@article {JRN54522, title = {Effect of light intensity and wavelength on concentration of plant secondary metabolites in the leaves of Flourensia cernua}, journal = {Biochemical Systematics and Ecology}, volume = {65}, year = {2016}, month = {04/2016}, pages = {108-114}, chapter = {108}, abstract = {

Flourensia cernua (tarbush) is a shrub that has encroached into grasslands in many areas of the northern Chihuahuan Desert and contains high levels of carbon-based secondary compounds. Concentrations of secondary compounds are affected by numerous biotic and abiotic influences, including amount and wavelength of solar radiation. However, responses to shade and ultraviolet light restriction are inconsistent among plant species and compound class. We conducted a three-year study to evaluate the effect of shade and UV light restriction on total phenolic and terpene concentrations in tarbush. Sixty plants were randomly assigned to one of three treatments (control, UV light restriction, or 50\% incident light restriction). Mean concentrations of total phenolics and total volatiles in tarbush were 82.4 and 12.5 mg/g DM, respectively. Total phenolics did not differ between UV-restricted and control plants, but were lower in shaded plants than the other treatments (P \< 0.05).\  Total volatiles tended to be greater for the UV-restricted treatment than control plants (P= 0.056), with shaded plants not different from either treatment. Treatment effects were detected for 18 individual compounds (P \< 0.05). Our results partially support the hypothesis that UV restriction and shading alter carbon-based secondary chemical concentrations.

}, keywords = {Flourensia cernua, phenolics, plant secondary metabolites, shade, terpenes, ultraviolet light}, doi = {10.1016/j.bse.2016.02.019}, url = {/files/bibliography/16-006.pdf}, author = {Richard E. Estell and E.L. Fredrickson and D. K. James} } @article {JRN53927, title = {Is differential use of Juniperus monosperma by small ruminants driven by terpenoid concentration}, journal = {Journal of Chemical Ecology}, volume = {40}, year = {2014}, month = {02/2014}, pages = {285-293}, chapter = {285}, abstract = {

We examined the relationship between volatile plant secondary metabolite concentrations and Juniperus monosperma herbivory by small ruminants. Two groups of animals (10 goats or 5 goats plus 4 sheep) browsed 16 paddocks (20 x 30 m) containing one-seed juniper for six days during two seasons. Juniper leaves were sampled from 311 saplings on the same day they were browsed. Saplings were categorized by size (short [\< 0.5 m], medium [0.5-1.0 m] or tall [\> 1.0 m]) and browsing intensity (light [\< 33\%], moderate [33-66\%] or heavy [\> 66\%]). Juniper bark was also collected from 12 saplings during spring. Total estimated terpenoid concentrations in leaves and bark were 18.3 \± 0.3 and 8.9 \± 0.8 mg/g, respectively, and the dominant terpene in both tissues was a-pinene (11.1 \± 0.2 and 7.6 \± 0.7 mg/g, respectively). Total terpenoid concentration was greater (P \< 0.001) in spring than summer (20.6 \± 0.5 vs. 16.7 \± 0.3 mg/g, respectively) and lower (P \< 0.001) in short saplings than medium or tall saplings (16.5 \± 0.6 vs. 19.8 \± 0.4 and 19.5 \± 0.4 mg/g, respectively). Total concentration also differed (P \< 0.001) among the three defoliation categories (16.1 \± 0.4, 18.7 \± 0.5, and 21.2 \± 0.6 mg/g for heavy, moderate, and light, respectively). The smallest subset of terpenes able to discriminate (P \< 0.001) between heavy and light browsing intensity categories included eight compounds ([E]-\ß-farnesene, bornyl acetate, \&$\#$39;-eudesmol, endo-fenchyl acetate, y-cadinene, a-pinene, cis-piperitol, and cis-p-menth-2-en-1-ol).

