Clinical Biochemistry and Hematology of the Elusive Sun-Tailed Monkey (Cercopithecus solatus) in Gabon Inaugural Data From the Only Semifree Ranging Colony in the World.код для вставкиСкачать
American Journal of Primatology 74:236–246 (2012) RESEARCH ARTICLE Clinical Biochemistry and Hematology of the Elusive Sun-Tailed Monkey (Cercopithecus solatus) in Gabon: Inaugural Data From the Only Semifree Ranging Colony in the World PEGGY MOTSCH1∗ , JEAN-PAUL GONZALEZ1 , AND DELPHINE VERRIER1,2 ‘Primatologie et Santé’, Unité de Recherche en Ecologie et Santé, Centre International de Recherches Médicales de Franceville (CIRMF), Franceville, Gabon 2 Centre de Primatologie, CIRMF, Franceville, Gabon 1 Equipe Clinical blood biochemistry and hematology are valuable tools to evaluate health and welfare in many animal species. In order to document the general biology of one of the most poorly known nonhuman primate species, and contribute to its conservation, the clinical blood biochemistry and hematology of the sun-tailed monkey (Cercopithecus solatus Harrisson) was investigated in its range of endemicity in Gabon. Data derived from 26 years of clinical monitoring of the only semicaptive colony of this species in the world, housed at CIRMF (Franceville, Gabon), were analyzed in order to establish reference values of age–sex classes. Consistent with previous reports in other primate species, age and sex significantly affected a number of biochemical and hematological parameters in C. solatus. Hematological analyses demonstrated significant differences in red blood cells, hemoglobin (HB), and hematocrit (HT), with males showing significantly greater values than females. In contrast, neutrophil counts were greater in females. An ontogenetic effect was detected for HB, HT, eosinophil, and monocyte counts, while lymphocytes significantly decreased with age. Biochemical analyses also showed significant differences, with females displaying greater cholesterol and alanine aminotransferase levels. Increase in levels of blood urea and aspartate aminotransferase coupled with decrease in albumin in old individuals suggested declining kidney, liver, and muscle functions with age. Interspecific comparisons were conducted and the effects of the unique semifree-ranging setting on the validity and value of the results presented are discussed. The reference values established will be useful in further ecological, parasitological, and virological studies of the sun-tailed monkey. Am. J. Primatol. 74:236–246, 2012. C 2012 Wiley Periodicals, Inc. Key words: Cercopithecus; clinical chemistry; guenons; hematology; reference values; semifreeranging population INTRODUCTION Growing concern is being raised about the health of nonhuman primates worldwide [Boesch, 2008; Gillespie et al., 2008; Walsh, 2008]. Indeed, in the past decades, some endangered great ape populations have been pushed to the brink of extinction by infectious diseases such as Ebola [Walsh et al., 2003] and severe respiratory syndromes [Kondgen et al., 2008; Leendertz et al., 2004]. In addition, nonhuman primates are increasingly threatened by both a number of diseases and the constant expansion of human activities into their home ranges [Gillespie et al., 2008]. Furthermore, due to their phylogenetic proximity and the increasing frequency of encounters with human populations, nonhuman primates represent a major source of pathogens that threaten human health [Keele et al., 2006; Rayner et al., 2011; Wolfe et al., 2005]. Documenting health, diseases, C 2012 Wiley Periodicals, Inc. and threats in nonhuman primates has, therefore, become a priority. Establishing baseline biologic data is an essential step for the assessment of animal health, for the diagnosis of pathologies, for comprehending the