Anthelmintic efficacy of cranberry vine extracts on ovine Haemonchus contortus

Veterinary Parasitology Available online 15 February 2018 In Press, Accepted Manuscript — Note to users Cover image Research paper Carly D. Baronea, , , Anne M. Zajacb, Laura A. Manzi-Smitha, Amy B. Howellc, Jess D.Reedd, Christian G. Kruegerd, Katherine H. Peterssona a Department of Fisheries, Animal, and Veterinary Sciences, University of Rhode Island, 120 Flagg Road, CBLS Rm 177, Kingston, Rhode Island, 02881, United States b Biomedical Sciences and Pathobiology, VA-MD College of Veterinary Medicine, Virginia Tech, 1410 Prices Fork Road, Blacksburg, VA, 24061 United States c Rutgers, The State University of New Jersey, Philip E. Marucci Center for Blueberry and Cranberry Research, 125a Lake Oswego, Chatsworth, NJ, 08019, United States d Department of Animal Science, University of Wisconsin-Madison, 1675 Observatory Drive, Rm 1146, Madison, Wisconsin, 53706, United States Received 21 July 2017, Revised 29 January 2018, Accepted 2 February 2018, Available online 15 February 2018 https://doi.org/10.1016/j.vetpar.2018.02.016 Get rights and content Highlights • Various life stages of H. contortus affected by CV extracts in vitro. • Accumulation of aggregate observed on adult worms exposed to CV. • Need for further studies of effects of feeding CV to H. contortus infected lambs. Abstract The discovery that plant secondary compounds, including proanthocyanidins (PAC), suppress gastrointestinal nematode (GIN) infection has provided promise for alternative methods of GIN control in small ruminants. This investigation is the first to examine the anthelmintic potential of cranberry vine (CV) against the GIN Haemonchus contortus. The purpose of this study was to explore the anti-parasitic activity of CV in the form of a specific organic proanthocyanidin extract (CV-PAC) and an aqueous extract (CV-AqE) containing PAC and other compounds. In vitro egg hatching, first (L1) and third (L3) stage larval and adult worm motility and L3 exsheathment were evaluated after a 24-hour incubation with CV products. In addition, CV treated worms were observed via scanning electron microscopy, and a preliminary investigation of the efficacy of CV powder against an experimental infection of H. contortus was conducted. The in vivo effect on an experimental infection was determined by administering 21.1 g CV powder to lambs (n = 9 per group) for three consecutive days, and collecting fecal egg count data for four weeks post-treatment. The effect of CV-PAC on egg hatching, L3 motility and exsheathment was limited. However, a substantial effect was observed on motility of post-hatch L1 (EC50 0.3 mg PAC/mL) and adults (EC50 0.2 mg PAC/mL). The CV-AqE showed more effect on egg hatching (EC50 5.3 mg/mL containing 0.6 mg PAC/mL) as well as impacting motility of L1 (EC50 1.5 mg/mL with 0.2 mg PAC/mL) and adults (EC50 3.4 mg/mL with 0.4 mg PAC/mL), but like CV-PAC, did not substantially effect L3 motility or exsheathment. Scanning electron microscopy revealed an accumulation of aggregate on the cuticle around the buccal area of adult worms incubated in CV-AqE and CV-PAC. In the preliminary in vivo study, there was a significant effect of treatment over time (p = 0.04), although differences in individual weeks were not significant. In summary, both extracts inhibited motility of L1 and adult worms. The higher efficacy of CV-AqE than CV-PAC at levels that contained the same concentrations of PAC tested alone, suggest that other secondary compounds in the CV-AqE contribute to the observed effects on the parasites. This first study of the in vitro and in vivo effects of CV sugges that this readily available plant product may have utility in integrated control of H. contortus and support the need for additional testing to provide further information. Keywords egg hatch; larval motility; larval exsheathment; scanning electron microscopy