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The Rumen Protozoa

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Abstract

In addition to the bacteria in the rumen there are many larger (5–250/mm long) organisms which at various times have been designated protozoa. Of these the ‘ovals’ (Quin’s and Eadie’s) are now known to be large bacteria (Orpin, 1976) and the ‘flagellates’ Neocallimastix frontalis, Piromonas communis and Sphaeromonas communis are the zoospores of phycomycete fungi (Orpin, 1977a, b). There are genuine flagellates in the rumen, e.g. Trichomonas spp., Monoceromonas sp. and Chilomastix sp., but almost nothing is known about their metabolism (Jensen and Hammon, 1964). The largest, most obvious and most important protozoa are the ciliates, of which there are two groups both in the subclass Trichostomatia. The so called ‘holotrich’ protozoa belong to the order Vestibuliferida and the entodiniomorphs to the order Entodiniomorphida, suborder Entodiniomorphina and family Ophryoscolecidae. As the properties and metabolism of these two protozoal groups are different, they will be considered separately below.

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... The family Ophryoscolecidae (Ciliophora, Entodiniomorphida) constitutes a diverse and monophyletic group of symbiotic ciliates of herbivorous mammals, essentially found associated to ruminants and pseudoruminants hosts (Cedrola et al. 2020;Firkins et al. 2020). Until now, the family includes approximately 200 species, distributed in three subfamilies (Entodininae, Diplodiniinae, and Ophryoscolecinae), and sixteen genera (Entodinium, Diplodinium, Diploplastron, Eodinium, Elytroplastron, Enoploplastron, Eremoplastron, Eudiplodinium, Metadinium, Ostracodinium, Polyplastron, Caloscolex, Epidinium, Epiplastron, Opistotrichum, and Ophryoscolex) (Williams & Coleman 1992), classified according to body and macronuclear shapes, and number and shape of skeletal plates (Williams & Coleman 1992). ...
... The family Ophryoscolecidae (Ciliophora, Entodiniomorphida) constitutes a diverse and monophyletic group of symbiotic ciliates of herbivorous mammals, essentially found associated to ruminants and pseudoruminants hosts (Cedrola et al. 2020;Firkins et al. 2020). Until now, the family includes approximately 200 species, distributed in three subfamilies (Entodininae, Diplodiniinae, and Ophryoscolecinae), and sixteen genera (Entodinium, Diplodinium, Diploplastron, Eodinium, Elytroplastron, Enoploplastron, Eremoplastron, Eudiplodinium, Metadinium, Ostracodinium, Polyplastron, Caloscolex, Epidinium, Epiplastron, Opistotrichum, and Ophryoscolex) (Williams & Coleman 1992), classified according to body and macronuclear shapes, and number and shape of skeletal plates (Williams & Coleman 1992). ...
... The subfamily Diplodiniinae is the most diverse group in the family Ophryoscolecidae and comprises the genus Ostracodinium, described by Dogiel (1927) to include species with two retractable ciliary zones in the anterior body portion, a broad skeletal plate covering almost all the right surface of the body and a variable number of contractile vacuoles (Dogiel 1927;Kofoid & MacLennan 1932;Williams & Coleman 1992). The genus currently comprises 28 species, classified according to body size and shape, position and shape of the nuclear apparatus, number and position of contractile vacuoles, and number and shape of caudal projections (Ito et al. 2001). ...
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The family Ophryoscolecidae (Ciliophora, Entodiniomorphida) constitutes a diverse and monophyletic group of symbiotic ciliates of herbivorous mammals. The family includes approximately 200 species, distributed in three subfamilies and sixteen genera. The subfamily Diplodiniinae is the most diverse group in Ophryoscolecidae and comprises the genus Ostracodinium, which includes species with two retractable ciliary zones in the anterior body portion, a broad skeletal plate covering almost all the right surface of the body and a variable number of contractile vacuoles. The genus currently comprises 28 species, classified according to body size and shape, position and shape of the nuclear apparatus, number and position of contractile vacuoles, and number and shape of caudal projections. The present study performs a systematic review of the genus Ostracodinium, based on morphological and molecular data, and provides data about geographic distribution and hosts of each species.
... However, even though protozoa can contribute up to 50% of the biomass in the rumen, the role of protozoa in the rumen microbial ecosystem remains unclear . Most protozoa in the rumen are ciliates, with a few flagellate species; ruminants commonly harbour distinct protozoal populations from birth and typically, this does not change through life (Williams and Coleman, 1992). Protozoal identification and taxonomy have usually relied on morphologic identification by optical microscopy . ...
... Despite repeated attempts, it has proven impossible to maintain rumen protozoa in axenic culture . Thus, most studies have concentrated on describing the activity of mixed bacterial and protozoal co-cultures, maintained either in in vitro or in in vivo (Williams and Coleman, 1992). Thus, while much progress has been made in describing the role of protozoa in the rumen (Williams and Coleman, 1992), it has been difficult to establish conclusively that activity is due to protozoa as opposed to associated bacteria. ...
... Thus, most studies have concentrated on describing the activity of mixed bacterial and protozoal co-cultures, maintained either in in vitro or in in vivo (Williams and Coleman, 1992). Thus, while much progress has been made in describing the role of protozoa in the rumen (Williams and Coleman, 1992), it has been difficult to establish conclusively that activity is due to protozoa as opposed to associated bacteria. Techniques to clone and express ciliate genes in phages have allowed genes from a range of rumen protozoa to be characterized (McEwan et al., 1999;Newbold et al., 2005;Belzecki et al., 2007). ...
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The rumen contains a great diversity of prokaryotic and eukaryotic microorganisms that allow the ruminant to utilize ligno-cellulose material and to convert non-protein nitrogen into microbial protein to obtain energy and amino acids. However, rumen fermentation also has potential deleterious consequences associated with the emissions of greenhouse gases, excessive nitrogen excreted in manure and may also adversely influence the nutritional value of ruminant products. While several strategies for optimizing the energy and nitrogen use by ruminants have been suggested, a better understanding of the key microorganisms involved and their activities is essential to manipulate rumen processes successfully. Diet is the most obvious factor influencing the rumen microbiome and fermentation. Among dietary interventions, the ban of antimicrobial growth promoters in animal production systems has led to an increasing interest in the use of plant extracts to manipulate the rumen. Plant extracts (e.g. saponins, polyphenol compounds, essential oils) have shown potential to decrease methane emissions and improve the efficiency of nitrogen utilization; however, there are limitations such as inconsistency, transient and adverse effects for their use as feed additives for ruminants. It has been proved that the host animal may also influence the rumen microbial population both as a heritable trait and through the effect of early-life nutrition on microbial population structure and function in adult ruminants. Recent developments have allowed phylogenetic information to be upscaled to metabolic information; however, research effort on cultivation of microorganisms for an in-depth study and characterization is needed. The introduction and integration of metagenomic, transcriptomic, proteomic and metabolomic techniques is offering the greatest potential of reaching a truly systems-level understanding of the rumen; studies have been focused on the prokaryotic population and a broader approach needs to be considered.
... Two transcripts were predicted to be involved in conjugation (GO:0000742 karyogamy involved in conjugation with cellular fusion). The dearth of transcripts annotated to conjugation is consistent with binary division being observed as the primary method of reproduction in E. caudatum [32]. ...
... Chitin degradation by protozoa, but not specifically E. caudatum, has indeed been reported [52][53][54]. Engulfment of fungal zoospores by Entodinium sp. has also been observed by scanning electron microscopy [32]. From a nitrogen utilization perspective, lysozyme can be inhibited to decrease the wasteful degradation of microbial proteins to improve nitrogen utilization efficiency in and decrease nitrogen excretion from ruminant livestock. ...
... It can be difficult, however, to distinguish the extracellular peptidases secreted from those discharged via the feed digestive vacuoles. Consistent with the rapid degradation and availability of free amino acids derived from microbial protein degradation, only a few transcripts were annotated to de novo synthesis of amino acids, which explains their dependence on bacterial protein as their main protein source [32]. However, small entodinia are often considered the most bacterivorous [3], and the dependence on preformed amino acids may explain the difficulty to grow E. caudatum in axenic cultures [9]. ...
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Background: Rumen ciliates play important roles in rumen function by digesting and fermenting feed and shaping the rumen microbiome. However, they remain poorly understood due to the lack of definitive direct evidence without influence by prokaryotes (including symbionts) in co-cultures or the rumen. In this study, we used RNA-Seq to characterize the transcriptome of Entodinium caudatum, the most predominant and representative rumen ciliate species. Results: Of a large number of transcripts, > 12,000 were annotated to the curated genes in the NR, UniProt, and GO databases. Numerous CAZymes (including lysozyme and chitinase) and peptidases were represented in the transcriptome. This study revealed the ability of E. caudatum to depolymerize starch, hemicellulose, pectin, and the polysaccharides of the bacterial and fungal cell wall, and to degrade proteins. Many signaling pathways, including the ones that have been shown to function in E. caudatum, were represented by many transcripts. The transcriptome also revealed the expression of the genes involved in symbiosis, detoxification of reactive oxygen species, and the electron-transport chain. Overall, the transcriptomic evidence is consistent with some of the previous premises about E. caudatum. However, the identification of specific genes, such as those encoding lysozyme, peptidases, and other enzymes unique to rumen ciliates might be targeted to develop specific and effective inhibitors to improve nitrogen utilization efficiency by controlling the activity and growth of rumen ciliates. The transcriptomic data will also help the assembly and annotation in future genomic sequencing of E. caudatum. Conclusion: As the first transcriptome of a single species of rumen ciliates ever sequenced, it provides direct evidence for the substrate spectrum, fermentation pathways, ability to respond to various biotic and abiotic stimuli, and other physiological and ecological features of E. caudatum. The presence and expression of the genes involved in the lysis and degradation of microbial cells highlight the dependence of E. caudatum on engulfment of other rumen microbes for its survival and growth. These genes may be explored in future research to develop targeted control of Entodinium species in the rumen. The transcriptome can also facilitate future genomic studies of E. caudatum and other related rumen ciliates.
... Any imbalance may lead to digestive disorders, the protozoa elimination can increase microbial protein supply and reduces methane production (Guyader et al., 2014), protozoa's population was identified and well-studied in many cattle breeds around the world (Agarwal et al., 2015), since they were first discovered by Gruby and Delafond (1843), studies on rumen protozoa have relied on morphologic identification by optical microscopy. There are currently no cultures collections of rumen ciliates, so researchers have to use photomicrographs for identification (Williams & Coleman, 1997) or line drawings (Dehority, 2017). No study has been yet published about Algerian local bovine rumen protozoa. ...
... Rumen fluid was collected from 20 cows fed on extensive pastures of Alfalfa spp, and barley crop residues, in addition of low diary quantity of cereals (IFB 249). The daily rumen pH values were about 6.45 in studied animals, these values were higher than those reported by Williams & Coleman, (1997). So, the extension of rumen pH over the 24 hour is probably the most relevant factor in the survival of ciliate protozoa in the rumen. ...
