In vitro evaluation of cashew nut shell liquid as a methane-inhibiting and propionate-enhancing agent for ruminants

Recent Advances in Enteric Methane Mitigation and the Long Road to Sustainable Ruminant Production

Mitigation of methane emission, a potent greenhouse gas, is a worldwide priority to limit global warming. A substantial part of anthropogenic methane is emitted by the livestock sector, as methane is a normal product of ruminant digestion. We present the latest developments and challenges ahead of the main efficient mitigation strategies of enteric methane production in ruminants. Numerous mitigation strategies have been developed in the last decades, from dietary manipulation and breeding to targeting of methanogens, the microbes that produce methane. The most recent advances focus on specific inhibition of key enzymes involved in methanogenesis. But these inhibitors, although efficient, are not affordable and not adapted to the extensive farming systems prevalent in low- and middle-income countries. Effective global mitigation of methane emissions from livestock should be based not only on scientific progress but also on the feasibility and accessibility of mitigation strategies.

Effects of cashew nut shell extract and monensin on in vitro ruminal fermentation, methane production, and ruminal bacterial community

The objective of this study was to evaluate the effects of cashew nut shell extract (CNSE) and monensin on ruminal in vitro fermentation, CH4 production, and ruminal bacterial community structure. Treatments were as follows: control (CON, basal diet without additives); 2.5 μM monensin (MON); 0.1 mg CNSE granule/g DM (CNSE100); and 0.2 mg CNSE granule/g DM (CNSE200). Each treatment was incubated with 52 mL of buffered ruminal content and 500 mg of total mixed ration for 24 h using serum vials. The experiment was performed as a complete randomized block design with 3 runs. Run was used as a blocking factor. Each treatment had 5 replicates, in which 2 were used to determine nutrient degradability, and 3 were used to determine pH, NH3-N, volatile fatty acids, lactate, total gas, CH4 production, and bacterial community composition. Treatment responses for all data, excluding bacterial abundance, were analyzed with the GLIMMIX procedure of SAS v9.4. Treatment responses for bacterial community structure were analyzed with a PERMANOVA test run with the R package vegan. Orthogonal contrasts were used to test the effects of (1) additive inclusion (ADD: CON vs. MON, CNSE100, and CNSE200); (2) additive type (MCN: MON vs. CNSE100 and CNSE200); and (3) CNSE dose (DOS: CNSE100 vs. CNSE200). We observed that pH, acetate, and acetate:propionate ratio in the CNSE100 treatment were lower compared with CNSE200, and propionate in the CNSE100 treatment was greater compared with CNSE200. Compared with MON, CNSE treatments tended to decrease total lactate concentration. Total gas production of CON was greater by 2.63% compared with all treatments, and total CH4 production was reduced by 10.64% in both CNSE treatments compared with MON. Also, compared with MON, in vitro dry matter degradabilities in CNSE treatments were lower. No effects were observed for NH3-N or in vitro neutral detergent fiber degradability. Finally, the relative abundances of Prevotella, Treponema, and Schwartzia were lower, whereas the relative abundances of Butyrivibrio and Succinivibrio were greater in all treatments compared with CON. Overall, the inclusion of CNSE decreased CH4 production compared with MON, making CNSE a possible CH4 mitigation additive in dairy cattle diets.

Effects of monensin and cashew nut-shell extract on bacterial community composition in a dual-flow continuous culture system

The objective of this study was to evaluate the effects of including monensin and two doses of CNSE in a high producing dairy cow diet on ruminal bacterial communities. A dual-flow continuous culture system was used in a replicated 4 × 4 Latin Square design. A basal diet was formulated to meet the requirements of a cow producing 45 kg of milk per d (17% crude protein and 27% starch). There were four experimental treatments: the basal diet without any feed additive (CON), 2.5 μM monensin (MON), 100 ppm CNSE granule (CNSE100), and 200 ppm CNSE granule (CNSE200). Samples were collected from the fluid and solid effluents at 3, 6, and 9 h after feeding; a composite of all time points was made for each fermenter within their respective fractions. Bacterial community composition was analyzed by sequencing the V4 region of the 16S rRNA gene using the Illumina MiSeq platform. Treatment responses for bacterial community structure were analyzed with the PERMANOVA test run with the R Vegan package. Treatment responses for correlations were analyzed with the CORR procedure of SAS. Orthogonal contrasts were used to test the effects of (1) ADD (CON vs. MON, CNSE100, and CNSE200); (2) MCN (MON vs. CNSE100 and CNSE200); and (3) DOSE (CNSE100 vs. CNSE200). Significance was declared at P ≤ 0.05. We observed that the relative abundance of Sharpea (P < 0.01), Mailhella (P = 0.05), Ruminococcus (P = 0.03), Eubacterium (P = 0.01), and Coprococcus (P < 0.01) from the liquid fraction and the relative abundance of Ruminococcus (P = 0.03) and Catonella (P = 0.02) from the solid fraction decreased, while the relative abundance of Syntrophococcus (P = 0.02) increased in response to MON when compared to CNSE treatments. Our results demonstrate that CNSE and monensin have similar effects on the major ruminal bacterial genera, while some differences were observed in some minor genera. Overall, the tested additives would affect the ruminal fermentation in a similar pattern.

