תפריט נגישות
ניגודיות עדינהניגודיות גבוהה
מונוכרום
הדגשת קישורים
חסימת אנימציה
פונט קריא
סגור
איפוס הגדרות נגישות
להורדת מודול נגישות חינם תפריט נגישותניגודיות עדינהניגודיות גבוההמונוכרוםהדגשת קישוריםחסימת אנימציהפונט קריאסגוראיפוס הגדרות נגישותלהורדת מודול נגישות חינםGardner, D.R., Pfister, J.A., Knoppel, E.D., Provenza, F.D, Peterson, C., Villalba, J.J.
Ticks are affected by the composition of the blood of their hosts. Immersion in solutions of fruit and kernel extracts from trees of the Meliaceae family inhibits egg production and embryogenesis in Hyalomma spp and Boophilus spp. ticks in vitro. The tetranor-triterpenoid Azadirachtin A (AzA) is the main acaricidal compound in these extracts. We investigated the effects of an extract of the neem tree (Azadirachta indica Juss.) containing 43% AzA, given as a feed additive to lambs artificially infested with adult engorging Dermacentor variabilis ticks. We assessed feed acceptance and toxicity to lambs, AzA concentration in peripheral blood using a novel LC/MS assay, and tick engorgement and egg production. After tick attached, the lambs were allotted to 3 dietary treatments:AzA0 (Control, n=10), AzA0.3 (n=5), and AzA0.6 (n=5), with feed containing 0, 0.3, and 0.6% AzA on a DM basis. Four days after attachment, ticks were sprayed in half of the AzA0 lambs with an ethanol:water:soap emulsion containing 0.6% AzA (Aza0S). In spite of its very pungent odor, the neem extract was well accepted by all but one lamb. No differences were found between groups in muscle and liver enzymes in blood, and there was no indication of toxicity. Plasma AzA concentrations after 7 and 14 days of feeding AzA were (3.32; 4.81) and (1.88, 4.35 μg/ml) for the AzA0.3 and AzA0.6 treatments, respectively, suggesting increased liver detoxication during the second week. Treatments were not lethal to ticks, but tick weight at detachment was 0.64, 0.56, 0.48, and 0.37 g for ticks from the AzA0, AzA0.3, AzA0S, and AzA0.6 treatments (P<0.004), suggesting that blood AzA was detrimental to ticks. As Azadirachtin affects embryo development and ticks at the moulting stages, we expect that one-host ticks will be more affected than the three-host tick D. variabilis. Our results thus suggest that ingestion by herbivores of plants containing compounds such as AzA may reduce external parasites.
Gardner, D.R., Pfister, J.A., Knoppel, E.D., Provenza, F.D, Peterson, C., Villalba, J.J.
Ticks are affected by the composition of the blood of their hosts. Immersion in solutions of fruit and kernel extracts from trees of the Meliaceae family inhibits egg production and embryogenesis in Hyalomma spp and Boophilus spp. ticks in vitro. The tetranor-triterpenoid Azadirachtin A (AzA) is the main acaricidal compound in these extracts. We investigated the effects of an extract of the neem tree (Azadirachta indica Juss.) containing 43% AzA, given as a feed additive to lambs artificially infested with adult engorging Dermacentor variabilis ticks. We assessed feed acceptance and toxicity to lambs, AzA concentration in peripheral blood using a novel LC/MS assay, and tick engorgement and egg production. After tick attached, the lambs were allotted to 3 dietary treatments:AzA0 (Control, n=10), AzA0.3 (n=5), and AzA0.6 (n=5), with feed containing 0, 0.3, and 0.6% AzA on a DM basis. Four days after attachment, ticks were sprayed in half of the AzA0 lambs with an ethanol:water:soap emulsion containing 0.6% AzA (Aza0S). In spite of its very pungent odor, the neem extract was well accepted by all but one lamb. No differences were found between groups in muscle and liver enzymes in blood, and there was no indication of toxicity. Plasma AzA concentrations after 7 and 14 days of feeding AzA were (3.32; 4.81) and (1.88, 4.35 μg/ml) for the AzA0.3 and AzA0.6 treatments, respectively, suggesting increased liver detoxication during the second week. Treatments were not lethal to ticks, but tick weight at detachment was 0.64, 0.56, 0.48, and 0.37 g for ticks from the AzA0, AzA0.3, AzA0S, and AzA0.6 treatments (P<0.004), suggesting that blood AzA was detrimental to ticks. As Azadirachtin affects embryo development and ticks at the moulting stages, we expect that one-host ticks will be more affected than the three-host tick D. variabilis. Our results thus suggest that ingestion by herbivores of plants containing compounds such as AzA may reduce external parasites.
