Anthelmintic effect of three tannin-rich Mediterranean shrubs in naturally infected sheep

•Effects of tannin-rich diet on fecal egg counts of nematodes were evaluated.•No significant difference in FEC between the treated and the control group was noted.•Combination of these shrubs does not exhibit favorable antiparasitic effect for GIN.

Gastrointestinal nematodes are recognized as some of the most important causes of production losses in extensive sheep farming. Due to the current trends and need for finding ecologically acceptable alternatives to chemically produced anthelmintics, many research efforts are focusing on secondary plant metabolites that showed promising anthelmintic effects (e.g. tannins). In this study we investigated the effect of a mixture of three tannin-rich Mediterranean shrubs (Arbutus unedo L., Pistacia lentiscus L. and Quercus ilex L.) on the fecal egg counts (FEC) of nematodes in naturally infected adult sheep. A total of 28 sheep was randomly assigned to a treated and control groups (n = 14) and the effects of tannin-rich diet on FEC were evaluated throughout 30 days of study. No significant difference in FEC between the treated and the control group was noted at days 0, 23, and 30 of the study, suggesting that these three shrubs in combination do not exhibit a favorable antiparasitic effect for gastrointestinal nematodes in naturally infected sheep.