Effects of cashew nut shell extract supplementation on production, rumen fermentation, metabolism, and inflammatory biomarkers in transition dairy cows

Cashew nut shell extract (CNSE) is a byproduct of the cashew nut industry, containing bioactive compounds that alter rumen fermentation patterns. Therefore, study objectives were to evaluate the effects of CNSE (59% anacardic acid and 18% cardol) on production, rumen fermentation variables, metabolism, and inflammation in transition dairy cows. A total of 51 multiparous Holstein cows were used in a randomized design and assigned to treatment based on their previous 305-d mature equivalent milk and parity. Cows were assigned to 1 of 2 treatments 21 d before expected calving: (1) CON (control diet; n = 17) or (2) CNSE-5.0 (control diet and 5.0 g/d CNSE granule [containing 50% CNSE]; n = 34). Following parturition, 17 cows (preselected at initial treatment assignment) from the CNSE-5.0 treatment were reallocated into a third treatment group: CNSE-2.5 (control diet and 2.5 g/d CNSE granule; n = 17), resulting in 3 total treatments postpartum: (1) CON, (2) CNSE-2.5, and (3) CNSE-5.0. Prepartum rumen pH was unaltered by treatment; however, postpartum rumen pH was increased (0.31 units) in CNSE cows relative to CON. Prepartum rumen ammonia N concentration tended to be decreased (34%) in CNSE-5.0 cows compared with CON, and there tended to be a quadratic effect on postpartum ammonia N, as it was decreased in CNSE-2.5 compared with CON and CNSE-5.0. Prepartum dry matter intake (DMI) was unaffected by treatment; however, postpartum DMI was increased (8%) in CNSE cows relative to CON. No treatment differences were observed in pre- or postpartum digestibility measurements. Milk and protein yields from cows fed CNSE tended to be increased (6% and 7%, respectively) relative to CON. No treatment differences were detected for energy-corrected milk, feed efficiency, body weight, body condition score, energy balance, milk composition, milk urea nitrogen, or somatic cell count. Prepartum fecal pH decreased (0.12 units) in CNSE-5.0 cows relative to CON cows but was similar between treatments postpartum. Supplementing CNSE did not affect prepartum glucose, nonesterified fatty acids (NEFA), β-hydroxybutyrate (BHB), or insulin. However, prepartum circulating blood urea nitrogen tended to be decreased and glucagon was decreased in CNSE-5.0 cows compared with CON (9 and 20%, respectively). Additionally, CNSE supplementation decreased glucose and insulin concentrations postpartum relative to CON cows (6% and 20%, respectively). Quadratic effects were detected for postpartum circulating NEFA and BHB such that their levels were increased in CNSE-2.5 cows relative to CON and CNSE-5.0. Pre- and postpartum circulating serum amyloid A, lipopolysaccharide-binding protein, and haptoglobin were unaffected by treatment. Overall, CNSE influenced some key rumen fermentation variables, altered postabsorptive metabolism, and increased production parameters in transition dairy cows.

Effects of cashew nutshell extract and monensin on microbial fermentation in a dual-flow continuous culture

The objective of this study was to compare cashew nutshell extract (CNSE) to monensin and evaluate changes in in vitro mixed ruminal microorganism fermentation, nutrient digestibility, and microbial nitrogen outflow. Treatments were randomly assigned to 8 fermenters in a replicated 4 × 4 Latin square design with 4 experimental periods of 10 d (7 d for diet adaptation and 3 d for sample collection). Basal diets contained 43.5:56.5 forage: concentrate ratio and each fermenter was fed 106 g of DM/d divided equally between 2 feeding times. Treatments were control (CON, basal diet without additives), 2.5 μM monensin (MON), 0.1 mg CNSE granule/g DM (CNSE100), and 0.2 mg CNSE granule/g DM (CNSE200). On d 8 to10, samples were collected for pH, lactate, NH3-N, volatile fatty acids (VFA), mixed protozoa counts, organic matter (OM), and neutral detergent fiber (NDF) digestibility. Data were analyzed with the GLIMMIX procedure of SAS. Orthogonal contrasts were used to test the effects of (1) ADD (CON vs. MON, CNSE100, and CNSE200); (2) MCN (MON vs. CNSE100 and CNSE200); and (3) DOSE (CNSE100 vs. CNSE200). We observed that butyrate concentration in all treatments was lower compared with CON and the concentration for MON was lower compared with CNSE treatments. Protozoal population in all treatments was lower compared with CON. No effects were observed for pH, lactate, NH3-N, total VFA, OM, or N utilization. Within the 24-h pool, protozoal generation time, tended to be lower, while NDF digestibility tended to be greater in response to all additives. Furthermore, the microbial N flow, and the efficiency of N use tended to be lower for the monensin treatment compared with CNSE treatments. Overall, our results showed that both monensin and CNSE decreased butyrate synthesis and protozoal populations, while not affecting OM digestibility and tended to increase NDF digestibility; however, such effects are greater with monensin than CNSE nutshell.

Effects of different feeding systems on ruminal fermentation, digestibility, methane emissions, and microbiota of Hanwoo steers

This study evaluates how different feeding systems impact ruminal fermentation, methane production, and microbiota of Hanwoo steers native to Korea. In a replicated 2 × 2 crossover design over 29 days per period, eight Hanwoo steers (507.1 ± 67.4 kg) were fed twice daily using a separate feeding (SF) system comprising separate concentrate mix and forage or total mixed rations (TMR) in a 15:85 ratio. The TMR-feeding group exhibited a considerable neutral detergent fiber digestibility increase than the SF group. However, ruminal fermentation parameters and methane production did not differ between two feeding strategies. In addition, TMR-fed steers expressed elevated Prevotellaceae family, Christensenellaceae R-7 group, and an unidentified Veillonellaceae family genus abundance in their rumen, whereas SF-fed steers were rich in the Rikenellaceae RC9 gut group, Erysipelotrichaceae UCG-004, and Succinivibrio. Through linear regression modeling, positive correlations were observed between the Shannon Diversity Index and the SF group's dry matter intake and methane production. Although feeding systems do not affect methane production, they can alter ruminal microbes. These results may guide future feeding system investigations or ruminal microbiota manipulations as a methane-mitigation practice examining different feed ingredients.

