the contents of Bacteroidota (at the phylum level), Prevotella (at the genus level) at 28-day-old (p < 0.05), and the content of Sutterella (at the genus level) at 56-day-old (p < 0.05), promoted the processes of energy metabolism, glycan biosynthesis and metabolism, metabolism of cofactors and vitamins (p < 0.05). A positive correlation was observed between Prevotella and metabolism of cofactors and vitamins, energy metabolism, and glycan biosynthesis and metabolism. A positive correlation was observed between Sutterella and energy metabolism. In conclusion, Anemoside B4 could effectively alleviate calf diarrhea, protect the integrity of intestinal mucosa, and change the structure of intestinal microbiota, indicating the potential value of Anemoside B4 in regulating intestinal microbiota and the prevention of intestinal diseases.

Mangosteen Peel Liquid-Protected Soybean Meal Can Shift Rumen Microbiome and Rumen Fermentation End-Products in Lactating Crossbred Holstein Friesian Cows

Rumen bypass protein can enhance protein availability in the lower gut. This study investigated the use of liquid-containing phytonutrients in dairy cows as a dietary additives to reduce rumen protein degradation. Four crossbred lactating Holstein Friesian cows (75% Holstein Friesian with 25% Thai native breed) with an initial body weight (BW) of 410 ± 20 kg were randomly assigned to a 2 × 2 factorial arrangement [two crude protein (CP) levels with soybean meal (SBM) or mangosteen peel liquid-protected soybean meal (MPLP)-SBM] in a 4 × 4 Latin square design experiment. Dietary treatments were as follows: T1 = SBM in low crude protein concentrate (LPC) (SBM-LPC); T2 = MPLP-SBM in LPC (MPLP-SBM-LPC); T3 = SBM in high crude protein concentrate (HPC) (SBM-HPC); T4 = MPLP-SBM in HPC (MPLP-SBM-HPC). Apparent digestibilities of organic matter (OM) and neutral detergent fiber (aNDF) were increased (p < 0.05) by CP level in the HPC diet (19% CP), with higher OM and aNDF digestibilities. High crude protein concentrate increased (p < 0.05) the propionic acid in the rumen but reduced (p < 0.05) the acetic acid-to-propionic acid ratio and methane (CH4) production. Rumen microbial populations of the total bacteria, Fibrobacter succinogenes and Butyrivibrio fibrisolvens were increased (p < 0.05) by HPC. Real-time PCR revealed a 30.6% reduction of rumen methanogens by the MPLP-SBM in HPC. Furthermore, efficiency of microbial nitrogen synthesis (EMNS) was 15.8% increased (p < 0.05) by the MPLP-SBM in HPC when compared to SBM-LPC. Milk yield and milk composition protein content were enhanced (p < 0.05) by both the CP level in concentrate and by MPLP inclusion. In this experiment, a high level of CP and the MPLP-SBM enhanced the ruminal propionate, shifted rumen microbiome, and enhanced milk yield and compositions.

Alleviation of heat stress by Chlorophytum borivilianum: impact on stress markers, antioxidant, and immune status in crossbred cows

Eighteen crossbred Karan Fries (KF) cows in mid-lactation (av. 130 days) were selected from the livestock herd of the institute. The treatment for the experimental cows was as follows: no supplement (control), a low dose of Chlorophytum borivilianum (CB) at a dose rate of 40 mg/kg BW/day (T1, n = 6), and a high dose of CB at a dose rate of 80 mg/kg BW/day (T2, n = 6) for a period of 90 days in hot-humid season. Physiological responses like respiration rate (RR), pulse rate (PR), and rectal temperature (RT) were recorded in the morning (8.00 A.M.) and afternoon (2.30 P.M.) at weekly intervals. The expression of pro-inflammatory (IL-1β and TNF-α) and anti-inflammatory cytokine (IL-10) in PBMCs, the plasma level of antioxidants (SOD, catalase, TBARS, and TAC), hormones (cortisol, prolactin), and energy metabolites (glucose, NEFA, urea, and creatinine) were determined. Dry and wet bulb temperatures and minimum and maximum temperatures were recorded, and the THI was calculated. The values of PR and RT were decreased (p < 0.01) in the T2 group in comparison to T1. Plasma glucose level was lower, and NEFA, urea, and creatinine level were higher (p < 0.01) in the control group as compared to T2 and T1 groups, respectively. Plasma cortisol and prolactin levels were significantly higher (p < 0.01) in the control group and were lower in T1 and T2 groups. Feeding of CB in high dose decreased (p < 0.01) plasma SOD, catalase, TBARS, and improved TAC levels in T2 over the T1 group. The dietary supplementation of CB at a dose rate of 80 mg/kg BW/day was more effective in lowering the stress level and augments the immunity by downregulating pro-inflammatory and anti-inflammatory cytokine levels. Therefore, dietary CB supplementation could be used as an effective heat stress ameliorator in dairy cows.

