Infraciliature and morphogenesis in three rumen Diplodinium ciliates, Diplodinium polygonale, Diplodinium leche, and Diplodinium nanum, observed by light microscopy

Infraciliature and morphogenesis of three rumen ophryoscolecid ciliates, Diplodinium polygonale Dogiel, 1925, Diplodinium leche Imai et al., 1992, and Diplodinium nanum Imai, 1988, are described from pyridinated silver carbonate-impregnated specimens. These three species have two polybrachykineties in the buccal area and a polybrachykinety in the dorsal ciliary zone. The vestibular polybrachykinety (VP) of D. polygonale and D. leche arises from the dorsal extremity of the adoral polybrachykinety (AP) as in Entodinium species, extending toward the left in D. polygonale and toward the left posterior in D. leche. The VP of D. nanum arises from the inner side of the AP, separate from its dorsal extremity, as in other Diplodinium species and extends toward the left posterior. These series of the polybrachykinety arrangements in D. polygonale, D. leche, and D. nanum can be regarded as transitional forms in the evolution of an Entodinium-like ancestor to Diplodinium. Morphogenesis of these three Diplodinium species is not different from that of other Diplodinium species.     

Sociobiology of biodegradation and the role of predatory protozoa in biodegrading communities

Predatory protozoa are known to enhance biodegradation by bacteria in a variety of systems including rumen. This is apparently counterintuitive since many protozoa do not themselves produce extracellular degradative enzymes and prey upon bacterial degraders. We propose a mechanism of protozoal enhancement of bacterial biodegradation based on the sociobiology of biodegradation. Since extracellular enzyme production by degraders involves a cost to the bacterial cell, cheaters that do not make the enzyme will have a selective advantage. In the presence of cheaters, degraders that physically attach to water-insoluble substrate will have a selective advantage over free-floating degraders. On the other hand, cheaters will benefit by being free floaters since they consume the solubilized products of extracellular enzymes. Predatory ciliated protozoa are more likely to consume free-floating cheaters. Thus, due to protozoan predation a control is exerted on the cheater population. We illustrate the dynamics of such a system with the help of a computer simulation model. Available data on rumen and other biodegradation systems involving protozoa are compatible with the assumptions and predictions of the model.     

Ciliate Protozoa in the Rumen of Brazilian Water Buffalo,Bubalus bubalis Linnaeus*

SYNOPSIS Total numbers and distribution of genera, subgenera and species were determined for the ciliate protozoa in rumen contents of 4 Brazilian water buffalo Bubalus bubalis Linnaeus. The fauna of one animal, housed in close proximity to European and zebu-type cattle, differed considerably from that of the remaining animals, which were somewhat isolated on a large ranch. Several of the protozoan species observed in the semi-isolated animals were first described in rumen contents from humped Indian cattle, and their subsequent occurrence in other hosts and geographic locations has been limited or absent. In all, 49 different species of protozoa were found, 8 of which have not been previously described. Three of the new species belong to the genus Entodinium: E. ciculum sp. n., E. spinonucleatum sp. n. and E. triangulum sp. n.: 4 to Diplodinium (Ostracodinium): D. (O.) brazili sp. n., D. (O.) esalqum sp. n., D. (O.) nucleolobum sp. n., and D. (O.) tiete sp. n.; and one to Diplodinium (Eudiplodinium): D. (E.) bubalus sp. n.     

Diplodinium (Ostracodinium) minorum sp. n., Ciliate from the Rumen of Domestic Sheep*

SYNOPSIS. Diplodinium (Ostracodinium) minorum sp. n., observed in rumen contents from several domestic sheep, resembles Diplodinium (O.) ypsilon and Diplodinium (O.) magnum. It differs from the latter 2 species primarily in the size and proportions of the body, size of the rectum and anus, and in the presence of a short right caudal lobe in many individuals. In the samples studied, D. (O.) minorum constituted from 0.06 to 0.67% of the total rumen ciliate population.     

