Anthelmintic effect and intake dynamics of oak (quercus spp.) and walnut (juglans regia) foliage in goats

Summary

Oak and Walnut are both of ethnoveterinary importance, especially for anthelmintic treatment of ruminants [1,2]. H2O and EtOH-water (1:1) extracts of oak and walnut foliage were used for phytochemical profiling and for in vitro assays with Caenorhabditis elegans and gastrointestinal nematodes (GIN). Oak extracts contained mainly tannins, walnut extracts were dominated by flavonoids. Oak EtOH extract caused significant lethal effects in adult C. elegans (LC50 1.5 mg/mL); motility of GIN L3 larvae was reduced by the EtOH extract but at substantially higher concentrations. Egg hatching was inhibited by both, the oak H2O and EtOH extract. In vivo: 42 lactating Alpine goats carrying natural GIN infections were allocated to 3 feeding groups: oak, walnut and control. Freshly harvested branches with foliage were offered to goats of the respective groups twice a day for a total of 17 days. Individual foliage intake and fecal egg counts (FEC) was performed every 2 – 3 days. Oak and walnut foliage feeding did not lead to a significant reduction of FEC. Time sampling data revealed a substantial variability in leaf intake between goats for both, oak and walnut, which however, did not coincide with the hypothesis that goats with heavy GIN infections consume more leaf material than animals with light infections. Summarizing these results suggests an anthelmintic activity of oak due to the presence of tannins which points to a preventive effect by limiting development of pasture dwelling GIN parasitic stages. Adult GIN within the host do not seem to be affected with the quantities used in the study.