Effect of silver nanoparticles (AgNP's) from Duddingtonia flagrans on cyathostomins larvae (subfamily: cyathostominae).

The in vitro effect of silver nanoparticles of the Duddingtonia flagrans filtrate enriched with chitin was evaluated on infective larvae of cyathostomins (L3). After biosynthesis, an assay was carried out with two experimental groups in microtubes, for a period of 24 h: G1 (AgNP's-D. flagrans (43.4 µg/mL) + 120 L3) and G2 (distilled water + 120 L3). At the end of this period, AgNP's-D. flagrans (G1) demonstrated an effect on L3 with a 43% reduction (p < 0.01) in relation to G2. Thus, the authors suggest new designs with AgNP's-D. flagrans for the control of cyathostomins.

Feeding horses with industrially manufactured pellets with fungal spores to promote nematode integrated control.

The usefulness of pellets industrially manufactured with spores of parasiticide fungi as a contribution to integrated nematode control was assessed in grazing horses throughout sixteen months. Two groups of 7 Pura Raza Galega autochthonous horses (G-T and G-P) were dewormed pour-on (1mg Ivermectin/kg bw) at the beginning of the trial, and other group (G-C) remained untreated. The G-P was provided daily with commercial pellets to which was added a mixture of fungal spores during the industrial manufacturing (2×106 spores of Mucor circinelloides and same dose of Duddingtonia flagrans/kg), and G-T and G-C received pellets without spores. The efficacy of the parasiticidal strategy was assessed by estimating the reduction in the faecal egg counts (FECR) and in the number of horses shedding eggs in the faeces (PHR), and also the egg reappearance periods (ERP). Blood analyses were performed to identify the changes in the red and white cell patterns. To ascertain if horses developed an IgG humoral response against the fungi, antigenic products collected from M. circinelloides and D. flagrans were exposed to the horse sera by using an ELISA. The faecal elimination of eggs of Parascaris equorum and strongyles ceased 2 weeks after treatment in G-T and G-P, thus the values of FECR and PHR were 100%. No P. equorum-eggs were detected later, and the strongyle egg reappearance period was 28 weeks in G-P, and 8 weeks in G-T. Strongyle egg-output values remained lower than 300 eggs per gram of faeces in the G-P, whereas numbers between 330 and 772 in G-C and G-T were recorded. Normal values for the erythrocytes, haemoglobin and haematocrit in horses consuming pellets with spores were recorded, and lower than normal in the other groups. Sensitization of horses to the fungal species was disproven. It is concluded that feeding horses with pellets industrially manufactured with fungal spores represents a very useful tool to implement an integrated control of helminths affecting horses. This strategy allows a decrease in their risk of infection, aids in reducing the frequency of anthelmintic treatment.

Fungal Antagonism Assessment of Predatory Species and Producers Metabolites and Their Effectiveness on Haemonchus contortus Infective Larvae.

The objective of this study was to assess antagonism of nematophagous fungi and species producers metabolites and their effectiveness on Haemonchus contortus infective larvae (L3). Assay A assesses the synergistic, additive, or antagonistic effect on the production of spores of fungal isolates of the species Duddingtonia flagrans, Clonostachys rosea, Trichoderma esau, and Arthrobotrys musiformis; Assay B evaluates in vitro the effect of intercropping of these isolates grown in 2% water-agar (2% WA) on L3 of H. contortus. D. flagrans (Assay A) produced 5.3 × 10(6) spores and associated with T. esau, A. musiformis, or C. rosea reduced its production by 60.37, 45.28, and 49.05%, respectively. T. esau produced 7.9 × 10(7) conidia and associated with D. flagrans, A. musiformis, or C. rosea reduced its production by 39.24, 82.27, and 96.96%, respectively. A. musiformis produced 7.3 × 10(9) spores and associated with D. flagrans, T. esau, or C. rosea reduced its production by 99.98, 99.99, and 99.98%, respectively. C. rosea produced 7.3 × 10(8) conidia and associated with D. flagrans, T. esau, or A. musiformis reduced its production by 95.20, 96.84, and 93.56%, respectively. These results show evidence of antagonism in the production of spores between predators fungi.

Efficacy of Clonostachys rosea and Duddingtonia flagrans in Reducing the Haemonchus contortus Infective Larvae.