Methane production and substrate degradation by rumen microbial communities containing single protozoal species in vitro

AIMS: To assess the effect of protozoal species on rumen fermentation characteristics in vitro. METHODS AND RESULTS: Entodinium caudatum, Isotricha intestinalis, Metadinium medium, and Eudiplodinium maggii from monofaunated wethers and mixed protozoa from conventional wethers were obtained by centrifugation, re-suspended at their normal densities in rumen fluid supernatants from defaunated or conventional wethers and incubated in vitro. The presence of protozoa increased the concentration of ammonia and altered the volatile fatty acids balance with more acetate and butyrate produced at the expense of propionate. Differences among species were observed, notably in the production of methane, which increased with E. caudatum as compared to other ciliates and to defaunated and mixed protozoa treatments (P < 0.05). The increased methanogenesis was not correlated to protozoal biomass indicating that the metabolism of this protozoan and/or its influence on the microbial ecosystem was responsible for this effect. CONCLUSIONS: Entodinium caudatum stimulated the production of methane, a negative effect that was reinforced by a concomitant increase in protein degradation. SIGNIFICANCE AND IMPACT OF THE STUDY: Comparison of individual species of protozoa highlighted the particular influence of E. caudatum on rumen fermentation. Its elimination (targeted defaunation) from the rumen could reduce methane production without affecting feed degradation.     

Effect of the rumen ciliates Entodinium caudatum,Epidinium ecaudatum and Eudiplodinium maggii,and combinations thereof,on ruminal fermentation and total tract digestion in sheep

The quantitative importance of individual ciliate species and their interaction in the rumen is still unclear. The present study was performed to test whether there are species differences in the influence on ruminal fermentation in vivo and if combinations of ciliates act additive in that respect. Six adult wethers fed a hay-concentrate diet were defaunated, then refaunated either with Entodinium caudatum (EC), Epidinium ecaudatum (EE) or Eudiplodinium maggii (EM) alone, then progressively with all possible species combinations. Feed, faeces, urine, ruminal fluid and gas were sampled for eight days always after at least 21 days of adaptation. With a linear mixed model, accounting for the 2 × 2 × 2 full factorial study design, mean marginal effect sizes, i.e., the magnitude of change in variables as caused by the presence of each ciliate species or of combinations of them, were estimated. The apparent digestibility of organic matter and neutral detergent fibre remained unaffected. The apparent N digestibility increased by 0.054 with EM (0.716 with defaunation). Ruminal ammonia increased by 1.6, 4.0 and 8.7 mmol/l in the presence of EM, EC and EE, respectively, compared to defaunation (6.9 mmol/l). In the EM + EE combination, ruminal ammonia was lower than would have been expected from an additive effect. With EE, total short-chain fatty acids increased by 23 mmol/l (100 mmol/l with defaunation), but not when EE was combined with EM. The acetate-to-propionate ratio decreased by 0.73 units in the presence of EE (4.0 with defaunation), but only when EE was the sole ciliate species in the rumen. In the presence of any ciliate species, the 16S rDNA copies of total Bacteria and major fibrolytic species decreased to 0.52- and 0.22-fold values, respectively of that found without protozoa. Total Archaea were unaffected; however, Methanobacteriales copies increased 1.44-fold with EC. The CH₄-to-CO₂ ratio of ruminal gas decreased by 0.036 with EM and 0.051 with EE (0.454 with defaunation). In conclusion, individual ciliates affected ruminal fermentation differently and, when different species were combined, sometimes in a non-additive manner. From the ciliates investigated, EE affected ruminal fermentation most and might play a dominant role in mixed ciliate populations.     

纤毛原生动物研究的经济意义

纤毛原生动物与人们日常生活息息相关,具有重要的科学研究意义和社会经济价值。纤毛原生动物不仅可以监测与净化水体,维持反刍动物瘤胃的内环境稳定,促进土壤生态系统的平衡,还可以作为海洋抗菌活性物质及遗传学研究的材料。通过将其在以上各方面的应用价值进行初步的探讨性总结,以期得到人们更多的重视。     

Rumen Ciliate Protozoa in Ohio White-tailed Deer (Odocoileus virginianus)

ABSTRACT. Rumen contents were obtained from 23 white-tailed deer (Odocoileus virginianus), located in the eastern portion of central Ohio. Samples were taken during late fall and winter over a 4-yr period, 1986–1990. Protozoan numbers ranged from 0.002 to 7.25 × 10⁶ per ml of rumen contents, with a mean of 2.96 × 10⁶. Six deer had protozoan concentrations higher than any values previously reported in ruminants. In all 23 animals, Entodinium dubardi was the only ciliate protozoan species present.     

