Marta D'Agosto

Evaluation of lugol solution used for counting rumen ciliates

The present study proposes a modification of the technique described by PURSER & MOIR (1959) for the quantitative evaluation of rumen ciliate based on an adaptation described by DEHORITY (I984). The modifying process includes: the replacement of two drops of brilliant green dye, for at least four hours, by three drops of lugol solution, for at least 15 minutes. It was made a comparative evaluation of these stainings. It was concluded that lugol solution can replace the brilliant green dye showing the following advantages: staining time reduction and subsequent speeding of sample processing; evidence of skeletal plates of entodiniomorphs making its identification easier; improved observation of small ciliates and inconspicuous structures; improved total counting and generic identification of the ciliates.

The influence of environmental characteristics on the distribution of ciliates (Protozoa, Ciliophora) in an urban stream of southeast Brazil

The aim of this research was to study the ciliated protozoa community at three sampling stations that receive different levels of domestic sewage along the São Pedro Stream in the municipality of Juiz de Fora, Minas Gerais, Brazil, in order to determine the influence of organic pollution on this community and to assess the feasibility of using ciliates as water quality indicators. Four physical-chemical parameters of the water samples were evaluated: dissolved oxygen concentration, electrical conductivity, pH and temperature. The sediment was obtained manually, using dredges with capacity of 300 mL, at each collection point. Point 1 was located in a rural region that receives a low sewage load, while Points 2 and 3 were located in populated regions receiving high sewage loads. We found 22 ciliate species, of which 18 are included in the saprobic system and are considered bioindicators. These showed beta-mesosaprobic environments at Point 1 and alfa-mesosaprobic to polisaprobic environments at Points 2 and 3. The low levels of dissolved oxygen and the high electrical conductivity values at Points 2 and 3, together with the strong similarity between the ciliate taxocenoses of these points and the weak similarity between Point 1 and the other two, confirm the high sewage loads received at the latter two points. The combination of the biological indicators and physical-chemical analyses therefore proved itself to be an efficient method of evaluating water quality, and has excellent potential to support decisions on the conservation of headwaters and recuperation of degraded environments in lotic systems.

Hematological changes of chickens experimentally infected with Plasmodium (Bennettinia) juxtanucleare

Plasmodium juxtanucleare is one of the agents that cause chicken malaria. High parasitemia causes anemia, diarrhea and weight loss that leads to death. This parasite is spread through the tropics and little is known about the physiological changes caused by P. juxtanucleare infections in chickens. The aim of this work was to determine hematological changes in chickens experimentally infected with this parasite. No weight or temperature differences between infected and control groups were detected. Low parasitemia was observed reaching a peak after 15 days; trophozoits was the most observed form, followed by schizonts detected on day 12 and gametocytes on day 27. Infected thrombocytes and thrombocytes with pyknotic nuclei and retracted cytoplasm were observed along the experimental infection. No changes were observed on the erythrocyte values. However, a reduction of thrombocyte number and an increase of total leukocyte and basophil numbers, all significant, were detected in infected chickens. Parasitemia was probably kept low by general immunological activation. These results suggest that classical hematology can monitor physiological changes caused by P. juxtanucleare infections in chickens.

Efeito da monensina e do óleo de soja sobre os protozoários ciliados do rúmen e correlação dos protozoários com parâmetros da fermentação ruminal e digestivos

Four lactating dairy cows with ruminal cannula and 155 DIM were allotted to a 4 × 4 Latin square and fed twice daily corn silage and concentrate (55:45, %DM) to evaluate the effect of monensin and soybean oil in the diet of lactating cows on the counting of ciliate protozoa beyond establishing correlations between number of protozoa with some parameters of digestion and ruminal fermentation. The treatments consisted of the inclusion of 33 ppm of sodium monensin or soybean oil at 4% DM, as following: control diet, without oil or monensin - CT; diet with monensin - MN; diet with soybean oil - OL; diet with the combination of 33 ppm of monensin and 4% of soybean oil - OM. Occurrence of 11 ciliate genera was observed, being Entodinium the predominant in all treatments. No significant soybean oil × monensin interaction was observed on protozoa number and genera. The genera Entodinium, Dasytricha, Eremoplastron and Isotricha reduced in the diets with oil, while monensin reduced the counting of Dasytricha, Eremoplastron and Epidinium. The total number of ciliate protozoa and cellulolytics protozoa was reduced by soybean oil and monensin effects, showing a defaunatory additive effect when combined the oil and the monensin. The ciliate cellulolytics was reduced by linoleic acid intake and was related positively with NDF ruminal digestibility and ruminal ammonia. The total number of protozoa was correlated with the molar proportion of propionate in the ruminal liquid, suggesting that monensin and soybean oil, due their defaunatory effect, can reduce the loss of methane in the rumen.

First Record of Trypanosoma chattoni in Brazil and Occurrence of Other Trypanosoma Species in Brazilian Frogs (Anura, Leptodactylidae)

The present study provides the first record of Trypanosoma chattoni Mathis and Leger, 1911, in a new host, Leptodactylus fuscus Schneider, 1799 (Anura, Leptodactylidae), and the occurrence of Trypanosoma rotatorium–like species in Leptodactylus chaquensis Cei, 1950. The anurans were captured in the State of Mato Grosso, Brazil. Blood samples were obtained by cardiac puncture, and blood smears were examined for the presence of hemoparasites. The Trypanosoma rotatorium–like species in this study refers to a short-bodied trypomastigote that has a conspicuous undulating membrane but lacks a free flagellum; T. chattoni refers to a monomorphic parasite that has a rounded body, a kinetoplast adjacent to the nucleus, and a short flagellum.

