Background and Aim: The emergence of drug-resistant strains of Eimeria spp. calls for the development of novel anticoccidial drugs. Plant extracts provide a possible natural source for such drugs. This study aimed to investigate the in vitro anticoccidial activity of encapsulated bromelain (EB) in chitosan nanocarriers on Eimeria spp. oocysts isolated from goats kept by farmers in Kenya.

Materials and Methods: Bromelain was extracted from the peel of ripe pineapples using standard methods. Eimeria spp. oocysts were isolated from the feces of goats using a flotation method. The inhibition of sporulation was assayed after exposing the oocysts to solutions of EB, non-EB (NEB), and diclazuril (positive control) at concentrations between 4 mg/mL and 0.125 mg/mL for 48 h. The oocysts were examined under a microscope (40x) to determine the effects of the drugs on the sporulation process. The percentage of sporulation inhibition was calculated after 48 h and the inhibition concentration 50% (IC₅₀) was determined by probit analysis.

Results: Bromelain manifested anticoccidial activity through the inhibition of the sporulation of coccidia oocysts. EB achieved inhibition with a lower dose compared with NEB. The IC₅₀ values of diclazuril, EB, and NEB were 0.078 mg/mL, 0.225 mg/mL, and 0.575 mg/mL, respectively. There were significant differences (p<0.01) between the IC₅₀ of EB and NEB compared with the standard treatment drug.

Conclusion: This preliminary study showed that EB has anticoccidial activity supporting further evaluation at an in vivo level to develop a novel drug for the management of coccidiosis in goats.

Keywords: anticoccidial activity, bromelain, chitosan, coccidia, goat, nanoencapsulation.