Nutritional Aspects of Ecologically Relevant Phytochemicals in Ruminant Production

This review provides an update of ecologically relevant phytochemicals for ruminant production, focusing on their contribution to advancing nutrition. Phytochemicals embody a broad spectrum of chemical components that influence resource competence and biological advantage in determining plant species' distribution and density in different ecosystems. These natural compounds also often act as plant defensive chemicals against predatorial microbes, insects, and herbivores. They may modulate or exacerbate microbial transactions in the gastrointestinal tract and physiological responses in ruminant microbiomes. To harness their production-enhancing characteristics, phytochemicals have been actively researched as feed additives to manipulate ruminal fermentation and establish other phytochemoprophylactic (prevent animal diseases) and phytochemotherapeutic (treat animal diseases) roles. However, phytochemical-host interactions, the exact mechanism of action, and their effects require more profound elucidation to provide definitive recommendations for ruminant production. The majority of phytochemicals of nutritional and pharmacological interest are typically classified as flavonoids (9%), terpenoids (55%), and alkaloids (36%). Within flavonoids, polyphenolics (e.g., hydrolyzable and condensed tannins) have many benefits to ruminants, including reducing methane (CH4) emission, gastrointestinal nematode parasitism, and ruminal proteolysis. Within terpenoids, saponins and essential oils also mitigate CH4 emission, but triterpenoid saponins have rich biochemical structures with many clinical benefits in humans. The anti-methanogenic property in ruminants is variable because of the simultaneous targeting of several physiological pathways. This may explain saponin-containing forages' relative safety for long-term use and describe associated molecular interactions on all ruminant metabolism phases. Alkaloids are N-containing compounds with vast pharmacological properties currently used to treat humans, but their phytochemical usage as feed additives in ruminants has yet to be exploited as they may act as ghost compounds alongside other phytochemicals of known importance. We discussed strategic recommendations for phytochemicals to support sustainable ruminant production, such as replacements for antibiotics and anthelmintics. Topics that merit further examination are discussed and include the role of fresh forages vis-à-vis processed feeds in confined ruminant operations. Applications and benefits of phytochemicals to humankind are yet to be fully understood or utilized. Scientific explorations have provided promising results, pending thorough vetting before primetime use, such that academic and commercial interests in the technology are fully adopted.

Growth-promoting effect of water-washed neem (Azadirachta indica A. Juss) fruit inclusion in West African dwarf rams

In a study to determine the growth-promoting effect of water-washed neem (Azadirachta indica A. Juss) fruit (WN) in West African Dwarf (WAD) rams, a total mixed ration was formulated with 0 (WN0), 2.5 (WN2.5), 5.0 (WN5), 7.5 (WN7.5), and 10.0 (WN10) % of WN inclusion. Twenty-five yearling rams (12.3 ± 2.0 kg) were assigned to one of the five dietary groups with five animals per group in a completely randomized design. Each group received the diet for 90 days inclusive of the initial 28 days used for anticoccidial efficacy trial. After the growth trial, three rams from each group were used for digestibility and nitrogen metabolism trial. Anticoccidial efficacy linearly increased (P = 0.002) with increased inclusion of WN and duration of feeding (P = 0.003). Feed intake (P = 0.018) and weight gain (P = 0.009) quadratically increased with WN5 inclusion compared to WN10. Optimal inclusion level of WN for daily weight gain was 5.1% (R² = 0.30). Digestibility of crude protein was linearly and quadratically increased (P = 0.032; P = 0.031, respectively) with up to WN7.5 inclusion. Nitrogen retention was similar among the treatments. Incorporation of water-washed neem fruit in the diets of West African dwarf rams improved nutrient utilization and animal health by increasing anticoccidial efficacy, feed intake, and weight gain. This is an indication that water-washed neem fruit could be used as growth promoter in sheep production.

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.

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.

Mitigation of Rumen Methane Emissions with Foliage and Pods of Tropical Trees

Simple Summary

Methane produced by enteric fermentation contributes to the emission of greenhouse gases (GHG) into the atmosphere. Methane is one of the GHG arising from anthropogenic activities with the greater contribution to global warming. This paper provides a brief introduction to the potential use of tropical foliage trees, pods, and secondary metabolites to reduce methane emissions from ruminant supply chains. A better knowledge of the available strategies for efficient foliage use in the tropics is essential in order to ensure increasing livestock production while preserving the environment. The mitigation of rumen methane production through the use of the foliage and metabolites of tropical trees represents an interesting challenge for scientists working in the field of ruminant nutrition.

Abstract

Methane produced by enteric fermentation contributes to the emission of greenhouse gases (GHG) into the atmosphere. Methane is one of the GHG resulting from anthropogenic activities with the greater global warming contribution. Ruminant production systems contribute between 18% and 33% of methane emissions. Due to this, there has been growing interest in finding feed alternatives which may help to mitigate methane production in the rumen. The presence of a vast range of secondary metabolites in tropical trees (coumarins, phenols, tannins, and saponins, among others) may be a valuable alternative to manipulate rumen fermentation and partially defaunate the rumen, and thus reduce enteric methane production. Recent reports suggest that it is possible to decrease methane emissions in sheep by up to 27% by feeding them saponins from the tea leaves of Camellia sinensis; partial defaunation (54%) of the rumen has been achieved using saponins from Sapindus saponaria. The aim of this review was to collect, analyze, and interpret scientific information on the potential of tropical trees and their secondary metabolites to mitigate methane emissions from ruminants.

Antimalarial Activity of Hydroalcoholic Root Extract of Acanthus polystachyus Delile (Acanthaceae) Against Plasmodium berghei-Infected Mice

Failure of the efficacy of antimalarial drugs is recognized in different classes of medicines for treating malaria, which urges the need for new drugs. This study tried to check the in vivo antimalarial activity of the root extracts of Acanthus polystachyus Delile against Plasmodium berghei–infected mice. The study revealed that the methanolic crude extract of the root of Acanthus polystachyus Delile showed significant (P < .01) parasitemia suppressive activities in both models compared with the negative control. Parasitemia suppressive activities were 25.26%, 33.46%, and 51.48% in a 4-day suppressive test and 23.31%, 31.20%, and 43.54% in prophylaxis test at 100, 200, and 400 mg/kg of the extract, respectively, as compared to the negative control. Besides, the extract increases mean survival time significantly in all tested doses in a 4-day suppressive test, but in the prophylaxis model, only mice treated with 200 and 400 mg/kg significantly lived longer. Based on this finding, the root of Acanthus polystachyus Delile has strong antimalarial activity, which may be a good candidate for new antimalarial agents.

