Dasytricha Ruminantium Research Articles

Improved and easy method for long-term in vitro culture of rumen ciliates Dasytricha ruminantium

The rumen ciliates are a diverse group of protozoa residing in the rumen of ruminant animals. They are primarily found in the orders Entodiniomorphida and Vestibuliferida, playing crucial roles in the digestion and breakdown of feed within the host's rumen, closely intertwined with the host's nutrient absorption. In vitro monocultures of representatives of rumen ciliates are important to better study them. So far, Entodinium caudatum and Epidinium caudatum, representatives of the order Entodiniomorphida, have been successfully cultivated as a monoculture in vitro. However, for the order Vestibuliferida, no representative species has been established a stable monoculture in vitro up to date, which hampers to study their physiology and metabolism. Therefore, we have developed a simple method for the in vitro cultivation of Dasytricha ruminantium, a representative rumen ciliate in the order Vestibuliferida. Utilizing an optimized culture medium with easily obtainable components, and the cultivation process is simple. This will facilitate further research in metabolism and other studies requiring large pure live materials.1.Filtration and separation for enriching D. ruminantium.2.A culture medium (DRM) suitable for the growth of D. ruminantium, with easily obtainable components.3.Simple cultivation process, facilitating the obtainment of a large number of monocultured D. ruminantium.

Rumen Ciliate Fauna of Domestic Sheep in Kastamonu, Turkey, and Infraciliature of Diplodinium quinquespinosum, Metadinium affine, and M. tauricum (Entodiniomorphida, Ophryoscolecidae).

Species distribution and composition of the ciliates found in the ruminal contents of 15 domestic sheep (Ovis aries) living in Kastamonu, Turkey, were investigated. Twenty-four species and 8 morphotypes belonging to 10 genera were identified. The density of the rumen ciliates in sheep was 108.2 (± 150.8) × 104 cells ml-1, and the mean number of ciliate species per host was 10.7 ± 4.6. Among the ciliate species identified, Dasytricha ruminantium was the most abundant, with a prevalence of 93.3%, whereas Diplodinium quinquespinosum, Eudiplodinium rostratum, and Metadinium tauricum were detected in only one animal (6.7% prevalence). D. quinquespinosum, Eudiplodinium rostratum, and Entodinium simulans m. dubardi were detected for the first time in sheep from Turkey. This is the first report of the presence of D. quinquespinosum in the rumen of ruminants in Turkey. The infraciliature of D. quinquespinosum, Metadinium affine, and M. tauricum (Entodiniomorphida, Ophryoscolecidae) was investigated. D. quinquespinosum and M. affine had Diplodinium-type infraciliature, whereas M. tauricum possessed Metadinium medium-type infraciliature.

Rumen protozoal dynamics during the transition from milk/grass to high-concentrate based diet in beef calves as affected by the addition of tannins or medium-chain fatty acids

Changes in rumen protozoal community during adaptation of 7-month-old beef calves from a milk/grass diet to a high-energy diet consisting of cereal-based concentrate plus wheat straw, both given ad libitum (diet C), were studied. Eighteen rumen-cannulated Limousine crossbred male calves were randomly assigned to three diets (C; C plus 20 g/kg of a 65:35 chestnut and quebracho tannin extract, T; and C plus 6 g/kg medium-chain fatty acid (MCFA) mixture, M). Fermentation variables were studied, and rumen ciliates were quantified and classified from rumen fluid sampled just before the morning feeding on days 0, 7, 14, 21 and 28 of the experiment. Protozoal population changed over time, but all calves harbored a stable population at the end of the experiment. Diversity decreased on time, and Entodinium and Isotricha species were the most abundant at the end of the trial. When occurred, defaunation was transient as protozoa were absent from M calves in three occasions on days 7 and 14 but were refaunated thereafter reaching a consistent population. Regardless the diet, proportions of Isotricha spp. and Dasytricha ruminantium, Epidinium spp. and Subfamily Diplodiniinae, decreased throughout the experiment, whereas Entodinium spp. increased reaching 0.93 of total protozoa. Dasytricha and protozoa from Subfamily Diplodiniinae disappeared from the rumen of all calves at the end of the study, except for Polyplastron multivesiculatum. Rumen variables were not affected by the addition of additives (P > 0.05). Rumen pH decreased across the study (P < 0.001) but did not reach acidotic values despite the high fermentability of the diet. Higher levels of lactate were observed on C calves at d14, but not in other dates (diet by day interaction, P = 0.03). Addition of tannin extract did not affect protozoal concentration and diversity, but MCFA might even lead to a transient defaunation. Transition to a high-concentrate diet does not necessarily reduce initial protozoal concentration, but diversity is affected towards a major proportion of Entodinium and, to a lesser extent, Isotricha. Dietary shift from weaning to a high-concentrate ration promotes a less diverse rumen protozoal population, but a high concentration is still maintained thereafter.

