Juniper Oil Yield, Terpenoid Concentration, and Antimicrobial Effects on Deer

Abstract

Samples of alligator (Juniperus deppeana), Rocky Mountain (J. scopulorum), and Utah (J. osteosperma) junipers were analyzed for volatile oil yield and terpenoid concentration. Oil yield varied (P < 0.05 among species, with alligator (0.6-0.9%) lowest, Utah (1.0-2.6%) higher, and Rocky Mountain juniper (1.6-2.9%) highest. Gas chromatographic analyses revealed that volatile oils consisted of 3 terpenoid groups: monoterpene hydrocarbons, oxygenated monoterpenes, and sesquiterpenes. Mean percentages for monoterpene hydrocarbons, oxygenated monoterpenes, and sesquiterpenes were as follows: Rocky Mountain juniper, 56, 15, and 28; Utah juniper 42, 43, and 11; and alligator juniper, 73, 25, and 1, respectively. Effects of volatile oils and fractions of oil upon starch, cellulose, and dry matter digestion were examined. Inhibition of cellulose digestion occurred between 0.6 and 1.0 tl of volatile oil per ml of medium, whereas major reductions in starch digestion occurred with 3-5 ld of volatile oil per ml of medium. Reduction (P < 0.05) in digestion of dry matter occurred between 0.7 and 1.3 Al of oil per ml of media. Monoterpene hydrocarbons inhibit starch, cellulose, and dry matter digestion less than either oxygenated monoterpenes or sesquiterpenes. J. WILDL. MANAGE. 44(1):107-113 Juniper species occupy approximately 30 million ha throughout the western United States. These conifers have little economic value, and in some areas are burned or removed mechanically to increase grass production. Many areas dominated by juniper are occupied by deer (Odocoileus spp.), but the role of juniper in meeting nutritional and cover requirements of deer is not understood fully. Junipers contain volatile oils (Powell and Adams 1973) which contain terpene compounds that are considered among the largest and most structurally diverse classes of organic products of secondary plant metabolism (Geissman and Crout 1969). Investigations have shown that volatile oils of big sagebrush (Artemisia tridentata) (Nagy et al. 1964, Nagy and Tengerdy 1968) and Douglas-fir (Pseudotsuga menziesii) (Oh et al. 1967) inhibited deer rumen microorganisms. Rumen microbial fermentation supplies approximately 50-70% of the energy requirements of ruminants (Annison and Lewis 1959). Changes in the rumen ecosystem such as amounts and kinds of microorganisms, pH, or concentration and proportion of end products of fermentation might influence rumen digestion. This can ultimately result in a lowered energy and nutrient supply to the host animal. Our research was part of a comprehensive study to determine effects of volatile oils from alligator, Utah, and Rocky Mountain junipers on mule deer (0. hemionus), and was conducted in 3 phases. The 1st 2 phases presented here examined volatile oil yield and concentration, and effects of volatile oils and selected fractions on rumen microbial activity in vitro. Phase 3 (Schwartz et al. 1980) evaluated mule deer preference for the 3 species and for feed treated with various levels or fractions of oils extracted from these species. 1 Present address: Alaska Department of Fish and Game, Moose Research Center, P.O. Box 3150, Soldotna, AK 99669. 2 Present address: U.S. Fish and Wildlife Service, Denver Wildlife Research Center, P.O. Box 2800, Kenai, AK 99611. J. Wildl. Manage. 44(1):1980 107 This content downloaded from 157.55.39.35 on Thu, 01 Sep 2016 05:48:09 UTC All use subject to http://about.jstor.org/terms 108 JUNIPER OIL EFFECTS ON DEER* Schwartz et al. Data were collected by Graduate Research Assistants W. W. Paintner, W. G. Jobman, and P. Smith. Financial support was provided by the USDA Forest Service. We thank J. A. Bailey for graduate student direction. Trade names listed do not indicate endorsement by the Forest Service.