Increase in Milk Yield from Cows through Improvement of Forage Production Using the N2-Fixing Legume Leucaena leucocephala in a Silvopastoral System

Simple Summary

In tropical livestock production, forage availability and quality are a serious constraint for milk and meat production. There is an urgent need to reduce the environmental impact of animal production while increasing productivity. The use of legume trees or shrubs associated with grasses effectively increased milk production and decreased the need to use nitrogen fertilizers by taking advantage of atmospheric nitrogen fixation.

Abstract

The objective was to evaluate milk production, N₂-fixation and N transfer, forage yield and composition (under two cutting intervals) in a silvopastoral system (SPS) with Leucaena leucocephala-Megathyrsus maximus and M. maximus-monoculture (MMM) with crossbred cows in a completely randomized design. Forage yield in the SPS was 6490 and 6907 kg DM ha⁻¹ for cutting intervals (CI) of 35 and 50 days. Forage yield for the MMM was 7284 and 10,843 kg DM ha⁻¹, and forage crude protein (CP) was 29.0% and 26.1% for L. leucocephala, harvested at 35 and 50 days, respectively. CP for the associated M. maximus was 9.9% and 7.8% for CI 35 and 50 days, respectively, and for MMM was 7.4% and 8.4%, harvested at 35 and 50 days. Milk production was 4.7 kg cow⁻¹ day⁻¹ for cows grazing MMM and 7.4 kg cow⁻¹ day⁻¹ under SPS. Nitrogen fixation in L. leucocephala (%Ndfa) was estimated to be 89% and 95%, at 35 and 50 days, with an N₂ transfer to the associated grass of 34.3% and 52.9%. SPS has the potential to fix and transfer important amounts of N₂ to the associated grass, and increase forage CP content and milk production.

Effects of pomegranate peel extract on ruminal and post-ruminal in vitro degradation of rumen inoculum of the dairy cow

This experiment was carried out to study the effect of water extracted pomegranate peel extract (PE) on ruminal protein degradation and post-ruminal digestion in the dairy cow. PE was added at six levels of total phenolics (g/kg of the basal diet); 3.75 (PE1); 4.4 (PE2); 5.05 (PE3); 5.70 (PE4); and 6.35 (PE5). Rumen degradable crude protein (rdCP) decreased with PE addition (L < 0.0001), but total CP degradability (tdCP) was not affected. Compared to PE0, PE2, and PE3 diets showed higher (L = 0.054, Q = 0.029) digestibility of bypass CP (dBCP). Increasing levels of PE resulted in a decrease in proteolytic bacteria numbers (p < 0.0001). At PE4 and PE5 levels, total VFA and acetate concentrations linearly decreased compared to PE0. PE inclusion lowered the acetate:propionate ratio (L = 0.0001) and Ammonia-N production after 24 h (L = 0.0008) of incubation. The total number of protozoa, genera Dasytricha and Isotricha, and subfamilies Entodiniinae, Diplodiniinae, and Ophrioscolecinae decreased with increasing dietary PE concentration (p < 0.0001). The results suggest that all levels of PE addition reduce the protozoal population and Ammonia-N concentration. All PE levels slowed down protein degradation in the rumen but PE2 and PE3 showed the greatest effect.

Manipulating the rumen microbiome to address challenges facing Australasian dairy farming

As dairy production systems expand globally, there is an increasing need to reduce the impact of dairy wastes on the environment by decreasing urinary N output and reducing emissions of green-house gasses (GHG). An understanding of rumen microbiome composition can result in the development of strategies that reduce methane emissions and nitrogen leakage, ultimately lowering the impact of dairying on the environment, while improving animal productivity. The strongest driver of the composition of the rumen microbiome was found to be the diet of the host animal. Thus, dietary manipulation offers a viable solution to alter the microbiome to address present-day challenges faced by the dairy industry. In the present review, we discuss such strategies and provide insight into rumen microbiome changes that have resulted in reduced GHG emissions and improved animal productivity.

Effects of Piper sarmentosum extract supplementation on growth performances and rumen fermentation and microflora characteristics in goats

This study was carried out to investigate the effect of diet Piper sarmentosum extract (PSE) on the growth performance, antioxidant properties, rumen fermentation and microflora in goats. Forty Hainan black goats with similar body weight were divided into four groups with supplementation of PSE in the concentrate at 0, 300, 600 and 1,200 mg/kg, respectively, and fed for 56 days. Results showed that average daily gain (ADG) was higher and feed intake/body gain (F/G) was lower in goats fed with PSE at 300 mg/kg (p < .05). The activities of glutathione peroxidase (GSH-Px) and total antioxidant capacity (T-AOC) in the serum of goats differed among treatments and were greatest linearly when PSE was added at 1,200 mg/kg (p < .05). The level of malondialdehyde (MDA) in the serum of goats differed among treatments and was lowest linearly when PSE was added at 1,200 mg/kg (p < .05). The level of protozoal protein in the rumen of goats differed among treatments and was lowest linearly when PSE was added at 1,200 mg/kg (p < .05). The concentrations of ruminal acetic acid and valeric acid and the ratio of acetate to propionate were reduced with PSE supplementation (p < .05). Protozoa, fungi, Ruminococcus flavefaciens and Fibrobacter succinogenes contents differed among treatments and were lowest linearly when PSE was added at 1,200 mg/kg (p < .05). Thus, supplementation of PSE at 300-1,200 mg/kg to goat concentrate is recommended for improving antioxidative ability and rumen efficiency and reducing protozoal content of goat.