physiological alterations induced by pathogens, stress and/or contaminants, and ultimately, for monitoring responses to translocations, therapy, or experimental treatments [Hambleton et al., 1979; Jain, ∗ Correspondence to: Peggy Motsch, CIRMF, BP 769 Franceville, Gabon. E-mail: email@example.com Received 04 July 2011; revised 19 October 2011; revision accepted 16 November 2011 DOI 10.1002/ajp.21993 Published online in Wiley Online Library (wileyonlinelibrary. com). Blood Parameters of Sun-Tailed Monkeys / 237 1986]. Clinical blood biochemistry and hematology, for instance, are valuable tools to evaluate health and welfare, and detect different metabolic disorders and diseases in many animal species [Jain, 1986], in particular, those for whom thorough clinical investigations cannot be easily conducted (e.g. wildlife) [De Thoisy et al., 2001]. The extent to which such parameters are useful for either clinical or research use depends, however, upon the availability of reference ranges. Reference blood biochemistry and hematology data are available for a number of nonhuman primate species that have been extensively used in laboratory research, including rhesus and cynomolgus macaques [Andrade et al., 2004], African green monkeys [Liddie et al., 2010], squirrel monkeys [Andrade et al., 2004; Ausman et al., 1976], and chimpanzees [Howell et al., 2003]. Except for these species, data remain often anecdotic, mostly because of the great difficulty in capturing and sampling free-ranging nonhuman primates. It is, however, important to document the clinical biology of these animals in order to contribute to both their conservation and the global effort on wildlife diseases epidemiological survey. The sun-tailed monkey (Cercopithecus solatus Harrisson) is one of the most poorly known nonhuman primate species. Due to its very cryptic nature, this guenon species was only first described in 1984 [Harrison, 1988]. It is endemic to a restricted forest area in Gabon [Brugiere et al., 1998; Gautier et al., 1992], although its precise distribution area is still debated [Coad et al., 2010; Motsch et al., 2011]. Most of the current knowledge concerning C. solatus is derived from the only captive colony of this species in the world, which is housed in a semifree-ranging rainforest enclosure at the Centre International de Recherches Médicales de Franceville (CIRMF), Gabon. Previous studies have described social and foraging behaviors, as well as social organization in the CIRMF sun-tailed monkeys [Charpentier et al., 2008; Peignot et al., 2000]. The aim of the present study was to report blood biochemical and hematological parameters obtained from the long-term monitoring of the CIRMF suntailed monkey colony and establish reference values of age–sex classes. In addition to contributing to the general description of the biology of this elusive species, such information will be useful in future studies of the colony linking animal health condition with sociality, reproductive performances, and infectious status. For comparison purposes, we also present data on blood biochemistry and hematology in two mustached guenons (C. cephus) and two hybrid guenons (C. cephus × C. nictitans) that live sympatrically within the CIRMF semifree-ranging rain forest enclosure. MATERIALS AND METHODS All procedures involved in the present study were approved by the Animal Care Committee of the Game and Wildlife Department of Libreville, Gabon (permit #01029). They complied with the current laws of the Gabonese Republic and relevant international guidelines. Animals were handled under the supervision of trained veterinarians, in accordance with standard operating procedures at CIRMF, as well as in accordance with the American Society of Primatologists (ASP) Principles for the