}, keywords = {goats, herbivory, one-seed juniper, Oxygenated terpenes, Resource availability hypothesis, sheep, targeted grazing, terpenes}, doi = {10.1007/s10886-014-0389-1}, url = {/files/bibliography/14-006.pdf}, author = {Richard E. Estell and S. A. Utsumi and Andr{\'e}s F. Cibils and D.M. Anderson} } @article {49847, title = {Within-plant distribution of volatile compounds on the leaf surface of Flourensia cernua}, journal = {Biochemical Systematics and Ecology}, volume = {48}, year = {2013}, month = {01/2013}, pages = {144-150}, chapter = {144}, abstract = {

We are using Flourensia cernua as a shrub model to study the role of terpenes on intake by livestock. Two experiments were conducted to examine distribution of volatile chemicals within a plant in an effort to minimize sample variability. In Exp. 1, leaves (current year\&$\#$39;s growth) were collected from 20 tarbush plants. Two leaders were sampled from each of three positions (outer canopy, subcanopy, and basal) in all four quadrants (based on ordinal direction). In Exp. 2, 10 leaders of current year\&$\#$39;s growth were removed from another 20 plants. Leaders were collected from the outer canopy of each quadrant and separated into thirds before removing leaves, thereby creating three leaf age categories. Volatile compounds were extracted with ethanol and analyzed with gas chromatography/mass spectrometry. Ninety-four chemicals (including 15 unknowns) were present on the leaf surface of F. cernua. Although 14 and 21 compounds differed (P \< 0.05) among quadrants in Exp. 1 and 2, respectively, no consistent quadrant effect was detected in either study. Leaf position differed (P \< 0.05) for 52 chemicals in Exp. 1 but outer canopy and subcanopy leaves differed for only 10 compounds. In Exp. 2, 63 compounds differed among leaf age categories. Immature leaves contained greater concentrations of 46 chemicals (P \< 0.05) than moderate or mature age categories, but moderate and mature leaves differed for only seven compounds. Estimated total concentration (i.e., cumulative concentration of all compounds) was not affected by leaf position but varied among leaf age categories (P \< 0.05; immature \> moderate \> mature). Differences in leaf position were attributed about equally to mono- and sesquiterpenes, whereas leaf age was affected to a greater extent by sesquiterpenes. Leaf position and maturity both affect terpene concentration and sampling variability for tarbush. However, little difference was detected between subcanopy and canopy positions. Thus, by avoiding basal sprouts and sampling from the mid-point of current year\&$\#$39;s growth, sampling variation should be minimal.

}, keywords = {Flourensia cernua, leaf age, plant secondary metabolites, terpenes, volatiles, within-plant distribution}, doi = {10.1016/j.bse.2012.11.020}, url = {/files/bibliography/13-002.pdf}, author = {Richard E. Estell and D. K. James and E.L. Fredrickson and D.M. Anderson} } @article {49867, title = {Effects of adding protein, condensed tannins, and polyethylene glycol to diets of sheep and goats fed one-seed juniper and low quality roughage}, journal = {Small Ruminant Research}, volume = {112}, year = {2013}, month = {04/2013}, pages = {56-68}, chapter = {56}, abstract = {

