Veterinária
URI permanente desta comunidadehttps://locus.ufv.br/handle/123456789/11842
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Item Viability and nematophagous activity of the freeze-dried fungus Arthrobotrys robusta against Ancylostoma spp. infective larvae in dogs(Veterinary Parasitology, 2010-10-20) Carvalho, Rogério Oliva; Braga, Fabio Ribeiro; Araújo, Jackson VictorViability and in vitro and in vivo activities of freeze-dried conidia of the predatory fungus Arthrobotrys robusta (I-31) were evaluated against infective larvae (L3) of Ancylostoma spp. in dogs. A. robusta conidia were lyophilized and stored at 4 °C for a month. Freeze-dried conidia were diluted to 1 × 103 conidia/ml and tested in vivo. The treated group consisted of a solution containing conidia (1 ml) and 1000 Ancylostoma spp. (L3) placed on Petri dishes plated with 2% water–agar (2% WA), at 25 °C, in the dark for 10 days. The control group consisted of 1000 Ancylostoma spp. L3, plated on 2% WA. After 10 days, Ancylostoma spp. L3 from both the treated and the control groups were recovered and counted. The in vivo test was performed on two dogs by administering a single oral dose of freeze-dried conidia (1.5 × 105) in aqueous solution to one animal and only water to the other. Fecal samples were collected at 12, 24 and 48 h after the treatments, plated 2% WA plates and incubated at 25 °C for 15 days. A thousand Ancylostoma spp. L3 larvae were spread on these plates. At day 15, infective L3 recovered from the treated and control groups were counted. In the in vitro test, A. robusta was able to survive the freeze-drying process, grow in the plates, form traps and capture Ancylostoma spp. L3. There was a 75.38% decrease in the number of infective larvae recovered from the treated group. The in vivo test showed that freeze-dried A. robusta conidia survived the passage through the gastrointestinal tract of the treated dog, was able to grow in the plates and capture Ancylostoma spp. L3, reducing the number of recovered L3 (p < 0.01). Freeze-drying can be an alternative method for conservation of conidia of nematophagous fungi.Item Ovicidal action of a crude enzymatic extract of the fungus Pochonia chlamydosporia against cyathostomin eggs(Veterinary Parasitology, 2010-05-11) Braga, Fabio Ribeiro; Araújo, Jackson Victor; Carvalho, Rogério Oliva; Silva, André Ricardo; Araujo, Juliana Milani; Soares, Filippe E. Feitas; Geniêr, Hugo L. André; Ferreira, Sebastião Rodrigo; Queiroz, José HumbertoThe aims of this study were to test the action of the fungal extract of Pochonia chlamydosporia (VC4) on the hatching of cyathostomin eggs plated in Petri dishes containing 2% water-agar (2% WA) and its enzymatic activity in fecal cultures, in two experimental assays (A and B). The fungus P. chlamydosporia (VC4) was cultured in Erlenmeyer flasks (250 ml) containing 50 ml of liquid minimal medium supplemented with 0.2% gelatin for production of the crude enzymatic extract. Approximately 1 kg of fresh feces was collected directly from the rectum of crossbred horses naturally infected with cyathostomins. The fecal material was used to obtain eggs and prepare fecal cultures. For assay A, one thousand eggs were plated on 4.5 cm diameter Petri dishes together with 5 ml of VC4 fungal filtrate and incubated at 26 °C in the dark for 24 h. The control group consisted of 1000 eggs in Petri dishes containing 10 ml of distilled water, which were incubated under the same conditions. After 24 h, the total number of cyathostomin larvae present in each plate of the treated and control groups was counted. For assay B, about 20 g of feces were added with 10 ml of fungal extract of P. chlamydosporia (VC4) and incubated at 26 °C for 8 days. Third stage larvae (L3) were recovered at the end of this period. Significant difference (p < 0.01) was found for the number of larvae between the treated group and the control at end of assay A. A 72.8% reduction in the hatching of cyathostomin eggs was found in the plates of the treated group compared with the control group. At the end of 8 days, the fungal extract of P. chlamydosporia (VC4), in assay B, was effective in reducing the number of L3 cyathostomins in the treated group by 67.0% compared with the control group. Significant difference (p < 0.01) was found between the means of L3 recovered from the treated group and the control group. The results of this work showed that crude enzymatic extract of P. chlamydosporia (VC4) was effective in reducing hatching of cyathostomin eggs and