Quantitative study of Trichodina heterodentata (Ciliophora: Mobilia) infrapopulations infesting tadpoles of a Brazilian endemic toad Rhinella pombali (Anura: Bufonidae)

In this work we investigated the quantitative aspects of the relationship between Rhinella pombali (Baldissera, Caramaschi & Haddad, 2004) tadpoles and their trichodinid ectoparasites. Specimens were collected from a small stream located at an agricultural area between rainforest fragments in southeastern Brazil. A total of 80 tadpoles were investigated. Trichodina heterodentata Duncan, 1977 was the only trichodinid ciliate species recovered. All tadpoles were naturally infested by T. heterodentata with a mean intensity of 695.14 ± 33.33 trichodinid ciliates per tadpole. A positive correlation was observed between the intensity of the infestation and tadpole weight. Intensity of infestation did not significantly influence mean trichodinid diameter in the populations studied. This is the first study investigating density-dependent effects in interspecific interactions between trichodinids and anurans.

Protozoan ciliate epibionts on the freshwater apple snail Pomacea figulina (Spix, 1827) (Gastropoda, Ampullariidae) in an urban stream of south‐east Brazil

The objective of this study was to record and analyze the prevalence of ciliated protozoa associated with prosobranchian snails of the species Pomacea figulina collected from an urban stream in south‐eastern Brazil. Four collections were carried out between December, 2005, and March, 2006, from which 23 snails and 10 ‘empty’ shells were obtained. The shells and opercula were scraped over Petri dishes and the ciliates were observed using bright field and phase contrast microscopy. Seven species of ciliates were recorded on the snails of P. figulina. Of the 23 snails analyzed, 82.60% (n = 19) were infested with at least one species of ciliate. No ciliates were found on the ‘empty’ shells and opercula. The results are discussed in terms of ecological aspects involved in this association.

Effect of an energy-deficient diet on populations of ciliate protozoans in bovine rumen

Foram utilizados 10 novilhos mesticos com cânula ruminal, distribuidos em dois grupos: no grupo controle (C; n=4) receberam dieta balanceada para ganho diario de 900g; no grupo tratado com carencia pronunciada de energia (CP; n=6), receberam dieta com 30% a menos do nivel de mantenca em energia. Apos 140 dias sob esses regimes de alimentacao, foram coletadas amostras do fluido ruminal e urina, para realizacao de provas bioquimicas e funcionais, antes e as 1, 3, 6 e 9 horas apos o fornecimento do alimento. A carencia energetica resultou em diminuicao significativa na quantidade dos protozoarios Entodinium, Eodinium, Isotricha, Dasytricha, Eremoplastron, Eudiplodinium, Metadinium, Charonina, Ostracodinium e Epidinium. Nao houve efeito da hora de coleta sobre o total de ciliados nos grupos C e CP. Maior numero de formas em divisao binaria foi registrado no grupo C, na sexta e nona horas pos-alimentacao (P<0,019). Observaram-se altas correlacoes positivas entre a contagem total de protozoarios e a fermentacao de glicose, amonia e o indice de excrecao urinaria de alantoina e negativa entre a contagem total de protozoarios e a reducao do azul de metileno, e correlacao media entre a contagem total de protozoarios e os acidos graxos volateis totais. A determinacao da populacao de protozoarios do rumen e um metodo simples de avaliacao, alem de que particularmente auxilia o diagnostico clinico da funcao ruminal.

First record of epibionts peritrichids and suctorians (Protozoa, Ciliophora) on Pomacea lineata (Spix, 1827)

This study made a survey on the ciliate protozoans from Peritrichid and Suctorian taxa, epibionts of Pomacea lineata (Spix, 1827) (Ampullariidae). Fifty mollusks were collected in places of irrigation ditches and shell was scraped with a scalpel and the extracted material was analyzed in vivo by light microscopy. All examined mollusks presented epibiont ciliates on their shells. For the first time epibiont ciliates in P. lineata was record. Seven genera of ciliates: five peritrichids and two suctorians, were identified and classified within the subclass Peritrichia: Carchesium Ehrenberg, 1838 (Vorticellidae), Epistylis Ehrenberg, 1830 (Epistylidae), Opercularia Stein, 1854 (Operculariidae), Vaginicola Lamarck, 1816 (Vaginicolidae) and Vorticella Linnaeus, 1767 (Vorticellidae); and Suctoria: Acineta Ehrenberg,1834 (Acinetidae) and Tokophrya Butschli,1889 (Tokophrydae). The results showed that P. lineata constitute the microenvironment of a ciliate protozoan community that presents complex trophic interactions.

Estádios evolutivos de tripanossomas de Hipostomus punctatus Valenciennes (Osteichthyes, Loricariidae) em infecção natural de Batracobdella gemmata Blanchard (Hirudinea, Glossiphoniidae)

Seventeen leeches obtained from armoured catfish (Hypostomus punclatus Valenciennes, 1840) infected with Trypanosoma spp. were examined. It was observed the presence of tripomastigotes, epimastigotes and amastigotes forms as well as dividing forms in the proboscis and in the stomach, different from the ones found in the vertebrate host as regards the morfometric features and developing forms. The examination of the contents of rectum did not show tripanosomes. These facts seem to demonstrate that Batracobdella gemmata (Blanchard, 1900) is an invertebrate host of trypanosomes and the transmission is done by means of inoculation.