Ethical Treatment of Non Human Primates. Study Animals and Sampling Procedures The CIRMF sun-tailed monkey colony was established between 1984 and 1998, with the introduction of five wild-born individuals (two males (M) and three females (F), aged from 1 to 2 years) into a 0.5ha forested enclosure. The age of the founders was estimated from dental eruption patterns. Between 1989 and 2011, 35 infants (19 M, 16 F) were born into the colony that numbered an average of 11.3 ± SD 4.2 individuals. Population size was 16 (7 M, 9 F) as of 2011. All individuals are identified by a unique code tattooed on the internal face of the thigh to allow for at-distance recognition. Furthermore, two female hybrid guenons (C. cephus × C. nictitans) have been living sympatrically with the sun-tailed monkeys since the 1990s, and two additional wildborn mustached guenons (one immature male and one adult female, kept as pets by local people), were also released into the semifree-ranging enclosure in 2005 and 2010, respectively. Animals forage freely in the forested enclosure (feeding on leaves, fruits, roots, bark, seeds, stems, and insects) [P. Motsch, personal observations; Peignot et al., 2000] and are supplemented with bananas, wild fruits, and soyabased homemade cake spread in a fenced feeding area twice a day. Water is available ad libitum. A long-term monitoring program of this colony has been conducted since its creation. Presence, births, and deaths are recorded and individuals are captured annually for veterinary health checks. At these occasions, animals are captured in the fenced feeding area and anaesthetized by blowpipe intramuscular injections of ketamine (10 mg/kg body weight). They are then transferred to the CIRMF Primate Center for medical examination and sampling. Blood samples (representing <7% of total blood volume) are taken from the femoral vein in both EDTAtreated tubes and tubes containing no anticoagulant. After completion of the physical, animals are returned to the fenced feeding area and monitored until full recovery from anesthesia prior to being released into the enclosure. Am. J. Primatol. 238 / Motsch et al. TABLE I. Hematological and Biochemical Parameters Tested Parameters Platelet count White blood cell Red blood cells Haemoglobin Hematocrit Mean corpuscular volume Mean corpuscular haemoglobin Mean corpuscular haemoglobin concentration Neutrophils Eosinophils Basophils Lymphocytes Monocytes Absolute neutrophils Absolute eosinophils Absolute basophils Absolute lymphocytes Absolute monocytes Albumin Calcium Cholesterol Creatinine Glucose Triglycerides Total protein Urea Gamma glutamyltranspeptidase Total birulin Direct birulin Alkanine phosphatase Aspartate aminotransferase Alanine aminotransferase Abbreviation Units WBC RBC HB HT VGM TCM 109 /l 109 /l 1012 /l g/dl % Fl pg CCM g/dl %Neutro %Eosino %Baso %Lympho %Mono Neutro Eosino Baso Lympho Mono GGT % % % % % 109 /l (cells) 109 /l (cells) 109 /l (cells) 109 /l (cells) 109 /l (cells) μmol/l mmol/l mmol/l μmol/l mmol/l g/l g/l mmol/l U/l AP ASAT ALAT μmol/l μmol/l U/l U/l U/l Hematological and Clinical Chemistry Analyses All analyses were conducted at the Laboratoire d’Analyses Médicales (LAM) of the CIRMF. The quality of the analyses is subject to in-house control, and LAM is also affiliated with the French national quality control scheme. Hematological parameters (Table I) were determined from fresh EDTA-treated blood using commercial kits (diluents, cleaner, lysing solution, Eosino FIX, and Basolyse II; Laboratory HORIBA ABX Diagnostics, Tokyo, Japan) on an ABX PENTRA C+ auto-analyzer (Laboratory HORIBA ABX Diagnostics). Blood biochemical parameters (Table I) were determined from fresh serum using commercial kits (BIOLAB kits, Laboratory Roche PESSIMEDICAL, Fontenay-sous-Bois, France