... Researchers demonstrated hemicellulolytic and cellulolytic activity in the rumen ciliates, especially for the group of large Entodinium (Nigri et al., 2017). Principally the large protozoa may colonize fiber fragments and directly ingest plant tissues favoring the action of cellulolytic bacteria (Williams et al., 1997). Such development of protozoa population during autumn with pasture with small dose of cereals, its effect would be degradative for the vegetal cell wall and will contribute to better utilization of the pastures. ...
Article
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The two main pregastric compartiments of ruminants: rumen and reticulum work as anaerobic fermenter which allows them to use energetic and nitrogen substrates which are indigestible by monograstric animals. They have a major importance in this fermenter, also these microbes : bacteria, protozoa and fungi, on the degradation of cell-wall carbohydrates: cellulose, hemicelluloses, pectic substances, on nitrogen digestion and finally on the utilisation of the major minerals and trace elements. The objective of this study is to identify and quantify the protozoa populations in the rumen of Algerian bovines local breed, adult animals living in a relatively humid climate, basic ration based on straw and pastures during hot days. Whereas in cold weather rations are based on straw, cereals and grass forage. Usually not 2 to 5 × 10 6 ml of rumen containing organisms however, under certain feeding conditions, they represent at least 50 % of the rumen microbial biomass. Due to the difficulties in cultivate in vitro, their role and their metabolism are less known than those of bacteria. Ciliated protozoa are capable of transforming a large number of food and bacterial constituents in metabolites and cellular compounds which will then be used by the host animal. The importance of these activities is however still very controversial since in the absence of protozoa in the rumen, Isolation carried out on rumen fluid sampled of 20 cows. Rumen fluid was diluted in formaldehyde 10 % solution, and distributed in Sedgewick Rafter chamber. Then observed in optical microscope using Lugol's iodine coloration. Classified in three genders according to size. 11 different genders were identified; a considerable population of rumen protozoa was identified and classified for first time on Algerian local breed (Atlas). Анотація. Завдяки багатокамерному шлунку, зокрема його основних відділів рубця і сітки, жуйні тварини можуть використовува-ти енергентичні і азотні компоненти корму, що не засвоюють тварини з однокамерним шлунком. Основну функцію перетравлення при цьому, виконує мікрофлора-бактерії, найпростіші та гриби, які забезпечують руйнування і засвоєння вуглеводів клітинної оболонки рослин: клітковини, геміцелюлози, пектинових речовин, а також метаболізмі азоту, мінеральних речовин і мікроелементів. Мета цього дослідження-виявлення і кількісне оцінювання популяцій найпростіших у рубці дорослії великої рогатої худоби алжирської місцевої породи у відносно вологому кліматі. За жарких погодних умов раціон тварин складається з соломи і випасу, в той час, як за холодних-солома, концентрати і трава. Зазвичай у рубці міститься від 2 до 5 × 10 6 мл найпростіших, проте за певних умов годівлі вони становлять щонайменше 50 % біомаси вмісту. Через труднощі культивування найпростіших in vitro їх роль у метаболізмі менш відома, ніж бактерій. Найпростіші можуть трансформувати більшу кількість харчових і бактеріальних компонентів у метаболіти та клітинні сполуки, які у подальшому використовує тварина-господар. Дослідження проведено на 20 коровах. Відібраний уміст рубця розбавляли у 10 % розчині формаліну і розподіляли у камері Sedgewick Rafter. Під світловим мікроскопом ідентифікували та описали 11 різних родів найтростіших. Вперше ідентифікована і класифікована популяція найпростіших рубця місцевої алжирської породи великої рогатої худоби (Atlas).
... Several studies have evaluated the effects of complete or partial RP inhibition; however, to this date, no practical suppressant has been identified and used in large scale. Ruminal protozoa make up less than 0.01% of the microbial cells in the rumen (Williams and Coleman, 1992). Though few in numbers, ruminal protozoa are relatively large compared to bacteria (5-250 µm long), consisting of 5-50% of the microbial mass in the rumen (Williams and Coleman, 1992;Sylvester et al., 2005). ...
... Ruminal protozoa make up less than 0.01% of the microbial cells in the rumen (Williams and Coleman, 1992). Though few in numbers, ruminal protozoa are relatively large compared to bacteria (5-250 µm long), consisting of 5-50% of the microbial mass in the rumen (Williams and Coleman, 1992;Sylvester et al., 2005). Ruminal protozoa are responsible for substantial microbial protein turnover due to predation of ruminal bacteria (Williams and Coleman, 1992). ...
... Though few in numbers, ruminal protozoa are relatively large compared to bacteria (5-250 µm long), consisting of 5-50% of the microbial mass in the rumen (Williams and Coleman, 1992;Sylvester et al., 2005). Ruminal protozoa are responsible for substantial microbial protein turnover due to predation of ruminal bacteria (Williams and Coleman, 1992). Complete inhibition of RP has been done to study the roles of RP and complete RP inhibition was suggested to increase microbial protein supply by 30% and reduce methane production by up to 11% (Newbold et al., 2015). ...
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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.
... However, the con-centration of ruminal ammonia N in all the lambs was more than the minimum level (5 mg/dL) required to support optimal growth of the rumen microbes (Sinclair et al., 1993). Reduction of ammonia N concentration in the rumen is usual when protozoa are inhibited (Williams and Coleman, 1992), probably due to reduced bacterial lyses (Hristov et al., 1999). Belanche et al. (2012) noted that the Entodiniinae were responsible for most ruminal bacterial breakdown. ...
... Table 5 illustrates that the dietary inclusion of PPE increased TPD absorbed (linear, P = 0.019; quadratic, P = 0.23), TPD excretion (linear, P = 0.002; quadratic, P = 0.25), and MNS (linear, P = 0.019; quadratic, P = 0.23). A decrease in concentration of rumen protozoa could increase the flow of microbial N to the intestine (Williams and Coleman, 1992). It has been shown that Entodinium spp. ...
Article
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ABSTRACT: Dietary natural plant secondary metabolites (PSM) extracted from a pomegranate peel (PP) byproduct have the potential to improve milk yield and the milk fatty acid profile of dairy cows. This experiment was performed to assess the influence of different dietary levels of PP extract (PPE) on feedlot performance, ruminal status, nutrient utilization, and antioxidant status in fattening Moghani lambs. Thirty-two lambs (initial BW of 22 ± 1.2 kg) were used in a completely randomized design with a 72-d period and 4 treatments: PPE0 (no extract), PPE15 (15 mL PPE/kg of diet DM), PPE30 (30 mL PPE/kg of diet DM), and PPE45 (45 mL PPE/kg of diet DM). Feed intake, lamb growth, diet digestibility, microbial nitrogen (N) synthesis (MNS), N retention, rumen parameters, and blood metabolites were determined. The addition of PPE to the diet of lambs had no effect on DMI (linear [L], P = 0.96; quadratic [Q], P = 0.65). In vivo digestibility coefficients of DM, OM, CP, and Ash-free NDF were not affected (L, P  0.28; Q, P  0.26) by different levels of PPE, but it increased ADG (L, P = 0.045; Q, P = 0.19) and G:F (L, P = 0.046; Q, P = 0.20). Rumen pH, VFA concentrations, and acetate-to-propionate ratio were not affected (L, P  0.14; Q, P  0.23) by PPE supplementation. Dietary inclusion of PPE decreased the ruminal concentration of ammonia N (L, P = 0.014; Q, P = 0.67), total protozoa enumeration (L, P < 0.001; Q, P = 0.043), Entodiniinae population (L, P < 0.001; Q, P = 0.19), urinary N excretion (L, P = 0.005; Q, P = 0.26), whereas MNS (L, P = 0.019; Q, P = 0.23) and N retention (L, P < 0.001; Q, P = 0.66) increased. Feeding PPE had no effect (L, P  0.11; Q, P  0.17) on plasma concentrations of glucose, triglycerides, cholesterol, total protein, albumin, or albumin-toglobulin ratio. Blood urea N (L, P = 0.021; Q, P = 0.32) decreased with dietary addition of PPE, while total antioxidant capacity (TAC) in the rumen fluid (L, P = 0.032; Q, P = 0.64) and TAC in the blood (L, P = 0.041; Q, P = 0.51) increased. Overall, dietary inclusion of PPE, up to 45 mL/kg of diet DM, linearly improved animal growth, N retention, and antioxidant capacities of the blood and rumen fluid. The PPE is a safe natural additive for use in sheep diets that can help to reduce environmental pollution by reducing urinary N excretion.
... Some of the ammonia nitrogen (NH 3 -N) is used as the nitrogen sources for ruminal microbes, primarily bacteria, to synthesize cellular proteins, which are the major direct nitrogen source for the host animals (Storm et al., 1983;Leng and Nolan, 1984;Hackmann and Firkins, 2015), but a large portion of the microbial cells (about 24% of the total ruminal bacteria daily) are engulfed by ruminal protozoa (Hespell et al., 1997), and approximately 50% of the engulfed bacterial proteins is hydrolyzed by protozoa to form oligopeptides and free amino acids (Jouany, 1996), which can be fermented back to SCFA and ammonia. Although varying in ability and rate (Belanche et al., 2012), all protozoa engulf microbial cells, even the small protozoa, and subsequently degrade the microbial proteins to oligopeptides and free amino acids (Williams and Coleman, 1992). Thus, ruminal protozoa mediate intraruminal recycling of microbial protein and consequently decrease the ruminal outflow of microbial proteins. ...
... The compositional alterations might have stemmed from direct and/or indirect effects. Rumen protozoa have multiple interactions with prokaryotes, such as predation, symbiosis (both endosymbiosis and ectosymbiosis), and commensalism (e.g., cross-feeding between protozoa and methanogens and amino-acid fermenters) (Williams and Coleman, 1992;Lloyd et al., 1996;Park and Yu, 2018b). The different inhibitor treatments might have caused different alterations of the prokaryotic microbiota indirectly by inhibiting the different protozoa to different extents. ...
Article
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Defaunation studies have shown that rumen protozoa are one of the main causes of low nitrogen utilization efficiency due to their bacterivory and subsequent intraruminal cycling of microbial protein in ruminants. In genomic and transcriptomic studies, we found that rumen protozoa expressed lysozymes and peptidases at high levels. We hypothesized that specific inhibition of lysozyme and peptidases could reduce the activity and growth of rumen protozoa, which can decrease their predation of microbes and proteolysis and subsequent ammoniagenesis by rumen microbiota. To test the above hypothesis, we evaluated three specific inhibitors: imidazole (IMI), a lysozyme inhibitor; phenylmethylsulphonyl fluoride (PMSF), a serine protease inhibitor; and iodoacetamide (IOD), a cysteine protease inhibitor; both individually and in combinations, with sodium dodecyl sulfate (SDS) as a positive control. Rumen fluid was collected from two Jersey dairy cows fed either a concentrate-based dairy ration or only alfalfa hay. Each protozoa-enriched rumen fluid was incubated for 24 h with or without the aforementioned inhibitors and fed a mixture of ground wheat grain, alfalfa, and grass hays to support microbial growth. Live protozoa cells were morphologically identified and counted simultaneously at 3, 6, 12, and 24 h of incubation. Fermentation characteristics and prokaryotic composition were determined and compared at the end of the incubation. Except for IOD, all the inhibitors reduced all the nine protozoal genera identified, but to different extents, in a time-dependent manner. IOD was the least inhibitory to protozoa, but it lowered ammoniagenesis the most while not decreasing feed digestibility or concentration of volatile fatty acids (VFA). ANCOM analysis identified loss of Fibrobacter and overgrowth of Treponema, Streptococcus, and Succinivibrio in several inhibitor treatments. Functional prediction (from 16S rRNA gene amplicon sequences) using the CowPI database showed that the inhibitors decreased the relative abundance of the genes encoding amino acid metabolism, especially peptidases, and lysosome in the rumen microbiota. Overall, inhibition of protozoa resulted in alteration of prokaryotic microbiota and in vitro fermentation, and peptidases, especially cysteine-peptidase, may be targeted to improve nitrogen utilization in ruminants.