The biochemical mechanisms that limit voluntary intake of one-seed juniper by browsing ruminants are not well understood. Twelve Rambouillet ewes (78 \± 2.3 kg BW) and 12 Boer-Spanish does (54 \± 1.4 kg BW) were used in a split-plot sequence design to investigate the effects of adding protein, quebracho tannins (QTs), and polyethylene glycol (PEG) on one-seed juniper intake and preference and on ruminal VFA and plasma AA concentrations. Animals received sudangrass hay and isoenergetic basal diets (4 does and 4 ewes/diet) with either rumen degradable (RDP) or rumen undegradable (RUP) protein (12.5\% CP) or no additional protein (control, 5\% CP) during four 15-d periods. The control, RDP, and RUP diets were considered the main plot, whereas the four supplement treatments were analyzed as the split-plot effects. Period 1 allowed for adaptation to basal diets and served as a baseline phase. In periods 2-4, animals were offered juniper leaves and twigs (period 2), juniper plus QT (10\% of basal diet; period 3), and juniper plus QT plus PEG (50 g/animal; period 4). Juniper intake by sheep and goats was not affected (P \> 0.88) by RDP or RUP when animals were first exposed to juniper, but marginally increased (P \< 0.10) in period 4 (QT + PEG) regardless of the basal diet. Prior exposure to juniper did not affect (P = 0.61) the preference ratio for juniper, but goats had higher preference ratio for juniper (P \< 0.01) when receiving PEG (period 4). Concentrations of total VFA tended to increase in sheep (P = 0.10) and goats (P = 0.14) fed protein supplements and molar proportions shifted toward acetate for goats fed RDP and RUP (P = 0.07) and to butyrate for sheep fed RDP (P = 0.01). Initial juniper exposure (period 2) elevated concentrations of acetate, propionate, and butyrate (P \< 0.01), but the effect was extinguished in periods 3 and 4 with addition of QT (P \< 0.05). Supplementation with PEG transiently mitigated the depressor effect of QT on acetate, propionate, and butyrate concentration at 12 h post juniper feeding (P \< 0.01). RDP in goats and to a greater extent RUP in sheep increased plasma concentrations of various AA, especially the branched chained Val, Ile, and Leu (P \< 0.05). Plasma concentrations of several AA, including Met, Cyst, Glu, Gly, Gln, Asn, Thr, Ser, and Phe, decreased with ingestion of juniper (period 2) and juniper plus QT (period 3). Concentrations of some AA that were depressed by ingestion of juniper and QT were partially restored with supplemental PEG (P \< 0.05). Protein, terpenes, tannins, and PEG interacted to influence rumen VFA and plasma AA, which were related to intake of juniper and basal diets.

}, keywords = {goats, juniper, rumen degradabe protein, rumen undegradable protein, sheep, terpenes}, doi = {10.1016/j.smallrumres.2012.09.006}, url = {/files/bibliography/13-012.pdf}, author = {S. A. Utsumi and Andr{\'e}s F. Cibils and Richard E. Estell and S. Soto-Navarro and Cheng, L. and Hallford, D.M.} } @conference {49943, title = {Distribution of antiherbivory compounds in Flourensia cernua}, booktitle = {American Society of Animal Science Joint Annual Meeting}, year = {2011}, month = {07/2011}, publisher = {Journal of Animal Science}, organization = {Journal of Animal Science}, address = {New Orleans, LA}, abstract = {Flourensia cernua is serving as a shrub model to study the influence of terpenes on intake by livestock at this location. Two studies (n=20 plants per study) were conducted to examine within plant distribution of volatile compounds to improve sampling protocol. Leaves from 3 positions (outer canopy, subcanopy, and basal) were collected from 4 quadrants (based on ordinal direction) in Exp. 1. Leaves were removed from 2 leaders of current year\&$\#$39;s growth for each position in each quadrant. In Exp. 2, 10 leaders of current year\&$\#$39;s growth were collected from the outer canopy in each quadrant and 3 leaf age categories were formed by separating leaders into thirds and removing leaves. Chemicals were extracted from 5 leaves in duplicate with ethanol and analyzed with gas chromatography/mass spectrometry. Data were log transformed and analyzed by univariate ANOVA and means were separated using Tukey\&$\#$39;s HSD. Ninety-three volatile compounds (including 15 unknowns) were present on the leaf surface of F. cernua. Only 7 compounds (including 3 unknowns) in Exp. 1 and 9 in Exp. 2 differed (P\<0.05) among quadrants, and no consistent effect of quadrant was observed in either study. In Exp. 1, 31 compounds differed (P\<0.05) among leaf positions, but outer canopy and subcanopy leaves did not differ for any compound. Basal leaves contained greater concentrations than outer canopy and subcanopy leaves for 10 compounds, and less than the other 2 positions for 10 compounds. Thirty-two compounds differed for leaf age in Exp. 2, with immature leaves containing greater concentrations than mature leaves for 30 compounds and greater than the middle age category for 26 compounds (P\<0.05). Total concentration (cumulative concentration of all compounds) did not differ among leaf positions but differed for leaf age (greater in immature than mature leaves; P\<0.05). Compounds that differed in Exp. 1 were represented about equally by mono- and sesquiterpenes, whereas compounds affected by leaf age were predominantly sesquiterpenes (only 3 of 32 were monoterpenes). Both leaf position and age affect terpene concentrations and sampling variability in this shrub.}, keywords = {chemical distribution, leaf age, terpenes}, author = {Richard E. Estell and E.L. Fredrickson and D. K. James and D.M. Anderson} } @article {50276, title = {Potential mechanisms to increase shrub intake and performance of small ruminants in Mediterranean shrubby ecosystems}, journal = {Small Ruminant Research}, volume = {74}, year = {2008}, month = {January 2008}, pages = {1-15}, abstract = {

