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1.
A survey was conducted to investigate the physiological levels of pipecolic acid (Pip) in rumen fluid and plasma of ruminants such as goats and cattle in the presence or absence of rumen protozoa. The concentration of Pip was determined using HPLC. Basal Pip levels in the rumen fluid and plasma of normal faunated animals were 21 ± 8 and 2.3 ± 1.3 µM, respectively, and levels increased 1–2 h after feeding. The Pip levels in the rumen fluid and plasma of faunated goats and cattle were significantly higher than those of defaunated goats and unfaunated cattle. A small amount of Pip was also found in the rumen fluids of the defaunated and unfaunated animals; this appeared to be derived from feeds such as hay cube and corn silage. The results obtained in the present study suggest that a significant amount of rumen‐produced Pip is likely to be absorbed into the plasma of the host animals and that rumen protozoa significantly enhance the concentration of Pip in the rumen fluid and plasma of ruminant animals.  相似文献   

2.
The objective of this study was to investigate the antioxidant status in ruminal fluid and blood plasma among three faunated and two defaunated (protozoa‐free) cattle (average bodyweight of 225 kg), fed hay plus concentrate. The extra cellular antioxidant activity of the mixed protozoa and bacteria suspensions were also studied in vitro. The antioxidant activity was detected by means of the free radical scavenging ability. The activity (units/microbial nitrogen) of the protozoal suspension increased from 59 (0 h) to 318 (18 h), and decreased to 40 (24 h) during incubation. The activity of the bacterial suspension also increased from 111 (0 h) to 644 (18 h), and decreased to 533 (24 h). The antioxidant activity (units/mL, U/mL) in the ruminal fluid of faunated (ranging from 116 to 254) and defaunated (ranging from 66 to 110) cattle was increased after 2 h and decreased after 5 h of feeding, being significantly higher in the faunated cattle. The antioxidant activity of blood plasma (U/mL) ranged from 248 to 316 in the faunated and 121–170 in the defaunated cattle during 0–5 h after feeding, being significantly higher in the faunated cattle. Therefore, defaunation possibly causes a decrease in the antioxidant level in the ruminal fluid, and may impair the health and performance of ruminants through an oxidant–antioxidant imbalance.  相似文献   

3.
The cell wall constituents of feces from three faunated and three defaunated (without ruminal ciliate protozoa) cattle fed on a Sudangrass hay and concentrate mixture (8:5) were analyzed. There was little difference in digestibility of dry matter between the faunated and defaunated cattle. Analysis of the fecal sugar residues revealed that the digestibilities of arabinose and galactose, derived from pectic and hemicellulosic substances located within the compound middle lamella, were higher in the defaunated cattle than the faunated cattle (P < 0.05), whereas the digestibilities of glucose and xylose, derived mainly from cellulose and xylan, were unchanged by the removal of protozoa. The digestibility of lignin was not different between the faunated and defaunated cattle, but those of mannose and p‐coumaric acid were lower in the defaunated than in the faunated animals (P < 0.05). The ratio of primary cell wall to secondary cell wall in fecal plant materials was lower for the defaunated than for the faunated cattle. The results in this study suggested that the defaunation enhanced the microbial degradation of the thin cell walls, but depressed the degradation of developed cell walls.  相似文献   

4.
The effect of the presence of ruminal protozoa on the composition of fecal microbiota in cattle was investigated. Six castrated Holstein cattle (mean bodyweight 137 kg) were divided into two groups: three faunated and three unfaunated. The fecal bacterial composition of the faunated and unfaunated cattle was compared using a culture method and by terminal restriction fragment length polymorphism (T‐RFLP) analysis. Approximately 0.4 to 2.3% of the bacterial cells detected by microscopy formed colonies on medium 10. The major terminal restriction fragments were detected in the T‐RFLP profiles generated by Hha I and Msp I digestion in both the faunated and unfaunated cattle. In particular, the Bacteroides group, the Clostridium coccoides group and the Clostridium leptum subgroup might be the known bacterial groups that protozoa influence by Msp I digestion. From the dendrogram analysis by T‐RFLP patterns, the faunated and unfaunated cattle were divided into two clusters, I and II, respectively. These results suggest that absence of protozoa in the rumen changes the composition of fecal bacteria.  相似文献   