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.

Nutritional evaluation of some Indian tree leaves and herbs as fodder and defaunating agent in sheep

Nutritional evaluation as a fodder and defaunating agent of four multipurpose tree leaves namely Ficus religiosa (Pipal), Ficus bengalensis (Bargad), Mangifera indica (Mango), Enterolobium timoba (Jungle jalebi) and two herbs namely Agave americana (Ramkanta) and Plantago major (Isafghol) was done in vitro. The mean content of OM, CP, EE, NDF, ADF, cellulose and lignin of these tree leaves and herbs were 88.6, 12.6, 2.4, 46.2, 33.5, 25.8 and 7.3% on DM basis, respectively. Enterolobium timoba leaves contained highest amount of CP (22.5%) while highest amount of ADF and lignin content was observed in Ficus bengalensis (41.1% / 12.1%) leaves. Total rumen protozoa as well as Holotrich and spirotrich protozoa number became zero due to inclusion of Agave americana and Enterolobium timoba leaves in the incubation media. Total volatile fatty acids (TVFA) and propionate production was higher where as NH3–N production was lower due to addition of Agave americana leaves in the incubation media. Highest IVTDMD and IVTOMD (61.4% / 64.1%) were observed for the Agave americana followed by Enterolobium timoba (59.8% / 62.5%) and Plantago major (57.5% / 59.2%) leaves. Activity of polysaccharide degrading enzymes like carboxymethyl cellulase and xylanase improved due to addition of Agave americana and Enterolobium timoba leaves in the incubation media. However, activity of β-glucosidase enzyme was similar among all the tested tree leaves and herbs. As a defaunating agent (removal of rumen protozoa / anti ciliate protozoal activity), Agave americana leaves were more effective in comparison to Plantage major leaves. The results indicated that among the tested tree leaves and herbs, Agave americana, Enterolobium timoba and Plantago major were good tree fodder for feeding to the animals and leaves of Agave americana and Enterolobium timoba could be used as defaunating agent for reducing rumen protozoal population to improve animal productivity.

Effect of treating recycled poultry bedding with tannin extracted from pomegranate peel on rumen fermentation parameters and cellulolytic bacterial population in Arabian fattening lambs

This study was conducted to investigate the effects of recycled poultry bedding (RPB) treated with different levels of pomegranate peel extract (PPE) as a tannin source on cellulolytic bacterial population and rumen fermentation parameters of fattening lambs. For this purpose, twenty-eight Arabian lambs (19.70 ± 2.45 kg body weight, 90 ± 12 days of age) were randomly assigned to four dietary treatments. Recycled poultry bedding was treated with PPE at four levels of 0 (control), 20.00, 25.00 and 30.00% on DM basis. Bacterial populations were enumerated by DNA extraction of samples of rumen liquor followed by real-time polymerase chain reaction analysis. Also, rumen samples were evaluated for pH, volatile fatty acid (VFA) and ammonia nitrogen (AN) concentrations. The populations of total bacteria, Ruminococcus albus and Fibrobacter succinogenes were decreased significantly as the level of PPE in the diet increased, however, the population of Ruminococcus flavefaciens was not affected. Dietary treatments did not have effect on ruminal pH, while AN concentration was decreased in the diets containing RPB treated with PPE compared to the control. Concentrations of total VFA and individual VFA remained unchanged by PPE-treated RPB inclusion in the diet. In conclusion, supplementing RPB with PPE improved nitrogen metabolism of fattening lambs, however, it decreased population of rumen cellulolytic bacteria R. flavefaciens.

Effects of long-term diet supplementation with Gliricidia sepium foliage mixed with Enterolobium cyclocarpum pods on enteric methane, apparent digestibility, and rumen microbial population in crossbred heifers1

In the last decades, strategies have been evaluated to reduce rumen methane (CH4) production by supplementing tropical forages rich in secondary compounds; however, most of these beneficial effects need to be validated in terms of their persistence over time. The aim of this study was to assess CH4 emissions over time in heifers fed with and without Gliricidia sepium foliage (G) mixed with ground pods of Enterolobium cyclocarpum(E). Two groups of 4 crossbred (Bos taurus x Bos indicus) heifers (284 ±17 kg initial weight) were fed with 2 diets (0% and 15% of a mixture of the pods and foliage [E + G:0 and E + G:15, respectively]) over 80 d, plus 2 wk before the experiment, in which every animal was fed a legume and pod-free diet. Every 14 d, CH4 production, apparent digestibility, volatile fatty acids (VFA), and microbial population were quantified for each animal. The experiment was conducted with a repeated measurements design over time. Diets fed differed in terms of their crude protein (CP), condensed tannins, and saponins content supplied by E. cyclocarpum and G. sepium. For most of the experiment, dry matter intake (DMI) and digestible dry-matter intake (DDMI) were 6.3 kg DMI/d and 512 g DDMI/kg, respectively, for both diets (diet: P > 0.05). Apparent digestible crude protein (DCP) was reduced by 21 g DCP/kg DM when the diet was supplemented with E + G:15 (P = 0.040). Molar proportions of VFA's in the rumen did not differ between diets or in time (P > 0.05). Daily methane production, expressed in relation to DMI, was 23.95 vs. 23.32 g CH4/kg DMI for the diet E + G:0 and E + G:15, respectively (diet: P = 0.016; Time: P > 0.05). Percent gross energy loss as CH4 (Ym) with grass-only diets was above 8.1%, whereas when feeding heifers with the alternate supplementation, Ym values of 7.59% (P = 0.016) were observed. The relative abundance of total bacterial, protozoa, and methanogenic archaeal replicates was not affected by time nor by the incorporation of legume and pods into the diet (P > 0.05). Results suggest that addition of G. sepium mixed with E. cyclocarpum pods can reduce CH4 production in heifers and this response remains over time, without effect on microbial population and VFA concentration and a slight reduction in CPD digestibility.

