ABSTRACT
Haemonchus contortus is a major health and welfare problem for small ruminants, responsible for economic losses through reduced productivity and increased mortality. The in vitro efficacy of Bidens pilosa was determined against this gastrointestinal nematode (GIN). Fresh eggs, embryonated eggs and larvae (L1 and L2) were incubated at room temperature in infused aqueous extract, macerated aqueous and ethanolic leaf extract of B. pilosa at concentrations of 0.625, 1.25, 2.5, 3.75 and 5 mg/ml for 48, 6 and 24 hours, respectively. Distilled water and 1.5% Tween 80 were used as negative controls. They did not affect development of eggs and larvae whereas extracts showed a concentration dependent activity eventhough aqueous extracts exhibited a weak activity on the different developmental stages of H. contortus compared to ethanolic extract. Ethanolic extract was more potent on larvae than on eggs. It inhibited 92.5±7.5% and 67.4±7.4% egg embryonation and egg hatch at 5 mg/ml, with IC50 values of 2.1 mg/ml and 3.3 mg/ml respectively and induced 100±0% and 89.8±3.2% L1 and L2 larvae mortality at 5 mg/ml with LC50 values of 1.8 and 1.96 mg/ml respectively. The overall findings of the current study indicated that the evaluated medicinal plant in occurrence B. pilosa possess potential anthelmintic effect and further in vivo and toxicity evaluation are indispensable to validate its use as anthelmintic for the control of GIN.
ABSTRACT
Background: Gastrointestinal nematodes (GIN) are a major threat to sheep productivity and endanger animal welfare worldwide particularly in developing countries. They cause loss of production through mortality, weight loss, reduced milk, meat and wool production. Thus, parasitism is an important limiting factor or constraint in livestock production. Aim: To evaluate the anthelmintic activity of organic and aqueous extracts of stem bark of Terminalia glaucescens against gastrointestinal nematodes of sheep using varieties of in vivo tests. Materials and Methods: Thirty (30) West African Dwarf Djallonke sheep acquired natural infection with gastrointestinal nematodes of both sexes, aged 6-10 months old and weighing between 9-13kg, use in bioassay were distributed into 5 groups (n=6). Two experiments using methanol (Groups A to E) and hot water extracts ( Groups A’ to E’) were simultaneously carried out. Groups A & A’ received 1.25% dimethyl sulfoxide (DMSO) and distilled water 1ml/10 kg bwt respectively, Groups B & B’ received Albendazole at 6.25mg/kg bwt, Groups C & C’, D & D’ and E & E’ received doses of 125, 250 and 500 mg/kg bwt of each extract. Sheep were subjected to different treatment with single dose of synthetic drug and double doses of plant extracts. Results: Methanol extract for all the doses tested was active in vivo on the adults of GIN, and reduced significantly (p<0.05) the faecal egg count (FEC) and total warm count (TWC) of the nematodes. The dose rate 500mg/kg showed the highest nematicidal activity of 77, 6% FEC and 73, 5% TWC reduction 14 days post-treatment. For hot water extract, these numbers were 65, 3% and 62, 1% for FEC and TWC respectively at the same dose for the same period of treatment. Conclusion: These results suggest the possible use of this medicinal plant in the control of gastrointestinal nematodes in sheep and justify their use in traditional veterinary practices; hence a toxicological study of the extract of this plant is required.