Variation of natural diet of free ranging mouflon affects their ruminal protozoa composition

The mouflon’s traditional classification as a grazer has recently been questioned, therefore new insight into the species’ feeding and digestion is needed. The presence and share of different ciliate genera in the rumen may contribute to an understanding of a species’ feeding physiology, therefore we analysed the composition of mouflon rumen ciliates and correlated their density with the percentage of different food types eaten by the animals. We found that the dominant ciliates were Entodinium spp., with a small proportion of Anoplodinium denticulatum, Eudiplodinium maggii, Epidinium ecaudatum caudatum and Dasytricha ruminantium. The main food types taken by the animals were deciduous tree leaves, grass and bramble. The density of ciliates from the Entodinium genus rose with an increase in deciduous leaves in the diet and fell with an increase of graminoids in the diet. The density of ciliates from the Anoplodinium and Eudiplodinium sub-genera increased with a rise in tree shoots and was reduced with a rise of deciduous leaves in the diet. These results confirm that the protozoal fauna vary with current food composition in intermediate feeders.

Rumen Ciliate Fauna of Domestic Sheep (Ovis aries) in İzmir, Turkey and Scanning Electron Microscopic Observations

Species composition and distribution of ciliates were investigated in the rumen contents of 15 domestic sheep (Ovis aries) living in İzmir, Turkey. Twenty-three species and 11 morphotypes belonging to nine genera were identified. The density of ciliates was 118.3 ± 63.5 × 104 cells ml−1, and the mean number of ciliate species per host was 13.5 ± 5.3. Entodinium simulans was the most abundant species, with a prevalence of 100%. Two morphotypes of Diplodinium flabellum were identified, such as D. flabellum m. aspinatum and D. flabellum m. monospinatum, and E. simulans m. dubardi was found for the first time in domestic sheep in Turkey. The scanning electron microscopic observations of Entodinium longinucleatum, E. bursa, E. rectangulatum m. rectangulatum, E. semahatae, E. exiguum, E. minimum, E. simulans m. caudatum, E. dilobum, Diplodinium flabellum m. aspinatum, D. dentatum, Isotricha prostoma, Metadinium affine, Enoploplastrom triloricatum, Dasytricha ruminantium, Ophryoscolex caudatus m. tricoronatus, Epidinium ecaudatum m. parvicaudatum, and Polyplastron multivesiculatum were studied.

Ciliate Protozoa from the Rumens of Japanese Serows (Capricornis crispus) Captured in the Northern Part of Shizuoka Prefecture, Japan

Ciliate fauna collected from the rumens of eight wild Japanese serows (Capricornis crispus) captured in the northern part of Shizuoka Prefecture, Japan, were compared with the ciliate faunas found in other Japanese wild ruminants. We identified six species belonging to two genera of ciliates (Entodinium nanellum, Ent. minimum, Ent. simplex, Ent. dubardi, Ent. longinucleatum, and Elytroplastron bubali), all of which had been reported in a previous study examining the rumen contents of Japanese serows in Gifu and Miyagi Prefectures. However, four of the previously identified ciliate species (Dasytricha ruminantium, Ent. lobosospinosum, Ent. ekendrae, and Epidinium ecaudatum) were not detected in this study. Ely. bubali was detected frequently, suggesting that this species is characteristic of the rumen of Japanese serows. Furthermore, the six ciliate species in this study were observed in over 70% of the studied serows, suggesting that these ciliate species are widely distributed in the rumens of serows in this study area.