... flagellates and ciliates, the latter being the most abundant and important (Williams and Coleman, 1997). Protozoa can degrade a wide range of substrates and play a critical role in fiber degradation, but they can also store large amounts of starch decreasing the rate of VFA that causes a drop in ruminal pH in ruminants fed high-concentrate diets. ...
... The final products generated in protozoa metabolism are similar to those produced by ruminal bacteria, but generally they protozoa produce greater amounts of hydrogen, acetate and butyrate. Some methanogenic archaea live in close association with protozoa, thus having immediate access to the hydrogen generated in the fermentation, that is used to produce CH4 (Williams and Coleman, 1997;Mackie et al., 2002). ...
Thesis
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Ruminants have the capacity of using fibrous feeds and low quality proteins to produce high-quality foods for humans, but they also have a low efficiency of nitrogen (N) utilization that is usually below 30%. As a consequence, a large part of the dietary N is excreted to the environment and contributes to soil and water eutrophication, being this problem especially marked in high-producing ruminants. Rumen metabolism is the most important factor contributing to the inefficient use of N in ruminants, especially in situations of an imbalance between the NH3-N generated in the degradation of protein and the use of NH3-N by the microbiota for microbial protein synthesis. In addition, it has been shown that protein degradation in the rumen generates CH4, thus contributing to greenhouse gases emissions. Therefore, reducing the ruminal degradation of protein cannot only increase the amount of feed protein reaching the small intestine, but also can reduce polluting emissions such as N and CH4. The general objective of this Doctoral Thesis is to investigate some aspects of the protein degradation in the rumen that are directly related to N losses and CH4 production, and in order to achieve this objective four Experiments (two in vitro and two in vivo) were conducted. The objective of Experiment 1 was to evaluate the inclusion of sunflower seed (SS) and sunflower meal (SM) protected against ruminal degradation in high-cereal diets on in vitro ruminal fermentation and CH4 production. Samples of SS and SM were sprayed with a solution of malic acid 1 M (400 ml/kg sample) and dried at 150°C for 1 h as a protective treatment. Four diets were formulated to contain either 13 (low) or 17 (high) g of crude protein (CP)/100 g dry matter (DM), and included SS and SM either untreated (13CON and 17CON diets) or treated as before described (13TR and 17TR diets). Diets were incubated in vitro with rumen fluid from sheep for 8 and 24 h. The treatment did not affect (p ≥ 0.57) total volatile fatty acid (VFA) production at any incubation time, but it reduced (p < 0.05) NH3-N concentrations by 19.2 and 12.5% at 8 and 24 h respectively. Both CH4 production and CH4/VFA ratio were lower (p < 0.02) in TR than in CON diets at 8 h, but differences disappeared (p > 0.05) at 24 h. The treatment increased the molar proportion of propionate (p = 0.001) and reduced that of isovalerate (p = 0.03) at 8 h compared with CON diets, but only a reduction of isovalerate proportion (p = 0.03) was detected at 24 h. There were no treatment x crude protein level interactions (p > 0.05) in any parameter, but high-protein diets had greater NH3-N concentrations (p < 0.001) and lower VFA production (p < 0.001) than low-protein diets at 24 h. The treatment reduced protein degradation, and CH4 production was decreased by 4.6 and 10.8% for low-and high-protein diets, respectively, at short incubation times without affecting VFA production, thus improving fermentation efficiency and decreasing polluting emissions. The objectives of Experiments 2 and 3 were to analyze the efficacy of a treatment combining malic acid and heating (MAH) to protect the protein in SS and SM against rumen degradation and to improve the growth, carcass characteristics and meat quality of lambs. Two high-cereal concentrates, either including untreated SS and SM (control concentrate) or MAH-treated SS and SM (MAH concentrate), were formulated. The Experiment 2 was conducted to analyze the 12-h in vitro fermentation of untreated and MAH-treated SS and SM samples, as well as of both concentrates, using ruminal fluid from sheep as inoculum. The results indicated that the MAH treatment modified the rumen fermentation pattern of SS, SM and the concentrate, increasing molar proportions of propionate. In addition, MAH treatment reduced (p = 0.009) the NH3-N concentrations for SM and tended (p = 0.065) to reduce them for the concentrate. However, no effects (p ≥ 0.100) on CH4 production were observed for any incubated feed. In Experiment 3, two homogeneous groups of 12 Lacaune lambs each (14.2  0.35 Kg body weight) were fed either the control or the MAH concentrate. Lambs were fed concentrate and barley straw ad libitum for 40 days (until reaching about 26 kg body weight). Feed intake and growth of lambs were recorded, blood samples were taken on days 0, 20, and the slaughter day for analysis of urea-N and amino acid-N, diet digestibility was determined, and ruminal and cecal samples were collected after slaughter. In addition, carcass characteristics and quality and fatty acid profile of meat were assessed. There were no significant effects of the MAH treatment on feed intake and growth of lambs. Organic matter digestibility tended to be greater (p = 0.07) in MAH-fed lambs than in the control group, but there were no differences (p ≥ 0.33) in the digestibility of CP, neutral detergent fiber (NDF) and acid detergent fiber (ADF). The hot carcasses of the lambs fed the MAH-treated concentrate were 7.9% heavier than those of the control group, but differences did not reach the significance level (p = 0.212). No differences between groups were detected in plasma concentrations of urea-N and amino acid-N (p = 0.755 and 0.500, respectively). There were no effects (p ≥ 0.172) of MAH treatment on ruminal papillae characteristics and post-mortem VFA concentrations and profile in the rumen and the cecum. The color of the ruminal epithelium was darker (p = 0.003) in the lambs fed the MAH-concentrate compared with the control group, which was attributed to either to a corrosive action of malic acid or to a greater abrasion of the MAH-treated sunflower husks. Compared with control lambs, those fed the MAH-concentrate showed greater (p = 0.016) amount of dorsal fat and greater (p ≤ 0.016) values of the color parameters a* (redness) and C* (chromaticity) in the rectus abdominis muscle. However, there were no differences (p > 0.05) in carcass measurements and in water-holding capacity, chemical composition, pH or color of longissimus dorsi muscle. Fatty acid profile of longissimus dorsi muscle was not affected (p > 0.117) by feeding the MAH-treated concentrate, with the exception of a trend (p = 0.055) to greater concentrations of C14:0 in the MAH-fed lambs. In conclusion, the MAH treatment increased the in vitro fermentation of SS, reduced the in vitro protein degradability of SM, and modified the VFA profile towards greater propionate production. However, under the conditions of the present study the inclusion of MAH-treated SS and SM in a concentrate for growing lambs did not influenced significantly feed intake, diet digestibility, growth performance and meat fatty acid profile, although it increased hot carcass weight by 7.9% and the amount of dorsal fat. In Experiment 4, the effects of spraying a solution of malic acid (1 M; 400 ml/kg) and ulterior heating to protect against ruminal degradation the proteins of SS and SM, as well as of a mixture of these both feeds (SSM; 45:55) were studied using in vivo, in situ and in vitro methods. Four rumen-fistulated sheep were fed two mixed diets composed of oat hay and concentrate (40:60) and differing only in the concentrate, that was either the control or the MAH concentrate used in Experiments 2 and 3. Sheep were fed the diets at 40 g DM/kg body weight0.75 into six equal meals per day using automatic dispensers. A crossover design with two 24-day experimental periods was used, and each period included successively 10 days of diet adaptation, 9 days for performing in situ incubations of SS, SM and SSM, one day for measuring ruminal parameters, and two days for rumen empting. From day 6 onwards a solution of (15NH4)2SO4 was continuously infused into the rumen of each sheep to label ruminal bacteria. Feeding the MAH diet did not affect either ruminal pH or concentrations of NH3-N and total VFA, but decreased (p ≤ 0.009) molar proportions of acetate and propionate and increased those of butyrate (p < 0.001). In addition, organic matter (OM) and lipid contents in ruminal bacteria were lower in sheep fed the MAH diet compared with the control diet, whereas both N content and 15N enrichment were greater (p ≤ 0.037). Estimates of effective degradability (ED) of different feed fractions in SS, SM and SSM were obtained considering the ruminal rates of particle comminution and passage and correcting the values for the microbial contamination measured by using the 15N infusion technique. The MAH treatment decreased the ED of most fractions in all tested feeds, increasing the supply of by-pass crude protein (CP) by 19.1 and 120% for SS and SM, respectively, and by 34% for crude fat in SS. The MAH treatment also increased the in vitro intestinal digestibility of the by-pass CP both for SS (from 60.1 to 75.4%) and SM (from 83.2 to 91.0%). The simultaneous heating of both feeds performed in SSM reinforced the protective effect increasing the by-pass CP without altering its intestinal digestibility. As a result, the intestinal digested CP content in SSM increased by 15.6% compared with the value estimated from the results obtained for SS and SM incubated independently. The results also confirm the previous observation that the effectiveness of MAH treatment is greater for high-CP feeds.
... According to Newbold et al. (2015), a lower number of ruminal protozoa reduced the amount of organic matter, especially NDF and ADF, but also decreased methane output. Williams and Coleman (1997) showed that the genus Diplodinium synthesized enzymes that degraded structural carbohydrates, i.e. cellulase and xylanase. YC appeared to inhibit the abundance of Diplodinium spp., and thus could limit fibre degradation in the rumen of sheep fed the YC diet. ...
Article
The aim of the study was to compare the effect of two yeast (Saccharomyces cerevisiae) preparations in the diet on the number of protozoa and carbohydrate-digesting enzymes in the rumen of sheep. The experiment was conducted in six sheep with a cannula in the rumen. The animals were divided into three groups of two sheep. Each group received a different sequence of three treatments (control–CON, live yeast–LY or yeast culture–YC), resulting in three study periods. Sheep were fed meadow hay and concentrate alone or the same ration supplemented with LY or YC at a dose of 5 or 30g/day, respectively. The rumen fluid and digesta were collected before (0h) and 2 and 4h after feeding. The lowest pH was recorded for sampling at 2 and 4h after feeding, and the highest at 0h. The number of Diplodinium spp. and Dasytricha sp. was lower when sheep were fed YC and LY, respectively, than when they were fed CON. Fibrolytic and amylolytic activities were lower 2 and 4 after feeding for all groups and YC, respectively, compared to the results at 0h. Our data suggested that the addition of LY and YC to the sheep diet modified the abundance of the protozoan genera Diplodinium and Dasytricha and could affect fibrolytic and amylolytic activities in the rumen.