Shrubby vegetation types called \“maquis\” and \“garrigue\” are widespread throughout the Mediterranean Basin, including the Adriatic littoral of Croatia. In Croatia and elsewhere, these shrublands represent traditional grazing areas and are a significant source of forage for small ruminants, particularly during the dry summer. Utilization of these Mediterranean shrublands is often limited by secondary compounds that adversely affect forage intake and animal health. Likewise, shrubs containing substantial quantities of secondary compounds dominate arid and semiarid rangelands globally. These secondary compounds reduce livestock productivity, cause significant toxicity and abortion problems, and reduce efficiency of use of rangeland shrubs worldwide. Feed additives (e.g., activated charcoal, polyethylene glycol, and calcium hydroxide) may be useful for enhancing shrub intake through decreased absorption and/or increased elimination of secondary compounds. The biological diversity of Mediterranean maquis vegetation may also positively influence shrub consumption by small ruminants. Consumption of combinations of shrubs containing varied classes of secondary compounds (e.g., tannins and saponins) may lead to complementary chemical interactions within the intestinal tract and/or post-absorption that reduces their toxic effects and/or increase efficiency of detoxification. Although goats consumed more total shrubs than sheep across experiments, both species responded similarly to supplemental charcoal, PEG, and calcium hydroxide.

}, keywords = {activated charcoal, calcium hydroxide, mediterranean shrub, polyethylene glycol, saponins, small ruminants, tannins, terpenes}, doi = {10.1016/j.smallrumres.2007.07.006}, url = {/files/bibliography/08-002.pdf}, author = {Rogosic, J. and Richard E. Estell and Ivankovic, S. and Kezic, J. and Razov, J.} } @article {50327, title = {Effects of Eugenol, Alpha-Terpineol, Terpin-4-ol, and methyl eugenol on consumption of alfalfa pellets by sheep}, journal = {Small Ruminant Research}, volume = {73}, year = {2007}, month = {Septembe 10, 200}, pages = {272-276}, abstract = {Many secondary compounds are typically present in unpalatable shrubs on rangelands in the western United States. However, the relationship between intake by livestock and concentration of individual chemicals has been examined for very few of these compounds. Four experiments were conducted to examine effects of individual volatile compounds on intake of alfalfa pellets by lambs. Forty-five lambs (9 lambs/treatment) were individually fed alfalfa pellets with eugenol, {\textquoteright}-terpineol, terpin-4-ol, or methyl eugenol applied at one of five concentrations in an ethanol carrier. Treatments were multiples (0, 0.5, 1, 2, and 10X) of the concentration (X) of each compound on the leaf surface of Flourensia cernua. Treatment solutions were sprayed on alfalfa pellets (0.64 kg.lamb-1.d-1, DM basis), and consumption was measured during a 20-min interval for five days. A day effect (P < 0.001 for both linear and quadratic contrasts) was detected for intake in all four experiments, but no day x treatment interactions were observed (P > 0.05). The day effect was generally due to lower intake on day 1, except for the methyl eugenol experiment, in which lambs consumed more pellets on day 1. No treatment effects were observed (P > 0.05) for any of the four chemicals tested; thus, eugenol, {\textquoteright}-terpineol, terpin-4-ol, and methyl eugenol were not related to intake of alfalfa pellets by lambs under the conditions of this study.}, keywords = {diet selection, Herviory, intake, sheep, terpenes}, url = {/files/bibliography/07-026.pdf}, author = {Richard E. Estell and E.L. Fredrickson and D.M. Anderson and M.D. Remmenga} } @article {50329, title = {Volatile compounds on the leaf surface of intact and regrowth tarbush (Flourensia cernua DC) canopies}, journal = {Journal of Chemical Ecology}, volume = {33}, year = {2007}, month = {September 25, 20}, pages = {1867-1875}, abstract = {