Rumen Ciliate Biota of Domestic Cattle (Bos taurus taurus) in İstanbul, Turkey and Infraciliature of Metadinium medium (Entodiniomorphida, Ophryoscolecidae)

The species composition and distribution of ciliates were investigated in the rumen contents of 15 domestic cattle (Bos taurus taurus L.) living in the European part of Istanbul, Turkey. Thirty-five species and 13 morphotypes belonging to 13 genera were identified. The density of rumen ciliates in cattle was 31.8 (± 21.3) × 104 cells ml−1, and the mean number of ciliate species per host was 12.9 ± 4.4. Of the ciliate species, Dasytricha ruminantium, Entodinium simulans, and Isotricha prostoma were the most abundant, each with a prevalence of 93.3%, whereas Diplodinium anisacanthum, D. dogieli, D. rangiferi, Enoploplastron triloricatum, Metadinium medium, and Ostracodinium munham were detected only in one animal (6.7% prevalence). Eodinium posterovesiculatum m. bilobosum and D. dogieli are new host records for cattle in Turkey. The infraciliature of M. medium (Entodiniomorphida, Ophryoscolecidae) was examined and detected for the first time. The buccal infraciliature of M. medium was composed of three polybrachykineties, a kinety loop, and paralabial kineties. A large dorso-adoral polybrachykinety, a gentle S-shaped curved vestibular polybrachykinety, and a kinety loop between the dorso-adoral polybrachykinety and adoral polybrachykinety were characteristics. Because of these features, M. medium-type buccal infraciliature was between the Ostracodinium gracile-type buccal infraciliature and the Ostracodinium mammosum-type buccal infraciliature.

Rumen ciliate protozoa of domestic sheep (Ovis aries) and goat (Capra aegagrus hircus) in Kyrgyzstan.

Species composition and concentration of rumen ciliate protozoa were investigated in the rumen contents of 14 domestic sheep and 1 goat living in Bishkek, Kyrgyzstan. This is the first report on rumen ciliates from ruminants living in Kyrgyzstan. In sheep 12 genera, 28 species and 12 morphotypes were detected, whereas in goat 8 genera, 12 species and 4 morphotypes were detected. The density of ciliates in sheep was (28.1 ± 20.0) × 10(4) cells mL(-1) and in goat was 37.0 × 10(4) cells mL(-1). Dasytricha ruminantium, Isotricha prostoma, Entodinium simulans and Ophryoscolex caudatus were major species (100%) in sheep, and for the first time, Diplodinium rangiferi was detected in a domestic goat.

Rumen ciliate biota of water buffalo (Bubalus bubalis Linnaeus, 1758) in Kastamonu, Turkey

Species composition and distribution of rumen ciliates were investigated in the rumen contents of six Anatolian water buffaloes living in Kastamonu, Turkey. Thirty-seven species and 19 morphotypes belonging to 11 genera were identified, all being first reports of rumen ciliates from Anatolian water buffaloes. The mean number of ciliates was 70.5 ± 62.3 × 104 cells in 1 mL of rumen contents, while the average number of ciliate species per host was 17.5 ± 3.6. Dasytricha ruminantium, Entodinium simulans, and En. longinucleatum were found to be the dominant species occurring in all animals. Entodinium ellipsoideum, Eudiplodinium dilobum, and Ostracodinium munham were isolated from buffaloes for the first time. No previously unknown species were observed.

Rumen ciliates in the African (Cape) buffalo (Syncerus caffer caffer) living in the vicinity of the Orpen Gate entrance into Kruger National Park, South Africa.

