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Research paper thumbnail of The nematophagous fungus Duddingtonia flagrans reduces the gastrointestinal parasitic nematode larvae population in faeces of orally treated calves maintained under tropical conditions. Dose/Response assessment

Veterinary Parasitology, 2018

A B S T R A C T This research was performed to assess the Duddingtonia flagrans chlamydospore dos... more A B S T R A C T This research was performed to assess the Duddingtonia flagrans chlamydospore dose/response administered in gastrointestinal parasitic nematode (GIN) naturally infected calves and its effect in reducing the GIN infective larvae (L 3) population in faeces in a cattle farm in the Mexican tropics. This study was carried out at the experimental research station " Las Margaritas " in Hueytamalco Municipality, Puebla State, Mexico. Forty zebu calves, between 6 to 12 months of age were randomly distributed into four groups of ten calves each. One control group and three treated groups with an aqueous suspension containing three different oral doses of D. flagrans chlamydospores based on their body weight (BW) were established as follows: Group 1 (Control); group 2, (Lowest fungal dose) 0.250 × 10 6 chlamydospores per kg/BW; group 3, (Medium fungal dose) 0.5 × 10 6 chlamydospores per kg/BW and group 4 (highest fungal dose), 1 × 10 6 chlamydospores per kg/BW. The corresponding fungal chlamydospore doses were daily administered for 10 consecutive days. Every group of calves was confined into individual pens and they received a maintaining nutritional regime based on Buffel grass, nutritional concentrated supplement and water ad libitum. Every third day; since one week before treatments each animal was sampled to collect faeces taken directly from rectum to determine the number of nematode eggs eliminated per g of faeces (epg), through the McMaster technique. Four faecal cultures of 20 g each from each individual faecal sample were elaborated in plastic Petri Dishes and incubated for 14 days at room temperature (18–25 °C). Criterion to estimate the efficacy of the different treatments was based on the mean number of the GIN infective larvae recovered from faecal cultures of treated groups and compared with the control group. Data were analysed using a completely randomized design through an ANOVA analysis, followed by a Duncan multiple range test. The efficacy in reducing the larvae population in faeces attributed to the effect of the different treatments were based on the Abbot´s formula giving as a result a larval rate reduction. Results showed a great variation in the epg account in the different groups along the experiment. The reduction of the larvae population attributed to the effect of the fungal administration in calves was observed from 4th to 11th day post-treatment in the three assessed dose. Results in group 2, treated with the lowest fungal dose showed 88.5, 57.6, 55.9 and 30% (58% overall reductions) in the GIN infective larvae populations in faeces of animals after 4, 7, 9 and 11 days post-treatment; respectively. In the group 3, treated with the medium fungal dose; 95.8, 80.4, 63.4 y 52.7% larvae reduction (73% overall reduction) were recorded. At the highest chlamydospore dose used (1 × 10 6) the results were: 88.9, 78.0, 59.3 and 67.3% (73.5% overall reduction) (p < .05). The species of identified nematodes through larvae morphometric and molecular taxonomy were Cooperia sp. and H. contortus. From the three D. flagrans chlamydospore assessed doses, the medium dose (0.5 × 10 6 D. flagrans chlamydos-pores per kg/BW) was sufficient to provide an important reduction of the nematode larvae population in faeces of calves in production under the Mexican tropics.

Research paper thumbnail of The nematophagous fungus Duddingtonia flagrans reduces the gastrointestinal parasitic nematode larvae population in faeces of orally treated calves maintained under tropical conditions. Dose/Response assessment

Veterinary Parasitology, 2018

A B S T R A C T This research was performed to assess the Duddingtonia flagrans chlamydospore dos... more A B S T R A C T This research was performed to assess the Duddingtonia flagrans chlamydospore dose/response administered in gastrointestinal parasitic nematode (GIN) naturally infected calves and its effect in reducing the GIN infective larvae (L 3) population in faeces in a cattle farm in the Mexican tropics. This study was carried out at the experimental research station " Las Margaritas " in Hueytamalco Municipality, Puebla State, Mexico. Forty zebu calves, between 6 to 12 months of age were randomly distributed into four groups of ten calves each. One control group and three treated groups with an aqueous suspension containing three different oral doses of D. flagrans chlamydospores based on their body weight (BW) were established as follows: Group 1 (Control); group 2, (Lowest fungal dose) 0.250 × 10 6 chlamydospores per kg/BW; group 3, (Medium fungal dose) 0.5 × 10 6 chlamydospores per kg/BW and group 4 (highest fungal dose), 1 × 10 6 chlamydospores per kg/BW. The corresponding fungal chlamydospore doses were daily administered for 10 consecutive days. Every group of calves was confined into individual pens and they received a maintaining nutritional regime based on Buffel grass, nutritional concentrated supplement and water ad libitum. Every third day; since one week before treatments each animal was sampled to collect faeces taken directly from rectum to determine the number of nematode eggs eliminated per g of faeces (epg), through the McMaster technique. Four faecal cultures of 20 g each from each individual faecal sample were elaborated in plastic Petri Dishes and incubated for 14 days at room temperature (18–25 °C). Criterion to estimate the efficacy of the different treatments was based on the mean number of the GIN infective larvae recovered from faecal cultures of treated groups and compared with the control group. Data were analysed using a completely randomized design through an ANOVA analysis, followed by a Duncan multiple range test. The efficacy in reducing the larvae population in faeces attributed to the effect of the different treatments were based on the Abbot´s formula giving as a result a larval rate reduction. Results showed a great variation in the epg account in the different groups along the experiment. The reduction of the larvae population attributed to the effect of the fungal administration in calves was observed from 4th to 11th day post-treatment in the three assessed dose. Results in group 2, treated with the lowest fungal dose showed 88.5, 57.6, 55.9 and 30% (58% overall reductions) in the GIN infective larvae populations in faeces of animals after 4, 7, 9 and 11 days post-treatment; respectively. In the group 3, treated with the medium fungal dose; 95.8, 80.4, 63.4 y 52.7% larvae reduction (73% overall reduction) were recorded. At the highest chlamydospore dose used (1 × 10 6) the results were: 88.9, 78.0, 59.3 and 67.3% (73.5% overall reduction) (p < .05). The species of identified nematodes through larvae morphometric and molecular taxonomy were Cooperia sp. and H. contortus. From the three D. flagrans chlamydospore assessed doses, the medium dose (0.5 × 10 6 D. flagrans chlamydos-pores per kg/BW) was sufficient to provide an important reduction of the nematode larvae population in faeces of calves in production under the Mexican tropics.