Advanced estimation and mitigation strategies: a cumulative approach to enteric methane abatement from ruminants

Methane, one of the important greenhouse gas, has a higher global warming potential than that of carbon dioxide. Agriculture, especially livestock, is considered as the biggest sector in producing anthropogenic methane. Among livestock, ruminants are the highest emitters of enteric methane. Methanogenesis, a continuous process in the rumen, carried out by archaea either with a hydrogenotrophic pathway that converts hydrogen and carbon dioxide to methane or with methylotrophic pathway, which the substrate for methanogenesis is methyl groups. For accurate estimation of methane from ruminants, three methods have been successfully used in various experiments under different environmental conditions such as respiration chamber, sulfur hexafluoride tracer technique, and the automated head-chamber or GreenFeed system. Methane production and emission from ruminants are increasing day by day with an increase of ruminants which help to meet up the nutrient demands of the increasing human population throughout the world. Several mitigation strategies have been taken separately for methane abatement from ruminant productions such as animal intervention, diet selection, dietary feed additives, probiotics, defaunation, supplementation of fats, oils, organic acids, plant secondary metabolites, etc. However, sustainable mitigation strategies are not established yet. A cumulative approach of accurate enteric methane measurement and existing mitigation strategies with more focusing on the biological reduction of methane emission by direct-fed microbials could be the sustainable methane mitigation approaches.

Replacement of lucerne by Enterolobium cyclocarpum leaves in the diet of growing goats

Animal production in tropical regions is commonly limited by the low crude protein content and digestibility of pastures, particularly during the dry season. The objective of the present study was to evaluate the effect of including Enterolobium cyclocarpum leaves (ECL) (0%, 15% and 30%) in diets as a partial replacement for lucerne on dry-matter intake (DMI), weight gain and nitrogen (N) balance in growing Saanen goats (12.6 ± 3.2 kg at 3 months of age) and the digestibility of the diet. Daily weight gain, DMI and digestibility were analysed in a 3 × 3 Latin square design replicated three times. The inclusion of ECL did not affect daily weight gain or DMI (P &gt; 0.05). There were no significant (P &gt; 0.05) differences for N intake among the diets, but the inclusion of 30% ECL significantly (P = 0.01) increased N excreted in faeces. These results suggest that ECL can be used as a partial substitute of lucerne in diets for growing goats, without affecting animal performance.

Addressing Global Ruminant Agricultural Challenges Through Understanding the Rumen Microbiome: Past, Present, and Future

The rumen is a complex ecosystem composed of anaerobic bacteria, protozoa, fungi, methanogenic archaea and phages. These microbes interact closely to breakdown plant material that cannot be digested by humans, whilst providing metabolic energy to the host and, in the case of archaea, producing methane. Consequently, ruminants produce meat and milk, which are rich in high-quality protein, vitamins and minerals, and therefore contribute to food security. As the world population is predicted to reach approximately 9.7 billion by 2050, an increase in ruminant production to satisfy global protein demand is necessary, despite limited land availability, and whilst ensuring environmental impact is minimized. Although challenging, these goals can be met, but depend on our understanding of the rumen microbiome. Attempts to manipulate the rumen microbiome to benefit global agricultural challenges have been ongoing for decades with limited success, mostly due to the lack of a detailed understanding of this microbiome and our limited ability to culture most of these microbes outside the rumen. The potential to manipulate the rumen microbiome and meet global livestock challenges through animal breeding and introduction of dietary interventions during early life have recently emerged as promising new technologies. Our inability to phenotype ruminants in a high-throughput manner has also hampered progress, although the recent increase in “omic” data may allow further development of mathematical models and rumen microbial gene biomarkers as proxies. Advances in computational tools, high-throughput sequencing technologies and cultivation-independent “omics” approaches continue to revolutionize our understanding of the rumen microbiome. This will ultimately provide the knowledge framework needed to solve current and future ruminant livestock challenges.

Does virginiamycin supplementation affect the metabolism and performance of Nellore bulls grazing under low and high gain rates?

This study aimed to evaluate the effect of virginiamycin on the metabolism and performance of growing Nellore bulls under low and high gain rates on pasture. In experiment 1, 80 Nellore bulls (age = 12 ± 2 months, body weight = 258 ± 15 kg) were assigned to 16 paddocks in a 2 × 2 randomized block factorial arrangement. In experiment 2, 12 cannulated Nellore bulls were assigned to three 4 × 4 balanced Latin squares. The factors were: (1) mineral salt without or with virginiamycin, and (2) low or high gain rate. No interaction was noted between factors (p > .10). Animals fed virginiamycin had greater average daily gain (14%, p < .01), body weight (11 kg, p = .05), plasma nonesterified fatty acid (20%, p < .01), serum calcium concentration (2.62%, p = .04), and total protozoa (p = .03) and had the same bacterial proportion (p > .27). Animals with a low gain rate had greater serum urea concentration (19.6%, p < .01) and ruminal ammonia nitrogen (62%, p < .01). Thus, virginiamycin increases the performance and changes the metabolism of growing Nellore bulls under low and high gain rates on pasture.