5.
The influence of rumen protozoa on the composition of rumen methanogens was studied by using seven growing Holstein cattle divided into two groups: four faunated and three unfaunated. 16S ribosomal RNA gene (rDNA) and methyl coenzyme‐M reductase (MCR) α subunit (mcrA) gene clonal libraries were constructed. The results of each analysis showed that Methanobacteriales was dominant in the rumen of both groups. By mcrA gene analysis, 22.1% of unfaunated clones were classified into unfaunated group 1, which was not detected from faunated cattle. The 16S rRNA gene analysis showed that the number of operational taxonomic units was higher in unfaunated than faunated cattle, suggesting the diversity of methanogens tended to be higher by the removal of protozoa. The results of the LIBSHUFF program indicated that the 16S rRNA gene and mcrA gene clone libraries for the faunated group differed from those for the unfaunated group (P = 0.001). It was suggested that the presence of protozoa strongly affected the composition of rumen methanogens.  相似文献   

6.
This study evaluated a technique for the nutritive defaunation of the rumen of cattle with subsequent single species refaunation using a cryopreserved monoculture of Entodinium caudatum (family Ophryoscolecidae). Four mature steers were nutritionally defaunated in two periods using two steers in each period. A diet containing (dry matter basis) 68% ground wheat grain, 7% wheat bran, 8% soybean oil and 17% wheat straw was used to decrease the pH of ruminal contents and to eliminate rumen ciliate protozoa. Protozoa‐free rumens were observed on day 8 and 9 in the first and second period, respectively, after the start of defaunation. A monoculture of E. caudatum (34/89/94) was transported from the Institute of Animal Physiology, Slovak Academy of Sciences in Ko?ice to the University of Kiel (Germany) in liquid nitrogen in October 1996. The inoculation was accomplished on day 15 in the second period by applying 30 ml culture medium with a monoculture of E. caudatum (34/89/94; average concentration of protozoal cells 2 650/ml) into the rumen of a defaunated steer via the ruminal fistula. The mono‐faunated steer was successfully inoculated with an average concentration of E. caudatum cells at 4.1 × 103/ml (SD = 0.2) on day 2 after the inoculation.  相似文献   

7.
Eight cows were used to evaluate the effects of supplementation of soy sauce oil (SO) or Ca salts of fatty acids (FA) on rumen fermentation and milk production. The control diet (CO) consisted mainly of hay, corn silage and a concentrate. In the experimental diets, 400 g/day per cow of SO or FA (soybean oil and rapeseed oil) was supplemented to the CO diet. Experimental period for the three treatments was 14 days, and milk samples were taken during the last 2 days and rumen sample was taken on the last day. Dry matter intake was not affected by the treatments. The number of rumen protozoa at 0 h increased by SO and FA diets. Total volatile fatty acids at 2 h after feeding of SO diet was decreased compared to CO. The milk composition yield did not differ among treatments, although the percentages of fat and protein were decreased by SO and FA diets. The proportions of C8–C16 fatty acids in milk fat decreased, and those of C18 increased by SO and FA diets. The proportion of cis‐9, trans‐11 conjugated linoleic acid in milk fat by SO and FA diets increased by 120% and 135%, respectively. In spite of the slight suppression of rumen fermentation by SO diet, negative effects on feed intake and milk production were not detected.  相似文献   

8.
Effects of protozoa on bacterial nitrogen recycling in the rumen   总被引：7，自引：0，他引：7  
The effects of protozoa on ruminal NH3-N kinetics and bacterial N recycling were measured in five sheep (57.6+/-7.1 kg BW, x +/- SD) with ruminal and duodenal cannulas in naturally faunated, defaunated, and refaunated periods. The sheep were fed a diet of 239 g of alfalfa haylage and 814 g of barley concentrate per day (DM basis) divided into 12 equal portions and allocated at 2-h intervals. A pulse dose of 300 mg of 15N as [15N]NH4Cl was administered into the rumen (on d 1 and 15) and 300 mg of 15N as [15N]urea was administered intravenously to the blood (d 8). Enrichment of 15N was measured in ruminal NH3-N, bacterial N, and plasma urea N over a period of 35 h. Total collection of urine was made for 5 d and analyzed for purine derivatives to calculate the flow of microbial N. Ruminal parameters and nutrient digestibilities were also measured. Sheep were defaunated using a rumen washing procedure 50 d prior to measurements in the defaunated period. Sheep were refaunated with ruminal contents from a faunated sheep receiving the same diet. Measurements began 26 d following refaunation, at which time protozoal numbers had returned to those in the originally faunated sheep. Data reported in parentheses are for faunated, defaunated, and refaunated sheep, respectively. Total culturable and cellulolytic bacterial numbers were unaffected by defaunation, but there was an increase in flow of microbial N from the rumen (10.8, 17.3, and 11.1 g N/d; P < .05) in the defaunated period. Flux, irreversible loss, and intraruminal recycling of NH3-N and recycling of NH3-N from plasma urea N were not affected by defaunation. Defaunation had no effect on reducing the absolute amount (13.8, 10.0, and 11.3 g N/d; P > .20) of bacterial N recycling and the percentage of N flux through the bacterial N pool. Total-tract digestion was reduced in defaunated compared with faunated sheep by 8, 17, 15, and 32% for OM, N, NDF, and ADF, respectively. In conclusion, defaunation improved ruminal N metabolism through the enhancement of bacterial protein synthesis, and improvement in the flow of microbial protein to the host animal.  相似文献   