Shrub expansion into desert grasslands is a serious problem resulting in loss of forage and rangeland productivity. Flourensia cernua DC (tarbush) is one such shrub contributing to the decline of Chihuahuan Desert grasslands. Our previous research has shown tarbush consumption by sheep and goats to be negatively related to leaf surface concentration of individual terpenes and epicuticular wax. Concentrations of compounds such as terpenes often change with plant age and phenology. Our objective was to examine the effect of altering the vegetative state of tarbush on volatile chemicals. Ninety tarbush plants were randomly selected and all biomass within 10 cm of the soil surface was removed from 45 plants during winter dormancy. Leaves were collected the following summer during active growth from the canopy of intact controls and resprouts. Leaf surface volatiles were analyzed by gas chromatography-mass spectroscopy and subjected to univariate analysis of variance and stepwise discriminate analysis. Of the 87 compounds present on tarbush leaves, 35 were greater in canopy samples and 16 were greater in regrowth samples based on univariate analysis (P\< 0.05). Mean concentration of total volatiles on canopy leaves tended to be less (P = 0.062) than that of regrowth (3642 vs. 4684 {\`\i}g/g DM). Nine compounds in the discriminant analysis ({\'a}-muurolene, iso-borneol, unknown$\#$6, p-cymen-8-ol, unknown$\#$7, sabinene, {\^a}-caryophyllene, {\"a}-cadinene, and {\'a}-copaene) explained 95\% of the variation between canopy and regrowth samples. Lower cumulative concentration of volatile compounds in canopy than regrowth samples suggests repsrouts may be less vulnerable to herbivory than intact tarbush.

