Evaluation of anthelmintic potential of aqueous leaf extract of Azadirachta indica in benzimidazole-resistant Haemonchus contortus of sheep

This study aimed to evaluate the anthelmintic potential of aqueous leaf extract of Azadirachta indica against benzimidazole-resistant Haemonchus contortus of sheep. A faecal egg count reduction test (FECRT) was conducted in organized sheep farms in Salem, Karur, Kanniyakumari, Kancheepuram and Thiruvallur districts of Tamil Nadu using fenbendazole. 560 dung samples collected from the above sheep farms were subjected to coprological examination revealed Haemonchus contortus eggs. FECRT and allele-specific PCR (AS-PCR) confirmed the benzimidazole resistance in samples from Kancheepuram and Thiruvallur districts. Aqueous extracts of A. indica leaves at different concentrations viz., 0.5, 1, 2 and 5 per cent, were tested against resistant strongyle nematodes of sheep reared in these farms with BZ resistance. Maximum inhibition of egg hatch was noticed in 5% aqueous extracts of A. indica (35.42±1.87 %) compared to other concentrations. The maximum mean larval paralysis observed was 28.89±1.11% in 5 % aqueous extract at 60 min. It was observed that increased concentration of extracts resulted in increased efficacy of inhibition on egg hatch and mean larval paralysis. It is concluded that A. indica could be a promising phytomedicine for the benzimidazole-resistant nematodes of sheep.