9.
Ruminal samples were collected at slaughter from 364 unfasted steers fed different finishing diets to obtain information on numbers and species distribution of ciliated protozoa in feedlot cattle. Total numbers of protozoa averaged 1.59 X 10(5)/g of ruminal contents. A total of 47 steers (12.9%) were defaunated, but 4.1% of the steers possessed numbers of protozoa greater than 10(6)/g. Entodinium species did not always dominate the protozoan populations; 41 faunated steers (11.2%) were devoid of entodinia, and 79 additional steers (21.7%) possessed populations dominated (greater than 50%) by other genera. Isotricha was the most commonly occurring genus supplanting Entodinium, but Polyplastron and Epidinium were frequently present in high concentrations. Tallow and soybean soapstock supplementation reduced (P less than .05) numbers of protozoa in steers consuming wheat diets. However, yellow grease supplementation did not affect numbers of protozoa in steers fed either sorghum or corn diets. Average ruminal pH was 6.20 on the wheat diet, 6.05 on the corn diet, and 5.69 and 6.23 for the two sorghum diets, respectively. We found no correlation between ruminal pH and numbers of protozoa on any diet. The presence of relatively high protozoan concentrations and few defaunated animals in feedlot cattle necessitates reevaluation of the role that ciliated protozoa play in ruminal metabolism of animals fed processed, high-concentrate diets.  相似文献   

10.
Milk and meat products derived from ruminants contain a mixture of positional and geometric isomers of C18:2 with conjugated double bonds, and cis‐9, trans‐11C18:2 (conjugated linoleic acid, CLA) is the predominant isomer. The presence of CLA in ruminant products relates to the biohydrogenation of unsaturated fatty acids by rumen bacteria. Although, it has been suggested that cis‐9, trans‐11 CLA is an intermediate that escapes complete ruminal biohydrogenation of linoleic acid, is absorbed from the digestive tract, and transported to tissues via circulation. Its major source is endogenous biosynthesis involving Δ9‐desaturase with trans‐11C18:1 produced in the rumen as the substrate. CLA has recently been recognized in animal studies as a nutrient that exerts important physiological effects, including anticarcinogenic effects, prevention of cholesterol‐induced atherosclerosis, enhancement of the immune response, reduction in fat accumulation in body, ability to enhance growth promotion, antidiabetic effects and improvement in bone mineralization. The present review focused on the origin of CLA in ruminant products, and the health benefits, metabolism and physiological functions of CLA.  相似文献   

11.
Suspensions of mixed rumen bacteria (B), protozoa (P), and mixed rumen microorganisms (BP) prepared from rumen contents of fistulated goats were anaerobically incubated with 1 mM p‐hydroxyphenylacetic acid (HPA) at 39°C for 24 h. Tyrosine (Tyr), phenylalanine (Phe), tryptophan (Trp) and other related compounds in both supernatants and hydrolyzates of microbial cells in all incubations were analyzed by HPLC. Large amounts of Tyr (32.1, 42.7 and 36.1% of disappeared HPA in B, P and BP, respectively) were produced from HPA during a 12 h incubation period. The formation of Tyr in P (178.6 µmol/g MN) was 1.5 and 2 times higher than in B and BP, respectively. Phe (7–11% of the disappeared HPA) and Trp (3–6% of the disappeared HPA) were also synthesized from HPA in B, P, and BP. Phe synthesis in P (46.3 µmol/g MN) was 1.7 times higher than in B but, in contrast, Trp synthesis in B, was 1.6 times higher than in P. The metabolites p‐hydroxyphenylpyruvic acid (in the range of 5–14% of disappeared HPA), phenylacetic acid (1–11%), p‐hydroxybenzoic acid (3–7%) and benzoic acid (1–6%) were produced from HPA in B, P and BP. Phenylpropionic acid (6% of the disappeared HPA) was produced only in B and BP.  相似文献   

