N-Hexane Fraction of Cashew Nut Shell Extract as a Potential Anticoccidial Agent in Broiler Chickens

Avian coccidiosis has long been been been a disease of major economic importance in the poultry industry worldwide. The anti-coccidial effect of n-hexane fraction of cashew nut shell (CNS) extract on Eimeria tenella infection in broiler chickens was studied. Median lethal dose (LD50) was used to determine the toxicity of the extract and to establish the dose for the in vivo studies. The chicks (2 weeks old) were grouped into five experimental groups A-E) of five chicks each; A: Normal control group (uninfected and untreated, only feed and water), B: Infected with 5000 sporulaed E. tenella oocysts and untreated, C: Infected and treated with 1.5% Amprolium®, D: Infected and treated with n-hexane fraction (750mg/kg), E: Infected and treated with n-hexane fraction (1500mg/kg). Preparative Tin Layer Chromatography, Gas Chromatography – Mass Spectrometry, and Fourier Transform Infrared Spectroscopy TLC, GC-MS and FTIR were used to further purify and determine the active ingredient in the fraction. The median lethal dose (LD50) was found to be >5000mg/kg body weight. There was a significant (p<0.05) increase in body weight of the chicks in group A (368.2±54.2g), C (417.00±42.8g), D (387.4±35.8g) and E (427.4±35.8g) at 7 days post infection with E. tenella oocysts when compared with group B (222.8±48.0g). The oocyst per gram (OPG) in the caecum of group B was significantly (p<0.05) higher (394120.0±115414) than what was found in group A (23.0±07.2), C (101±66.1), D (10149±6656.1) and E (2249.3±232.1). The gross lesion scores of +3 and +1 were recorded for groups B and C respectively. Further fractionation revealed four sub-fractions (A1, A2, A3 and A4) in which sub-fraction A2 showed the highest inhibitory activity against sporulated E. tenella oocysts based on the percentage oocysts lysis of 91.5% and the remaining unlysed oocysts (8.5%) which were found to be unviable. Based on GC-MS and FTIR spectroscopy, the active compound in sub-fraction A2 of the CNS n-hexane fraction maybe 2-(5-bromopentyl)- 7,9-Diethyl-2,4-bis (dimethylamino) -10-imino-8-thio-1,7,9-triazaspiro [4.5]-1,3-decadiene-6,8-dione. This finding suggested that, the compounds present in the active fraction A of CNS extract possess anticoccidial effects against E. tenella infection in broiler chicks.