Assessment of Azadirachta indica seed kernel extracts to restrict the rampancy of antinematicidal-resistant Haemonchus contortus in ovine

Abstract EN

The current study was executed to evaluate the potency of crude aqueous methanol extract (CAME) of Azadirachta (A.) indica seed kernels in controlling the prevalence of oxfendazole (OXF), levamisole HCL (LEV) and ivermectin (IVM)-resistant Haemonchus (H.) contortus in sheep.

Faecal egg count reduction test (FECRT), calculated by the RESO program, revealed an emergence of resistance among the parasite populations against the aforementioned antinematicidals particularly OXF [FECR% = -56 and lower confidence interval (LCI) = -311].

The recorded FECR% for LEV and IVM was 75 and 78 whilst the LCI for both of them was 38 and 42, respectively.

Egg hatch assay (EHA) also exhibited a disastrous level of resistance in H.

contortus toward OXF.

Antinematicidal activity of A.

indica seed kernels was assessed using FECRT, EHA and adult motility test (AMT).

Mean egg per gram of faeces (EPG) recorded post-treatment of sheep at low (2g g ־k¹ BW) and high (4g kg ־¹ BW) doses of A.

indica CAME was 539±367.11 SE and 147±58.45 SE, respectively, as compared to the control group (mean EPG= 987±364.26 SE).

There was no significant difference statistically (P>0.05) in FECR% (45.62 vs 85.14) in sheep at low and high doses of the plant.

The results of AMT revealed a dose and time dependent efficacy of CAME of the assessed plant to kill antinematicidal-resistant adult worms with calculated LC50 values of 52.20, 15.40, 3.26, 1.55 and 0.80 mg ml-1 after 2, 4, 6, 8 and 10 hours.

Accordingly, high dose (4g kg ־¹ BW) of A.

indica seed kernel extract could be used to treat sheep carrying antinematicidal- resistant populations of H.

contortus.