12.
Dietary unsaturated fatty acids (FA) are intensively hydrogenated in the rumen, resulting in reduced amount of poly‐unsaturated fatty acids (PUFA) and accumulation of several biohydrogenation (BH) products. In this study, BH of PUFA originating from different oilseeds (linseed, soya beans, sunflower seed and rapeseed) present in crushed oilseeds or their free oils were assessed in vitro. The assay substrates were incubated in buffered rumen fluid for 0, 6, 12 and 24 h. After incubation, the FA pattern of the incubated samples was analysed using gas chromatography. Biohydrogenation is defined as disappearance of double bonds (DB) calculated from the contents of unsaturated FA. After 24‐h incubation, the DB contents of all oilseeds were reduced (p < 0.001) by 40–60%. The reduction was higher (p < 0.001) for the crushed form compared with the oil form. In addition, linseed and sunflower seed known as oilseeds with high contents of linolenic acid C18:3 c9,12,15 (LNA) and linoleic acid C18:2 c9,12 (LA), respectively, showed a higher (p < 0.001) accumulation of the BH intermediates conjugated linoleic acid (CLA, isomer C18:2 c9t11) and vaccenic acid (C18:1 t11) for the crushed form, when compared with the oil. These results suggest an inherent effect of the physical form of the assay oilseeds on in vitro BH. Changes in FA pattern during BH in vitro can be attributed to both source and physical form of the assay oilseeds. However, further investigations are warranted to ensure whether the observed in vitro effects on ruminal BH can be confirmed in vivo.  相似文献   

13.
A quantitative method of analysis for 2-aminoethylphosphonic acid (AEP) was developed using reverse-phase HPLC. The detection limit for AEP was 15 nM, and the detector response (peak area) was linear from AEP levels up to 100 microM (R = .99). Mean recovery of AEP added to strained ruminal fluid from faunated sheep was 98.2%. When AEP was added to a fermentation mixture at a concentration of 22.6 micrograms/ml, 78% disappeared during a 24-h incubation. 2-Aminoethylphosphonic acid was readily detected in preparations of mixed ruminal ciliate protozoa as well as in mixed and pure strains of ruminal bacteria, feedstuffs, and ruminal fluid and duodenal digesta from defaunated sheep. The occurrence of AEP in feed and bacterial hydrolysates was confirmed by organic phosphorus analyses. The concentration of AEP in mixed ruminal protozoa was three times greater than its concentration in mixed ruminal bacteria (4,304 vs 1,383 micrograms/g DM, respectively). The AEP values for pure ruminal bacterial cultures ranged from 733 micrograms/g DM in Bacteroides succinogenes B21a to 1,166 micrograms/g DM in Butyrivibrio fibrisolvens H17c. Ruminal fluid and duodenal digesta from defaunated sheep contained AEP concentrations of 30 micrograms/ml and 90 micrograms/g DM, respectively. The concentration of AEP in feedstuffs ranged from 25 micrograms/g DM in wheat straw to 263 micrograms/g DM in oats. Because AEP occurrence is not limited to ruminal ciliate protozoa, it is of little value as a marker for protozoal presence in or passage out of the rumen.  相似文献   

14.
Five female sika deer and three male Holstein cattle were offered alfalfa hay cubes at 2% (deer) and 2.5% (cattle) of bodyweight, respectively. The passage rate through the digestive tract, digestibility and rumen fermentation of the animals were determined. The rate of ruminal passage was higher and the total mean retention time in the digestive tract was shorter in deer than in cattle. In addition, the rate of post‐ruminal passage in deer was lower. The digestibilities of dry matter, organic matter, crude protein and fiber in deer were significantly lower than in cattle (P < 0.05). The concentration of total volatile fatty acids in the rumen was significantly higher in deer than in cattle. The molar percentage of acetic acid was lower and that of valeric acid was higher in deer (P < 0.05). The number of protozoa was somewhat higher in deer. These results suggested that the lower digestibility in deer might be a result of the shorter retention time in the digestive tract.  相似文献   

