Organic Broadcaster

Research shows organic fermented grape extract works as natural dewormer in lambs

By Kimberly Cash

Gastrointestinal nematode parasitism is one of the greatest threats to economic sheep production in the United States. With increased incidences of anthelmintic resistance and constraints of organic production, there is increased interest in alternative natural dewormers, such as plants containing condensed tannins (CT). Condensed tannins have been shown at certain levels to produce benefits in reduction of nematodes and increased protein absorption.³ The drive to find organic, natural, and sustainable practices to maintain healthy livestock is crucial in providing global food security. Early research suggests that phyto-therapy, the use of plants high in polyphenols, as a natural anthelmintic should be evaluated.³

Sources of Condensed Tannins
Many types of forages are high in CT such as chicory, birdsfoot trefoil, sainfoin, and sericea lespedeza, and although they can be used in production agriculture the amount of CT consumed by grazing animals is difficult to measure. Results of various research suggests these plants reduce fecal egg counts and worm burdens compared to animals fed a diet containing low levels of CT, but the amount needed to have significant results is still being examined.³ Research also suggests that fruits with dark skins such as red grapes and blueberries have a high level of CT.¹ Vineyard by-products available for the producer to purchase in liquid form, such as juice or fermented product, or in the dry form, such as grape pomace consisting of skin, seeds, stems, and pulp, all contain high levels of CT. The use of these CT-rich products could make small ruminant production in the U.S. more sustainable by using fewer synthetic anthelmintics and by reducing instances of parasite resistance.

Why Grapes?
Previous research has shown that grape pomace from the wine industry has efficacy against larval helminth life stages. Grape pomace also has efficacy against egg hatchability and larval development.² The overall effect of different treatments on eggs per gram of feces of individual lambs revealed time as well as dose as a dependent response. Additional data revealed a gradual reduction in fecal egg counts, which differed significantly from 60 to 120 days as compared to the day 0 values in sheep fed diets supplemented with CT both at 3 percent and 2 percent levels. No difference was shown in fecal egg counts of sheep fed a diet without CT.³ Other data revealed significantly lower nutrient intake by sheep fed diets containing CT than those without CT, but weight gain was higher in sheep fed either a CT diet over the no CT diet.³ Grape products have therefore been suggested as an alternate parasite management in sheep.

Effect on Animal Performance
The widely accepted explanation for positive effects of CT protein digestion and metabolism is that CT-protein complexes escape ruminal degradation and the protein is available in the lower tract. The CT, in moderate levels of 20 to 40 g CT/kg of DM, bind to protein by hydrogen bonding at near neutral pH (pH 6.0 – 7.0) in the rumen to form CT-complexes, but dissociate and release bound protein at pH less than 3.5 in the abomasum.³ Research found that when sheep consumed high CT it facilitated protection of protein from degradation by rumen microbes, which minimized the effects of internal parasites.4 It was also found that it affected overall gastrointestinal nematode (GIN) numbers and increased animal performance in ways that involved a direct effect on the parasite and an indirect effect through improved protein supply.³ Protecting dietary protein against degradation in the rumen and subsequently increasing amino acid supply to the abomasum and small intestine resulted in improved nutritional status of the animal and possible improved production.

This study used 45 Katahdin ewe and ram lambs (23.13 kg ± 0.60) naturally infected with GIN. For the duration of the 63 day project, lambs were grazed on fescue pasture with ad libitum access to fresh water and organic-approved mineral supplements. Lambs were stratified by fecal egg count, weight, and sex, and were allocated randomly to one of three treatments: 1) an oral dose (10 mL per 4.54 kg of BW) of fermented Pinot Noir grape extract at seven-day (D7) intervals, 2) the same dose at 14-day (D14) intervals, or 3) control (oral dose of 30 mL water at 14-day intervals).

Condensed tannins were extracted, purified, and standardized from the organic Pinot Noir by the Protein-Precipitable Phenolics method and found to have a concentration of 0.20 mg/mL. Sampling procedures and analysis included fecal egg counts, BCS, FAMACHA© and weight every seven days. Fecal material was collected rectally, with eggs counted using a modified McMaster procedure. Data was expressed as eggs per gram (EPG) of feces.

The goal was to maintain animals above health thresholds for the duration of the study. Egg counts and PCV data were analyzed as a randomized design using repeated measure analysis with treatment and time. Pre-trial and trial periods were analyzed separately using SAS (SAS Institute, Inc). The study was conducted from October 2014 to December 2014.

Fecal egg counts were lower (P = 0.05) at the end of 63 days and packed cell volumes or red blood cell counts were increased (P = 0.05) for D7 and D14 lambs compared to control lambs. Body condition scores and FAMACHA© scores did not differ (P ≥ 0.05) across treatments.

Average daily gain and total weight gain were greater (P = 0.02) for D7 and D14 lambs compared to control lambs.

Fermented grape extract can be an effective organic and sustainable strategy for controlling nematodes and increasing lamb performance in an organic pasture setting. Additional research is needed to determine the most accurate dose of condensed tannins needed to see the most benefit, the dosage timing and how it works with the nematode life cycle, and the bioactivity of the CT that are required to produce the best results. An increase in total weight gain and average daily gain suggests an added benefit of CT’s ability to bind to protein causing a by-pass protein effect. The results answered the initial question of “Does it work?” Yes, it does. But, as with many research projects, with that answer comes many more questions that need further exploration.

Kimberly Cash is a graduate student in the Department of Natural Sciences at Lincoln University in Jefferson City, Mo. This research poster was presented as part of the Organic Research Forum at the 2015 MOSES Organic Farming Conference. It received second place.

This project was supported by the Ceres Trust Graduate Grant program and conducted at the Lincoln University Allen T. Busby Farm, one of the largest university owned organic farms in the central U.S. The fermented organic Pinot Noir grape extract was provided by Badger
Mountain Winery in Kennewick, Wash.

1 King, A. and G. Young. 1999. Characteristics an occurrence of phenolic phytochemicals. Journal of the American Dietetic Association. 99: 213-218.

2 LeShure, S. 2014. Efficacy of Naturally Occurring Anthelmintics in Fruit By-Products to Control Intestinal Parasites in Small Ruminants. North Central Region Sustainable Agriculture Research and Education Field Notes. Graduate Grant GNC12-161, pg. 1-11.

3 Min, B. R. and S. P. Hart. 2013. Tannins for suppression of internal parasites. Journal of Animal Science, 81: 102-109.

4 Reed, J.D. 1995. Nutritional toxicology of tannins and related polyphenols in forage legumes. Journal of Animal Science, 73: 1516-28.

From the May | June 2015 Issue

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