Wm. Kirk Suedmeyer, D.V.M.
Kansas City Zoological Gardens
6700 Zoo Drive
Kansas City, MO 64132 USA, and
Ellen S. Dierenfeld, Ph.D.
Wildlife Health Sciences
Wildlife Conservation Society
2300 Southern Boulevard
Bronx, NY 10460 USA
Numerous abnormalities are encountered when improper dietary ratios or deficiencies are present. These include increased capillary permeability, phospholipid deficiency, changes in reproduction, mitochondrial “swelling” resulting in altered cellular respiratory and phosphorylating mechanisms, and various dermal abnormalities.1-3,5 These deficiencies are accompanied, in most animals, by significant decreases in the dienoic and tetraenoic FA's with concomitant increases in monoenoic and trienoic FA's.
A recently imported female Black rhinoceros (Diceros bicornis michaeli), “Lucy”, demonstrated two episodes of hyperbilirubinemia, anemia, moderate hypophosphatemia, and hypercalcemia less than 12 months after arrival.
Monocytosis and elevation of alkaline phosphatase were associated with these episodes. In addition, these episodes correlated with major stressful events. The episodes resolved over the course of two or three months. The animal appeared to improve with supportive care and the supplementation of fresh browse flown in on a weekly basis.
Based on this, serum % relative FA profiles were evaluated in five black rhinoceros before and after supplementation with a flaxseed based product (Missing Link, Designing Health, Valencia, California 91355 USA). FA % relative analysis of this product revealed 50% linolenic acid and 18% linoleic acid. The supplement was administered on a daily basis to two four-year-old, captive born male rhinoceros “Rudy” and “Tucker” (Ru and Tu), one long-term imported rhinoceros (Dal49), and the recently imported three-year-old female rhinoceros “Lucy” (Lu). In July of 1997, “Luyisa” (Luy) a three-year-old intact female eastern black rhinoceros was imported from the Addo Elephant Park in South Africa to the Kansas City Zoological Gardens. Initial FA evaluation within one month of arrival demonstrated no abnormalities when compared to the supplemented rhinoceros. Supplementation was therefore not initiated.
Several FA profiles were evaluated over the course of four months after arrival, whereupon changes consistent with the initial un-supplemented rhinoceroses were noted (Table 1).
Of 37 FA’s profiled, consistent changes were noted in octadecadienoic (linoleic-18:2), octadecatrienoic (linolenic-18:3), gamma linolenic omega 6 (18:3), eicosatrienoic omega 6 (20:3), and eicosatetraenoic omega 6 (arachidonic-20:4). In addition, the ratios of 20:3/20:4, and 20:3/20:5 “improved” in all five rhinoceros supplemented (Table 1). In the human and laboratory animal literature, the 20:3/20:4 ratio may predict a FA (linoleic) deficiency or imbalance.1 Ratios above 0.4 are indicative of an imbalance.1 The 20:3/20:5 \ratio may predict a FA (linolenic) deficiency.1 Again, ratios above 0.4 are indicative of an imbalance.1 In every rhinoceros evaluated, these ratios improved after supplementation.
Diets in four of the rhinoceros were also evaluated for FA composition. Dietary analysis on an as fed weight: weight basis without supplementation revealed a linoleic to linolenic acid ratio of 3:1. Diets were composed of alfalfa hay, a ground aspen pelleted feed (Mazuri Moose Maintenance, Purina Mills, Inc. St. Louis, Missouri, USA), small amount of oranges, a commercial salt block, and various browse items (mulberry Morus sp, Pyracanthus sp, honeysuckle Lonicera sp, and willow Saliaceae sp) when available.
In the human and laboratory animal literature, the trienoic acid that accumulates during fat deficiency is eicosatrienoic acid.1 In each rhinoceros, the eicosatrienoic acid levels decreased or disappeared after supplementation. In the most recently imported rhinoceros (Luy) eicosatrienoic acid levels gradually increased without supplementation.
After supplementation, eicosatrienoic acid levels improved. Compared to the human and laboratory animal results of FA evaluation, supplementation with a FA supplement may be indicated in the black rhinoceros. The only addition to the diets of these rhinoceros was the FA supplement. Recent research has demonstrated high levels of linolenic acid are contained in fresh browse items favored by the rhinoceros.7 In addition, it has been demonstrated that FA levels in fresh-cut browse decrease dramatically over a short period of time.8 During the winter of 1997, the ill rhinoceros (Lucy) was not supplemented with fresh browse items, but continued on the FA supplement. No recurrence of clinical signs has occurred despite additional stressful events.
Changes in the FA profiles were consistent in all five rhinoceros. Based on initial results, and compared to the human and laboratory animal literature, fatty acid supplementation appears to be a component of Lucy’s improvement. To date, one year after supplementation with FAs, this rhinoceros is clinically normal. Further feeding trials are continuing with analysis of each dietary component for FA determination.
To date, no adverse side effects of supplementation have been noted. Potential adverse effects of long-term supplementation will have to be investigated before recommendations can be made regarding supplementation of this product to rhinoceroses.4
TABLE 1. SERUM % RELATIVE FATTY ACID PROFILES IN FIVE BLACK RHINOCEROS
*b = before supplementation
**a = after supplementation
The authors would like to thank Dr. Mike Nance, Garden City, Kansas, and Dr. Bob Collett, Missing Link Products, Designing Health, Inc. (Valencia, California). Additional appreciation is extended to Dr. Chris Miller, Miami Metrozoo, and Dr. Tom Alvarado, Dallas Zoo, for contributing serum samples from their black rhinoceros for continued evaluation of fatty acids in rhinoceros.
- Alfin-Slater R.B., L. Aftergood. 1971. Physiological Functions of Essential Fatty Acids. In: Paoletti R. (ed.) Progress in Biochemical Pharmacology: Biochemistry and Pharmacology of Free Fatty Acids. S. Karger, New York, New York, Pp. 216-226.
- Bazan, N.G., R. Brenner, N. Giusto. 1977. Function and Biosynthesis of Lipids. Plenum Press, New York, New York, Pp. 575.
- Deuel, J.H. 1957. The Lipids: Their Chemistry and Biochemistry. Interscience Publishers, Inc. New York, New York, Vol. 3, Pp. 812, 819-820.
- Hall, J.A., 1996. Potential adverse effects of long-term consumption of (n-3) fatty acids. Comp. 18:879-892.
- Korver D.R., K. Klasing. 1997. Dietary fish oils alters specific and inflammatory immune responses in chicks. Am Soc Nutritional Sci. Pp. 2039-2046.
- Lands W.E., B. Libelt, A Morris, N.C. Kramer, T. Prewitt, P. Bowen, D. Schemeisser, M. Davidson, J. Burns. 1992. Maintenance of lower proportions of (n-6) eicosanoid precursors in phospholipids of human plasma in response to added dietary (n-3) fatty acids. Biochemica et Biophysica Acta 1180: 147-162.
- Wright, J.B., D.L. Brown. 1997. Identification of 18:3 (n-3) linolenic acid, 18:3 (n-6) linoleic acid and 18:2 (n-6) linoleic acid in Zimbabwean browses preferred by wild black rhinoceroses (Diceros bicornis) determined by GC-MS analysis. Anim. Feed Sci Technol. 69: 195-199.
- Wright, J.B. 1998. A comparison of essential fatty acids, total lipid, and condensed tannin in the diet of captive black rhinoceros (Diceros bicornis) in North America and in browsees native to Zimbabwe, Africa. MS. Thesis, Cornell University, Ithaca