Dietary manipulation: a sustainable way to mitigate methane emissions from ruminants

Methane emission from the enteric fermentation of ruminant livestock is a main source of greenhouse gas (GHG) emission and a major concern for global warming. Methane emission is also associated with dietary energy lose; hence, reduce feed efficiency. Due to the negative environmental impacts, methane mitigation has come forward in last few decades. To date numerous efforts were made in order to reduce methane emission from ruminants. No table mitigation approaches are rumen manipulation, alteration of rumen fermentation, modification of rumen microbial biodiversity by different means and rarely by animal manipulations. However, a comprehensive exploration for a sustainable methane mitigation approach is still lacking. Dietary modification is directly linked to changes in the rumen fermentation pattern and types of end products. Studies showed that changing fermentation pattern is one of the most effective ways of methane abatement. Desirable dietary changes provide two fold benefits i.e. improve production and reduce GHG emissions. Therefore, the aim of this review is to discuss biology of methane emission from ruminants and its mitigation through dietary manipulation.

Strategic supplementation of cassava top silage to enhance rumen fermentation and milk production in lactating dairy cows in the tropics

High-quality protein roughage is an important feed for productive ruminants. This study examined the effects of strategic feeding of lactating cows with cassava (Manihot esculenta) top silage (CTS) on rumen fermentation, feed intake, milk yield, and quality. Four early lactating crossbred dairy cows (75% Holstein-Friesian and 25% Thai) with body weight (BW) 410 ± 30 kg and milk yield 12 ± 2 kg/day were randomly allotted in a 4 × 4 Latin square design to four different supplementation levels of CTS namely, 0, 0.75, 1.50, and 2.25 kg/day of dry matter (DM). Strategic supplementation of CTS significantly affected ruminal fermentation end-products, especially increased propionate production, decreased protozoal population and suppressed methane production (P < 0.05). Increasing the CTS supplementation level substantially enhanced milk yield and the 3.5% FCM from 12.7 to 14.0 kg/day and from 14.6 to 17.2 kg/day (P < 0.05) for non-supplemented group and for the 2.25 kg/day supplemented group, respectively. We conclude that high-quality protein roughage significantly enhances rumen fermentation end-products, milk yield, and quality in dairy cows.

Effects of polyphenolic extract from Eucommia ulmoides Oliver leaf on growth performance, digestibility, rumen fermentation and antioxidant status of fattening lambs

To investigate the effects of polyphenolic extract from Eucommia ulmoides Oliver leaf (PEEU) on growth performance, digestibility, rumen fermentation and antioxidant status of fattening lambs, 30 weaned male Huzhou lambs were equally divided into three treatments and fed the basal diet supplemented with 0 (CON), 5 (PEEU5) or 10 (PEEU10) g/kg PEEU. Dietary PEEU supplementation did not affect growth performance and apparent digestibility of nutrients. Compared with the CON group, lambs in the PEEU10 group had lower ammonia nitrogen concentration (p < .01) and acetic acid to propionic acid ratio (p < .05) and higher the molar proportion of propionate (p < .05) in rumen fluid. Ammonia nitrogen concentration (p < .01) and the molar proportion of propionate (p < .05) were affected by an interaction between PEEU and sampling day. Dietary PEEU supplementation at 10 g/kg increased total antioxidant capacity (p < .05), superoxide dismutase (p < .05) and glutathione peroxidase (p < .01) activities in serum and glutathione peroxidase activity (p < .05) in liver and decreased (p < .05) malondialdehyde content in serum and liver compared with the CON group. In conclusion, dietary PEEU supplementation affected rumen fermentation patterns and improved antioxidant status of fattening lambs.

Acetonic extract of Vernonia amygdalina (Del.) attenuates Cd-induced liver injury: Potential application in adjuvant heavy metal therapy

Exposure to cadmium (Cd), even at low doses, is of serious health concern because it does not undergo metabolic degradation to less toxic metabolite. Liver injury/disease, with a world-wide increasing incidence, is one of the consequences of exposure to Cd toxicity. This study aimed at determining the effects of acetonic extract of Vernonia amygdalina leaf (AEVAL) in a Wistar rat model of Cd-induced liver injury. Phytochemical screening of the extract was carried out and its oral LD₅₀ was determined to guide the choice of therapeutic doses. Thereafter, thirty male Wistar rats were recruited for this study. The experimental groups received 4 weeks oral graded doses of the extract (100, 200 and 400 mg/kg) following Cd-induced liver injury. Cd-induced liver injury (5 mg/kg i.p for 5 consecutive days) was characterized by deleterious alterations in the levels of AST, ALT, ALP, total bilirubin and hepatic total protein (p ˂ 0.05). Also, deleterious alteration of oxidative stress indicators (GSH, SOD and CAT) and lipid peroxidation index (TBARS) was observed in the liver homogenates. Histopathological examination showed evidence of degenerated hepatocytes as well as inflammation with disseminated steatosis. These conditions were significantly attenuated (p ˂ 0.05) following treatment with graded doses of the extract, with the highest dose expressing least therapeutic effects. This study concluded that AEVAL attenuated Cd-induced liver injury and is, potentially, a suitable option in adjuvant therapy for heavy metal toxicity.