... Dominant with grass based diets, AA is mainly liberated by bacterial and fungal populations responsible for the degradation of fibrous and structural carbohydrates. In contrast PA and BA are typically produced by bacterial and ciliate protozoal populations responsible for the degradation of starchy, more soluble carbohydrates [40] [41]. ...
... The increased number of total protozoa in RF inoculated with termite gut bacteria might be due to the ingestion of inoculant bacteria by protozoa (Krause et al. 2003). It is well known that protozoa to a large extent ingest rumen bacteria resulting in increased bacterial turnover (Wallace and McPherson 1987;Williams and Coleman 1991) and consequently increased ruminal ammonia concentration (Guyader et al. 2014). Similar to results of the current study, several other studies found that inoculated microorganisms disappeared from the rumen shortly after inoculation, and rumen protozoa played an important role (Krause et al. 2000;Krause et al. 2001). ...
Article
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The digestive tract of termite (Microcerotermes diversus) contains a variety of lignocellulose-degrading bacteria with exocellulases enzyme activity, not found in the rumen, which could potentially improve fiber degradation in the rumen. The objectives of the current study were to determine the effect of inoculation of rumen fluid (RF) with three species of bacteria isolated from termite digestive tract, Bacillus licheniformis, Ochrobactrum intermedium, and Microbacterium paludicola, on in vitro gas production (IVGP), fermentation parameters, nutrient disappearance, microbial populations, and hydrolytic enzyme activities with fibrous wheat straw (WS) and date leaf (DL) as incubation substrate. Inoculation of RF with either of three termite bacteria increased (P0.05) on gas production characteristics, dry matter, organic matter and neutral detergent fiber disappearance, pH, and concentration and composition of volatile fatty acids. Population of proteolytic bacteria and protozoa, but not cellulolytic bacteria, were increased (P0.05). Overall, the results of this study indicated that transferring lignocellulose-degrading bacteria, isolated from digestive tract of termite, to rumen liquid increased protozoa and proteolytic bacteria population and consequently increased protease activity and ammonia-N concentration in vitro, however, no effect on fermentation and fiber degradation parameters were detected. These results suggest that the termite bacteria might be rapidly lysed by the rumen microbes before beneficial effects on the rumen fermentation process could occur.
... There is a high degree of genetic diversity within the rumen fungal communities (Kittelmann et al., 2012). Ciliate protozoa are represented by comparatively small numbers in the rumen, but a large number of different species have been described based on morphological features (Williams and Coleman, 1992). ...
Conference Paper
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Forage is exposed to a unique population of microbes that begin to ferment and digest the plant cell wall components and break these components down into carbohydrates and sugars. Rumen microbes use carbohydrates along with ammonia and amino acids to grow. The microbes ferment sugars to produce VFAs (acetate, propionate, butyrate), methane, hydrogen sulfide, and carbon dioxide but immature ruminants, such as young growing calves from birth to about 2 to 3 months of age, are functionally non-ruminants. The aim of this study was to compare the distribution and quantification of microbial populations in the liquid and solid fractions in the rumen of three week old calves.
... (Table 2) followed the procedures [22]. Ciliated protists in the fermentation ruminal fluid were counted microscopically and identified [65]. ...
Article
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Background: Parallel in vitro and in vivo experiments were designed to evaluate promising chemotherapeutic alternatives for controlling haemonchosis in ruminants. In vitro anthelmintic activities (egg hatch test - EHT; larval development test - LDT) of aqueous and methanolic herbal extracts Mix1 and Mix2 were investigated. The in vivo effects of dietary supplementation with Mix1 and Mix2 on the parasitological status, inflammatory response, antioxidant parameters and microbial community of the lambs infected experimentally with Haemonchus contortus were investigated. Lambs were divided into four groups for the in vivo study: uninfected control lambs (C), infected lambs (I), infected lambs supplemented with Mix1 (I + Mix1) and infected lambs supplemented with Mix2 (I + Mix2). The experimental period was 70 days. Results: The number of eggs per gram (EPG) of feces was quantified 22, 30, 37, 44, 51, 58, 65 and 70 days post-infection, and mean abomasal worm counts were assessed 70 days post-infection. Quantitative analyses identified 57.3 and 22.2 mg/g phenolic acids, 41.5 and 29.5 mg/g flavonoids and 1.4 and 1.33 mg/g protoberberine-type alkaloids in Mix1 and Mix2, respectively. The methanolic extracts of the herbal mixtures in both in vitro tests had higher anthelmintic effects (P < 0.01) than the aqueous extracts, but the effects did not differ significantly between Mix1 and Mix2 (P > 0.05). I + Mix1 and I + Mix2 lowered mean EPGs between 44 and 70 d by 58.1 and 51.6%, respectively. The level of IgG antibodies against H. contortus increased significantly after infection in each infected group. Conclusion: These results represent the first monitoring of the in vitro anthelmintic effects of herbal mixtures on H. contortus. The in vivo experiment indicated that the anthelmintic effect was not sufficient for the elimination of parasites, but this herbal treatment may affect the host over a longer term, reducing the parasitic infection in the host.
... Barker and Brown (1994) have proposed that protozoa act as the Trojan horses of the microbial world. This concept has received much interest in the ecology of zoonotic foodborne pathogens since they frequently commingle with protists in the intestinal tract of their animal hosts and cycle in the environment prior to infecting humans via contaminated water or food (Williams and Coleman 1997;Dehority 2003;Ravva, Sarreal and Mandrell 2010). Bacterial survival from protozoan digestion likely involves the ability to mount a rapid response to a variety of stresses shortly after being phagocytized. ...
Article
Pathogenic E. coli remains undigested upon phagocytosis by Tetrahymena and is egested from the ciliate as viable cells in its fecal pellets. Factors that are involved in the survival of Shiga toxin-producing E. coli serovar O157: H7 (EcO157) from digestion by Tetrahymena were identified by microarray analysis of its transcriptome in the protozoan phagosome. Numerous genes belonging to anaerobic metabolism and various stress responses were upregulated significantly ≥ 2-fold in EcO157 cells in the food vacuoles compared with in planktonic cells that remained uningested by the protist. Among these were the oxidative stress response genes, ahpF and katG. Fluorescence microscopy and staining with CellROX® Orange confirmed the presence of reactive oxygen species in food vacuoles containing EcO157 cells. Frequency distribution analysis of the percentage of EcO157 viable cells in Tetrahymena fecal pellets revealed that the ΔahpCF and ΔahpCFΔkatG mutants were less fit than the wild type strain and ΔkatG mutant after passage through the protist. Given the broad use of oxidants as sanitizers in the food industry, our observation of the oxidative stress response in EcO157 during its interaction with Tetrahymena emphasizes the importance of furthering our knowledge of the physiology of this human pathogen in environments relevant to its ecology and to food safety.
... Thus, the effect of saponin in the rumen seems to be similar to that of lipids, as mentioned above. Saponin acts on protozoa by forming irreversible saponin complexes with cholesterol from the cell membranes of these microorganisms (Williams and Coleman, 1997). Using both YM and vitamin E combined the protective action of vitamin E on cellular membranes with the action of antioxidants from YM, which resulted in increased production and efficiency of ruminal microbial synthesis when compared with YM alone. ...
Article
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The objective of this study was to evaluate the effect of adding ground soybeans and antioxidants to diet of buffaloes on intake, ruminal microbial production, total and ruminal digestibility of nutrients, and ruminal fermentation parameters. Four crossbred buffaloes with a mean weight of 506±29 kg were distributed in a 4×4 Latin square. Four diets were tested: control; diet with ground soybeans; diet with ground soybeans and supplementation with yerba mate; and diet with ground soybeans and supplementation with yerba mate and vitamin E. The addition of ground soybeans had negative effects on intake of dry matter, organic matter, crude protein, neutral detergent fiber, and acid detergent fiber, as well as ruminal digestibility of neutral detergent fiber and total carbohydrates but did not influence total digestibility of nutrients. Yet, the ground soybeans diet increased the concentration of butyrate and microbial production in the rumen. The diet with ground soybeans supplemented with yerba mate decreased the concentration of acetate and increased the concentration of propionate and increased the efficiency of synthesis and the production of microbial protein in the rumen. There was a positive additive effect of vitamin E in the presence of yerba mate, enhancing the synthesis and production efficiency of microbial protein. Thus, the addition of ground soybeans and antioxidants to diet of buffaloes improves the efficiency of microbial protein synthesis and increases the production of butyrate, without, in general, altering the total digestibility of nutrients.
... Además, el acetato y el propionato se incrementaron proporcionalmente como lo representa la relación A:P. Asimismo, la capacidad de los metanógenos de producir metano a partir de la oxidación del acetato no es tan abundante en el rumen y el tiempo requerido para que ocurra la reacción es limitado (37). Los resultados presentados en este estudio están de acuerdo con los reportado por Saminathan et al (38), quienes observaron PPM similares y detectaron que la mayoría de los metanógenos se redujeron con la presencia de TC, pero se incrementaron algunas otras arqueas. ...
Article
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Objective.This research aimed to evaluate the inclusion of Cucurbita foetidissima (BG) leaves as a partial or total substitution of alfalfa hay (AH) in beef cattle diets on in vitro methane output, gas kinetics and volatile fatty acids production. Materials and Methods.Five experimental treatments were formulated with the inclusion of BG as alfalfa hay (AH) substitute at 0, 25, 50, 75 and 100% in experimental treatments denominated CON (control), BG25, BG50, BG75 and BG100, respectively. Results.Lignin and organic matter decreased with BG inclusion (p<0.05). However, NDF, CT and TPC increased with higher levels of BG (p<0.05). Maximum gas production diminished with BG inclusion (p<0.05); whereas, microbial protein production, specific gas production rate and latency period were not affected (p>0.05). Methane production decreased linearly with BG inclusion (p<0.05). Nevertheless, CO2 production showed no changes with inclusion of graded levels of BG in the experimental treatments (p>0.05). Additionally, acetate and butyrate were not affected by BG inclusion (p>0.05); although, propionate increased linearly among treatments (p<0.05). Furthermore, inclusion of 75% of BG reduced 31% in vitro methane production without changes in CO2 production, suggesting an inhibition of endogenous methanogenesis. Conclusions.These results promote the inclusion of BG leaves as a potential and environmentally friendly forage source for beef cattle feeding.
... This result can be attributed to diverse ureolytic bacteria that do not limit the conversion of urea to ammonia (Cook, 1976;Jin et al., 2017), and the increased number of rumen protozoa in the LU treatment in comparison with UC treatment ( Table 6). Rumen protozoa play an important role in the bacterial protein breakdown (Williams and Coleman, 1992), and the protozoal elimination results in a decrease in rumen ammonia based on a meta-analysis (Newbold et al., 2015). Previous study reported that the maximum concentration of microbial protein in the rumen was associated with an ammonia concentration of 8.8 mg/dL (Hume et al., 1970), which is comparable to that the concentration in the LU treatment (10.76 mg/dL). ...