The biocontrol is proven effective in reducing in vitro and in situ free-living stages of major gastrointestinal helminths, allowing progress in reducing losses by parasitism, maximizing production, and productivity. This study aimed at evaluating the predatory activity of fungal isolates of Duddingtonia flagrans and Clonostachys rosea species and its association on infective larvae (L3) of H. contortus in microplots formed by grasses and maintained in a protected environment. All groups were added with 10 mL of an aqueous suspension with 618 H. contortus L3 approximately. Group 1 was used as control and only received the infective larvae. Groups 2 and 3 received D. flagrans chlamydospores and C. rosea conidia at doses of 5 × 10(6). Group 4 received the combination of 5 × 10(6) D. flagrans chlamydospores + 5 × 10(6) C. rosea conidia. D. flagrans and C. rosea showed nematicidal effectiveness reducing by 91.5 and 88.9%, respectively, the population of H. contortus L3. However, when used in combination efficiency decreased to 74.5% predation of H. contortus L3. These results demonstrate the need for further studies to determine the existence of additive effects, synergistic or antagonistic, between these species.

Assessing the efficacy of Duddingtonia flagrans chlamydospores per gram of faeces to control Haemonchus contortus larvae.

The aims were (a) to quantify the number of Duddingtonia flagrans chlamydospores per gram of faeces (CPG) recovered from sheep administered with different oral doses and, (b) to describe the relationship between CPG and eggs per gram of faeces (EPG) on the efficacy to reduce Haemonchus contortus infective larvae. Three doses of chlamydospores per kg BW were orally administered during seven days: (T1) non treated control group, (T2) 1 x 10(6), (T3) 2.5 x 10(6) and (T4) 5 x 10(6). Three lambs, infected with H. contortus, were used per group. Faeces were obtained from the rectum of each lamb during the fungal administration period (days 0-6) and for six days after that period. Four coproculture replicates were made from each animal in days 2, 4, 6, 8 and 10. A higher chlamydospore dose produced higher CPG in faeces (p < 0.05), but a clear dose dependent effect was not found either in the larvae reduction or in the CPG:EPG ratio. When ratios were re-analyzed, independently of the treatment groups of origin, a better efficacy was obtained with a ratio from 5 to 10 CPG:EPG and a higher ratio (> 10 per egg) showed a lower reduction efficacy (p < 0.05). The binomial analysis showed that for each unit of increment in CPG:EPG ratio there was a reduction of larvae number until a point (between 5 and 10 CPG:EPG) where no further reduction was detected. The surface response test indicated that the number of larvae was reduced by CPG until possible saturation. The highest CPG:EPG ratios did not necessarily improve efficacy of D. flagrans.

In vitro nematocidal activity of plant extracts of Mexican flora against Haemonchus contortus fourth larval stage.

Fourteen plant extracts were evaluated in vitro against the fourth larval stage of Haemonchus contortus. The plants species used were Tagetes erecta, Argemone mexicana, and Castela tortuosa. The assays were run in 24-well cell culture plates at room temperature with three replicates. After exposure, aliquots were taken from the corresponding wells and transferred to a microscope for observation. Evaluation criteria were based on the average of live and/or dead larvae. ANOVA test and Tukey test were used to determine significant differences among the treatments. After 96 h, the T. erecta acetonic extract produced 99.7% lethal activity, followed by C. tortuosa hexanic extract (85.8%) and T. erecta methanolic extract (58.3%) (P < 0.0001).

Phenotype characterization of Pelibuey native lambs resistant to Haemonchus contortus.

Specific phenotypic traits of the blood-feeder nematode Haemonchus contortus were characterized on Pelibuey native, cross-breed sheep in a tropical region of Mexico with background of anthelmintic problems. Data were collected on 4-month-old lambs (n= 63) and analyzed weekly in three stages: stage 1 (S1, not infected (0-3 weeks)); S2, first infection with 350 H. contortus infective larvae (L(3)) per kg of body weight by oral route (3-10 weeks); and S3, second infection with 175 H. contortus L(3) per kg of body weight by oral route (10-18 weeks). Once infection took place, sheep grazed in a free-nematode experimental paddock, and hemoncosis-related traits, such as the number of eggs per gram of feces (epg), packed cell volume (%pvc), and eosinophils (%eo), were measured each week. Results were analyzed on specific traits and stages using SAS statistics. Statistical differences of the main phenotypic traits (P < 0.05) were observed throughout S2 on Pelibuey high (hr) and low (lr) responders, respectively: epg mean, 475 +/- 340.5 and 1439 +/- 243.6; %pvc mean, 31 +/- 0.3 and 27 +/- 0.2; and %eo mean, 2.5 +/- 0.3 and 1.99 +/- 0.2. In addition, lr and hr sheep grazed for 3 months on an area infected with Haemonchus, Cooperia, and Strongyloides, and the hr sheep showed a low number of epg after being exposed to multiple infections, so that no further treatment was required. These results showed that the selection of animals resistant to nematodes can be an alternative method of control against anthelmintic resistance problems in order to improve animal health and avoid a negative environmental impact.