Samples of rumen contents were obtained from 10 African (Cape) buffalo living in the vicinity of the Orpen Gate entrance into Kruger National Park in South Africa. Total number of ciliate protozoa per animal ranged from 3.15 to 23.25 x 10³. Forty three different species and forms were observed, of which 35 are a new host record. The total number of species and forms per animal varied from 10 to 17. Eudiplodinium maggii occurred in all 10 animals, followed by Dasytricha ruminantium in nine animals. Diplodinium posterovesiculatum, Eudiplodinium magnodentatum and Ostracodinium mammosum were present in seven animals with all other species and forms occurring in five or less animals.

Evaluating the effects of chitosan, plant oils, and different diets on rumen metabolism and protozoan population in sheep

Chitosan (CH) has been shown to be a promising natural antimicrobial agent. This study examined the effects on rumen metabolism when providing diets containing high forage (HFD), low forage (LFD), and maize silage (MSD) to a 24-h batch culture in which the diets were not supplemented (control) or were supplemented with CH (100 mg/L), sunflower oil (SF, 35.0 g/kg dry matter), rapeseed oil (RP, 35.0 g/kg dry matter), or SF and RF with chitosan combinations (SFCH and RPCH). Dry matter digestibility in the batch culture was influenced by CH and was decreased in HFD compared with the control (P < 0.01). Decreasing total number of protozoa and the number of Entodinium spp. was evident, especially in LFD and MSD, with all additives. RPCH had a predominantly adverse effect on Dasytricha ruminantium in MSD. Interactions of the diets × additives in the majority of rumen ciliate populations were detected. The concentrations of trans-vaccenic acid and conjugated linoleic acid (c9, t11-CLA) were unchanged by chitosan. However, the combination of SF and RF with chitosan (SFCH and RPCH) positively affected fatty acid profiles, which might be related to differences in diets, SF or RP composition, and different microbial activity in the batch cultures.

Protozoa and digestive tract parameters in Blue wildebeest (Connochaetes taurinus) and Black wildebeest (Connochaetes gnou), with description of Entodinium taurinus n. sp.

Rumen contents from four blue wildebeest (Connochaetes taurinus) and six black wildebeest (Connochaetes gnou) were collected from two locations during two winter culling seasons. A total of 16 species of protozoa were found in blue wildebeest with Dasytricha ruminantium, Opisthotrichum janus and Ostracodinium gracile occurring in all four animals. In black wildebeest, 23 species of protozoa were observed with only Diplodinium bubalidis (caudal spine morphotype) and Ostracodinium damaliscus being present in all animals. In the blue wildebeest, the total number of species in an individual animal varied from 9 to 11 and in the black wildebeest, the number ranged from 4 to 14. Concentrations of cells per ml ranged from 1110 to 5880 in the blue wildebeest and 3120 to 6240 in the black wildebeest. This study is the first report on protozoa species in the blue and black wildebeest. A new species of Entodinium is described, Entodinium taurinus n. sp., observed in the rumen contents of three blue wildebeest. Several physical parameters of the digestive tract were also measured, including distribution, pH and density of gastrointestinal contents in different sections of the total tract. In vitro gas production was estimated for rumen, cecum and colon contents.

Dasytricha Dominance in Surti Buffalo Rumen Revealed by 18S rRNA Sequences and Real-Time PCR Assay

The genetic diversity of protozoa in Surti buffalo rumen was studied by amplified ribosomal DNA restriction analysis, 18S rDNA sequence homology and phylogenetic and Real-time PCR analysis methods. Three animals were fed diet comprised green fodder Napier bajra 21 (Pennisetum purpureum), mature pasture grass (Dicanthium annulatum) and concentrate mixture (20% crude protein, 65% total digestible nutrients). A protozoa-specific primer (P-SSU-342f) and a eukarya-specific primer (Medlin B) were used to amplify a 1,360 bp fragment of DNA encoding protozoal small subunit (SSU) ribosomal RNA from rumen fluid. A total of 91 clones were examined and identified 14 different 18S RNA sequences based on PCR-RFLP pattern. These 14 phylotypes were distributed into four genera-based 18S rDNA database sequences and identified as Dasytricha (57 clones), Isotricha (14 clones), Ostracodinium (11 clones) and Polyplastron (9 clones). Phylogenetic analyses were also used to infer the makeup of protozoa communities in the rumen of Surti buffalo. Out of 14 sequences, 8 sequences (69 clones) clustered with the Dasytricha ruminantium-like clone and 4 sequences (13 clones) were also phylogenetically placed with the Isotricha prostoma-like clone. Moreover, 2 phylotypes (9 clones) were related to Polyplastron multivesiculatum-like clone. In addition, the number of 18S rDNA gene copies of Dasytricha ruminantium (0.05% to ciliate protozoa) was higher than Entodinium sp. (2.0 × 10(5) vs. 1.3 × 10(4)) in per ml ruminal fluid.