Article
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The rumen bacteria in the solid, liquid, and epithelial fractions are distinct and play important roles in the degradation of urea nitrogen. However, the effects of urea on rumen bacteria from the three fractions remain unclear. In this study, 42 Hu lambs were fed a total mixed ration based on concentrate and roughage (55:45, dry matter basis) and randomly assigned to one of three experimental diets: a basal diet with no urea (UC, 0 g/kg), a basal diet supplemented with low urea levels (LU, 10 g/kg DM), and a basal diet supplemented with high urea levels (HU, 30 g/kg DM). After an 11-week feeding trial, six animals from each treatment were harvested. Rumen metabolites levels were measured, and bacteria of the rumen solid, liquid, and epithelial fractions were examined based on 16S rRNA gene sequencing. Under urea supplementation, the concentrations of ammonia and butyrate in the rumen increased, whereas the concentration of propionate decreased. The population of total protozoa was the highest in the LU treatment. Prevotella 1 was the most abundant genus in all samples. The unclassified Muribaculaceae, bacteria within the families Lachnospiraceae and Ruminococcaceae, and Christensenellaceae R7 were abundant in the solid and liquid fractions. Butyrivibrio 2 and Treponema 2 were the abundant bacteria in the epithelial fraction. Principal coordinate analysis showed separation of the solid, liquid and epithelial bacteria regardless of diet, suggesting that rumen fraction had stronger influences on the bacterial community than did urea supplementation. However, the influences on the bacterial community differed among the three fractions. In the solid and liquid fractions, Succinivibrionaceae UCG 001 and Prevotella 1 showed decreased abundance with dietary urea supplementation, whereas the abundance of Oscillospira spp. was increased. Howardella spp. and Desulfobulbus spp. were higher in the epithelial fraction of the UC and LU treatments relative to HU treatment. Comparisons of predictive function in the rumen solid, liquid, and epithelial fractions among the three treatments also revealed differences. Collectively, these results reveal the change of the rumen bacterial community to dietary urea supplementation.
... We should further expand this work to trichostomatid families such as the Protocaviellidae and Protohallidae from domestic and wild rodents and Gilchristinidae, Rhinozetidae, and Telamonididae from elephants, rhinos and wild pigs, respectively. Moreover, improvements to trichostomatid cultivation techniques, which are still poorly developed (Williams and Coleman, 1992;Dehority and Wright, 2014;Newbold et al., 2015;Belzecki et al., 2016), would be of great importance to obtain suitable samples for morphology and molecular characterization approaches. Collectively, this information will contribute to develop more robust phylogenetic hypotheses, to elaborate taxonomic reformulations, contributing to elucidate the many taxonomic incongruences presented above and to establish new classification schemes that reflect evolutionary divergences within Trichostomatia. ...
Article
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The gastrointestinal tracts of most herbivorous mammals are colonized by symbiotic ciliates of the subclass Trichostomatia, which form a well-supported monophyletic group, currently composed by ∼1,000 species, 129 genera, and 21 families, distributed into three orders, Entodiniomorphida, Macropodiniida, and Vestibuliferida. In recent years, trichostomatid ciliates have been playing a part in many relevant functional studies, such as those focusing in host feeding efficiency optimization and those investigating their role in the gastrointestinal methanogenesis, as many trichostomatids are known to establish endosymbiotic associations with methanogenic Archaea. However, the systematics of trichostomatids presents many inconsistencies. Here, we stress the importance of more taxonomic works, to improve classification schemes of this group of organisms, preparing the ground to proper development of such relevant applied works. We will present a historical review of the systematics of the subclass Trichostomatia highlighting taxonomic problems and inconsistencies. Further on, we will discuss possible solutions to these issues and propose future directions to leverage our comprehension about taxonomy and evolution of these symbiotic microeukaryotes.
... Furthermore, anthocyanin could support a synchronized release of nitrogen and carbohydrates from purple field corn stover, which is responsible for microbial efficiency enhancement [36]. More reasons could be that protozoa engulf other microbes as their main nutrient source [58] and as a result, defaunation could be more rumen efficient in terms of proteosynthesis enhancing the duodenal flow of microbe mass. Similarly, defaunation also enhanced the efficiency of efficiency microbial protein synthesis (EMPS) (+6.8%) as a result of both, and a greater microbial synthesis was reported [59]. ...
Article
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Simple Summary: The use of purple field corn stover contains enriched anthocyanin. Moreover, the effect of anthocyanin in purple field corn could inhibit methane (CH4) synthesis by changing hydrogen from the CH4 route to form propionic acid. However, purple field corn was found to have poor digestibility owing to its fiber linkage structure. Pleurotus ostreatus and Volvarialla volvacea are species of white-rot fungal mushroom, famous and abundant in tropical regions. These fungi have potential to decrease indigestion of cell wall contents and increase cell wall digestibility of rice straw material by secondary metabolites namely lignin peroxidase, manganese peroxidase, and laccase enzyme, and showed the structural polymer found in rice straw and purple field corn residue. Accordingly, feeding purple field corn stover fermented with P. ostreatus or V. volvacea will increase feed utilization and reduce CH4 production in beef cattle. Abstract: This objective is to elucidate the effect of purple field corn stover treated with Pleurotus ostreatus and Volvarialla volvacea on feed utilization, ruminal ecology, and CH4 synthesis in tropical beef cattle. Four male Thai native beef cattle (100 ± 30 kg of body weight (BW) were assigned randomly as a 2 × 2 factorial arrangement in a 4 × 4 Latin square design. Factor A (roughage sources) was rice straw and purple field corn stover and factor B was species of white-rot fungi (P. ostreatus and V. volvacea). After fermentation, crude protein (CP) was increased in rice straw and purple field corn stover fermented with P. ostreatus and V. volvacea. The unfermented purple field corn stover contained 11.8% dry matter (DM) of monomeric anthocyanin (MAC), whereas the MAC concentration decreased when purple field corn stover was fermented with white rot fungi. There were no changes (p > 0.05) in DM intake of body weight (BW) kg/d and g/kg BW 0.75 among the four treatments. The organic matter (OM), CP, and acid detergent fiber (ADF) intake were different between rice straw and purple field corn stover and were the greatest in the purple field corn stover group. Moreover, the current study showed that neutral detergent fiber (NDF) and ADF digestion was higher in purple field corn stover than in rice straw, but there were no significant differences between P. ostreatus and V. volvacea. There were significant effects of roughage sources on ammonia nitrogen (NH3-N) at 4 h after feeding. Bacterial population was changed by feeding with purple field corn stover fermented with P. ostreatus and V. volvacea. On the other hand, the number of protozoa was reduced by approximately 33% at 4 h after feeding with purple field corn stover (p < 0.01). Propionic acid concentration was different between roughage sources (p < 0.01) enhanced with purple field corn stover fermented with P. ostreatus and V. volvacea. In addition, methane production decreased by 15% with purple field corn stover fermented with P. ostreatus and V. volvacea compared to rice straw. There were significant differences on all nitrogen balances parameters (p < 0.05), except the fecal N excretion (p > 0.05) were not changed. Furthermore, microbial crude protein and efficiency of microbial N synthesis were enhanced when purple field corn stover fermented with P. ostreatus and V. volvacea was fed compared to rice straw group. Base on this study, it could be Animals 2019, 9, 1084 2 of 17 summarized that P. ostreatus or V. volvacea can enhance the quality of purple field corn stover and modulate rumen fermentation and feed digestion in Thai native beef cattle.
... Diplodiniinae ciliates, Diplodinium and Eudiplodinium, presented high fibrolytic activity and play an important role in rumen fiber digestion (Takenaka et al., 2004;Williams and Coleman, 1992). Possibly due to their fibrolytic activity, presented significant increases in concentration during the dry season, when the vegetation have higher fiber level (Araújo Filho, 2002). ...
Article
Objetivou-se neste trabalho determinar a influência estacional sobre a composição botânica da dieta e nos protozoários do rúmen de cinco ovinos mestiços Santa Inês providos de fístulas ruminais e mantidos em pastagens naturais de vegetação de Caatinga, Estado de Pernambuco, Brasil. As amostras foram coletadas em julho de 2005 e janeiro de 2006, compreendendo, respectivamente, as estações chuvosa e seca. A composição botânica da dieta foi determinada através de amostras de extrusa coletadas via fístula ruminal, que após serem analisadas indicaram que durante a estação chuvosa as espécies vegetais mais comuns na dieta dos animais são herbáceas e gramíneas (88%), com Herissantia tiubae representando 51,7% do total. Na estação seca a dieta consistiu de espécies arbustivas (67,4%), comumente Capparis yco (26,3%) e Bauhinia cheilantha (22,3%). Sob tais condições, foram também verificadas variações nas populações de protozoários ruminais, os quais apresentaram maior concentração total (p
... The ruminal protozoal community accounts for 50% of the rumen biomass (Williams and Coleman, 1997). These organisms are eukaryotic in origin, possessing a 18s rRNA subunit (Newbold et al., 2015). ...
Article
Resource use is continually being limited due to this growth, therefore, production of high-quality animal protein sources, such as meat and milk, are challenged. The rumen microbiome is extensive and serves to provide several metabolic requirements for the animal for growth. Recently, a significant amount of research is being driven towards understanding the rumen microbiome due to its large effect on metabolic requirements. A study was conducted to replace alfalfa with nonforage fiber sources in dairy cows. It was determined milk yield and intake are maintained when nonforage fibers replace forage sources, while decreasing methane levels. Water consumption decreased when cows were fed a straw and dried distillers grains and solubles mixture in replacement of alfalfa. The microbial community observed no differences in alpha diversity measures, despite the abundance of some taxa being correlated with methane production. These dietary treatments do not alter microbial community composition to determine performance differences. Examination into substrate production by these microbes may provide insight into how energy is diverted in dairy cows fed nonforage fiber sources. A metagenomic analysis was conducted characterizing the genomic capacity within the microbial community in beef cattle fed diets based on forage quality to evaluate methane mechanisms within the microbial community. In high-quality forage diets, the propionate pathway becomes enhanced, acting as a hydrogen sink for methanogenesis. Betaproteobacteria genes were identified to be present in the propionate pathway, which becomes enhanced in high-quality forage-based diets, indicating a syntrophic relationship may be occurring to reduce methane emissions in beef cattle. Advisors: Samodha C. Fernando and Paul J. Kononoff
... Interestingly however, the reduction in CH4 was significant only when OEO was added to the adapted culture suggesting that microbial adaptation and/or modification played a role in OEO effect. Compared to rumen, continuous culture fermenters were reported to have limited number of protozoa (Fenchel et al., 1977;Williams and Coleman, 1997) and in previous studies (Lin et al., 2012;Patra and Yu, 2012;Mbiriri et al., 2016), the effects of OEO and its components or other EO on CH4 production were attributed in part to their effects on protozoa. Therefore, it is possible that the lack of OEO effect in the unadapted culture was due to protozoa absence in collected inoculum from continuous culture fermenters while the effect of OEO in the adapted culture could be due to lower methanogenic bacterial activity in these cultures. ...