Batch culture analysis to identify potent organic acids for suppressing ruminal methane production

We performed an in vitro rumen batch culture study to screen 11 commercially available organic acids for methane-suppressing ability and analyzed the rumen microbiota to determine the mode of action of the acids that showed potent methane-suppressing activity. Nine of the 11 acids showed methane-suppressing activity. Maleic anhydride, itaconate, citrate, and fumarate, which showed the highest activity, were further examined. These four acids showed methane-suppressing activity irrespective of the hay-to-concentrate ratios of the substrate. Maleic anhydride and itaconate decreased total gas and short-chain fatty acid production. Maleic anhydride and fumarate increased propionate production, while itaconate increased butyrate production. Maleic anhydride, itaconate, and citrate increased lactate production. Fumarate increased the abundance of bacteria involved in propionate production. Maleic anhydride, itaconate, and citrate increased the abundance of bacteria involved in lactate production. Thus, the results indicate that maleic anhydride, itaconate, and citrate may decrease methane in part by stimulating the acrylate pathway.

Prevotella: A Key Player in Ruminal Metabolism

Ruminants are foregut fermenters that have the remarkable ability of converting plant polymers that are indigestible to humans into assimilable comestibles like meat and milk, which are cornerstones of human nutrition. Ruminants establish a symbiotic relationship with their microbiome, and the latter is the workhorse of carbohydrate fermentation. On the other hand, during carbohydrate fermentation, synthesis of propionate sequesters H, thus reducing its availability for the ultimate production of methane (CH4) by methanogenic archaea. Biochemically, methane is the simplest alkane and represents a downturn in energetic efficiency in ruminants; environmentally, it constitutes a potent greenhouse gas that negatively affects climate change. Prevotella is a very versatile microbe capable of processing a wide range of proteins and polysaccharides, and one of its fermentation products is propionate, a trait that appears conspicuous in P. ruminicola strain 23. Since propionate, but not acetate or butyrate, constitutes an H sink, propionate-producing microbes have the potential to reduce methane production. Accordingly, numerous studies suggest that members of the genus Prevotella have the ability to divert the hydrogen flow in glycolysis away from methanogenesis and in favor of propionic acid production. Intended for a broad audience in microbiology, our review summarizes the biochemistry of carbohydrate fermentation and subsequently discusses the evidence supporting the essential role of Prevotella in lignocellulose processing and its association with reduced methane emissions. We hope this article will serve as an introduction to novice Prevotella researchers and as an update to others more conversant with the topic.

Nutritional Interventions to Reduce Methane Emissions in Ruminants

Methane is the single largest source of anthropogenic greenhouse gases produced in ruminants. As global warming is a main concern, the interest in mitigation strategies for ruminant derived methane has strongly increased over the last years. Methane is a natural by-product of anaerobic microbial (bacteria, archaea, protozoa, and fungi) fermentation of carbohydrates and, to a lesser extent, amino acids in the rumen. This gaseous compound is the most prominent hydrogen sink product synthesized in the rumen. It is formed by the archaea, the so-called methanogens, which utilize excessive ruminal hydrogen. Different nutritional strategies to reduce methane production in ruminants have been investigated such as dietary manipulations, plant extracts, lipids and lipid by-products, plant secondary metabolites, flavonoids, phenolic acid, statins, prebiotics, probiotics, etc. With the range of technical options suggested above, it is possible to develop best nutritional strategies to reduce the ill effects of livestock on global warming. These nutritional strategies seem to be the most developed means in mitigating methane from enteric fermentation in ruminants and some are ready to be applied in the field at the moment.

Harnessing plant bioactivity for enteric methane mitigation in Australia

This review provides examples of the utilisation of plant bioactivity to mitigate enteric methane (CH4) emissions from the Australian ruminant production systems. Potential plant-based mitigation strategies that reduce CH4 without major impacts on forage digestibility include the following: (i) low methanogenic tropical and temperate grass, legume and shrub forage species, which offer renewable and sustainable solutions and are easy to adopt, but may have restricted geographical distribution or relatively high costs of establishment and maintenance; (ii) plant-based agricultural by-products including grape marc, olive leaves and fruit, and distiller’s grains that can mitigate CH4 and provide relatively cheap high-nutrient supplements, while offsetting the impact of agricultural waste, but their use may be limited due to unfavourable characteristics such as high protein and water content or cost of transport; (iii) plant extracts, essential oils and pure compounds that are abundant in Australian flora and offer exciting opportunities on the basis of in vitro findings, but require verification in ruminant production systems. The greatest CH4 mitigation potential based on in vitro assays come from the Australian shrubs Eremophila species, Jasminum didymium and Lotus australis (>80% CH4 reduction), tropical forages Desmanthus leptophyllus, Hetropogon contortus and Leucaena leucocephala (~40% CH4 reduction), temperate forages Biserrula pelecinus (70–90% CH4 reduction), perennial ryegrass and white clover (~20% CH4 reduction), and plant extracts or essential oils from Melaleuca ericifolia, B. pelecinus and Leptospermum petersonii (up to 80% CH4 reduction). Further research is required to confirm effectiveness of these plant-based strategies in vivo, determine optimal doses, practical modes of delivery to livestock, analyse benefit–cost ratios and develop pathways to adoption.

Addition of ginkgo fruit to cattle feces and slurry suppresses methane production by altering the microbial community structure

The effect of ginkgo fruit addition on methane production potential of cattle feces and slurry was assessed in relation to other fermentation products and the microbial community. Holstein cattle fresh feces and slurry were left at 30°C for 0, 30, 60, 90, and 180 days with/without ginkgo fruit to monitor the effect on fermentation potential. With the addition of ginkgo fruit, methane production potential of feces was reduced on Day 30 and thereafter, and that of slurry was consistently reduced over the experimental period. As a general trend, ginkgo fruit addition resulted in decreased acetate and increased propionate in feces and acetate accumulation in slurry. With ginkgo fruit addition, MiSeq analyses indicated decreases in methanogen (in particular Methanocorpusculum), Ruminococcaceae, and Clostridiaceae populations and increases in Bacteroidaceae and Porphyromonadaceae populations, which essentially agreed with quantitative real-time polymerase chain reaction (qPCR) assay results. These data indicate that direct addition of ginkgo fruit to cattle excreta is useful for reducing methane emissions by altering the microbial community structure. The application of ginkgo fruit to lower methane emissions from cattle excreta is, therefore, useful in cases in which the excreta is left without special management for a long period of time.

