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United States Department of Agriculture

Agricultural Research Service

Research Project: Optimizing the Biology of the Animal-Plant Interface for Improved Sustainability of Forage-Based Animal Enterprises

Location: Forage-Animal Production Research

2013 Annual Report


1a.Objectives (from AD-416):
Objective 1: Determine the disposition of ergot alkaloids in forage-animal tissues/fluids, and implications for human health and food safety and the fundamental biological processes underlying ergot alkaloid-[forage-animal]-plant-environment interactions. Subobjective 1.A: Determine tissue distribution of ergovaline and lysergic acid in cattle consuming diets containing ergot alkaloids. Subobjective 1.B: Determine the metabolites of ergovaline and lysergic acid in urine and bile of exposed steers. Subobjective 1.C: Determine the metabolites formed and disappearance rate of ergovaline and lysergic acid when incubated in mixed rumen microbial cultures. Subobjective 1.D: Identify the transport route, mechanism, and possible metabolism of ergotamine, ergovaline, and lysergic in the bovine small intestine. Subobjective 1.E: Determine the effect of EI TF fescue on gene expression and histology of equine endometrium. Subobjective 1.F: Determine the serotonin and a-adrenergic receptors present in ruminal and mesenteric vasculature. Subobjective 1.G: Determine the effect of dose- and time-defined exposure of EA on physiological, biochemical, and molecular parameters of maturing cattle. Subobjective 1.H: Determine the effect of dose and short term EA exposure on rumen motility. Subobjective 1.I: To determine the effects the EA exposure and body fat store on adipose tissue EA accumulation and the subsequent effects on tissue metabolism, homeostasis and development of necrotic fat in cattle. Subobjective 1.J: Determine the impact of increasing dietary concentrations and “pulse” feeding of EI TF seed (source of EA) on epigenetic modifications (DNA methylation) of promoter elements responsible for pro-inflammatory (IL-1beta, IL-6 IFN-gamma and TNF-alpha) and anti-inflammatory (IL-10 & IL-13) cytokine production in the young adult (5-10 y) and aged (20+ y) horse.

Objective 2: Improve productivity of forage-based animal systems through optimization of legume/grass mixtures and management of nontoxic (novel) and or control of toxic (wild-type) endophyte-infected tall fescue in pasture systems. Subobjective 2.A: Determine the effects of EI TF seed head expression on EA concentrations, animal performance and recovery from FTOX. Subobjective 2.B: Use supplementation to mitigate FTOX by improving our knowledge concerning how supplemental nutrients interact with forage quality and EI TF to affect animal performance.

Objective 3: Determine forage nutrient and forage plant secondary metabolite effects on the gut biome to improve the health, well being and forage utilization efficiencies of forage-animals. Subobjective 3.A: Determine the effect of clover phenolic compounds on cellulolytic and amylolytic bacteria. Subobjective 3.B: Determine whether amine production in the equine large intestine during carbohydrate overload is a consequence of carbohydrate availability or of decreased large intestinal pH and the interaction between plant carbohydrate concentrations and plant phenolic concentrations on the activity of gastrointestinal microbes.


1b.Approach (from AD-416):
Forage systems provide low cost feed while mitigating man’s impact on the environment. Currently, the available fundamental biological information for predicting animal performance in response to plant nutrients under varying environmental, genetic, physiological status, and management conditions is limited. Even more problematic is the poor understanding of the effects of plant nutraceuticals and anti-quality factors on nutrient intake, metabolism and assimilation for product, health maintenance, or work by the animal. To increase the sustainability of forage-based enterprises, it is essential that a better understanding be developed of the fundamental biological processes underlying the interactions between the animal, plant, and environment. This is particularly essential for endophyte-infected forages that produce toxicants. This Project Plan, through the development and utilization of cutting-edge technologies and real world testing, proposes to decipher the complex interactions within the animal-plant interface in order to accomplish the following objectives: improve productivity of forage-based animal systems through optimization of legume/grass mixtures and management of nontoxic (novel) and or control of toxic (wild-type) endophyte-infected tall fescue in pasture systems; determine forage nutrient and forage plant secondary metabolite effects on the gut biome to improve the health, well-being and forage utilization efficiencies of forage-animals; determine the fundamental biological processes underlying the interactions between forage animals, plants, and the environment including the epigenetic effects of forage nutrients and secondary metabolites in the forage-animal; and define the toxicokinetics and toxicodynamics of the ergot alkaloids in forage-animals.


3.Progress Report:
This report documents the early progress made in meeting objectives of the 2012-2017 Project Plan. Non-toxic endophyte tall fescues were planted to serve as control pastures in evaluating effects of nutrient supplementation on mitigation of fescue toxicosis. A mesenteric and vein bioassay was developed and validated for studying serotonergic and adrenergic receptors. Ergot alkaloid-induced vasoconstriction in steers grazed on seed head suppressed toxic fescue pastures was alleviated in 2 to 3 weeks after they were placed on non-toxic diets, and it was alleviated in those grazed on unsuppressed toxic fescue pastures in 5 to 6 weeks after the steers were placed on non-toxic diets. Goats have been ruminally fistulated and once recovered from the surgeries will be used for in vitro studies that will determine the effect of biochanin A on cellulolytic rumen bacteria.


