Undergraduate Honors Thesis Projects

Date of Award

Spring 4-13-2017

Document Type

Honors Paper

Degree Name

Equine Pre-Veterinary/Pre-Graduate Studies-BS


Equine Science


Dr. Steffanie Burk

First Committee Member

Dr. Jeffrey Lehman

Second Committee Member

Dr. Karen Steigman


Papaya, Equine, Benzyl Isothiocyanate, Strongyle, Papain, Anthelmintic

Subject Categories

Other Veterinary Medicine


Seeds of Carica papaya L. (Caricaceae) are a promising source of investigation for a novel anthelmintic to treat equine strongyle infestation. Strongyles are small redworms that attach to the intestinal wall in the equine. They can cause colic, poor hair coat, poor body condition, and, in severe cases, death. The objective of this study was to determine if benzyl isothiocyanate (BITC) and papain, two compounds found in papaya seeds, could be used to prevent migration of third stage cyathostome larvae (L3) in vitro using larval migration inhibition assays. The assays involved incubating larvae in solution, followed by larval migration through chambers containing a 25 µm mesh. Larval migration inhibition assays were performed using BITC and papain at concentrations of 0.01 µg/ml, 0.025 µg/ml, 0.05 µg/ml, 0.1 µg/ml, 0.2 µg/ml, 0.3 µg/ml, and 0.5 µg/ml. Ivermectin was used as a positive control at 150 µg/ml. Distilled water was used as a negative control. Linear regression was used to compare the responses of larvae to BITC and papain. At the highest BITC concentration (0.5 µg/ml), the percent of larvae that did not migrate (97.1% ± 4.2%), was comparable to the commercially available anthelmintic ivermectin (96.9% ± 4.4%). At the highest papain concentration (0.5 µg/ml), the percent of larvae that did not migrate was 69.4% ± 22.9%. As concentration of each compound increased, so did the number of non-migrating larvae as a percentage of the control. At the concentrations tested, BITC (y=- 130.8x+78.5, =0.64, P=0.017) appeared more promising than papain (y= -118.2x+115.4, R2=0.55, P=0.036). Further testing with additional replicates and more larvae per treatment is needed to confirm these findings.