Growth and morphologic response of rumen methanogenic archaea and bacteria to cashew nut shell liquid and its alkylphenol components

The growth and morphology of rumen methanogenic archaea (15 strains of 10 species in 5 genera, including 7 strains newly isolated in the present study) and bacteria (14 species in 12 genera) were investigated using unsupplemented in vitro pure cultures and cultures supplemented with cashew nut shell liquid (CNSL) and its phenolic compound components, anti-methanogenic agents for ruminant animals. Growth of most of the methanogens tested was inhibited by CNSL and alkylphenols at different concentrations ranging from 1.56 to 12.5 μg/ml. Of the alkylphenols tested, anacardic acid exhibited the most potent growth inhibition. Three gram-negative bacterial species involved in propionate production were resistant to CNSL and alkylphenols (>50 μg/ml). All the methanogens and bacteria that were sensitive to CNSL and alkylphenols exhibited altered morphology; disruption of the cell surface was notable, possibly due to surfactant activity of the tested materials. Cells division was inhibited in some organisms, with cell elongation and unclear septum formation observed. These results indicate that CNSL and alkylphenols, particularly anacardic acid, inhibit both rumen bacteria and methanogens in a selective manner, which could help mitigate rumen methane generation.

Feeding cashew nut shell liquid decreases methane production from feces by altering fecal bacterial and archaeal communities in Thai local ruminants

The effect of feeding cashew nut shell liquid (CNSL) on fecal fermentation products and microbiota was investigated in Thai native cattle and swamp buffaloes. Four of each animal were fed rice straw and concentrate diet with control pellets without CNSL for 4 weeks, followed by the same diet with pellets containing CNSL for another 4 weeks, so that CNSL was administered at a level of 4 g/100 kg body weight. Feces were collected the last 2 days in each feeding period. CNSL alkyl phenols were recovered from feces (16%-28%) in a similar proportion to those in the diet, indicating that most functional anacardic acid was not selectively removed throughout the digestive tract. In vitro production of gas from feces, particularly methane, decreased with CNSL feeding. The proportion of acetate in feces decreased with CNSL feeding, whereas that of propionate increased, without affecting total short-chain fatty acid concentration. CNSL feeding changed fecal microbial community, particularly in swamp buffaloes, which exhibited decreases in the frequencies of Treponema, unclassified Ruminococcaceae, and Methanomassiliicoccaceae. These results suggest that CNSL feeding alters not only rumen fermentation but also hindgut fermentation via modulation of the microbial community, thereby potentially attenuating methane emission from the feces of ruminant animals.

Different Non-Structural Carbohydrates/Crude Proteins (NCS/CP) Ratios in Diet Shape the Gastrointestinal Microbiota of Water Buffalo

The microbiota of the gastrointestinal tract (GIT) are crucial for host health and production efficiency in ruminants. Its microbial composition can be influenced by several endogenous and exogenous factors. In the beef and dairy industry, the possibility to manipulate gut microbiota by diet and management can have important health and economic implications. The aims of this study were to characterize the different GIT site microbiota in water buffalo and evaluate the influence of diet on GIT microbiota in this animal species. We characterized and compared the microbiota of the rumen, large intestine and feces of water buffaloes fed two different diets with different non-structural carbohydrates/crude proteins (NSC/CP) ratios. Our results indicated that Bacteroidetes, Firmicutes and Proteobacteria were the most abundant phyla in all the GIT sites, with significant differences in microbiota composition between body sites both within and between groups. This result was particularly evident in the large intestine, where beta diversity analysis displayed clear clustering of samples depending on the diet. Moreover, we found a difference in diet digestibility linked to microbiota modification at the GIT level conditioned by NSC/CP levels. Diet strongly influences GIT microbiota and can therefore modulate specific GIT microorganisms able to affect the health status and performance efficiency of adult animals.

Microbial community structure of the bovine rumen as affected by feeding cashew nut shell liquid, a methane-inhibiting and propionate-enhancing agent

The effect of cashew nut shell liquid (CNSL) feeding on bacterial and archaeal community of the bovine rumen was investigated by analyzing clone libraries targeting 16S rRNA genes, methyl-coenzyme reductase A-encoding genes (mcrA), and their respective transcripts. Rumen samples were collected from three non-lactating cows fed on a hay and concentrate diet with or without CNSL supplementation. DNA and complementary DNA (cDNA) libraries were generated for investigating rumen microbial communities. MiSeq analysis also was performed to understand more comprehensively the changes in the microbial community structures. Following CNSL supplementation, the number of operational taxonomical unit (OTU) and diversity indices of bacterial and archaeal community were decreased. Bacterial OTUs belonging to Proteobacteria, including Succinivibrio, occurred at a higher frequency with CNSL feeding, especially in cDNA libraries. The methanogenic archaeal community became dominated by Methanomicrobium. A bacterial community shift also was observed in the MiSeq data, indicating that CNSL increased the proportion of Succinivibrio and other genera known to be involved in propionate production. Methanogenic archaeal community shifts to increase Methanoplanus and to decrease Methanobrevibacter also were observed. Together, these results imply the occurrence of significant changes in rumen communities, not only for bacteria but also for methanogens, following CNSL feeding.

Network analysis and functional estimation of the microbiome reveal the effects of cashew nut shell liquid feeding on methanogen behaviour in the rumen

The effects of cashew nut shell liquid (CNSL) feeding on the methane (CH4 ) emission and the ruminal microbiome of Lai Sind beef cattle were investigated. Changes in the methane production and rumen microbiome by CNSL feeding were monitored by a respiration chamber and 16S rRNA gene amplicon sequencing respectively. The results demonstrated that CNSL feeding mitigated 20.2%-23.4% of the CH4 emission in vivo without apparent adverse effects on feed intake and feed digestibility. The rumen fluid analysis revealed a significant increase in the proportion of propionate in the total short-chain fatty acids. The relative abundance of methanogen (order Methanobacteriales) decreased significantly, indicating the direct inhibitory effect of CNSL on methanogens. The predicted function of the rumen microbiome indicated that carbohydrate and lipid metabolisms including propionate production were upregulated by CNSL feeding, whereas CH4 metabolism was downregulated. A network analysis revealed that methanogen changed its partner bacteria after CNSL feeding. The δ13 C of CH4 ranged from -74.2‰ to -66.6‰ with significant fluctuation by CNSL feeding, in agreement with the shift of the rumen microbiome. Our findings demonstrate that CNSL feeding can mitigate the CH4 emission from local cattle production systems in South-East Asia by modifying the rumen microbiome and its function.