4.Accomplishments
1. Evaluation of a ruminally dosed tall fescue seed extract as a model for fescue toxicosis. Consumption of endophyte infected fescue results in reduced feed intake and subsequent animal performance. Little is understood in regards to how the toxins impact animal nutrient digestion and metabolism independent of these changes in feed intake because the toxins are typically a component of grazed forage. A steer model of fescue toxicosis was developed and validated whereby the toxins are dosed ruminally and feed intake is controlled. This model will provide a means to study the impact of fescue toxicosis on animal nutrient digestion and metabolism and hereby increase our understanding of this phenomenon.

2. Rapid determination of fasting heat production and respiratory quotient in Holstein steers using the washed rumen technique. Consumption of endophyte infected fescue results in reduced feed intake and subsequent animal performance. Little is understood in regards to how the toxins impact animal nutrient digestion and metabolism independent of these changes in feed intake because the toxins are typically a component of grazed forage. A steer model was developed and validated for rapidly determining fasting metabolism. This model will provide a means to determine fasting metabolism in steers experiencing fescue toxicosis because the toxins are added in a known quantity to the rumen using our seed extract. This model will be useful for other areas as it is an improved means of estimating energy requirements.

3. Alteration of fasting heat production during fescue toxicosis. Consumption of endophyte infected fescue results in reduced feed intake and subsequent animal performance. Little is understood in regards to how the toxins impact animal nutrient digestion and metabolism independent of these changes in feed intake because the toxins are typically a component of grazed forage. Determined the fasting metabolism of steers that were ruminally dosed with ergot alkaloids. This experiment determined that steers experiencing fescue toxicosis have a reduction in basal metabolic rate.

4. Ergot alkaloids from endophyte-infected tall fescue decrease reticuloruminal epithelial blood flow and volatile fatty acid absorption. Consumption of endophyte infected fescue results in reduced feed intake and subsequent animal performance. Little is understood in regards to how the toxins impact animal nutrient digestion and metabolism independent of these changes in feed intake because the toxins are typically a component of grazed forage. A previously developed model of fescue toxicosis was used to determine that the presence of fescue toxins reduces rumen epithelial blood flow and volatile fatty acid absorption. These effects can contribute to the reduced growth rates when animals consume toxic fescue.

5. Timing of chemical application to suppress seed head emergence of tall fescue. Treatment of toxic endophyte-infected tall fescue with Chaparral herbicide can suppress emergence of toxic seed heads to enhance cattle performance and mitigate fescue toxicosis, but the time of year to apply the chemical for optimum suppression is not known. It was determined from a small-plot experiment that maximum suppression occurs when tall fescue is treated in the late-spring when seed emergence is initiated rather than in early spring or late fall. Plant losses were observed with late fall and early spring, but not with the late-spring application. These results provide a recommendation for maximizing the suppression of tall fescue seed heads and the benefits to animal performance and well being.


Review Publications
Taghavi-Nezhad, M., Alipoura, D., Flythe, M.D., Zamani, P. 2013. The effect of essential oils of Zataria multiflora and Mentha spicata on the in vitro rumen fermentation, and growth and deaminative activity of amino acid-fermenting bacteria isolated from Mehraban sheep. Small Ruminant Research. 81(2):178-181.

Harlow, B.E., Lawrence, L.M., Flythe, M.D. 2013. Diarrhea-associated pathogens, lactobacilli and cellulolytic bacteria in equine feces: responses to antibiotic challenge. Veterinary Microbiology. 166:225-232.

Johnson, J.M., Aiken, G.E., Phillips, T.D., Barrett, M., Klotz, J.L., Schrick, F.N. 2012. Steer and pasture responses for a novel endophyte tall fescue developed for the upper transition zone. Journal of Animal Science. 90:2402-2409.

Kirch, B.H., Moser, L.E., Waller, S.S., Klopfenstein, T.J., Klotz, J.L. 2011. Protein degradation of smooth bromegrass switchgrass and big bluestem in grazing cattle. The Professional Animal Scientist. 27:422-427.

Klotz, J.L., Brown, K.R., Xue, Y., Matthews, J.C., Boling, J.A., Burris, W.R., Bush, L.P., Strickland, J.R. 2012. Alterations in serotonin receptor-induced contractility of bovine lateral saphenous vein in cattle grazing endophyte-infected tall fescue. Journal of Animal Science. 90:682-693.

Aiken, G.E., Tabler, S.F., Looper, M.L., Brauer, D.K., Strickland, J.R., Shrick, F.N. 2006. Influence of stocking rate and steroidal implants on growth rate of steers grazing toxic tall fescue and subsequent physiological responses. Journal of Animal Science. 84:1626-1632.

Earing, J.R., During, A.C., Gellin, G.L., Lawrence, L.M., Flythe, M.D. 2012. Bacterial colonization of the equine gut; comparison of mare and foal pairs by PCR-DGGE. Journal of Applied Microbiology. 2:79-86.

Koontz, A.F., Bush, L.P., Klotz, J.L., Mcleod, K.R., Schrick, F.N., Harmon, D.L. 2012. Evaluation of a ruminally dosed tall fescue seed extract as a model for fescue toxicosis in steers. Journal of Animal Science. 90:914-921.

Last Modified: 10/25/2014
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