The objective of this project was to better define the similarities and differences in gastrointestinal morphology present in lemur species. Measurements of the gastrointestinal tract of lemurs were obtained at necropsy from the captive population at Duke University Primate Center. Measurements of body length and weight, as well as gastrointestinal length, were recorded from five prosimian species: Propithecus tattersalli, Propithecus verreauxi, Varecia variegata, Hapalemur griseus, and Lemur catta. Photographs and measurements were used to obtain illustrations. Preliminary results suggest differences in gastrointestinal morphology among lemur species that coincide with differences in diet. Distinct sacculations in either the cecum or the colon were present for H. griseus, L. catta, P. verreauxi, and P. tattersalli, but not for V. variegata. The Propithecus specimens possessed a much greater ratio of gastrointestinal length to body length than the other three species. A short, blunt cecum and a shortened and sacculated colon were unique characteristics of the H. griseus specimens. These differences correlate well with a dietary shift from consumption of large amounts of structural plant cell wall (Propithecus sp.) to consumption of variable or moderate amounts (H. griseus, L. catta, and V. variegata). They also suggest that captive groups would benefit from further diet refinement in captivity. Am. J. Primatol. 52:133–142, 2000. © 2000 Wiley‐Liss, Inc.

Significant concern has been generated about the susceptibility of captive lemurs to iron storage disease, which has led some researchers to propose husbandry changes regarding dietary iron. In the current study we sought to determine the history, severity, and prevalence of iron storage disease within a large captive lemur population. Iron concentration and hemosiderin accumulation in a target organ, the liver, were assessed in necropsy specimens from 15 different species (n=153) of lemurs over a 12-yr period at the Duke University Primate Center. Banked liver tissue was used to quantify liver iron concentration (LIC) via neutron activation analysis (NAA). Prussian blue staining was used to accentuate the presence of liver iron for evaluation using an established scoring system. Of the 153 reports examined, 49 (32%) of the animals were considered positive for the presence of hemosiderin in the liver, lymph node, duodenum, and kidney, with 36 of the 49 (73%) showing deposition of iron in the liver. Total iron scores (TIS) ranged from 0.3+/-0.3 in Lemur catta to 33.3+/-1.7 in Cheirogaleus medius. The mean LIC ranged from 209+/-1.4 microg/g wet weight in L. catta to 2957+/-414 microg/g in C. medius. Management practices may have contributed to some of the results observed in this study. Although evidence of excess iron deposition in the liver was present across several species studied, the levels were not as pervasive as previously reported in other captive lemur populations. Hemochromatosis was not observed, and excess iron was not related to the cause of death in any of the animals studied. The current findings suggest that iron overload in lemurs may be more complex than was previously believed.

Lemurs kept in captivity have been reported to be highly prone to accumulate excessive amounts of iron in tissues (hemosiderosis). Diagnosis of the condition is most commonly made during a postmortem examination because an antemortem diagnosis requires a liver biopsy, a procedure that may not be well tolerated by all animals. The lack of a noninvasive method to evaluate iron status in captive lemurs limits investigators' ability to effectively screen animals for the presence of hemosiderosis, and to detect the condition early when treatment protocols are most effective. This study was conducted in an effort to provide data regarding iron analyte values in healthy captive lemurs of multiple species. The relationship of various iron-related metabolites was evaluated in 177 clinically normal lemurs of nine different species. Serum iron (sI), total iron binding capacity (TIBC), and ferritin concentration were measured directly and the percent transferrin saturation (TS) was calculated. Significant differences in various iron metabolites were observed among several species, suggesting that normal reference values for iron metabolites in lemurs may need to be developed on a species by species basis.

The nutrient content and intake of locally available North Carolina browse was evaluated for use as a supplement to a herbivorous primate diet of commercial biscuit and produce. Twice weekly from May to October 1997, total dietary intakes were determined for two groups of folivorous lemurs. Group I consisted of Propithecus diadema diadema (n = 1) and P. tattersalli (n = 1) and group II consisted of P. verreauxi coquereli (n = 3). Six pooled samples of the diet and weekly samples of three browse species, Rhus copallina, Albizia julibrissin, and Liquidamber styrachiflua were analyzed for dry matter, energy, fiber, and nitrogen content. Browse species were also analyzed for nonprotein nitrogen and acidinsoluble nitrogen. Group average dry matter intakes were 37.1 ± 2.2% (mean ± SEM) and 49.7 ± 3.0% of amount offered for groups I and II, respectively. Browse contributed 40.7 ± 2.9% and 29.6 ± 2.4% of the total daily intake for groups I and II, respectively. Browse species differed (P < 0.05) for dry matter, energy, neutral detergent fiber, acid detergent fiber, cellulose, lignin, total nitrogen, nonprotein nitrogen, available nitrogen, and available protein. R. copallina and L. styrachiflua were similar in total nitrogen, available nitrogen, and nonprotein nitrogen; A. julibrissin was higher. L. styrachiflua was highest in lignin. Dry matter, acid detergent fiber, and lignin in browse samples increased seasonally (P < 0.05), whereas available protein decreased (P < 0.01). Animals were offered and consumed R. copallina most often, followed by A. julibrisson and L. styrachiflua. With the exception of R. copallina, animals generally consumed only the immature leaves, flowers, or seeds of species offered. Daily dry matterThe use of trade names in this publication does not imply endorsement by the North Carolina ARS or criticism of similar products not mentioned. intake varied because of both browse offered and consumed and biscuit and produce diet consumed. Thus, increased fiber density can be a major benefit of browse use only when incorporated into the total diet with respect to species use, quantity of other diet ingredients offered, and targeted nutrient intakes. Zoo

The relative efficacies and cardiorespiratory effects of three injectable anesthetic combinations containing medetomidine were evaluated in ring-tailed lemurs (Lemur catta). In addition, the direct effects of medetomidine on heart rate and blood pressure were evaluated in lemurs anesthetized with isoflurane. For injectable anesthesia, captive adult ring-tailed lemurs were anesthetized with medetomidine and ketamine (0.04-0.06 mg/kg, i.m. and 3 mg/kg, i.m., respectively), medetomidine, butorphanol, and ketamine (0.04 mg/kg, i.m., 0.4 mg/kg, i.m., and 3 mg/kg, i.m., respectively), or medetomidine, butorphanol, and midazolam (0.04 mg/kg, i.m., 0.4 mg/kg, i.m., and 0.3 mg/kg, i.m., respectively). For inhalation anesthesia, lemurs were mask-induced and maintained with isoflurane for 30 min before receiving medetomidine (0.04 mg/kg, i.m.). Sedation produced by medetomidine-ketamine was unpredictable and of short duration. Both medetomidine-butorphanol-ketamine (MBK) and medetomidine-butorphanol-midazolam (MBMz) provided adequate anesthesia for routine physical exams; however, the effects of MBMz lasted longer than those of MBK. Heart rates and respiratory rates were within clinically normal ranges for all groups, and lemurs remained normotensive throughout the study. Common side effects such as hypertension and bradycardia associated with the use of alpha2-adrenergic receptor agonist combinations in other species were not observed. Likewise, medetomidine administration had no effect on HR in lemurs receiving isoflurane. Lemurs in all groups were well ventilated and remained well oxygenated throughout the procedures, though arterial partial pressure of O2 was lowest in the MBMz group. All three injectable medetomidine combinations were effective in ring-tailed lemurs but only MBK and MBMz provided adequate depth and duration of anesthesia for use as sole regimes. For many clinical procedures in lemurs, MBMz offers advantages over MBK because of its longer duration of action and its rapid and more complete reversibility with specific antagonists.