Protozoa and digestive tract parameters of the impala

Intestinal contents were collected from eight impala at three different localities during the winter hunting season (2005-2009), as well as from another 24 animals from a one-year trial at a game farm called Ditholo (2003-2004). Gas production, protozoa counts and several other physiological parameters were measured from both rumen and caecum or colon contents. Only higher ophryoscolecid and Isotrichidae species of protozoa were counted and identified. Ostracodinium gracile was present in all 32 impala. Eudiplodinium maggii was present in 31 animals and Eudiplodinium impalae and Epidinium (either ecaudatum or caudatum) in 30 animals. Dasytricha ruminantium was present in only 11 of the impala. Concentrations of protozoa were correlated with the season of sample collection and highly correlated with the animals living on the game farm. Gas production (mL/g of wet rumen ingesta) was weakly correlated with protozoa concentration but not with the season of collection.

Influence of inoculated maize silage and sunflower oil on the in vitro fermentation, ciliate population and fatty acid outputs in the rumen fluid collected from sheep

The effect of maize silage (MS) supplemented with sunflower oil (SO) on the rumen fermentation parameters, growth of ciliate population and fatty acid outputs&lt;I&gt; &lt;/I&gt;was investigated for 72 hours using a batch culture fermentation technique. The rumen fluid from ruminally fistulated sheep was mixed with McDougall’s buffer (1:1) and added (35 ml) to fermentation bottles containing 1.5 g (0.38 g of DM) of MS with or without SO (30 g/kg of DM). Four types of MS were used: uninoculated (MS) or inoculated with &lt;I&gt;Lactobacillus plantarum&lt;/I&gt; CCM 4000 (MS+LP), &lt;I&gt;Lactobacillus fermentum&lt;/I&gt; LF2 (MS+LF) or &lt;I&gt;Enterococcus faecium &lt;/I&gt;CCM 4231 (MS+EF) in simultaneous incubations at 39 ± 0.5°C for 72 h &lt;I&gt;in vitro&lt;/I&gt;. Total gas production was decreased by SO (by 16–17%) in MS and all inoculated MS. Methane production was not significantly influenced by SO. The concentration of total volatile fatty acids, molar proportions of acetate, propionate and &lt;I&gt;n&lt;/I&gt;-butyrate were influenced by SO (&lt;I&gt;P&amp;nbsp;&amp;lt;&amp;nbsp;&lt;/I&gt;0.05; &lt;I&gt;P &amp;lt; &lt;/I&gt;0.01; &lt;I&gt;P &amp;lt; &lt;/I&gt;0.001). SO had no significant effect on the total ciliate number and growth of the examined ciliate species &lt;I&gt;Entodinium &lt;/I&gt;spp., &lt;I&gt;Dasytricha ruminantium&lt;/I&gt;, &lt;I&gt;Polyplastron multivesiculatum&lt;/I&gt;,&lt;I&gt; Enoploplastron triloricatum&lt;/I&gt; and&lt;I&gt; Diplodinium denticulatum&lt;/I&gt;. The number of &lt;I&gt;Dasytricha ruminantium&lt;/I&gt; with MS+LP was higher (&lt;I&gt;P &amp;lt; &lt;/I&gt;0.01) as compared to MS. Outputs of &lt;I&gt;trans&lt;/I&gt; vaccenic acid (TVA), linoleic acid, conjugated linoleic acid (CLA) and α-linolenic acid were influenced by SO (&lt;I&gt;P&amp;nbsp;&amp;lt;&amp;nbsp;&lt;/I&gt;0.05;&lt;I&gt; P &amp;lt; &lt;/I&gt;0.01; &lt;I&gt;P &amp;lt; &lt;/I&gt;0.001). However, the output of CLA was increased only in MS+LF (&lt;I&gt;P &amp;lt;&lt;/I&gt; 0.001). It can be concluded that the supplementation of sunflower oil into maize silage is not effective as dietary antiprotozoal agents in a short-time interval, but it might positively affect the rumen bacterial population and activities. Sunflower oil with inoculated and uninoculated maize silage could be effective for an increase of TVA in the rumen fluid of sheep.&amp;nbsp; &amp;nbsp;