and BIOMERIEUX kits, Laboratory MEDILAB, Mèze, France) on a HITACHI 902 automatic analyzer (Laboratory MEDIM EQUIP, Mèze, France). Am. J. Primatol. Data Analyses A total of 162 hematological profiles and 145 serum biochemical profiles obtained from 32 individuals (15 females and 17 males; 1 to 20 observations per individual) from 1985 to 2010 were used. Only data from healthy individuals were included in the present study. Data were classified into four age groups: (1) immature individuals (IM; 0 to 4 years of age); (2) adolescent males (SUB for subadults; aged from 4 to 7 years); (3) adults (AD; females aged >4 years and mature males aged >7 years); and (4) old individuals (OL; >12 years of age). Statistical analyses were performed using SPSS® (version 17.0 for Windows; SPSS, Chicago, IL). The Kolmogorov–Smirnov test was used to determine whether the data were normally distributed, and an F-test was used to confirm homogeneity of variances. Linear mixed models were used to analyze data with a repeated-measure pattern [Littell et al., 1998]. Individuals were used as random effect, and the age at the time of capture as ranks for repeated measures. Gender and age class were included as factors to test for sex, age, and sex × age interaction effects by mixed analysis of variance (ANOVA). For each mixed-model analysis, the covariance structure was examined, and the best fit selected based on lowest Schwarz’s Bayesian criterion. Sidak adjustments were performed to allow for multiple pairwise comparisons. Values are reported as means, and results were considered significantly different at P < 0.05. RESULTS Hematology The hematological values obtained for each age group and for the entire C. solatus CIRMF population are presented in Table II, while age and sex differences are summarized in Table III. Platelets, red blood cells (RBC), hemoglobin (HB), hematocrit (HT), and neutrophils (%) were influenced by sex (P < 0.05 in all cases; Table III). Males displayed significantly greater levels of RBC, HB and HT, and lower platelets and neutrophils (%), as compared to females (Table IV). Age also had a significant effect on some hematological parameters (Table III). In both sexes, immature individuals had significantly lower eosinophils (%) and monocytes (%), and greater lymphocytes (%) than the other age classes (P < 0.05 in all cases). Old individuals showed significantly reduced lymphocytes (%) as compared to adolescent males and adults but greater eosinophils (%) than adolescents (P < 0.05 in all cases). In males, immature individuals had significantly lower RBC, HB, HT, and mean corpuscular haemoglobin (TCM), and greater platelets than the other age classes (P < 0.05 in all cases), while old individuals showed significantly greater neutrophils (%) (P < 0.05). In females, immature individuals had 72 72 72 72 72 72 72 72 72 72 72 72 72 72 72 72 72 72 476.6 8.8 5.3 11.8 36.9 71.3 22.3 31.4 46.2 1.9 0.2 41.0 9.9 3.9 0.2 0.00 2.1 0.5 104.1 4.2 0.7 1.2 4.4 3.7 2.1 3.0 18.7 2.5 0.4 20.3 12.7 2.3 0.3 0.03 0.9 0.6 SD 357.0–659.0 5.0–20.0 4.0–7.0 10.0–15.0 31.0–45.0 65.0–77.0 18.0–25.0 24.0–35.0 19.0–73.0 0.0–7.0 0.0–1.0 12.0–74.0 0.0–41.0 1.5–9.5 0.0–0.8 0.00–0.08 0.6–3.8 0.0–2.0 95% CIs 21 21 21 21 21 21 21 21 21 21 21 21 21 21 21 21 21 21 470.3 6.5 5.7 13.6 41.8 73.4 23.7 32.2 45.4 2.2 0.2 40.2 11.2 4.2 0.2 0.02 3.9 0.5 N Mean 128.7 1.7 0.9 2.6 7.3 3.6 0.7 1.6 20.2 2.2 0.4 19.5 14.5 3.5 0.3 0.05 2.5 0.8 SD 308.0–657.0 4.0–10.0 4.0–7.0 11.0–18.0 34.0–53.0 66.0–79.0 22.0–25.0 29.0–34.0 19.0–76.0 0.0–7.0 0.0–1.0 11.0–77.0 1.0–42.0 1.1–9.9 0.0–0.7 0.0–0.1 1.0–8.4 0.0–2.8 95% CIs Adolescent males 47 47 47 47 47 47 47 47 47 47 47 47 47 47 47 47 47 47 404.4 6.6 5.4 12.7 39.0 74.2 23.7 31.8 55.8 2.2 0.1 34.2 7.7 3.6 0.3 0.03 1.1 