Date of Award

2019

Degree Type

Thesis

Degree Name

Master of Science in Biological and Environmental Sciences (MSBES)

Department

Fisheries, Animal and Veterinary Science

First Advisor

Katherine Petersson

Abstract

Gastrointestinal nematodes (GIN) represent a major health concern in small ruminants as well as a constraint for producers. The prevalence of anthelmintic resistance in small ruminant GIN has increased rapidly worldwide, creating the need for alternative control methods to address the issue. The discovery that plant secondary compounds, including proanthocyanidins (PAC), suppress GIN infections has provided promise for alternative methods of GIN control. Although the mechanism is not well understood, studies have shown in vitro and in vivo evidence of anti-parasitic effects of bioactive plants. Recently a study from our laboratory provided in vitro evidence of anthelmintic activity of cranberry vine (CV) PAC organic extracts as well as CV aqueous extracts (CV-AqE) against Haemonchus contortus first stage larvae (L1) and adult worm motility and some activity of CV-AqE against egg hatching. This previous study also showed a slight suppression of fecal egg count (FEC) in vivo when chopped cranberry was fed to parasitized lambs. The current study was designed to further investige the effects of CV on GIN infections in sheep. This study utilized two feeding trials in order to investigate the in vivo effects of CV. In the first feeding trial, lambs experimentally infected with Haemonchus contortus were given a 100% CV pellet (CVP) as a supplement to their regular grain. Although the palatability and consumption of the pellet was a major issue, supplementing the CVP into the diet appeared to suppress the FEC compared to untreated sheep at the end of the six-week trial, with no difference observed in packed cell volume (PCV) or total worm burden. In the second feeding trial, lambs with a mixed natural and experimental GIN infection were fed two levels of a 50% cranberry vine pellet that had been formulated to contain equivalent amounts of digestible dry matter. Under the conditions of the study, the FEC of the lambs consuming 500g of CV per day did not change over the course of the study unlike the control group and the lambs consuming 250g of CV per day. Although further research is needed to better understand this phenomenon, it is suggested that CV may have potential as a viable and sustainable option for northeast sheep producers to utilize as a strategy for GIN control.

Available for download on Sunday, August 16, 2020

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