... The rapid establishment of protozoa requires a wellstructured bacterial population. Bacteria promote physico−chemical characteristics in the ruminal environment (Fonty et al., 1988), and are a nitrogen source for growth of protozoa (Williams and Coleman, 1997). ...
Article
This review aims to explain how microbial colonization of the gastrointestinal tract (GIT) in young dairy calves is related to health and, consequently, to the performance of these animals. The review addresses everything from the fundamental aspects of microbial colonization to the current understanding about the microbiota manipulation to improve performance in adult animals. The ruminal microbiota is the most studied, mainly due to the high interest in the fermentative aspects, the production of short-chain fatty acids, and microbial proteins, and its effects on animal production. However, in recent years, the intestinal microbiota has gained space between studies, mainly due to the relationship to the host health and how it affects performance. Understanding how the GIT's microbiota looks like and how it is colonized may allow future studies to predict the best timing for dietary interventions as a way to manipulate it and, consequently, improve the health and performance of young ruminants.
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Livestock farming is very important in Asia and the pacific region as a source of livelihood for resource poor farmers’ — provision of food and food products and as a source of income. However, livestock productivity in many countries is below their genetic potential because of inadequate and imbalanced feeds and feeding, poor reproductive management and animal diseases exacerbated by lack of effective support services, such as animal husbandry extension, artificial insemination (AI) and/or veterinary services. The International Atomic Energy Agency (IAEA) and the Regional Cooperative Agreement for Research, Development and Training Related to Nuclear Science and Technology for Asia and the Pacific (RCA), with technical support of the Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, implemented a Technical Cooperation (TC) project entitled “Integrated Approach for Improving Livestock Production using Indigenous Resources and Conserving the Environment” (RAS/5/044). The overall objective of the project was to improve livestock productivity through better nutritional and reproduction strategies while conserving the environment. The specific objectives were (i) to improve animal productivity and decrease emission of selected greenhouse gases, (methane and carbon dioxide) and selected nutrients (nitrogen and phosphorus) into the environment; and (ii) to identify and adopt better breeding strategies that would improve animal productivity. This publication contains research results presented by scientists during the final review meeting incorporating the contributions of the experts associated with RAS/5/044. It is hoped that this publication will help stimulate further discussion, research and development into ways of improving the efficiency and productivity of livestock thus leading to higher income for smallholder farmers in the region. The IAEA officers responsible for this publication were O. Perera, A. Schlink and E.N. Odongo of the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture.
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The study investigated amelioration effects of coconut oil (CO) on growth performance, nutrient digestibility, ruminal fermentation, and blood metabolites in Hainan Black goat kids. Twenty-four Hainan Black goat kids (10 days of age) were assigned randomly to four treatments for 90 days, including pre-weaning (10–70 d of age) and post-weaning (70-100 d of age) days. The treatment regimens were control (CON), low CO (LCO), medium CO (MCO), and high CO (HCO) with 0, 4, 6, 8 g CO per goat per day, respectively. During the pre-weaning period, the average daily gain (ADG) linearly and quadratically increased ( P < 0.05), whereas the average daily feed intake (ADFI) linearly decreased, and the feed conversion ratio (FCR) also decreased linearly and quadratically by increasing CO supplementation ( P < 0.05). During the post-weaning period, increasing CO supplementation linearly and quadratically increased the BW at 100 days and ADG ( P < 0.05), but quadratically decreased the ADFI and FCR ( P < 0.05). The digestibility of ether extract (EE) linearly and quadratically increased with increasing CO supplementation ( P < 0.05). Supplementation of CO linearly increased ruminal pH (P < 0.05), but linearly decreased ( P < 0.05) ammonia-N, total VFAs, molar proportions of acetate, ruminal microbial enzyme activity of carboxymethyl-cellulase, cellobiase, xylanase, pectinase and α-amylase, and number of total protozoa, the abundance of Ruminococcus albus, Ruminococcus flavefaciens, Fibrobacter succinogenes, Butyrivibrio fibrisolvens, Prevotella ruminicola , and Ruminobacter amylophilus . The estimated methane emission decreased linearly and quadratically with increasing CO addition ( P < 0.05). The serum concentration of triglycerides (TG), non-esterified fatty acids (NEFA) and growth hormone (GH) linearly ( P < 0.05) increased by raising the CO supplementation. The present results indicate that CO supplementation at 6 g/day per goats is optimum due to improved growth performance and decreased estimated methane emission. Supplementation CO up to 8 g/day depressed growth and feed conversion due to its suppression of growth performance, rumen protozoa, cellulolytic bacteria and microbial enzyme activity, and reduced ADF and ADF digestibility.
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Ferulic acid (FA) is one of the most abundant hydroxycinnamic acids in the plant world, especially in the cell wall of grain bran, in comparison with forage and crop residues. Previous studies noted that FA was mainly linked with arabinoxylans and lignin in plant cell walls in ester and ether covalent forms. After forages were ingested by ruminant animals or encountered rumen microbial fermentation in vitro, these cross-linkages form physical and chemical barriers to protect cell-wall carbohydrates from microbial attack and enzymatic hydrolysis. Additionally, increasing studies noted that FA presented some toxic effect on microbial growth in the rumen. In recent decades, many studies have addressed the relationships of ester and/or ether-linked FA with rumen nutrient digestibility, and there is still some controversy whether these linkages could be used as a predicator of forage digestibility in ruminants. The authors in this review summarized the possible relationships between ester and/or ether-linked FA and fibre digestion in ruminants. Rumen microbes, especially bacteria and fungi, were found capable of breaking down the ester linkages within plant cell walls by secreting feruloyl and p-coumaroyl esterase, resulting in the release of free FA and improvement of cell wall digestibility. The increasing evidence noted that these esterases secreted by rumen microbes presented synergistic effects with xylanase and cellulase to effectively hydrolyze forage cell walls. Some released FA were absorbed through the rumen wall directly and entered into blood circulation and presented antioxidant effects on host animals. The others were partially catabolized into volatile fatty acids by rumen microbes, and the possible catabolic pathways discussed. To better understand plant cell wall degradation in the rumen, the metabolic fate of FA along with lignin decomposition mechanisms are needed to be explored via future microbial isolation and incubation studies with aims to maximize dietary fibre intake and enhance fibre digestion in ruminant animals.
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Chapter
Protozoa is an informal name used to describe a polyphyletic group of single-celled eukaryotic organisms (protists) that feed mostly by heterotrophy. Over 26 000 morphospecies of protists have been named, spanning all modern eukaryotic supergroups. They are incredibly diverse in terms of physiology and lifestyle, which has enabled them to colonise a wide range of moist environments, including marine, freshwater and extreme habitats. Many species have evolved specialised anatomical structures for feeding, motility and exchange of genetic material. They can be free-living, parasitic or symbiotic, or can transition between these states. Some are also capable of forming dormant cysts or spores, which enable them to resist environmental stress. Species were traditionally defined based on morphological features and modes of nutrition, which do not always correlate with phylogenetic similarity; thus, it is difficult to ascertain their true biodiversity and biogeography. However, some appear to be abundant and widespread in nature, while others are rare and limited to very specific environmental niches. Key Concepts • ‘Protozoa’ is not a formal phylogenetic taxon but is loosely used to describe diverse unicellular eukaryotic organisms (protists) with a mostly heterotrophic lifestyle. • Protists are found in virtually all moist environments on Earth, including fresh and marine water, soil, extreme environments and the fluids of plants and animals. • Protists may be free-living, parasitic or symbiotic, or may transition between these lifestyles. • In order to persist under stressful conditions, some species may form dormant cysts or spores. These structures also enable protists to survive passive transport from one location to the next. Protists may have a variety of specialised anatomical structures for feeding, locomotion and the exchange of genetic material, including extrusomes, pseudopodia and cilia. • The taxonomy of protists was traditionally based on morphological features and nutritional mode but, has since been revised based on biochemical and genetic similarities. Many of the previously described morphospecies are actually clusters of several phylogenetically distinct entities. • As a group, protists are incredibly abundant and geographically widespread. Common species may be present in densities of tens of thousands of cells per litre of water (or gram of soil), for example. However, some species are relatively rare. • Despite their capacity for global distribution, most species display some degree of endemism.
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Ruminants are an important part of world animal production. The main factors affecting their production rates are age, diet, physiological condition and welfare. Disorders related to low level of welfare can significantly affect the microbiological composition of the digestive system, which is essential to maintain high production rates. The microbiology of the ruminant gastrointestinal tract may be significantly affected by inappropriate keeping system (especially in juveniles), psychological stress (e.g. transport), or heat stress. This results in an increased risk of metabolic diseases, reduced fertility and systemic diseases. Therefore, the paper focuses on selected disorders i.e., aforementioned inappropriate maintenance system, psychological stress, heat stress and their effects on the microbiome of the digestive system.
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This experiment compared incidence of frothy bloat, as well as ruminal, physiological, and performance responses of beef heifers receiving a bloat-provoking diet and supplemented with Yucca schidigera extract. Sixteen ruminally cannulated Angus-influenced heifers were ranked by body weight (BW) and assigned to 4 groups of 4 heifers each. Groups were enrolled in a replicated 4 × 4 Latin square design containing 4 periods of 28 d, and a 21-d washout interval between periods. Groups were assigned to receive no Y. schidigera extract (CON), or Y. schidigera extract at (as-fed basis) 1 g/heifer daily (YS1), 2 g/heifer daily (YS2), or 4 g/heifer daily (YS4). During each period, heifers (n = 16/treatment) were housed in individual pens, and fed a sorghum (Sorghum bicolor L.)-based bloat-provocative diet at 2% of their BW. Diet and treatments were individually fed to heifers, twice daily in equal proportions (0700 and 1600 hours). Heifers were assessed for bloat score (0 to 5 scale, increasing according to bloat severity) 3 hr after the morning feeding. Blood samples were collected on days 0, 7, 14, 21, and 28 prior to (0 hr) and at 3, 6, and 9 hr relative to the morning feeding. Rumen fluid samples were collected at the same time points on days 0 and 28. Orthogonal contrasts were tested to determine whether inclusion of Y. schidigera extract (0, 1, 2, or 4 g/heifer daily) yielded linear or quadratic effects, and explore an overall effect of Y. schidigera extract supplementation (CON vs. YS1 + YS2 + YS4). Rumen fluid viscosity was impacted quadratically by Y. schidigera extract inclusion (P = 0.02), being greatest in YS1, followed by YS2, and equivalent between CON and YS4 heifers. Heifers receiving Y. schidigera extract had greater (P ≤ 0.05) rumen propionate, iso-valerate, and valerate concentrations, as well as less (P < 0.01) acetate : propionate ratio compared with CON heifers. Inclusion of Y. schidigera extract linearly increased (P ≤ 0.04) average daily gain and feed efficiency. No other treatment effects were noted (P ≥ 0.19) including bloat score (1.07 ± 0.03 across treatments), ruminal protozoa count, plasma concentrations of cortisol, haptoglobin, urea N, total protein, and rumen concentration of total volatile fatty acids. Supplementing Y. schidigera extract up to 4 g/d favored rumen propionate concentrations and linearly increased growth and feed efficiency but failed to mitigate incidence of frothy bloat in beef heifers consuming a grain-based bloat-provocative diet.
