Effect of tanninipherous plants extracts on hatchability of Haemonchus contortus eggs

Parasites are resistants to the main existing anthelmintic drugs on the market, so tanninipherous plants could be a sustainable alternative against gastrointestinal nematodes. The aim of this work was to evaluate the anthelmintic action of tanninipherous plants extracts on egg hatch assay (EHA) of Haemonchus contortus (H. contortus). The present research was conducted at the Institute of Animal Science (IZ/APTA/SAA) located in the city of Nova Odessa/São Paulo/Brazil. The leaves of the Fabaceae Peptadenia colubrina, Leucaena pulverulenta, Stylosanthes guianensis and Neonotonia wightii cv. tinaroo were collected at agrostological field at IZ/APTA/SAA, dried at 35°C and ground. Their actives were extracted with a solution of acetone:water (70:30), followed by washings with dichloromethane and freeze-dried. The percentages of total tannins (TT) and condensed tannins (CT) were calculated and values for TT and CT to P. colubrina was 12.7% and 0.89% respectively, followed by L. pulverulenta (7,5% and 6,9%), S. guianensis (2.4% and 1%) and N. wightii cv. tinaroo (1.1% and 0.09%). The extract concentration used to inhibit eggs hatching was 0.012 mg/mL to 50 mg/mL. Data were analyzed by SAS/Probit to determine Lethal Concentration (LC50) with independent variables (dose) transformed by natural logarithms (log-dose). The lowest LC50 was for P. colubrina (0.10 mg/mL), followed by S. guianensis (4.45 mg/mL), N. wightii cv. tinaroo (46.5 mg/mL) and finally L. pulverulenta, which did not reach the concentration of LC50. Among the tested plants P. colubrina has shown to be more effective in inhibiting the hatchability of H. contortus eggs.