15.
《Animal Science Journal》2017,88(2):267-276
Papaya leaf methanolic extract (PLE) at concentrations of 0 (CON), 5 (LLE), 10 (MLE) and 15 (HLE) mg/250 mg dry matter (DM) with 30 mL buffered rumen fluid were incubated for 24 h to identify its effect on in vitro ruminal methanogenesis and ruminal biohydrogenation (BH). Total gas production was not affected (P > 0.05) by addition of PLE compared to the CON at 24 h of incubation. Methane (CH4) production (mL/250 mg DM) decreased (P < 0.05) with increasing levels of PLE. Acetate to propionate ratio was lower (P <0.05) in MLE (2.02) and HLE (1.93) compared to the CON (2.28). Supplementation of the diet with PLE significantly (P <0.05) decreased the rate of BH of C18:1n‐9 (oleic acid; OA), C18:2n‐6 (linoleic acid; LA), C18:3n‐3 (linolenic acid; LNA) and C18 polyunsaturated fatty acids (PUFA) compared to CON after 24 h incubation, which resulted in higher concentrations of BH intermediates such as C18:1 t11 (vaccenic acid; VA), c9t11 conjugated LA (CLA) (rumenic acid; RA) and t10c12 CLA. Real‐time PCR analysis indicated that the total bacteria, total protozoa, Butyrivibrio fibrisolvens and methanogen population in HLE decreased (P <0.05) compared to CON, but the total bacteria and B. fibrisolvens population were higher (P < 0.05) in CON compared to the PLE treatment groups.  相似文献   

16.
The effects of corn dried distillers grains with solubles (DDGS) feeding on rumen fermentation and milk production in cows were evaluated using diets high in neutral detergent fiber (NDF, 45.9–46.6%). The control diet (Control) consisted mainly of hay, corn silage and concentrates. In the experimental diets, the concentrates were replaced with DDGS as 10% dry matter (DM) (10%DDGS) and 20% DM (20%DDGS). Eight cows were used for each 14‐day treatment period. Effect of DDGS feeding on DM intake was not significant. Ruminal volatile fatty acids and ammonia‐N at 5 h after feeding of 20%DDGS were decreased compared to Control, whereas protozoal count at 2 h after feeding of 20%DDGS was higher than that of 10%DDGS. Milk yield of cows fed DDGS diets was greater than that of Control, although percentages of milk protein and solids‐not‐fat were decreased by DDGS diets. The proportions of C10:0, C12:0, C14:0 and C16:0 in the milk fat decreased, and those of C18:0, C18:1, C18:2 and cis‐9, trans‐11 conjugated linoleic acid (CLA) increased markedly with elevated DDGS. Increase in trans‐11 C18:1 was observed in the rumen fluid at 5 h after feeding. These findings suggest that DDGS feeding enhanced milk yield, as well as CLA synthesis under a high dietary NDF condition.  相似文献   

17.
Vitamin E (Vit. E) is discussed to influence ruminal biohydrogenation. The objective of this study was to investigate the influence of a Vit. E supplementation on rumen fermentation characteristics, ruminal microbial protein synthesis as well as ruminal organic matter fermentation. Furthermore, we aimed to investigate the influence of Vit. E supplementation on short‐chain fatty acids (SCFA) and protozoa concentrations in the rumen and, in addition, on transfer rates of middle‐chain and long‐chain fatty acids into the duodenum in lactating dairy cows. Eight rumen and duodenum fistulated German Holstein cows were assigned to either a group receiving 2,327 IU/d Vit. E (138.6 IU/kg DM DL‐α‐tocopherylacetate; n = 4) or a control group (23.1 IU/kg DM; n = 4). Neither ruminal protein synthesis nor organic matter fermentation was influenced by treatment. Vit. E did not act on the concentrations of short‐chain fatty acids and protozoa in rumen fluid. Duodenal flow of C13:0 (1.3 versus 0.2 g/d, p = 0.014) and iso‐C14:0 (1.0 versus 0.5 g/d, p = 0.050) was higher in the Vit. E group. We observed a trend for higher duodenal flows for C12:0 (1.6 versus 0.9 g/d, p = 0.095) and anteiso‐C15:0 (12.2 versus 8.9 g/d, p = 0.084). Transfer rate of C12:0 tended to be higher in the Vit. E group (125.61 versus 73.96, p = 0.082). No other transfer rates were affected by treatment. Further studies are necessary to investigate the influence of Vit. E on rumen microbiota and their fatty acid production as well as on the impact of different doses of Vit. E supplementation on variables of protein synthesis efficiency.  相似文献   

