In vitro Studies on Anticoccidial Effects of Healthy Sheep Bile against Eimeria magna and Eimeria exigua Oocysts and Sporozoites Isolated from Domestic Rabbits

Abstract

Background: Coccidiosis is one of the most common diseases that hinder the raising of rabbits. The disease causes symptoms such as diarrhea and loss of appetite. Acute infection causes bloody feces and negatively affects fertility. Diarrhea may be bloody due to the intestinal epithelium withering off as many oocysts and merozoites burst out of the cells. This leads to the deaths of rabbits resulting in huge economic losses for commercial rabbit systems. Methods: The study aims to determine the optimal effective concentration of bile collected from healthy sheep gall bladder inhibiting in vitro sporulation and viability of E. magna and E. exigua oocysts and sporozoites isolated from rabbit intestine. Un-sporulated oocysts were exposed (1×102) to six treatments: 2.5% potassium dichromate solution as the non-treated control, four concentrations of bile (12.5%, 25%, 50% and 100%) and Toltrazuril 25 mg/ml as traditional medicine for anti-oocyst activities. In addition, 250, 500, 750 and 1000 mg/mL concentrations of bile were evaluated for effect on sporozoite viability. The oocysts were examined after 25, 50, 75 and 100 hours and sporozoites after 12 and 24 hours of treatment. Result: GC-Mass analysis showed that sheep bile contains 12 biologically active compounds. In addition, quantitative analysis revealed total phenols (50.65±0.5) and total flavonoids (9.39±0.4). After 100 hours of exposure, sheep bile was able to prevent sporulation of E. magna and E. exigua oocysts at 100% and 50% concentrations and the rate of inhibition was about 96% and 79%, respectively. Additionally, bile exhibited the least discouraging of 11% at a dose of 125 mg/mL and the highest suppression of 95% of E. magna and E. exigua sporozoites viable at 1000 mg/ml. Generally, the inhibition rate typically increased with longer incubation times and greater doses. Findings have scientifically validated the use of bile in fighting against coccidiosis. Additional studies are required to separate the active compounds found in bile and their mechanisms of action and potential applications in rabbit farms.