therefore could be used as a biological control agent of this nematode.Item Viability of the nematophagous fungus Pochonia chlamydosporia after passage through the gastrointestinal tract of horses(Veterinary Parasitology, 2009-11-24) Braga, Fabio Ribeiro; Araújo, Jackson Victor; Silva, André Ricardo; Carvalho, Rogério Oliva; Araujo, Juliana Milani; Ferreira, Sebastião Rodrigo; Carvalho, Giovanni RibeiroThe predatory capacity of the nematophagous fungus Pochonia chlamydosporia (isolate VC4) embedded in sodium alginate pellets after passage through the gastrointestinal tract of horses was assessed in vitro against Oxyuris equi eggs. Twelve previously dewormed crossbred mares, average weight of 362.5 kg (±21) were used in the experiment. Each animal of the treated group received an oral dose (100 g) of sodium alginate pellets containing P. chlamydosporia mycelial mass. The control group received pellets without fungus. Faecal samples from fungus-treated and control groups were collected at intervals of 8, 12, 24, 36, 48 and 72 h after pellet administration and placed in Petri dishes containing 2% water-agar. One thousand eggs of O. equi were plated in Petri dishes of both treated and control groups, with six replicates, and incubated in oven, 25 °C, in the dark, for 30 days. At the end of the experiment, one hundred eggs were removed from each Petri dish and classified according to the following parameters: type 1, physiological and biochemical effect without morphological damage to eggshell, with hyphae adhered to the shell; type 2, lytic effect with morphological change in the eggshell and embryo without hyphal penetration, and type 3, lytic effect with morphological change in the eggshell and embryo, with hyphal penetration and internal egg colonization. Chlamydospore production was observed in Petri dishes of the treated group. The isolate VC4 remained viable after passing through the gastrointestinal tract of horses and maintained the ovicidal activity against O. equi eggs when compared with the control group (p < 0.01) after each collection interval: 29.1% (8 h), 28.2% (12 h), 31.1% (24 h), 27.4% (36 h), 30.9% (48 h) and 28.4% (72 h). The results suggest that P. chlamydosporia could be used as an effective biological control agent of O. equi eggs in natural conditions.Item Statistical experimental design to assess the influence of enzymes of nematophagous fungi versus helminths(Research in Veterinary Science, 2014-09-08) Braga, Fabio Ribeiro; Soares, Filippe Elias de Freitas; Araujo, Juliana Milani; Fonseca, Leandro Abreu da; Hiura, Emy; Gava, Maylla Garschagen; Vieira, Fernanda Toledo; Paz, Jeanne Saraiva da; Carvalho, Lorendane Milena de; Faccini, João Victor; Queiroz, José Humberto de; Araújo, Jackson VictorThe present work used Plackett–Burman experimental design to assess the influence of enzymes of nematophagous fungi versus Strongyloides westeri and trichostrongylides larvae and Platynosomum fastosum eggs. The variables studied in the Plackett–Burman design were the proteases and chitinases of AC001 or VC4 as destructive agents of S. westeri and trichostrongylides larvae, and P. fastosum eggs. All tested enzymes had a significant effect (P < 0.05) on the destruction of S. westeri larvae. Furthermore, only VC4 and AC001 proteases showed a significant effect (P < 0.05) on the destruction of trichostrongylides larvae. On the other hand, chitinases of VC4 showed the highest significance (P < 0.05) on the destruction of P. fastosum eggs. It is proposed that statistical planning for the use of enzymes derived from nematophagous fungi is a viable way to elucidate some questions about their mechanism of action.Item Influence of the preservation period in silica-gel on the predatory activity of the isolates of Duddingtonia flagrans on infective larvae of cyathostomins (Nematoda: Cyathostominae)(Experimental Parasitology, 2011-05-24) Braga, Fabio Ribeiro; Araújo, Jackson Victor; Araujo, Juliana Milani; Tavela, Alexandre de Oliveira; Ferreira, Sebastião Rodrigo; Soares, Filippe E. Freitas; Benjamin, Laércio dos Anjos; Frassy, Luiza NemeThe continued maintenance of nematophagous fungi predatory activity under laboratory conditions is one of the basic requirements for a successful biological control. The purpose of this study was to evaluate the influence of time on the preservation of the fungus Duddingtonia flagrans (AC001 and CG722) stored in silica-gel for 7 years and their subsequent predatory activity on cyathostomin L3 larvae in 2% water-agar medium (2% WA). Samples of the isolates AC001 and CG722, originating from vials containing grains of silica-gel sterilized and stored for 7 years, were used. After obtaining fungal conidia, the predation test was conducted over 7 days on the surface of 9.0 cm Petri dishes filled with 2% WA. In the treated groups each Petri dish contained 500 cyathostomin L3 and conidia of fungal isolates in 2% WA. In the control group (without fungi) the plates contained 500 L3 in 2% WA. The experimental results showed that isolated AC001 and CG722 were efficient in preying on cyathostomin L3 (p < 0.01) compared to control (without fungus). However, no difference was observed (p > 0.01) in the predatory activity of the fungal isolates tested. Comparing the groups, there was a significant reductions of cyathostomin L3 (p < 0.01) of 88.6% and 78.4% on average recovered from the groups treated with the isolates AC001 and CG722, respectively, after 7 days. The results of this test showed that the fungus D. flagrans (AC001 and CG722) stored in silica-gel for at least 7 years maintained its predatory activity on cyathostomin L3.Item In vitro biological control of infective larvae of Ancylostoma ceylanicum(Revista Brasileira de Parasitologia Veterinária, 2012-02-14) Fernandes, Fernanda Mara; Araújo, Jackson Victor; Braga, Fabio Ribeiro; Gazzinelli-Guimarães, Pedro Henrique; Araujo, Juliana Milani; Ferreira, Sebastião Rodrigo; Carvalho, Rogério Oliva; Mello, Ingrid Ney Kramer de; Fujiwara, Ricardo ToshioThe aim of this study was to evaluate the predatory activity of the fungus Duddingtonia flagrans (AC001) on infective larvae of Ancylostoma ceylanicum after gastrointestinal transit in hamsters. Twenty animals were used in the experiment, divided into two groups: a treated group (10 animals) and a control group (10 animals). In the group treated with D. flagrans, each animal received mycelium from the AC001 isolate, at an oral dose of 5 mg/25 g of live weight. To evaluate the predatory activity of the fungus, fecal samples were collected from the animals in both groups, at the times of 6, 8, 12, 24 and 36 hours after the treatment. Then, subsamples of 2 g of feces were placed in Petri dishes containing 2% water-agar (2% WA) culture medium and 1000 L3 of A. ceylanicum. Over the study period, the following percentage reductions were observed: 43.2% (6 hours), 30.8% (8 hours), 25.8% (12 hours), 30% (24 hours) and 11% (36 hours). The fungus D. flagrans presented predatory activity on the L3 of A. ceylanicum, after passing through the hamsters' gastrointestinal tract. It was therefore concluded that the fungus D. flagrans may be an alternative for biological control of the L3 of A. ceylanicum.Item Biological control of horse cyathostomin (Nematoda: Cyathostominae) using the nematophagous fungus Duddingtonia flagrans in tropical southeastern Brazil(Veterinary Parasitology, 2009-05-05) Braga, Fabio Ribeiro; Araújo, Jackson Victor; Silva, André Ricardo; Araujo, Juliana Milani; Carvalho, Rogério Oliva; Tavela, Alexandre Oliveira; Campos, Artur Kanadani; Carvalho, Giovanni RibeiroThe viability of a fungal formulation using the nematode-trapping fungus Duddingtonia flagrans was assessed for the biological control of horse cyathostomin. Two groups (fungus-treated and control without fungus treatment), consisting of eight crossbred mares (3–18 years of age) were fed on Cynodon sp. pasture naturally infected with equine cyathostome larvae. Each animal of the treated group received oral doses of sodium alginate mycelial pellets (1 g/(10 kg live weight week)), during 6 months. Significant reduction (p < 0.01) in the number of eggs per gram of feces and coprocultures was found for animals of the fungus-treated group compared with the control group. There was difference (p < 0.01) of 78.5% reduction in herbage samples collected up to (0–20 cm) between the fungus-treated group and the control group, during the experimental period (May–October). Difference of 82.5% (p < 0.01) was found between the fungus-treated group and the control group in the sampling distance (20–40 cm) from fecal pats. During the last 3 months of the experimental period (August, September and October), fungus-treated mares had significant weight gain (p < 0.01) compared with the control group, an increment of 38 kg. The treatment with sodium alginate pellets containing the nematode-trapping fungus D. flagrans reduced cyathostomin in tropical southeastern Brazil and could be an effective tool for biological control of this parasitic nematode in horses.