The bio-surfactant mannosylerythritol lipid acts as a selective antibacterial agent to modulate rumen fermentation

Methyl-mannosylerythritol lipid (MEL), a new sugar esterified lipid synthesized by Pseudozyma aphidis, was assessed for its functionality in modulating rumen fermentation and microbiota toward more propionate and less methane production. A pure culture study using rumen representatives showed that MEL selectively inhibited the growth of most Gram-positive bacteria including Streptococcus bovis, ruminococci, and Fibrobacter succinogenes, but not Gram-negative bacteria such as Megasphaera elsdenii, Succinivibrio dextrinosolvens, and Selenomonas ruminantium. A batch culture study revealed that MEL significantly decreased methane production in a dose-dependent manner with accumulation of hydrogen, while propionate production was enhanced. A continuous culture (Rusitec) study confirmed all of these changes. A feeding study revealed that sheep fed a MEL diet showed an increased proportion of propionate, while proportions of acetate and butyrate were decreased without affecting total VFA level. These changes disappeared after cessation of MEL feeding. Based on these results, dietary application of MEL can favorably modify rumen fermentation in terms of the efficiency of dietary energy utilization.

Antioxidant, Antimicrobial, and Anticancer Effects of Anacardium Plants: An Ethnopharmacological Perspective

Anacardium plants have received increasing recognition due to its nutritional and biological properties. A number of secondary metabolites are present in its leaves, fruits, and other parts of the plant. Among the diverse Anacardium plants' bioactive effects, their antioxidant, antimicrobial, and anticancer activities comprise those that have gained more attention. Thus, the present article aims to review the Anacardium plants' biological effects. A special emphasis is also given to their pharmacological and clinical efficacy, which may trigger further studies on their therapeutic properties with clinical trials.

The Applications of Origanum Vulgare and Its Derivatives in Human, Ruminant and Fish Nutrition – A Review

Origanum vulgare L. is an aromatic enduring herb that belongs to Lamiaceae family. The bioactive constituents of this herb, such as carvacrol and thymol possess several medicinal properties, such as antioxidant, antidiabetic, anti-inflammatory, antimicrobial, antiviral, antiparasitic, anti-neoplastic, and immune modulatory. Moreover, it is considered a standard natural, less toxic, and residue free feed additive, that is successfully used in livestock and fish. Additionally, in human, Origanum vulgare is extensively used with promising health benefits against respiratory, digestive and urinary disorders. This review casts light on description, chemical composition and structure of Origanum vulgare, as well as its therapeutic applications in human and its biological activities in ruminants and fish, data that will be possibly useful for physiologists, nutritionists and veterinarians.

Inclusion of a blend of copaiba, cashew nut shell and castor oil in the protein-energy supplement for grazing beef cattle improves rumen fermentation, nutrient intake and fibre digestibility

Context Essential oils are secondary plant compounds extracted from plants, with potential for the modulation of rumen fermentation. Aims Two experiments, namely one in vivo and another in vitro, were conducted to analyse the effects of a commercial blend of essential oils (EO; copaiba (Copaifera langsdorffii), cashew nut shell (Anacardium occidentale) and castor oil (Ricinus communis) and monensin as dietary feed additives in protein–energy supplements (PES) provided to grazing beef cattle, on ruminal fermentation, intake, total nutrient digestibility and protein dietary efficiency. Methods In the in vivo experiment, four entire Nellore bulls cannulated in the rumen (374 ± 15.66 kg; mean ± s.d.) were used in a 4 × 4 Latin-square design to evaluate the effects of EO concentration and monensin on voluntary intake, digestibility, and rumen and metabolic characteristics of grazing beef cattle provided with supplementation during the rainy season. Treatments were as follows: control (CON; PES without additives); monensin (MON; PES with inclusion of monensin at 20 mg/kg DM consumed); EO150 (PES with inclusion of EO at 150 mg/kg DM consumed); EO300 (PES with inclusion of EO at 300 mg/kg DM consumed). In the in vitro experiment, the effects EO150, EO300 and EO450, MON and CON on DM and neutral detergent-fibre (NDF) digestibility, and total gas production, were evaluated in four consecutive runs using a gas-production (GP) system. Key results In the in vivo experiment, DM intake, forage DM intake, crude protein intake and NDF intake were similar (P &gt; 0.05) between EO150 and MON, but both were greater than those in EO300 and CON (P &lt; 0.05). A lower EO concentration (EO150) increased (P &lt; 0.05) NDF digestibility and improved nitrogen utilisation efficiency. In the in vitro experiment, the addition of MON and EO150 did not modify (P &gt; 0.05) GP, DM and NDF digestibility compared with the control, but EO300 and EO450 decreased GP at 12 and 24 h and decreased DM and NDF digestibility at 48 h compared with the control, MON and EO150. Conclusions In vivo and in vitro results suggested that EO (copaiba oil, cashew nut shell and castor) at low doses (150 mg/kg DM) has the potential to improve ruminal fermentation in grazing beef cattle receiving supplements, but medium and high doses of EO can have adverse effects. Implications EO blends could be an alternative to MON for grazing beef cattle with access to supplements.

Selection of plant oil as a supplemental energy source by monitoring rumen profiles and its dietary application in Thai crossbred beef cattle

Objective

The present study was conducted to select a plant oil without inhibitory effects on rumen fermentation and microbes, and to determine the optimal supplementation level of the selected oil in a series of in vitro studies for dietary application. Then, the selected oil was evaluated in a feeding study using Thai crossbred beef cattle by monitoring growth, carcass, blood and rumen characteristics.