Dose-response effects of sage (Salvia officinalis) and yarrow (Achillea millefolium) essential oils on rumen fermentation in vitro

This study aimed at determining the chemical composition of sage essential oil (SEO) and yarrow essential oil (YEO), and investigate in vitro their impacts on gas production kinetics, ruminal digestibility and fermentation, and rumen methanogenesis at different dosages (0, 250, 500 and 750 mg L-1 for SEO; and 0, 250, 500, 750 and 1000 mg L−1 for YEO). Alpha-pinene and 1,8 cineol were two major constituents of both SEO and YEO. Both SEO and YEO had a linear and quadratic effect on asymptotic gas production (P<0.05). The gas production rate increased linearly with SEO and curve-linearly with YEO dosages (P<0.05). In vitro degradability of dry matter and organic matter decreased only by YEO. The partitioning factor (PF) and the microbial biomass (MB) decreased and increased linearly with YEO and SEO dosages, respectively (P<0.05). Total volatile fatty acids (VFA ) were not affected by SEO, but decreased in a linear and quadratic manner with YEO dosage (P<0.05). The VFA pattern was modified in a linear and quadratic manner by both SEO and YEO (P<0.05). Ammonia concentration increased linearly only with YEO increasing doses. The methane to total gas (TG) ratio decreased quadratically only by SEO with reductions of 6.7, 13 and 4.2% at the doses of 250, 500 and 750 mg L−1, respectively. These results revealed that SEO modifies the rumen fermentation positively towards producing more MB and less methane in the dose range of 0-750 mg L−1, however, YEO adversely affected the rumen fermentation at all the tested doses.

Improving ruminal fermentation and nutrient digestibility in dairy steers by banana flower powder-pellet supplementation

The present study aimed to investigate the effect of banana flower powder pellet (BAFLOP pellet) on nutrient digestibility, rumen ecology and microorganism population. Four rumen-fistulated dairy steers of 200 ± 20 kg bodyweight were randomly assigned to receive four dietary treatments according to a 4 × 4 Latin square design. The treatments were as follows: control (T1), NaHCO3 supplementation at 20 g/kg of total dry-matter feed intake (DMI; T2), BAFLOP-pellet supplementation at 20 g/kg of DMI (T3) and BAFLOP-pellet supplementation at 40 g/kg of DMI (T4). All cattle were fed roughage–concentrate mix (30 : 70 ratio) at 25 g/kg bodyweight. Standard management protocols were employed during the experimental periods. The results showed that nutrient digestibility was increased in steers supplemented with NaHCO3 and BAFLOP pellets at 40 g/kg DMI (P < 0.05). Although ruminal temperature and blood urea nitrogen were not influenced by dietary supplementation, ruminal pH was increased (P < 0.05) in steers supplemented with NaHCO3 and BAFLOP pellets at 40 g/kg DMI. In addition, NaHCO3 supplementation increased bacterial and protozoal populations, whereas populations of fungal zoospores were similar among treatments. Supplementation with BAFLOP pellets at 40 g/kg DMI increased the bacterial count, whereas protozoal numbers were similar to those in the control group (P < 0.05). On the basis of the present findings, BAFLOP-pellet supplementation improved nutrient digestibility, ruminal pH and microbial population, without having any adverse effects on voluntary feed intake. The present study showed promising results for BAFLOP pellets (40 g/kg DMI) as a rumen dietary buffering agent, suggesting that these pellets could be used a replacement for sodium bicarbonate in ruminants fed high-concentrate diets.

Improving the antiprotozoal effect of saponins in the rumen by combination with glycosidase inhibiting iminosugars or by modification of their chemical structure

The antiprotozoal effect of saponins is transitory, as when saponins are deglycosylated to sapogenins by rumen microorganisms they become inactive. We hypothesised that the combination of saponins with glycosidase-inhibiting iminosugars might potentially increase the effectiveness of saponins over time by preventing their deglycosylation in the rumen. Alternatively, modifying the structure of the saponins by substituting the sugar moiety with other small polar residues might maintain their activity as the sugar substitute would not be enzymatically cleaved. The aim of this in vitro study was to evaluate the acute antiprotozoal effect and the stability of this effect over a 24 h incubation period using ivy saponins, a stevia extract rich in iminosugars, ivy saponins with stevia extract, and a chemically modified ivy saponin, hederagenin bis-succinate (HBS). The effects on fermentation parameters and rumen bacterial communities were also studied. Ivy saponins with stevia and HBS had a greater antiprotozoal effect than ivy saponins, and this effect was maintained after 24 h of incubation (P<0.001). The combination of ivy and stevia extracts was more effective in shifting the fermentation pattern towards higher propionate (+39%) and lower butyrate (-32%) and lower ammonia concentration (-64%) than the extracts incubated separately. HBS caused a decrease in butyrate (-45%) and an increase in propionate (+43%) molar proportions. However, the decrease in ammonia concentration (-42%) observed in the presence of HBS was less than that caused by ivy saponins, either alone or with stevia. Whereas HBS and stevia impacted on bacterial population in terms of community structure, only HBS had an effect in terms of biodiversity (P<0.05). It was concluded that ivy saponins with stevia and the modified saponin HBS had a strong antiprotozoal effect, although they differed in their effects on fermentation parameters and bacteria communities. Ivy saponins combined with an iminosugar-rich stevia extract and/or HBS should be evaluated to determine their antiprotozoal effect in vivo.

Antiprotozoal Effect of Saponins in the Rumen Can Be Enhanced by Chemical Modifications in Their Structure

The antiprotozoal effect of saponins is transitory, as when saponins are deglycosylated to the sapogenin by rumen microorganisms they become inactive. We postulated that the substitution of the sugar moiety of the saponin with small polar residues would produce sapogen-like analogs which might be resistant to degradation in the rumen as they would not be enzymatically cleaved, allowing the antiprotozoal effect to persist over time. In this study, we used an acute assay based on the ability of protozoa to break down [¹⁴C] leucine-labeled Streptococcus bovis and a longer term assay based on protozoal motility over 24 h to evaluate both the antiprotozoal effect and the stability of this effect with fifteen hederagenin bis-esters esterified with two identical groups, and five cholesterol and cholic acid based derivatives carrying one to three succinate residues. The acute antiprotozoal effect of hederagenin derivatives was more pronounced than that of cholesterol and cholic acid derivatives. Modifications in the structure of hederagenin, cholesterol, and cholic acid derivatives resulted in compounds with different biological activities in terms of acute effect and stability, although those which were highly toxic to protozoa were not always the most stable over time. Most of the hederagenin bis-esters, and in particular hederagenin bis-succinate (TSB24), hederagenin bis-betainate dichloride (TSB37) and hederagenin bis-adipate (TSB47) had a persistent effect against rumen protozoa in vitro, shifting the fermentation pattern toward higher propionate and lower butyrate. These chemically modified triterpenes could potentially be used in ruminant diets as an effective defaunation agent to, ultimately, increase nitrogen utilization, decrease methane emissions, and enhance animal production. Further trials in vivo or in long term rumen simulators are now needed to confirm the in vitro observations presented.

