Arthrobotrys cladodes and Pochonia chlamydosporia in the biological control of nematodiosis in extensive bovine production system.

Cattle production in extensive systems favours the occurrence of gastrointestinal nematodes, and the use of nematophagous fungi complements the control strategies for these nematodes. The aim of this study was to evaluate the effectiveness of the fungi Arthrobotrys cladodes and Pochonia chlamydosporia in the biological control of gastrointestinal parasitic nematodes in grazing cattle. Twenty-four calves were randomly divided into four groups and allocated to independent paddocks from February 2018 to January 2019. In the first group, the animals received pellets containing P. chlamydosporia. In the second group, the animals received pellets containing A. cladodes. In the third group, the animals received pellets containing a combination of the fungi A. cladodes and P. chlamydosporia. In the control group, the animals received pellets without fungus. The combined use of A. cladodes and P. chlamydosporia showed greater efficacy in the biological control of bovine gastrointestinal parasitic nematodes than the same fungi used separately. The parasite load was lower and weight gain was greater (P ⩽ 0.05) in the groups of cattle treated with nematophagous fungi. Therefore, the use of A. cladodes and P. chlamydosporia is promising in the biological control of nematodiosis in cattle.

Arthrobotrys cladodes and Pochonia chlamydosporia: Nematicidal effects of single and combined use after passage through cattle gastrointestinal tract.

Nematodiosis are responsible for financial losses in cattle production systems due to treatment costs, falling production rates and animal deaths. The incorporation of sodium alginate pellets containing nematophagous fungi in the bovine diet is a method for the control of nematodiosis. The aims of this study were to evaluate the viability of Arthrobotrys cladodes and Pochonia chlamydosporia contained in sodium alginate pellets after passage through the bovine gastrointestinal tract, as well as to evaluate the effects of single and combined use of these fungi against bovine parasitic nematodes. The reduction in parasitic nematode infective larvae of bovines by the combined use of Arthrobotrys cladodes and Pochonia chlamydosporia was more than the reduction in infective larvae by Arthrobotrys cladodes or Pochonia chlamydosporia alone in the collections 12, 24 and 36 h after giving the pellets to the animals. Arthrobotrys cladodes and Pochonia chlamydosporia combined promoted maximum reduction of infective larvae of 86.3%. Therefore, the combination of Arthrobotrys cladodes and Pochonia chlamydosporia may be an effective method to control gastrointestinal nematodiosis affecting grazing cattle.

In vitro biological control of bovine parasitic nematodes by Arthrobotrys cladodes, Duddingtonia flagrans and Pochonia chlamydosporia under different temperature conditions.

Variations in temperature can affect the development of nematophagous fungi, especially when they are used in the biological control of parasitic nematodes in the pastures where cattle are reared. The aim of this work was to evaluate the effects of temperature on the performance of nematophagous fungi in the biological control of bovine parasitic nematodes. The mycelial growth, chlamydospore production and nematicidal activity of Duddingtonia flagrans, Arthrobotrys cladodes and Pochonia chlamydosporia were evaluated at 15, 20, 25, 30 and 35°C. The fungal strains achieved mycelial growth, chlamydospore production and nematicidal activity on parasitic nematodes under all temperature conditions tested. The fungi showed higher growth at intermediate temperatures (20, 25 and 30°C) than at the extremes of 15 and 35°C. At 25 and 30°C, D. flagrans realized 96.8 and 94.5% nematicidal activity on bovine parasitic nematodes, respectively. Arthrobotrys cladodes effected nematicidal activity of 85.3 and 83.5%, at 20 and 25°C, respectively. At 20 and 30°C, P. chlamydosporia achieved nematicidal activity of 81.3 and 87.4%, respectively. The maximum chlamydospore production was reached at 20, 25 and 30°C for D. flagrans, at 20 and 25°C for A. cladodes and P. chlamydosporia. The results of this study demonstrated that the tested fungal strains of D. flagrans, A. cladodes and P. chlamydosporia, when used in the biological control of bovine parasitic nematodes, were not limited by in vitro temperature variations. Therefore, the use of these strains of fungi as biological control agents of parasitic nematodes is promising.

Reduction of bovine strongilides in naturally contaminated pastures in the southeast region of Brazil.