Methods

Rumen fluid was incubated with substrates containing one of three different types of plant oil (coconut oil, palm oil and soybean oil) widely available in Thailand. The effects of each oil on rumen fermentation and microbes were monitored and the oil without a negative influence on rumen parameters was selected. Then, the dose-response of rumen parameters to various levels of the selected palm oil was monitored to determine a suitable supplementation level. Finally, an 8-month feeding experiment with the diet supplemented with palm oil was carried out using 12 Thai crossbred beef cattle to monitor growth, carcass, rumen and blood profiles.

Results

Batch culture studies revealed that coconut and soybean oils inhibited the most potent rumen cellulolytic bacterium Fibrobacter succinogenes, while palm oil had no such negative effect on this and on rumen fermentation products at 5% or higher supplementation level. Cattle fed the diet supplemented with 2.5% palm oil showed improved feed conversion ratio (FCR) without any adverse effects on rumen fermentation. Palm oil-supplemented diet increased blood cholesterol levels, suggesting a higher energy status of the experimental cattle.

Conclusion

Palm oil had no negative effects on rumen fermentation and microbes when supplemented at levels up to 5% in vitro. Thai crossbred cattle fed the palm oil-supplemented diet showed improved FCR without apparent changes of rumen and carcass characteristics, but with elevated blood cholesterol levels. Therefore, palm oil can be used as a beneficial energy source.

In vitro evaluation of the association of chitosan and cashew nut shell liquid as additives for ruminants

ABSTRACT This study evaluated the in vitro digestibility of nutrients from different diets added with chitosan (Q), technic cashew nut shell liquid (LCC) and the association of Q and LCC. The treatments used consisted of 4 diets (forage: concentrate ratio of 100: 0, 50:50, 40:60 and 20:80) associated with 4 additives (control, chitosan, LCC and the association of Q + LCC), totaling 16 treatments, in a 4x4 factorial randomized block design. The dosages used were: Control (without additives), LCC (600mg/kg DM), Chitosan (900mg/kg DM), and LCCQ (600mg/kg LCC DM + 900mg/kg Chitosan DM). In the laboratory, samples were analyzed for IVDMD, IVNDFD, IVCPD, pH and RAN (ruminal ammonia nitrogen). For pH and RAN analyses, samples were taken at 0, 2, 4, 6 and 8 hours after incubation. The results showed higher digestibility of DM, NDF and CP for diets with chitosan and technic cashew nut shell liquid alone and higher pH and RAN values in the diets containing the two additives. The association of additives brings better results for animal nutrition and increases ruminant productivity.

Molecular evaluation of anti-inflammatory activity of phenolic lipid extracted from cashew nut shell liquid (CNSL)

BACKGROUND

Anacardium occidentale L phenolic lipid (LDT11) is used in traditional medicine as anti-inflammatory, astringent, antidiarrheal, anti-asthmatic and depurative. Phenolic derivatives, such as anacardic acid, extracted from cashew nut shell liquid (CNSL) have demonstrated biological and pharmacological properties, and its profile makes it a candidate for the development of new anti-inflammatory agents. The objective of the present study was to evaluate the anti-inflammatory profile of a derivative, synthesized from LDT11, on an in vitro cellular model.

METHODS

Organic synthesis of the phenolic derivative of CNSL that results in the hemi-synthetic compound LDT11. The cytotoxicity of the planned compound, LDT11, was analyzed in murine macrophages cell line, RAW264.7. The cells were previously treated with LDT11, and then, the inflammation was stimulated with lipopolysaccharide (LPS), in intervals of 6 h and 24 h. The analysis of the gene expression of inflammatory markers (TNFα, iNOS, COX-2, NF-κB, IL-1β and IL-6), nitric oxide (NO) dosage, and cytokine IL-6 were realized.

RESULTS

The results showed that the phenolic derivative, LDT11, influenced the modulatory gene expression. The relative gene transcripts quantification demonstrated that the LDT11 disclosed an immunoprotective effect against inflammation by decreasing genes expression when compared with cells stimulated with LPS in the control group. The NO and IL-6 dosages confirmed the results found in gene expression.

DISCUSSION

The present study evaluated the immunoprotective effect of LDT11. In addition to a significant reduction in the expression of inflammatory genes, LDT11 also had a faster and superior anti-inflammatory action than the commercial products, and its response was already evident in the test carried out six hours after the treatment of the cells.

CONCLUSION

This study demonstrated LDT11 is potentially valuable as a rapid immunoprotective anti-inflammatory agent. Treatment with LDT11 decreased the gene expression of inflammatory markers, and the NO, and IL-6 production. When compared to commercial drugs, LDT11 showed a superior anti-inflammatory action.

Does intra-ruminal nitrogen recycling waste valuable resources? A review of major players and their manipulation

Nitrogenous emissions from ruminant livestock production are of increasing public concern and, together with methane, contribute to environmental pollution. The main cause of nitrogen-(N)-containing emissions is the inadequate provision of N to ruminants, leading to an excess of ammonia in the rumen, which is subsequently excreted. Depending on the size and molecular structure, various bacterial, protozoal and fungal species are involved in the ruminal breakdown of nitrogenous compounds (NC). Decelerating ruminal NC degradation by controlling the abundance and activity of proteolytic and deaminating microorganisms, but without reducing cellulolytic processes, is a promising strategy to decrease N emissions along with increasing N utilization by ruminants. Different dietary options, including among others the treatment of feedstuffs with heat or the application of diverse feed additives, as well as vaccination against rumen microorganisms or their enzymes have been evaluated. Thereby, reduced productions of microbial metabolites, e.g. ammonia, and increased microbial N flows give evidence for an improved N retention. However, linkage between these findings and alterations in the rumen microbiota composition, particularly NC-degrading microbes, remains sparse and contradictory findings confound the exact evaluation of these manipulating strategies, thus emphasizing the need for comprehensive research. The demand for increased sustainability in ruminant livestock production requests to apply attention to microbial N utilization efficiency and this will require a better understanding of underlying metabolic processes as well as composition and interactions of ruminal NC-degrading microorganisms.