Comparison of nisin and monensin effects on ciliate and selected bacterial populations in artificial rumen

The effect of daily supplementation of nisin (2 mg/L), monensin (5.88 mg/L) and nisin and monensin (2 + 5.88 mg/L) on ovine ruminal ciliates and bacteria was investigated using the artificial rumen RUSITEC. Major groups in RUSITEC were Entodinium spp. and Dasytricha ruminantium. The supplementation of nisin significantly increased the population of both major ciliate groups. The supplementation of monensin significantly decreased the population of both groups. The combined effect of nisin and monensin was similar to the effect of monensin. Monensin had strong antiprotozoic effects in contrast to the stimulatory effects of nisin. D. ruminantium followed by Entodinium spp. appeared more resistant to tested compounds than other rumen ciliates. Tested additives did not significantly influence the presence and growth of amylolytic streptococci and enterococci but nisin showed a tendency to decreasing the concentration of Escherichia coli and lactobacilli.

Fatty acid profiles of rumen fluid from sheep fed diets supplemented with various oils and effect on the rumen ciliate population

The profile of trans-fatty acids and the protozoan population were evaluated in four ruminally fistulated sheep fed a diet with meadow hay: barley grain ratio (80:20%) plus sunflower oil (SO), rapeseed oil (RO) or linseed oil (LO) (5% wt/wt). The concentrate was daily mixed with individual oils and offered at 07.00 h. A 4 × 4 Latin square with 4-week periods was used. The concentration of trans-vaccenic acid (TVA) was the highest 4 h after feeding (36.1 g/100 g FA with SO; 34.5 g/100 g FA with RO) and then decreased with the time after feeding (&lt;i&gt;P&lt;/i&gt; &lt; 0.05). The concentration of &lt;i&gt; cis9, trans&lt;/i&gt;11 conjugated linoleic acid (c9,t11-CLA) with RO increased from 3.23 g/100 g FA (2 h after feeding) to 4.67 g/100 g FA (4 h after feeding). The concentration of c9,t11-CLA with SO increased from 2.09 g/100 g FA (2 h after feeding) to 2.31 g/100 g FA (4 h after feeding). The concentration of c9,t11-CLA with LO was the highest 4 h after feeding (2.07 g/100 g FA). Overall effects of the oil supplements and time after feeding on short-chain fatty acids (SCFA), medium-chain fatty acids (MCFA) and long-chain fatty acids (LCFA) in the rumen fluid were evident. A strong interaction of oil supplements and time after feeding was detected in the concentration of UFA and SFA (&lt;i&gt;P&lt;/i&gt; &lt; 0.001). A significant effect of LO on the rumen ciliate population was observed; the total protozoan concentration and the number of &lt;i&gt;Entodinium&lt;/i&gt; spp. were decreased as well as &lt;i&gt;Dasytricha ruminantium, Isotricha&lt;/i&gt; spp., &lt;i&gt;Polyplastron multivesiculatum, Ophryoscolex c. tricoronatus&lt;/i&gt; and&lt;i&gt; Eremoplastron dilobum&lt;/i&gt;.