18.
Microalgae might be considered as an alternative source of fat and/or protein for ruminant's diets. However, changes in populations of ruminal micro‐organisms associated with biohydrogenation process, methane and ammonia production in response to microalgae dietary supplementation have not been well characterized. Thus, 16 cross‐bred goats were divided into two groups. Each goat of both groups was fed individually with alfalfa hay and concentrates separately. The concentrates of the control group had no microalgae while those of the treated group were supplemented with 10 g lyophilized Chlorella vulgaris/kg concentrate (chlor). On the 30th experimental day, samples of rumen fluid were collected for microbial DNA extraction, fatty acid profile and enzyme activity analyses. The results showed that the chlor diet compared with the control increased significantly the populations of Methanosphaera stadtmanae, Methanobrevibacter ruminantium and Methanogens bacteria and protozoa in the rumen of goats. A significant reduction in the cellulase activity and in the abundance of Ruminococcus albus, and a significant increase in the protease activity and in the abundance of Clostridium sticklandii in the rumen liquid of goats fed with the chlor diet, compared with the control, were found. Chlorella vulgaris supplementation promoted the formation of trans C18:1, trans‐11 C18:1 and monounsaturated fatty acids (MUFA), while the proportions of C18:0 and long‐chain fatty acids (LCFA) reduced significantly in the rumen liquid of goats. This shift in ruminal biohydrogenation pathway was accompanied by a significant increase in Butyrivibrio fibrisolvens trans C18:1‐producing bacteria. In conclusion, the supplementation of diets with microalgae needs further investigation because it enhances the populations of methane‐producing bacteria and protozoa.  相似文献   

19.
The study examined the effects of blend of 80% canola oil and 20% palm oil (BCPO) on nutrient intake and digestibility, growth performance, rumen fermentation and fatty acids (FA) in goats. Twenty‐four Boer bucks were randomly assigned to diets containing 0, 4 and 8% BCPO on a dry matter basis, fed for 100 days and slaughtered. Diet did not affect feed efficiency, growth performance, intake and digestibility of all nutrients except ether extract. Intakes and digestibilities of ether extract, unsaturated fatty acids (FA) and total FA were higher (P < 0.05) while digestibility of C18:0 was lower (P < 0.05) in oil‐fed goats than the control goats. Total volatile FA, acetate, butyrate, acetate/propionate ratio and methane decreased (P < 0.05) with increasing BCPO but propionate, NH3‐N and rumen pH did not differ between diets. Ruminal concentration of C18:0, n‐3 FA and total FA increased (P < 0.05) while C12:0, C14:0, C15:0 and n‐6 FA decreased with increasing BCPO. Analysis of the FA composition of Triceps brachii muscle showed that concentrations of C16:0, C14:0 and C18:2n‐6 were lower (P < 0.05) while C18:1n‐9, C18:3n‐3 and C20:5n‐3 were higher in oil‐fed goats compared with control goats. Dietary BCPO altered muscle lipids without having detrimental effects on nutrient intake and digestibility and growth performance in goats.  相似文献   

20.
The purpose of this study was to investigate the diversity and fluctuation in the ciliate protozoan population in the rumen of cattle. DNA was extracted from the rumen of three ruminally cannulated, crossbred cattle and a polymerase chain reaction (PCR)‐derived clone library was constructed, using a specific primer set targeting 18S ribosomal RNA genes of ciliate protozoa. DNA fragments of seven selected clones were validated for standard DNA of the protozoa‐specific real‐time PCR assay. Furthermore, population fluctuation of ciliate protozoa and methanogens in the cattle rumen was determined by real‐time PCR. A total of 60 clones were sequenced, phylogenetically analyzed, and classified into 24 operational taxonomic units (OTUs) based on a 99% similarity criterion. More than 80% sequences were phylogenetically placed in the genus Entodinium. The rest of the sequences were placed in the genus Diploplastron (5%), Dasytricha (8.3%) and Isotricha (3.3%). The results suggest that Entodinium was the dominant group in the rumen of cattle used in this study. The ciliate protozoan population showed no significant change in numbers during the monitoring period and reached a peak at 3 h after feeding. Changes in the protozoa population were lower than those of the methanogens.  相似文献   

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