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The economic importance of genetically improving feed efficiency has been recognized by cattle producers worldwide. It has the potential to considerably reduce costs, minimize environmental impact, optimize land and resource use efficiency, and improve the overall cattle industry’s profitability. Feed efficiency is a genetically complex trait that can be described as units of product output (e.g. milk yield) per unit of feed input. The main objective of this review paper is to present an overview of the main genetic and physiological mechanisms underlying feed utilization in ruminants and the process towards implementation of genomic selection for feed efficiency in dairy cattle. In summary, feed efficiency can be improved via numerous metabolic pathways and biological mechanisms through genetic selection. Various studies have indicated that feed efficiency is heritable and genomic selection can be successfully implemented in dairy cattle with a large enough training population. In this context, some organizations have worked collaboratively to do research and develop training populations for successful implementation of joint international genomic evaluations. The integration of “-omics” technologies, further investments in high-throughput phenotyping, and identification of novel indicator traits will also be paramount in maximizing the rates of genetic progress for feed efficiency in dairy cattle worldwide.
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This study aimed to characterize the rumen microbiota structure of cattle grazing in tropical rangelands throughout seasons and their responses in rumen ecology and productivity to a N-based supplement during the dry season. Twenty pregnant heifers grazing during the dry season of northern Australia were allocated to either N-supplemented or un-supplemented diets and monitored through the seasons. Rumen fluid, blood, and feces were analyzed before supplementation (mid-dry season), after two months supplementation (late-dry season), and post supplementation (wet season). Supplementation increased average daily weight gain (ADWG), rumen NH3–N, branched fatty acids, butyrate and acetic:propionic ratio, and decreased plasma δ15N. The supplement promoted bacterial populations involved in hemicellulose and pectin degradation and ammonia assimilation: Bacteroidales BS11, Cyanobacteria, and Prevotella spp. During the dry season, fibrolytic populations were promoted: the bacteria Fibrobacter, Cyanobacteria and Kiritimatiellaeota groups; the fungi Cyllamyces; and the protozoa Ostracodinium. The wet season increased the abundances of rumen protozoa and fungi populations, with increases of bacterial families Lachnospiraceae, Ruminococcaceae, and Muribaculaceae; the protozoa Entodinium and Eudiplodinium; the fungi Pecoramyces; and the archaea Methanosphera. In conclusion, the rumen microbiota of cattle grazing in a tropical grassland is distinctive from published studies that mainly describe ruminants consuming better quality diets.
Chapter
One of the key areas in animal husbandry is to improve the quality (nutritional value) of dairy and meat products by enriching them with Conjugated Linoleic Acids (CLAs) like (cis-9, trans-11)- and (trans-10, cis-12)-octadecadienicacids; the former (rumenic acid) predominates all the CLAs. Though Vaccenic Acid (VA) is the immediate precursor of rumenic acid, dietary unsaturated fatty acids like Oleic Acid (OA), Linoleic Acid (LA) and a-Linolenic Acid (ALA) are the distant precursors of CLAs; and that CLA and VA are formed as intermediates during the biohydrogenation of the dietary OA, LA and ALA into fully saturated stearic acid. The mutual inter-relationship of rumen microbiota encompassing bacteria, protozoa and fungi facilitates the biohydrogenation process. Thus, this chapter critically evaluates the knowledge accumulated during the past four decades on the precursor of CLAs, micro-organisms involved in the production of CLA, the mechanism of biohydrogenation, and chemical synthesis of CLA, coupled with the rationale for biohydrogenation and factors affecting the production of CLA.
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Objective: The aim of the study was to compare the effect of two plant additives, rich in polyphenolic compounds, supplemented to sheep diets on microorganisms and carbohydrate fermentation in rumen. Methods: In the experiment, 6 ewes of the Polish Mountain breed were fitted with ruminal cannulas. Sheep were divided into three feeding groups. The study was performed in a cross-over design of two animals in each group, with three experimental periods (n=6 per each group). The animals were fed a control diet (CON) or additionally received 3 g of dry and milled lingonberry leaves (VVI) or oak bark (QUE). Additionally, plant material was analyzed for tannins concentration. Results: Regardless of sampling time, QUE diet increased the number of total protozoa, as well as Entodinium spp., Diplodinium spp. and Isotrichidae family, while decreased bacterial mass. In turn, a reduced number of Diplodinium spp. and increased Ophryoscolex spp. population were noted in VVI fed sheep. During whole sampling time (0, 2, 4 and 8 h), the number of protozoa in ruminal fluid of QUE sheep was gradually reduced as opposed to animals receiving CON and VVI diet, where rapid shifts in the protozoa number were observed. Moreover, supplementing sheep with QUE diet increased molar proportions of butyrate and isoacids in ruminal fluid. Unfortunately, none of the tested additives affected gas production. Conclusion: The addition of VVI or QUE in a small dose to sheep diets differently affected rumen microorganisms and fermentation parameters, probably because of various contribution of catechins in tested plant materials. However, it is stated that QUE diet seems to create more favorable conditions for growth and development of ciliates. Nonetheless, the results of the present study showed that VVI and QUE additives could serve as potential natural modulators of microorganism populations and, consequently, carbohydrate digestion in ruminants.
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Ruminants inhabit the consortia of gut microbes that play a critical functional role in their maintenance and nourishment by enabling them to use cellulosic and non-cellulosic feed material. These gut microbes perform major physiological activities, including digestion and metabolism of dietary components, to derive energy to meet major protein (65-85%) and energy (80%) requirements of the host. Owing to their contribution in digestive physiology, rumen microbes are considered one of the crucial factors affecting feed conversion efficiency in ruminants. Any change in the rumen microbiome has an imperative effect on animal physiology. Ruminal microbes are fundamentally anaerobic and produce various compounds during rumen fermentation, which are directly used by the host or other microbes. Methane (CH4) is produced by methanogens through utilizing metabolic hydrogen during rumen fermentation. Maximizing the flow of metabolic hydrogen in the rumen away from CH4 and toward volatile fatty acids (VFA) would increase the efficiency of ruminant production and decrease its environmental impact. Understanding of microbial diversity and rumen dynamics are crucial not only for the optimization of host efficiency but also required to mediate emission of greenhouse gases (GHGs) from ruminants. There are various strategies to modulate rumen microbiome, mainly including dietary interventions and the use of feed additives like plant secondary compounds. Phytogenic feed additives, mainly plant secondary compounds, have shown to modulate rumen microflora and change rumen fermentation dynamics leading to enhanced animal performance. Many in vitro and in vivo studies aimed to evaluate the use of plant secondary metabolites in ruminants have been conducted using different plants or their extract or essential oils. This review specifically aims to provide insights into the ecology of rumen microbes, their dietary interactions, and respective role in rumen fermentation. Moreover, a comprehensive overview of the modulation of rumen microbiome by using phytogenic compounds (essential oils, saponins, and tannins) for manipulating rumen dynamics to mediate methane emanation from livestock is presented. We have also discussed the pros and cons of each strategy along with future prospective of dietary modulation of rumen microbiome to improve the performance of ruminants while decreasing GHG emissions.
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Background: Diet has a profound impact on the rumen microbiota, and the impact can vary among the different rumen ecological niches (REN). This study investigated the effects of dietary replacement of soybean meal (SBM) with dried distillers grains with solubles (DDGS) on the rumen microbiota occupying different REN of growing Hu lambs. After a 9-week feeding trial, 6 lambs from each dietary treatment (SBM vs. DDGS-based diets) were slaughtered for sample collection. The microbiota of the rumen solid, liquid, and epithelium fractions was examined using amplicon sequencing analysis of bacterial 16S rRNA gene, functional prediction, and qPCR. Results: No interaction of dietary protein source (PS) and REN were detected for virtually all the measurements made in this study. The DDGS substitution resulted in very limited influence on bacterial community structure. However, the metabolic pathways predicted from 16S rRNA gene sequences varied greatly between SBM- and DDGS-based diets. The populations of rumen total bacteria, fungi, sulfate-reducing bacteria (SRB), and methanogens were not influenced by DDGS substitution, but the population of protozoa was reduced. The bacterial communities in rumen solid (RS) and liquid (RL) were similar in taxonomic composition but were different in relative abundance of some taxa. In contrast, the bacterial composition and relative abundance of rumen epithelium (RE) were greatly distinct from those of the RS and the RL. In alignment with the bacterial relative abundance, the metabolic pathways predicted from 16S rRNA genes also varied greatly among the different REN. The populations of total bacteria, protozoa, and methanogens attached to the RE were smaller than those in the RS and RL, and the fungal population on the rumen epithelium was smaller than that in the RS but similar to that in the RL. On the contrary, the SRB population on the RE was greater than that in the RS and RL. Conclusions: Substitution of SBM with DDGS had greater impact to the protozoa than to the other microbes, and the microbial community structure and functions at different REN are distinct and niche-adapted.
Article
This study was carried out to test the hypothesis that the inclusion of condensed tannins (CT) from Cistus ladanifer aerial part or extract in a diet composed of dehydrated lucerne and supplemented with 60 g/kg of soybean oil can modulate the rumen microbiome and increase the production of healthy biohydrogenation intermediates (BI). Hence, thirty-six lambs were used to evaluate the effect 3 levels of C. ladanifer CT (0, 1.25 and 2.5% of CT) and two ways of CT supply (C. ladanifer aerial parts and C. ladanifer CT extract) on rumen fatty acids and volatile fatty acids profile and ciliate protozoa and bacteria community composition. The experiment lasted 35 days, and rumen samples were collected immediately after slaughter. Ciliate protozoa were analyzed by microscopic counting, and high-throughput 16 S rRNA gene sequencing was used to analyse rumen bacterial composition. Condensed tannins diets did not affect ruminal fermentation. The inclusion of C. ladanifer aerial part or extract in lamb diets did not increase the t11-18:1 in the rumen content. On the other hand, the t11-18:1 proportion was lower in the rumen of lambs fed both C. ladanifer diets and the highest level of extract diet when compared with the lowest level of extract diet and the diets without CT inclusion. Regarding the rumen microbiome, the total of ciliates was not influenced by the CT level in diets but decreased with the inclusion of C. ladanifer aerial part in the diet. Entodinium genus was strongly and positively related with both total BI and t11-18:1 and it also was the ciliate genus most negatively related with rumen estimate biohydrogenation (BH) completeness. Independently of the diets, the bacterial community of rumen content was dominated by Firmicutes (49.8%) and Bacteroidetes (30.8%) phyla. The Lachnobacterium was the genus most closely related with t11-18:1 and negatively related with 18:0 and BH completeness, which suggests that the Lachnobacterium plays an important role on the BH when diets without CT inclusion and lower dose of C. ladanifer extract was fed to lambs, being responsible for t11-18:1 ruminal production. Cistus ladanifer aerial part and extract influenced the ruminal microbial composition, but at the conditions used, the increase in the ruminal production of healthy BI was not observed, highlighting the inconsistent BH response to dietary CT and underlining the need to develop efforts to increase knowledge about this CT source and its interactions with other feed factors and with the ruminal microbial community.