The effect of microbial oil, evening primrose oil, and borage oil on rumen ciliate populations in an artificial rumen (Rusitec)

Microbial (MO), borage (BO) and evening primrose (EPO) 5% (wt/wt) oils were supplemented to a diet consisting of meadow hay and ground barley (60:40) for six days following a five-day adaptation period in an artificial rumen (Rusitec) inoculated with sheep rumen fluid having an Atype ciliate population. After the adaptation period, the following rumen ciliate genera and species were established: Entodinium spp., Dasytricha ruminantium, Eremoplastron bilobum, Diploplastron affine, Polyplastron multivesiculatum and Isotricha spp. (I. prostoma and I. intestinalis). The total ciliate population as well as the population of Eremoplastron decreased (P<0.05 and P<0.01, respectively) in the group supplemented with BO. In contrast, the population of Polyplastron increased (P<0.01) following BO supplementation. The populations of Dasytricha, Eremoplastron, and Isotricha spp. decreased (P<0.01) in the group with EPO supplement, in contrast to the population of Entodinium spp., which increased (P<0.05). MO supplementation decreased the populations of Eremoplastron and Isotricha spp. (P<0.01). None of the oil supplements influenced the population of Diploplastron. The results of this study showed that the examined species of rumen ciliates had no uniform response to the tested oils. Responses strongly depended on the composition of oils and the resultant concentration of the main fatty acid components.

Horizontal gene transfer from Bacteria to rumen Ciliates indicates adaptation to their anaerobic, carbohydrates-rich environment

BackgroundThe horizontal transfer of expressed genes from Bacteria into Ciliates which live in close contact with each other in the rumen (the foregut of ruminants) was studied using ciliate Expressed Sequence Tags (ESTs). More than 4000 ESTs were sequenced from representatives of the two major groups of rumen Cilates: the order Entodiniomorphida (Entodinium simplex, Entodinium caudatum, Eudiplodinium maggii, Metadinium medium, Diploplastron affine, Polyplastron multivesiculatum and Epidinium ecaudatum) and the order Vestibuliferida, previously called Holotricha (Isotricha prostoma, Isotricha intestinalis and Dasytricha ruminantium).ResultsA comparison of the sequences with the completely sequenced genomes of Eukaryotes and Prokaryotes, followed by large-scale construction and analysis of phylogenies, identified 148 ciliate genes that specifically cluster with genes from the Bacteria and Archaea. The phylogenetic clustering with bacterial genes, coupled with the absence of close relatives of these genes in the Ciliate Tetrahymena thermophila, indicates that they have been acquired via Horizontal Gene Transfer (HGT) after the colonization of the gut by the rumen Ciliates.ConclusionAmong the HGT candidates, we found an over-representation (>75%) of genes involved in metabolism, specifically in the catabolism of complex carbohydrates, a rich food source in the rumen. We propose that the acquisition of these genes has greatly facilitated the Ciliates' colonization of the rumen providing evidence for the role of HGT in the adaptation to new niches.

The effects of organic selenium supplementation on the rumen ciliate population in sheep

The effect of selenium supplementation on the rumen protozoan population of sheep was demonstrated. Both the total and generic counts of rumen ciliates in sheep fed a diet with basal Se content (70 microg/kg dry matter) were compared to those of animals given feed supplemented with inorganic (disodium selenite) or organic Se (selenized yeast) (310 microg/kg dry matter). The genera of Entodinium, Isotricha, Dasytricha, Ophryoscolex, Diploplastron and Polyplastron occurred in all sheep except for the control, in which Ophryoscolex was not observed. The population of Ophryoscolex caudatus f. tricoronatus was significantly higher in sheep supplemented with organic Se than in animals given inorganic Se (by 160 %). Supplementation of feed with selenized yeast induced significant growth in the Diploplastron population (by 63 %) while no change occurred in sheep given selenite. The populations of Dasytricha ruminantium and Polyplastron multivesiculatum were higher than control in both Se-supplemented groups. The ciliate population of Entodinium spp. was not influenced by Se supplements. Our results suggest a protective effect of Se feed supplementation on the development of some rumen ciliate species in young ruminants.