Effects of Medicinal Plants and Organic Selenium against Ovine Haemonchosis

SIMPLE SUMMARY: Maintaining high productivity in small ruminants is hindered by infection with the parasitic gastrointestinal nematode (GIN) Haemonchus contortus. There is an increasing interest to find alternative treatments for controlling GINs due to the rapid development of resistance to synthetic anthelmintics. Supplementary feeding of plant nutraceuticals or mineral supplements may contribute to improving the resilience of lambs. The trace element selenium and vitamin E act synergistically as antioxidants in circulation, but the natural occurrence of selenium is very low in the soil, grain, and roughage. The aim of this study was therefore to determine the long-term effects of medicinal plants and organic selenium in lambs experimentally infected with H. contortus. The results indicated that both supplements favorably affected the infected lambs and may provide a new approach to controlling haemonchosis in small ruminants. ABSTRACT: The objective of this study was to determine the effect of traditional medicinal plants typical to Central Europe as well as organic selenium on increasing the resistance of lambs to gastrointestinal nematode (GIN) infection with Haemonchus contortus. 21 female lambs were infected with third-stage larvae of H. contortus on the day (D) 0 and re-infected on D49 and D77. The animals were divided into three groups based on a treatment diet: a basal diet (control), a diet enriched with dry plants (Herbmix), and a diet enriched with selenized yeast (Selplex). The number of eggs per gram (EPG) of feces was quantified on D21, D28, D35, D42, D49, D56, D63, D70, D77, D84, D91, D98, D105, D112, and D119. The mean reductions in EPG on D28 were 43.4 and 28.6% for Selplex and Herbmix, respectively. The reduction in egg output was nearly uniform throughout the experiment for Selplex. However, for Herbmix the mean reduction was only 19.8% up to D91 and 46.1% after D91. Glutathione peroxidase activity in the blood from D35 to D98 was two to three-fold higher for Selplex than the other groups. Both supplements slowed the dynamics of GIN infection and gradually increased the resistance of lambs against ovine haemonchosis.