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Nitrate ( ) supplementation is an effective methane (CH4) mitigation strategy for ruminants but may produce nitrite ( ) toxicity. It has been reported that rumen protozoa have greater ability for and reduction than bacteria. It was hypothesised that the absence of ruminal protozoa in sheep may lead to higher accumulation in the rumen and a higher blood methaemoglobin (MetHb) concentration. An in vivo experiment was conducted with defaunated (DEF) and faunated (FAU) sheep supplemented with 1.8% in DM. The effects of rumen protozoa on concentrations of plasma and ruminal and , blood MetHb, ruminal volatile fatty acid (VFA) and ruminal ammonia (NH3) were investigated. Subsequently, two in vitro experiments were conducted to determine the contribution of protozoa to and reduction rates in DEF and FAU whole rumen digesta (WRD) and its liquid (LIQ) and solid (SOL) fractions, incubated alone (CON), with the addition of or with the addition of . The results from the in vivo experiment showed no differences in total VFA concentrations, although ruminal NH3 was greater (p < .01) in FAU sheep. Ruminal , and plasma concentrations tended to increase (p < .10) 1.5 hr after feeding in FAU relative to DEF sheep. In vitro results showed that reduction to NH3 was stimulated (p < .01) by incoming in both DEF and FAU relative to CON digesta. However, adding increased (p < .05) the rate of accumulation in the SOL fraction of DEF relative to both fractions of FAU digesta. Results observed in vivo and in vitro suggest that and are more rapidly metabolised in the presence of rumen protozoa. Defaunated sheep may have an increased risk of poisoning due to accumulation in the rumen.
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In addition to a wide variety of anaerobic and facultative anaerobic bacteria, camel rumen also harbors a diverse of eukaryotic organisms. In the present study, the eukaryotic communities of camel rumen were characterized using 18S rRNA amplicon sequencing. Metagenomic DNA was isolated from rumen samples of fourteen adult Bikaneri and Kachchhi breeds of camel fed different diets containing Jowar, Bajra, Maize, and Guar. Illumina sequencing generated 27,161,904 number of reads corresponding to 1543 total operational taxonomic units (OTUs). Taxonomic classification of community metagenome sequences from all the samples revealed the presence of 92 genera belonging to 16 different divisions, out of which Ciliophora (73%), Fungi (13%) and Streptophyta (9%) were found to be the most dominant. Notably, the abundance of Ciliophora was significantly higher in the case of Guar feed, while Fungi was significantly higher in the case of Maize feed, indicating the influence of cellulose and hemicellulose content of feedstuff on the composition of eukaryotes. The results suggest that the camel rumen eukaryotes are highly dynamic and depend on the type of diet given to the animal. Pearson’s correlation analysis suggested the ciliate protozoa and fungi were negatively correlated with each other. To the best of our knowledge, this is first systematic study to characterize camel rumen eukaryotes, which has provided newer information regarding eukaryotic diversity patterns amongst camel fed on different diets.
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The proceedings of a workshop held during the Third European Multicolloquium of Parasitology at Cambridge, U.K., on 7-13 September 1980, are reported. Individual contributions (from workers such as A.H. FAIRLAMB, M. MULLER, W. E. GUTTERIDGE, R. A. KLEIN, F. R. OPPERDOES, G. COOMBS to name a few), commentary and discussions are included (there are 116 references) gathered together in one paper. Only the contributions by F. Opperdoes to this workshop are shown below.
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The digestive tract of 15 elephants from South Africa and two from Zaire were sampled in order to determine the identity, density and population composition of the intestinal protozoa. The following orders were represented: Gymnostomatida, Trichostomatida and Entodiniomorphida. Altogether 17 species were identified, of which three are new. The new species as well as a new genus are described.
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Washed suspensions of the ruminal ciliates, Isotricha prostoma and Entodinium simplex, concentrated C¹⁴-labeled oleic, palmitic, stearic, and linoleic acids within the cells during short incubation periods. Radioautographs demonstrated that oleic acid-1-C¹⁴ was hydrogenated to stearic acid by I. prostoma, and Warburg manometric data showed that the sodium salts of oleic, valeric, caproic, and acetic acids, and methyl myristate, methyl laurate, and the triglyceride tributyrin stimulated fermentation of I. prostoma. The total lipid and free fatty acid contents of I. prostoma were determined.
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All ruminants are dependent on the microorganisms that live in their forestomach - the rumen - to break down ingested feed constituents into a form that the host animal can utilize. Protozoa are part of this complex ruminal population and are essential for the nutritional well-being and productivity of the host ruminant. Over 30 different genera (nearly 300 species) of protozoa from the rumen ecosystem have been described since their initial discovery nearly 150 years ago. This book brings together, for the first time, the available information on these protozoa. It comprehensively describes the characteristic anatomical features of value for their identification and includes detailed sections on techniques and methodologies for the isolation and cultivation of these fastidious, oxygen-sensitive microorganisms. Their occurrence, biochemistry, physiology, and role in the ruminal ecosystem are fully reviewed. Particular emphasis is given to potential improvement of the nutrition and productivity of the host ruminant through manipulation of the protozoal population and its activities.
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Three experiments were conducted to determine the influence of the presence of protozoa on copper (Cu) metabolism in sheep fed corn silage or corn silage supplemented with casein, fish meal or soybean meal. For each diet, eight rams were kept fauma-free; eight additional rams were faunated and housed separately from them. The faunated rams in all treatments grew faster and consumed more feed and, consequently, more Cu. However, they had a lower (P < .01) ruminal Cu solubility and accumulated less Cu in their livers than the fauna-free rams when fed corn silage alone or in combination with soybean meal (insoluble, ruminally degraded protein). Such effects were not significant when corn silage was supplemented with fish meal (protein resistant to ruminal degradation). The presence of ciliate protozoa in the rumen had no effect on the accumulation of Cu in the liver of sheep fed corn silage supplemented with casein (soluble, ruminally degraded protein) and produced conflicting results on ruminal Cu solubility. Hence, the effect of protozoa on Cu metabolism is indirect and depends on the type of
Chapter
Interspecific hydrogen transfer is necessary for methanogenesis by rumen microorganisms, and as the production of methane represents a loss of carbon from the host ruminant, is a process of great economic significance.1 Ruminal hydrogenogens include bacteria,2 chitridomycete fungi3 and holotrich ciliate protozoa.4 Close physical associations between rumen ciliates and methanogenic bacteria have been demonstrated5 as well as metabolic interactions.6 In this report we show how direct measurements of dissolved hydrogen and methane can provide information on the kinetics and stoichiometries of species interactions both in crude rumen liquor and in a defined methanogenic coculture.
Chapter
The exact role of rumen protozoa in ruminant nutrition is not well defined, but it is implicit that a group of organisms which is present in all wild and domesticated ruminants and contributes as much as half the biomass of the microbial population must make a significant contribution to the economy of the system. Rumen ciliates are classified into holotrichs, which ferment a wide range of soluble carbohydrates1 and entodiniomorphs, which are principally particle feeders (i.e. cellulolytic and amylolytic).2 Some species of the latter have a limited ability to utilize soluble carbohydrates. The production of hydrogen by rumen ciliates3,4 occurs in a specialized organelle, the hydrogenosome.5,6 At some times oxygen is present in the rumen at low concentrations7 and rumen ciliates show high affinity oxygen consumption. Here we show that four different species of ciliates have oxygen-sensitive hydrogenases, so that the availability of hydrogen for interspecies hydrogen transfer will fluctuate depending on ambient oxgyen concentrations.
Chapter
This chapter focuses on the role of rumen fungi in plant cell-wall degradation, their properties, and their relations with the other rumen microorganisms. In the rumen, the conversion of plant material to short-chain fatty acids (SCFA) is carried out by a complex microbial population. Electron microscopy shows the fungi colonizing the lignocellulosic tissues of plant particles present in the rumen. The close association of fungi with plant fibers suggests that these microorganisms have the ability to degrade plant components. Rumen fungi are not essential for the survival of ruminants—as they are present in only very low numbers, or even absent, in ruminants that are fed low-fiber diets—but play an important role in the digestion of poor-quality forages. The role of these fungi in vivo and their contribution to plant cell-wall degradation and proteolysis are still open to questions.
Chapter
Recent advances in the elucidation of the metabolic capabilities of some protists living in ecosystems where oxygen concentrations are low highlight certain common features of their roles in their environments. In this review we survey the symbiotic protozoa and chytridomycete fungi of the rumen alongside parasitic protozoa infecting the human intestine and urogenital tract: many of these show striking metabolic similarities. We emphasize the putative activities of these organisms in situ as inferred by extrapolation from work with isolated organisms or axenic cultures.
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The defaunating capabilities of alkanate 3SL3 and calcium peroxide were evaluated in sheep (70 kg BW). Alkanate 3SL3 was more suitable as a defaunating agent than calcium peroxide. The most efficacious procedure for using alkanate 3SL3 was a 3 d dose (25 ml/d in 200 ml water) without feeding during the first 2 d and a single supplemental dose (70 ml in 200 ml water) 8 d later. Nutrient digestibilities were lower for defaunated than control sheep, but differences were not significant (P>.10). Compared to faunated sheep, the sheep defaunated with alkanate 3SL3 had similar ruminal pH (6.0 vs 5.8 and 6.2 vs 6.6) and lower (P<.05) concentrations of ruminal ammonia (21.3 vs 2.0 and 19.8 vs 4.3 mg/dl) and total volatile fatty acids (115.5 vs 96.8 and 104.0 and 71.8 mM) at 2 and 4 h, respectively, after the morning feeding. The tendency for lower nutrient digestibility by defaunated sheep may be related to lower ruminal ammonia concentration resulting from defaunation. Using an in vitro system, it was determined that nystatin was required in concentrations too great (6 or 12 mg/ml ruminal contents) to be economically feasible.
Article
Gnotobiotic cultures of Entodinium caudatum were prepared from the clones of this protozoon. The organism grew well with any of the bacterial species investigated, irrespective of shape, origin, and gram-staining property. The cultures with E. coli, as well as Streptococcus bovis, were maintained for over 2 mth. The protozoa free from living bacteria were prepared from the gnotobiotic cultures established. These axenic protozoa could be kept alive in the presence of dead bacterial cells for up to 3 wk, but their growth was extremely slow and the population densities maintained were much lower than those in the cultures with living bacteria.
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Of the 11 ciliate protozoa present in the rumen of the sable antelope, two are holotrichs and nine entodiniomorphs. One new species Diplodinium (Eudiplodinium) sablei is described. The seven antelopes investigated gave an average total number of protozoa per cm3 rumen fluid of 1,79 ± 0,39 × 105, a relatively low figure typical of grazing wild ungulates.Van die 11 siliaat-protozoa teenwoordig in die rumen van die swartwitpens was twee holotriche en nege entodiniomorphe vorme. Een nuwe spesies Diplodinium (Eudiplodinium) sablei word beskryf. Die sewe swartwitpense wat ondersoek is, het gemiddeld 1,79 ± 0,39 × 10* protozoa per cm3 rumenvloeistof gehad, 'n relatief lae syfer tipies van weiende wildsbokke.