}, keywords = {Flourensia cernua, plant secondary metabolites, regrowth, tarbush, terpenes}, doi = {10.1007/s10886-007-9360-8 }, url = {/files/bibliography/07-029.pdf}, author = {E.L. Fredrickson and Richard E. Estell and M.D. Remmenga} } @article {50547, title = {Effects of gamma-terpinene, terpinolene, alpha-copaene, and alpha-terpinene on consumption of alfalfa pellets by sheep}, journal = {Journal of Animal Science}, volume = {83}, year = {2005}, month = {August 15, 2005}, pages = {1967-1971}, abstract = {Although plant secondary chemistry influences shrub consumption by free-ranging ruminants, the effects of many specific compounds on herbivory have not been examined. We conducted four experiments to examine effects of individual terpenes on alfalfa pellet intake by lambs. Forty-five lambs (9 lambs/treatment) were individually fed alfalfa pellets sprayed with either gamma-terpinene, terpinolene, alpha-copaene, or alpha-terpinene at one of five concentrations in an ethanol carrier. Treatments (0, 0.5, 1, 2, and 10X) were multiples of the concentration (X) of a specific terpene on the leaf surface of Flourensia cernua. Terpenes were applied to alfalfa pellets (0.64 kg.lamb-1.d-1, DM basis), and consumption was measured during a 20-min interval for 5 d. A day effect (P \< 0.02) was detected for gamma-terpinene on intake (P \< 0.0001 for both linear and quadratic contrasts). A treatment effect (P \< 0.02) was observed for alpha-copaene with intake on the 2X treatment lower than other treatments. No effect of terpinolene or alpha-terpinene on intake was detected in this study. None of the chemicals tested were strongly related to intake of alfalfa pellets by lambs under the conditions of this study. http://jas.fass.org/cgi/reprint/83/8/1967}, keywords = {diet selection, herbivory, intake, sheep, terpenes}, url = {/files/bibliography/05-013.pdf}, author = {Richard E. Estell and E.L. Fredrickson and D.M. Anderson and M.D. Remmenga} } @conference {50649, title = {Effects of {\~a}-terpinene, terpinolene, {\'a}-copaene, and {\'a}-terpinene on consumption of alfalfa pellets by sheep}, booktitle = {2004 Joint Annual Meeting, American Dairy Science Association/American Society of Animal Science/Poultry Science Association}, volume = {Vol. 82 (Suppl. 1)}, year = {2004}, month = {July 25, 2004}, pages = {34}, publisher = {Journal of Animal Science}, organization = {Journal of Animal Science}, address = {St. Louis, MO}, abstract = {Secondary chemistry influences shrub consumption by free-ranging ruminants. However, effects of many specific terpenes on herbivory have not been examined. Four experiments were conducted to examine effects of individual terpenes on alfalfa pellet intake by lambs. Forty-five lambs (9 lambs/treatment) were individually fed alfalfa pellets sprayed with either {\~a}-terpinene, terpinolene, {\'a}-copaene, or {\'a}-terpinene at one of five concentrations in an ethanol carrier. Treatments (0, .5, 1, 2, and 10X) were multiples of the concentration (X) of a specific terpene on the leaf surface of Flourensia cernua. Terpenes were applied to alfalfa pellets (0.64 kg{\textperiodcentered}lamb-1{\textperiodcentered}d-1, DM basis), and consumption was measured during a 20-min interval for 5 d. Lambs were adapted to handling and individual pen feeding for 10 d and were maintained and fed alfalfa pellets in one group (except during 20-min tests) at a mean total daily intake of 3.9\% of BW (DM basis). A day effect (P <0.02) was detected for intake with {\~a}-terpinene (P <0.0001 for both linear and quadratic contrasts). A treatment effect (P <0.02) was observed for {\'a}-copaene, with intake on the 2X treatment lower than other treatments. No effect of terpinolene or {\'a}-terpinene on intake was observed during the 20-min interval. None of the chemicals tested were strongly related to intake of alfalfa pellets by lambs under the conditions of this study.}, keywords = {alfalfa pellet intake, intake, lambs, sheep, terpenes}, author = {Richard E. Estell and E.L. Fredrickson and D.M. Anderson and Kris Havstad and M.D. Remmenga} } @article {51438, title = {Relationship of tarbush leaf surface secondary chemistry to livestock herbivory}, journal = {Journal of Range Management}, volume = {47}, year = {1994}, note = {Permission to post articles granted by the Society for Range Management; www.rangelands.org.}, month = {1994}, pages = {424-428}, abstract = {

Tarbush (Flourensia cernua DC.) is an abundant shrub native to the Chihuahuan desert. Limited use as a forage by ruminants has been observed. The objective of this studey was to eexamine the leaf surface chemistyr of tarbush inrelation to degree of use by ruminants. Mature tarbush leaves were collected on 2 sites during 2 periods approximately 2 weeks apart from plants exhibiting either high (\>45\%) or low (\<10\%) use when browsed by cattle, sheep, and goats confined to a small area (5 plants per use category for each site/period combination). A greater (P\<0.05) concentration of epicuticular wax was detected on the leaf surface of plants used to a lower degree. Epicuticular wax concentration was 8.2 and 10.3\% of the leaf dry matter for high and low used plants, repectively. Several leaf surface compounds were related to period, while site and degree of use were seldom related to individual mon- and sesquiterpenes measure in this study. Camphene and 10 unidentified compounds differed between periods (P 0.10). Two unidentified compounds were related to site (P \< 0.10) and 2 others were related to use (P\<.0.10). In summary, individual leaf surface compounds on tarbush do not appear to greatly affect degree of us of tarbush by livestock, but collectively ( based on epicuticular wax data), these compunds may influence the diet selected by browsing ruminants.

}, keywords = {Epicuticular wax, herbivores, Leaves, livestock, monoterpenes, Plant biochemistry, plants, shrubs, terpenes, terpenoids}, doi = {10.2307/4002991 }, url = {/files/bibliography/418.pdf}, author = {Richard E. Estell and E.L. Fredrickson and D.M. Anderson and W. Mueller and M.D. Remmenga} }