Potency of cashew nut shell liquid in rumen modulation under different dietary conditions and indication of its surfactant action against rumen bacteria

Background

Cashew nut shell liquid (CNSL) is an agricultural byproduct containing alkylphenols that has been shown to favorably change the rumen fermentation pattern only under experimentally fixed feeding conditions. Investigation of CNSL potency in rumen modulation under a variety of feeding regimens, and evidence leading to the understanding of CNSL action are obviously necessary for further CNSL applications. The objective of this study was to evaluate the potency of CNSL for rumen modulation under different dietary conditions, and to visually demonstrate its surfactant action against selected rumen bacteria.

Methods

Batch culture studies were carried out using various diets with 5 different forage to concentrate (F:C) ratios (9:1, 7:3, 5:5. 3:7 and 1:9). Strained rumen fluid was diluted with a buffer and incubated with each diet. Gas and short chain fatty acid (SCFA) profiles were characterized after 18 h incubation at 39 °C. Monensin was also evaluated as a reference additive under the same conditions. Four species of rumen bacteria were grown in pure culture and exposed to CNSL to determine their morphological sensitivity to the surfactant action of CNSL.

Results

CNSL supplementation decreased total gas production in diets with 5:5 and 3:7 F:C ratios, whereas the F:C ratio alone did not affect any gas production. Methane decrease by CNSL addition was more apparent in diets with 5:5, 3:7, and 1:9 F:C ratios. An interactive effect of CNSL and the F:C ratio was also observed for methane production. CNSL supplementation enhanced propionate production, while total SCFA production was not affected. Monensin decreased methane production but only in a diet with a 1:9 F:C ratio with increased propionate. Studies of pure cultures indicated that CNSL damaged the cell surface of hydrogen- and formate-producing bacteria, but did not change that of propionate-producing bacteria.

Conclusion

CNSL can selectively inhibit rumen bacteria through its surfactant action to lead fermentation toward less methane and more propionate production. As CNSL is effective over a wider range of dietary conditions for such modulation of rumen fermentation in comparison with monensin, this new additive candidate might be applied to ruminant animals for various production purposes and at various stages.

Ginkgo fruit extract as an additive to modify rumen microbiota and fermentation and to mitigate methane production

Ginkgo fruit, an unused byproduct of the ginkgo nut industry, contains antimicrobial compounds known as anacardic acids. Two major cultivars of ginkgo, Kyuju (K) and Tokuro (T), were evaluated for their potential as a feed additive for ruminants. In batch culture, we incubated a mixture of hay and concentrate in diluted rumen fluid with or without 1.6% (fruit equivalent) ginkgo fruit extract. We conducted another series of batch culture studies to determine the dose response of fermentation. We also conducted continuous culture using the rumen simulation technique (RUSITEC) with cultivar K and carried out a pure culture study to monitor the sensitivity of 17 representative rumen bacterial species to ginkgo extract and component phenolics. Although both K and T extracts led to decreased methane and increased propionate production, changes were more apparent with K extract, and were dose-dependent. Total gas production was depressed at doses ≥3.2%, suggesting that 1.6% was the optimal supplementation level. In RUSITEC fermentation supplemented with 1.6% ginkgo K, methane decreased by 53% without affecting total gas or total VFA production, but with decreased acetate and increased propionate. Disappearance of dry matter, neutral detergent fiber, and acid detergent fiber were not affected by ginkgo, but ammonia levels were decreased. Quantitative PCR indicated that the abundance of protozoa, fungi, methanogens, and bacteria related to hydrogen and formate production decreased, but the abundance of bacteria related to propionate production increased. MiSeq analysis (Illumina Inc., San Diego, CA) confirmed these bacterial changes and identified archaeal community changes, including a decrease in Methanobrevibacter and Methanomassiliicoccaceae and an increase in Methanoplanus. Pure culture study results supported the findings for the above bacterial community changes. These results demonstrate that ginkgo fruit can modulate rumen fermentation toward methane mitigation and propionate enhancement via microbial selection.

Use of Asian selected agricultural byproducts to modulate rumen microbes and fermentation

In the last five decades, attempts have been made to improve rumen fermentation and host animal nutrition through modulation of rumen microbiota. The goals have been decreasing methane production, partially inhibiting protein degradation to avoid excess release of ammonia, and activation of fiber digestion. The main approach has been the use of dietary supplements. Since growth-promoting antibiotics were banned in European countries in 2006, safer alternatives including plant-derived materials have been explored. Plant oils, their component fatty acids, plant secondary metabolites and other compounds have been studied, and many originate or are abundantly available in Asia as agricultural byproducts. In this review, the potency of selected byproducts in inhibition of methane production and protein degradation, and in stimulation of fiber degradation was described in relation to their modes of action. In particular, cashew and ginkgo byproducts containing alkylphenols to mitigate methane emission and bean husks as a source of functional fiber to boost the number of fiber-degrading bacteria were highlighted. Other byproducts influencing rumen microbiota and fermentation profile were also described. Future application of these feed and additive candidates is very dependent on a sufficient, cost-effective supply and optimal usage in feeding practice.