Computer assisted sperm analysis of motility patterns of postthawed epididymal spermatozoa of springbok (Antidorcas marsupialis), impala (Aepyceros melampus), and blesbok (Damaliscus dorcus phillipsi) incubated under conditions supporting domestic cattle in vitro fertilization

The need for information on the reproductive physiology of different wildlife species is important for ex situ conservation using such methods as in vitro fertilization (IVF). Information on species reproductive physiology and evaluation of sperm quality using accurate, objective, repeatable methods, such as computer-assisted sperm analysis (CASA) for ex situ conservation has become a priority. The aim of this study was to evaluate motility patterns of antelope epididymal spermatozoa incubated for 4 h under conditions that support bovine IVF using CASA. Cauda epididymal spermatozoa were collected postmortem from testicles of springbok (N = 38), impala (N = 26), and blesbok (N = 42), and cryopreserved in biladyl containing 7% glycerol. Spermatozoa were thawed and incubated in Capacitation media and modified Tyrode lactate (m-TL) IVF media using a protocol developed for domestic cattle IVF. The study evaluates 14 motility characteristics of the antelope epididymal sperm at six time points using CASA. Species differences in CASA parameters evaluated under similar conditions were observed. Several differences in individual motility parameters at the time points were reported for each species. Epididymal sperm of the different antelope species responded differently to capacitation agents exhibiting variations in hyperactivity. Motility parameters that describe the vigor of sperm decreased over time. Spermatozoa from the different antelope species have different physiological and optimal capacitation and in vitro culture requirements. The interspecies comparison of kinematic parameters of spermatozoa between the antelopes over several end points contributes to comparative sperm physiology which forms an important step in the development of species specific assisted reproductive techniques (ARTs) for ex situ conservation of these species.     

Ciliate Protozoa in the Rumen of Sassaby Antelope, Damaliscus lunatus lunatus, Including the Description of a New Species and Form

ABSTRACT. Composition of rumen ciliate fauna in five Zambian, sassaby antelopes was determined. Six genera, 18 species, and four forms were identified. One new species and form, belonging to the subfamily Diplodiniinae, were found, then labeled Ostracodinium damaliscus n. sp. and Diplodinium bubalidis f. aspinosum n. f., respectively. Only ophryoscolecid species were present while isotrichids were absent. Twelve of 18 total species are commmonly found in African antelopes. Three of those 12 species, Entodinium fyferi, Enoploplastron garstangi and Opisthotrichum janus , are only found in African antelopes. Percentage composition was low in the genera ml of rumen fluid, and the average number of ciliate species per host was 17.2.     

The Invasive Nature of an Infectious Bacterial Symbiont

ABSTRACT. Xenosomes are infectious bacterial symbionts that exist exclusively in the cytoplasm of the small philasterine marine ciliate Parauronema acutum. We have used this host-symbiont system as a model to study infection. In the past we postulated that infection took place by a process in which the symbionts escaped digestion and entered into the host's cytoplasm through the food vacuole during phagocytosis. This is clearly not the case. We now present evidence based on electron microscopic observations that the symbionts infect in a manner involving direct penetration of the protozoan's cell membranes. We have obtained additional data that suggest that, following entrance of the symbionts into the cytoplasm, only a single xenosome is required to establish an infection.     

Capacitation status of frozen–thawed spermatozoa from wild ruminant species

Semen from Barbary sheep (Ammotragus lervia), Bighorn sheep (Ovis canadensis), Mouflon sheep (Ovis musimon), Fallow deer (Dama dama), collected by electroejaculation, and semen from Wildebeest antelope (Connochaetes taurinus), collected post mortem, were frozen using a standardized technique and a commercial freezing medium (Triladyl). Sperm quality was assessed by measuring their capacitation status (chlortetracycline assay) in addition to classic assessment: motility, viability (plasma membrane integrity), and acrosome integrity. Sperm cryosurvival measured in terms of recovery (from the initial, pre-freeze values) of motility, viability, and acrosome integrity was relatively high in most species. However, proportion of premature-capacitated spermatozoa (B + AR patterns) increased many times in relation to that of fresh semen: from 8% to 78% in Barbary sheep; from 27% to 61% in Bighorn sheep; and from 12% to 68% in Mouflon sheep. The use of a standardized technique for freezing of spermatozoa from wild ruminant species produced, in most of the cases, acceptable results. This approach may be extensively used to carry out sperm cryopreservation in field conditions. Chlortetracycline assay allowed identifying the same fluorescent patterns observed in spermatozoa from domestic animals and produced additional information on sperm cryosurvival. That is, it revealed those cells that survive freeze–thawing and are potentially fertile: non-capacitated (F pattern) and capacitated acrosome-intact spermatozoa (B pattern).