Biological control through the use of nematophagous fungi is a sustainable alternative for combatting helminthes in domestic animals and allows a reduction in the use of anthelmintics. The objective of this research was to evaluate the efficacy of the Arthrobotrys cladodes var macroides fungus in a pelleted formulation, based on sodium alginate and administered twice a week orally, as an alternative for the biological control of nematodes in field-grown young cattle. The experiment was conducted in a farm located in the municipality of Viçosa, MG, where 12 cattle, seven to nine months old, were allocated in two groups (treated group and control group) and distributed in pickets of Brachiaria decumbens, naturally infested with nematode larvae. The animals in the treated group received 1g of sodium alginate matrix pellets for every 10 kg of animal live weight, containing the nematophagous fungus Arthrobotrys cladodes var macroides and administered twice a week in conjunction with commercial feed. In the control group, each animal received 1 g of pellets for every 10 kg of animal live weight, without fungal mycelium added to the feed. Samples of feces and pastures were collected fortnightly for 12 months. The results showed that the most prevalent nematode genera in the coprocultures were Haemonchus sp., Cooperia sp. and Oesophagostomum sp., reflecting the results found in forage. The pasture that contained the animals that received feed with the fungus presented a reduction of 59% and 52% of larvae recovered at distances of 20 cm and 40 cm from the fecal pats, respectively. The mean number of eggs per gram of feces each month and animal body weight did not differ (p > 0.05) between the treated and control groups. Stool and soil samples from both groups were colonized by A. cladodes fungus and other fungi. Administration of Arthrobotrys cladodes var macroides mycelium by means of a sodium alginate matrix twice weekly reduced larval infestation of the surrounding pasture, indicating that this fungus may be a promising biological control of infecting forms of nematodes present in the environment.

Transcriptome analysis highlights the influence of temperature on hydrolase and traps in nematode-trapping fungi.

Pine wilt disease caused by Bursaphelenchus xylophilus poses a serious threat to the economic and ecological value of forestry. Nematode trapping fungi trap and kill nematodes using specialized trapping devices, which are highly efficient and non-toxic to the environment, and are very promising for use as biological control agents. In this study, we isolated several nematode-trapping fungi from various regions and screened three for their high nematocidal efficiency. However, the effectiveness of these fungi as nematicides is notably influenced by temperature and exhibits different morphologies in response to temperature fluctuations, which are categorized as "NA," "thin," "dense," and "sparse." The trend of trap formation with temperature was consistent with the trend of nematocidal efficiency with temperature. Both of which initially increased and then decreased with increasing temperature. Among them, Arthrobotrys cladodes exhibited the highest level of nematocidal activity and trap formation among the tested species. Transcriptome data were collected from A. cladodes with various trap morphologies. Hydrolase activity was significantly enriched according to GO and KEGG enrichment analyses. Eight genes related to hydrolases were found to be consistent with the trend of trap morphology with temperature. Weighted gene co-expression analysis and the Cytoscape network revealed that these 8 genes are associated with either mitosis or autophagy. This suggests that they contribute to the formation of "dense" structures in nematode-trapping fungi. One of these genes is the serine protein hydrolase gene involved in autophagy. This study reveals a potentially critical role for hydrolases in trap formation and nematocidal efficiency. And presents a model where temperature affects trap formation and nematocidal efficiency by influencing the serine protease prb1 involved in the autophagy process.

First report of interaction of nematophagous fungi on Libyostrongylus douglassii (Nematoda: Trichostrongylidae) / Primeiro relato da interação de fungos nematófagos sobre Libyostrongylus douglassii (Nematoda: Trichostrongilidae)

Libyostrongylus douglassii is a gastrointestinal nematode parasite of ostriches that can cause up to 50% mortality in young birds. The objective of this study was to compare the predatory capacity of two isolates of the predatory fungi Duddingtonia flagrans(AC001 and CG722 isolates) and one of Arthrobotrys cladodes (CG719) on infective larvae (L3) of L. douglassii under laboratory conditions, in 2% water-agar medium. The results showed that the fungi tested were effective in preying upon the L3 of L. douglassii (P < 0.05), compared with the control group. However, there was no difference in predatory capacity between the fungi tested (P > 0.05) during the seven days of experimental testing. In comparison with the control, without fungus, there were significant decreases (P < 0.05) of 85.2% (AC001), 81.2% (CG722) and 89.2% (CG719) in the average numbers of L3 of L. douglassii recovered from treatments with the isolates tested. In the present study, the three isolates of the predatory fungi D. flagrans (AC001 and CG722) and A. cladodes (CG719) were efficient at in vitro destruction of the L3 of L. douglassii.

Libyostrongylus douglassii é um nematóide parasito gastrintestinal de avestruzes que pode causar até 50% de mortalidade em aves jovens. O objetivo deste trabalho foi comparar a capacidade predatória de dois isolados de fungos predadores Duddingtonia flagrans (isolados AC001 e CG722) e um Arthrobotrys cladodes (CG719) sobre larvas infectantes (L3) de L. douglassii em condições laboratoriais, em meio ágar­água 2%. Os resultados demonstraram que os fungos testados foram eficientes em predar as L3 de L. douglassii (P < 0,05) em relação ao grupo controle. Contudo, não foi observada nenhuma diferença na capacidade predatória entre os fungos testados (P > 0,05) durante os sete dias do ensaio experimental. Em comparação ao controle, sem fungo, houve uma redução significativa (P < 0,05) de 85,2% (AC001); 81,2% (CG722) e 89,2% (C719) na média de L3 recuperadas nas placas do grupo tratado com os isolados testados. No presente trabalho, os três isolados de fungos predadores D. flagrans (AC001 e CG722) e A. cladodes (CG719) foram eficientes na destruição in vitro das L3 de L. douglassii.