Manipulation of ruminal fermentation and methane production by dietary saponins and tannins from mangosteen peel and soapberry fruit

Four fistulated Holstein Friesian heifers were used in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement. The main factors were two roughage-to-concentrate ratios (R:C, 70:30 and 30:70) and two supplementation levels of soapberry fruit-mangosteen peel (SM) pellets (0 and 4% tannins-saponins of total diets). Rice straw was used as a roughage source. The diet was fed ad libitum as a total mixed ration. SM pellets contained crude tannins and saponins at 12.1 and 15.7% of DM, respectively. It was found that at R:C 30:70 the DM intake and the digestibility of DM, CP and NDF were increased (p < 0.05), while SM pellet supplementation reduced the DM digestibility (p < 0.05). Ruminal pH was decreased at R:C 30:70. Total VFA and propionate was increased at high concentrate level and after SM pellet supplementation (p < 0.05); simultaneously, the acetate concentration and the acetate-to-propionate ratios were decreased (p < 0.05). Methane production was decreased at R:C 30:70 and additionally when SM pellets were supplemented (p < 0.05). This was in agreement with the percentage of methanogens in total ruminal DNA. Furthermore, the number of fungal zoospores were reduced at a higher concentrate proportion (R:C 30:70) and by SM-pellet supplementation (p < 0.05). Protozoal populations were diminished when SM pellets were supplemented (p < 0.05). In this study, it was shown that the roughage-to-concentrate ratio, as well as the supplementation of SM pellets containing condensed tannins and saponins, caused changes in ruminal microorganisms and their fermentation end-products.

Supplementation of Flemingia macrophylla and cassava foliage as a rumen enhancer on fermentation efficiency and estimated methane production in dairy steers

Four rumen-fistulated dairy steers, 3 years old with 180 ± 15 kg body weight (BW), were randomly assigned according to a 4 × 4 Latin square design to investigate on the effect of Flemingia macrophylla hay meal (FMH) and cassava hay meal (CH) supplementation on rumen fermentation efficiency and estimated methane production. The treatments were as follows: T1 = non-supplement, T2 = CH supplementation at 150 g/head/day, T3 = FMH supplementation at 150 g/head/day, and T4 = CH + FMH supplementation at 75 and 75 g/head/day. All steers were fed rice straw ad libitum and concentrate was offered at 0.5 % of BW. Results revealed that supplementation of CH and/or FMH did not affect on feed intake (P > 0.05) while digestibility of crude protein and neutral detergent fiber were increased especially in steers receiving FMH and CH+FMH (P < 0.05). Ruminal pH, temperature, and blood urea nitrogen were similar among treatments while ammonia nitrogen was increased in all supplemented groups (P < 0.05). Furthermore, propionic acid (C3) was increased while acetic acid (C2), C2:C3 ratio, and estimated methane production were decreased by dietary treatments. Protozoa and fungi population were not affected by dietary supplement while viable bacteria count increased in steers receiving FMH. Supplementation of FMH and/or FMH+CH increased microbial crude protein and efficiency of microbial nitrogen supply. This study concluded FMH (150 g/head/day) and/or CH+FMH (75 and 75 g/head/day) supplementation could be used as a rumen enhancer for increasing nutrient digestibility, rumen fermentation efficiency, and microbial protein synthesis while decreasing estimated methane production without adverse effect on voluntary feed intake of dairy steers fed rice straw.

Level of Leucaena leucocephala silage feeding on intake, rumen fermentation, and nutrient digestibility in dairy steers

The objective of this experiment was to determine effects of Leucaena silage (LS) feeding on feed intake, nutrient digestibility, and rumen fermentation in dairy steers. Four rumen fistulated dairy steers, 167 ± 12 kg body weight (BW), were randomly assigned to receive dietary treatments according to a 4 × 4 Latin square design. Treatments were as follows: T1 = 100 % untreated rice straw (RS), T2 = 70 % RS + 30 % LS, T3 = 40 % RS + 60 % LS, and T4 = 100 % LS, respectively. All animals were fed rice straw and LS ad libitum with concentrate mixture supplemented at 0.2 % BW. The results found that dry matter intake and nutrient digestibility were the highest in dairy steers fed 60 % LS (P < 0.05). Ruminal temperature and pH were not affected by LS feeding (P > 0.05) while ruminal ammonia nitrogen and blood urea nitrogen concentration were linearly increased with increasing levels of LS feeding (P < 0.01). On the other hand, total volatile fatty acids and propionate (C3) were improved by LS feeding especially in steers fed 60 % LS (P < 0.05) whereas acetate (C2) production and C2/C3 ratio were decreased. Moreover, methane production was reduced together with increasing LS feeding level (P < 0.05). Based on this study, it could be concluded that 60 % LS feeding could enhance feed intake, digestibility, and rumen fermentation end-product while reducing methane production in dairy steers. This study suggested that LS could be used as high-quality roughage for ruminant feeding in the tropical region.