Limits to Dihydrogen Incorporation into Electron Sinks Alternative to Methanogenesis in Ruminal Fermentation

Research is being conducted with the objective of decreasing methane (CH4) production in the rumen, as methane emissions from ruminants are environmentally damaging and a loss of digestible energy to ruminants. Inhibiting ruminal methanogenesis generally results in accumulation of dihydrogen (H2), which is energetically inefficient and can inhibit fermentation. It would be nutritionally beneficial to incorporate accumulated H2 into propionate or butyrate production, or reductive acetogenesis. The objective of this analysis was to examine three possible physicochemical limitations to the incorporation of accumulated H2 into propionate and butyrate production, and reductive acetogenesis, in methanogenesis-inhibited ruminal batch and continuous cultures: (i) Thermodynamics; (ii) Enzyme kinetics; (iii) Substrate kinetics. Batch (N = 109) and continuous (N = 43) culture databases of experiments with at least 50% inhibition in CH4 production were used in this meta-analysis. Incorporation of accumulated H2 into propionate production and reductive acetogenesis seemed to be thermodynamically feasible but quite close to equilibrium, whereas this was less clear for butyrate. With regard to enzyme kinetics, it was speculated that hydrogenases of ruminal microorganisms may have evolved toward high-affinity and low maximal velocity to compete for traces of H2, rather than for high pressure accumulated H2. Responses so far obtained to the addition of propionate production intermediates do not allow distinguishing between thermodynamic and substrate kinetics control.

Effect of monensin withdrawal on rumen fermentation, methanogenesis and microbial populations in cattle

This study was designed to obtain information on the residual influence of dietary monensin on ruminant fermentation, methanogenesis and bacterial population. Three ruminally cannulated crossbreed heifers (14 months old, 363 ± 11 kg) were fed Italian ryegrass straw and concentrate supplemented with monensin for 21 days before sampling. Rumen fluid samples were collected for analysis of short chain fatty acid (SCFA) profiles, monensin concentration, methanogens and rumen bacterial density. Post-feeding rumen fluid was also collected to determine in vitro gas production. Monensin was eliminated from the rumen fluid within 3 days. The composition of SCFA varied after elimination of monensin, while total production of SCFA was 1.78 times higher than on the first day. Methane production increased 7 days after monensin administration ceased, whereas hydrogen production decreased. The methanogens and rumen bacterial copy numbers were unaffected by the withdrawal of monensin.

Effects on enteric methane production and bacterial and archaeal communities by the addition of cashew nut shell extract or glycerol-an in vitro evaluation

The objective of the study was to evaluate the effect of cashew nut shell extract (CNSE) and glycerol (purity >99%) on enteric methane (CH4) production and microbial communities in an automated gas in vitro system. Microbial communities from the in vitro system were compared with samples from the donor cows, in vivo. Inoculated rumen fluid was mixed with a diet with a 60:40 forage:concentrate ratio and, in total, 5 different treatments were set up: 5mg of CNSE (CNSE-L), 10mg of CNSE (CNSE-H), 15mmol of glycerol/L (glycerol-L), and 30mmol of glycerol/L (glycerol-H), and a control without feed additive. Gas samples were taken at 2, 4, 8, 24, 32, and 48h of incubation, and the CH4 concentration was measured. Samples of rumen fluid were taken for volatile fatty acid analysis and for microbial sequence analyses after 8, 24, and 48h of incubation. In vivo rumen samples from the cows were taken 2h after the morning feeding at 3 consecutive days to compare the in vitro system with in vivo conditions. The gas data and data from microbial sequence analysis (454 sequencing) were analyzed using a mixed model and principal components analysis. These analyses illustrated that CH4 production was reduced with the CNSE treatment, by 8 and 18%, respectively, for the L and H concentration. Glycerol instead increased CH4 production by 8 and 12%, respectively, for the L and H concentration. The inhibition with CNSE could be due to the observed shift in bacterial population, possibly resulting in decreased production of hydrogen or formate, the methanogenic substrates. Alternatively the response could be explained by a shift in the methanogenic community. In the glycerol treatments, no main differences in bacterial or archaeal population were detected compared with the in vivo control. Thus, the increase in CH4 production may be explained by the increase in substrate in the in vitro system. The reduced CH4 production in vitro with CNSE suggests that CNSE can be a promising inhibitor of CH4 formation in the rumen of dairy cows.

Encapsulated nitrate and cashew nut shell liquid on blood and rumen constituents, methane emission, and growth performance of lambs

Nitrate can be a source of NPN for microbial growth at the same time that it reduces ruminal methane production. The objective of this study was to evaluate the effects of 2 encapsulated nitrate products used as urea replacers on blood and rumen constituents, methane emission, and growth performance of lambs. Eighteen Santa Inês male lambs (27 ± 4.9 kg) were individually allotted to indoor pens and assigned to a randomized complete block design with 6 blocks and 3 dietary treatments: control (CTL) = 1.5% urea, ENP = 4.51% encapsulated nitrate product (60.83% NO3(-) in the product DM), and ENP+CNSL = 4.51% ENP containing cashew nut shell liquid (60.83% NO3(-) and 2.96% cashew nut shell liquid [CNSL] in the product DM). Diets were isonitrogenous with 60:40 concentrate:forage (Tifton 85 hay) ratio. The experiment lasted for 92 d and consisted of 28 d for adaptation (a weekly 33% stepwise replacement of CTL concentrate by nitrate-containing concentrates) and 64 d for data collection. The ENP and ENP+CNSL showed greater (P < 0.05) red blood cell counts than CTL. Blood methemoglobin (MetHb) did not differ (P > 0.05) among treatments, with mean values within normal range and remaining below 1.1% of total hemoglobin. There was an increase (P < 0.05) in total short-chain fatty acids concentration at 3 h postfeeding for ENP, with an additional increase (P < 0.05) observed for ENP+CNSL. No treatment effects (P > 0.05) were observed on acetate to propionate ratio. Methane production (L/kg DMI) was reduced (P < 0.05) with nitrate inclusion, recording 28.6, 19.1, and 19.5 L/kg DMI for CTL, ENP, and ENP+CNSL, respectively. Addition of CNSL did not result (P > 0.05) in further reduction of methane production when compared with ENP. Final BW, DMI, ADG, and feed efficiency were similar (P > 0.05) among treatments. Values for DMI were 1.11, 1.03, and 1.04 kg/d and for ADG were 174, 154, and 158 g for CTL, ENP, and ENP+CNSL, respectively. In conclusion, encapsulated nitrate products showed no risks of toxicity based on MetHb formation. The products persistently reduced methane production without affecting performance. Inclusion of cashew nut shell liquid in the product formulation had no additional benefits on methane mitigation.