1.2 N Mean 87.7 2.6 0.8 2.5 6.8 4.9 2.3 3.2 16.3 3.0 0.4 16.1 9.8 1.7 0.2 0.04 0.8 1.3 SD 95% CIs 256.0–541.0 3.0–13.0 4.0–7.0 10.0–17.0 31.0–52.0 66.0–82.0 19.0–27.0 25.0–37.0 28.0–80.0 0.0–8.0 0.0–1.0 6.0–60.0 0.0–40.0 1.7–7.9 0.1–0.8 0.0–0.1 0.2–3.1 0.1–3.7 Adults 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 167.4 2.1 1.3 2.3 7.3 5.0 2.7 3.6 17.8 1.4 0.5 13.5 14.9 1.9 0.2 0.04 0.7 0.9 SD 232.0–833.0 3.0–10.0 3.0–8.0 10.0–17.0 30.0–53.0 66.0–82.0 17.0–27.0 23.0–35.0 29.0–84.0 3.0–8.0 0.0–1.0 5.0–53.0 1.0–46.0 1.3–7.1 0.0–0.4 0.0–0.1 1.4–4.1 0.0–2.8 95% CIs Old adults 440.8 6.3 5.6 12.8 38.3 73.4 23.5 31.9 58.0 4.9 0.5 19.1 17.9 3.3 0.2 0.02 2.5 0.6 N Mean Hematological values are presented as means with sample size (N), standard deviation (SD), and 95% confidence intervals (95% CIs). Platelets WBC RBC HB HT VGM TCMH CCMH %Neutro %Eosino %Baso %Lympho %Mono Neutro Eosino Baso Lympho Mono Parameters N Mean Immature TABLE II. Hematological Parameters in Cercopithecus solatus With Age-Specific Reference Values 155 155 155 155 155 155 155 155 155 155 155 155 155 155 155 155 155 155 446.0 7.6 5.4 12.4 38.3 72.6 23.1 31.7 50.9 2.3 0.2 35.8 10.3 3.9 0.2 0.02 2.9 0.6 N Mean 118.0 3.5 0.8 2.1 6.1 4.4 2.3 3.0 18.5 2.7 0.4 19.2 12.6 2.9 0.3 0.04 2.1 0.8 SD 95% CIs 281.0–640.0 4.0–14.0 4.0–7.0 10.0–17.0 31.0–52.0 66.0–79.0 19.0–27.0 25.0–35.0 19.0–80.0 0.0–8.0 0.0–1.0 7.0–68.0 0.0–42.0 1.1–8.8 0.0–0.6 0.0–0.1 0.6–7.6 0.0–2.8 All ages Blood Parameters of Sun-Tailed Monkeys / 239 Am. J. Primatol. 240 / Motsch et al. TABLE III. Influence of Sex and Age on Hematological and Blood Biochemical Parameters in Cercopithecus solatus Statistics N F df Psex Page Page × sex Sex effect Age or age × sex effect Platelets WBC RBC HB HT VGM TCMH CCMH %Neutro 155 155 155 155 155 155 155 155 155 693.57 31,880.44 3,208.42 4,040.09 3,884.59 13,788.22 5,084.80 6,453.35 11,251.56 1,27 1,20 1,30 1,31 1,31 1,14 1,21 1,17 1,27 0.039 0.155 0.000 0.000 0.000 0.158 0.074 0.273 0.048 0.004 0.000 0.112 0.001 0.030 0.132 0.068 0.857 0.848 0.010 0.021 0.033 0.000 0.000 0.077 0.037 0.452 0.035 F>M n.s. F<M F<M F<M n.s. n.s. n.s. F>M %Eosino %Lympho %Mono Albumin Calcium Cholesterol Creatinine Glucose Triglyceride Total protein Urea GGT AP Total birulin Direct birulin ASAT ALAT 155 155 155 138 138 138 138 138 138 138 138 138 138 138 138 138 138 121.49 5,386.79 333.23 161.96 1,213.49 547.42 248.16 221.09 363.13 563.26 96.28 1,644.35 62.70 859.09 352.90 250.33 3,643.48 1,33 1,26 1,31 1,27 1,43 1,21 1,30 1,35 1,102 1,24 1,20 1,21 1,18 1,28 1,23 1,27 1,21 0.887 0.267 0.442 0.830 0.833 0.042 0.499 0.761 0.916 0.793 0.399 0.355 0.399 0.413 0.480 0.767 0.018 0.001 0.000 0.000 0.000 0.795 0.515 0.002 0.191 0.548 0.336 0.009 0.819 0.065 0.784 0.187 0.024 0.051 0.293 0.216 0.520 0.830 0.447 0.077 0.419 0.477 0.455 0.392 0.072 0.313 0.131 0.136 0.114 0.493 0.114 n.s. n.s. n.s. n.s. n.s. F>M n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. n.s. F>M IM>SU>AD>OL in M IM>(AD & OL) in F OL>(AD, IM & SU) in M (AD & OL)>(SU & IM) in M IM<(SU, AD& OL) in M n.s. IM<(SU, AD & OL) in M n.s. (AD & IM)>OL in F; OL> (AD, SU & IM) in M IM<(AD &OL) and SU<OL IM>AD>OL and SU>OL IM<(AD &OL) OL<(IM, SU &AD) n.s. n.s. AD>(IM &OL) and SU>(IM &OL) n.s. n.s. n.s. OL>AD n.s. n.s. n.s. n.s. OL>(AD &SU) IM>OL Parameters Mixed ANOVAs with individuals included as random effect and the age at the time of capture as ranks for repeated measures were used to account for the repeated measure pattern of the data. Gender and age class were included as factors to test for sex, age, and age × sex interaction effects. Results were considered statistically significant at P < 0.05. F, females; M, males; IM, immature individuals; SU, adolescent males; AD, adults; OL, old individuals; n.s., not significant (P > 0.05). Significant results are in bold (P < 0.05). TABLE IV. Summary of the Hematological and Biochemical Parameters Showing Statistically Significant Differences Between the Sexes (P < 0.05) in Cercopithecus solatus Females Males Parameters N Mean SD 95% CIs N Mean SD 95% CIs Platelets RBC HB HT % Neutro Cholesterol ALAT 68 68 68 68 68 63 63 456.1 5.0 11.1 34.8 56.3 3.1 69.0 108.1 0.8 1.0 3.1 16.0 0.8 47.4 274.0–833.0 3.4–8.0 9.0–13.0 27.0–43.0 17.0–87.0 1.8–6.4 16.0–225.0 87 87 87 87 87 75 75 436.5 5.7 13.4 41.2 46.7 2.8 52.5 127.2 0.7 2.2 6.4 19.4 1.0 32.1 230.0–774.0 4.1–7.3 9.5–19.1 30.0–54.0 15.0–84.0 1.5–6.9 9.0–152.0 Values are presented as means with sample size (N), standard deviation (SD), and 95% confidence intervals (95% CIs). significantly greater white blood cells than the other age classes (P < 0.05), while old individuals exhibited significantly lower neutrophils (%) (P < 0.05). Blood Chemistry The biochemical values obtained for each age group and for the entire C. solatus population are Am. J. Primatol. presented in Table V, while age and sex differences are summarized in Table III. Sex had a significant effect on cholesterol and alanine aminotransferase (ALAT) only (values presented in Table IV), with females displaying greater circulating concentrations than males (P < 0.05 in both cases; Table III). Creatinine was elevated in adults and adolescent males, urea, and aspartate aminotransferase 230.0–771.0 2.0–3.5 1.9–6.1 49.0–133.0 2.2–7.1 0.3–2.5 31.0–72.0 1.5–10.0 33.0–410.0 84.0–1,427.0 2.4–25.0 0.6–14.0 32.0–176.0 24.0–152.0 95% CIs 21 21 21 21 21 21 21 21 21 21 21 21 21 21 557.4 2.3 2.5 122.0 4.7 0.8 63.1 3.2 138.7 480.9 14.6 5.9 69.7 49.9 181.8 0.2 0.5 48.4 1.7 0.4 10.7 2.0 89.6 381.4 8.9 3.8 36.9 29.7 N Mean SD 220.0–752.0 1.9–2.5 1.5–3.5 65.0–220.0 3.2–7.7 0.2–1.9 39.0–76.0 1.0–9.1 38.0–292.0 63.0–1,316.0 4.1–32.2 1.8–13.0 29.0–146.0 17.0–87.0 95% CIs Adolescent males 46 46 46 46 46 46 46 46 46 46 46 46 46 46 548.9 2.4 3.0 109.6 3.9 1.0 64.3 2.8 164.5 388.4 11.8 3.3 81.3 61.3 159.8 0.3 0.9 46.0 1.9 0.7 9.4 1.8 175.3 281.2 7.2 2.7 37.8 40.4 N Mean SD 95% CIs 224.0–764.0 1.8–2.7 1.8–4.6 51.0–168.0 0.6–7.6 0.5–3.2 43.0–76.0 0.9–6.9 59.0–481.0 76.0–801.0 3.2–23.7 0.5–8.0 34.0–139.0 21.0–149.0 Adults 15 15 15 15 15 15 15 15 15 15 15 15 15 15 389.3 2.4 2.6 72.7 3.0 1.2 53.1 4.6 162.8 434.9 10.5 5.2 129.8 55.8 162.5 0.6 0.7 25.4 1.1 1.4 10.6 2.8 148.5 432.3 6.8 4.8 76.6 62.1 187.0–656.0 1.8–4.0 1.7–4.0 46.0–129.0 0.4–4.0 0.2–4.7 40.0–72.0 1.3–9.2 48.0–554.0 56.0–1,605.0 3.4–22.0 1.3–15.0 41.0–313.0 10.0–225.0 95% CIs Old Adults N Mean SD Blood biochemical values are presented as means with sample size (N), standard deviation (SD), and 95% confidence intervals (95% CIs). 182.0 0.5 1.1 27.1 1.4 0.6 13.7 2.4 156.6 452.1 7.4 4.4 46.6 37.4 56 56 56 56 56 56 56 56 56 56 56 56 56 56 Albumin Calcium Cholesterol Creatinine Glucose Triglyceride Total protein Urea GGT AP Total birulin Direct birulin ASAT ALAT 557.7 2.5 3.1 84.6 4.1 1.1 58.2 4.0 178.2 688.2 12.0 5.4 93.6 64.4 N Mean SD Parameters Immature TABLE V. Blood Biochemical Parameters in Cercopithecus solatus With Age-Specific Reference Values 138 138 138 138 138 138 138 138 138 138 138 138 138 138 536.3 2.4 2.9 97.2 3.9 1.0 60.4 3.6 166.1 535.0 12.2 4.8 89.8 60.2 178.9 0.4 0.9 40.9 1.6 0.7 12.2 2.3 153.0 411.1 7.5 4.0 49.1 40.6 N Mean SD 95% CIs 218.0–761.0 1.9–2.8 1.8–4.6 50.0–167.0 0.8–7.1 0.3–2.5 40.0–76.0 1.0–9.1 48.0–410.0 72.0–1,316.0 3.3–25.0 0.7–13.0 32.0–172.0 18.0–152.0 All ages Blood Parameters of Sun-Tailed Monkeys / 241 Am. J. Primatol. 242 / Motsch et al. Fig. 1. Hematological reference values for the sun-tailed monkeys, mustached guenons, and guenon hybrids of the CIRMF colony as compared to other primate species. SOL, sun-tailed monkeys; CEP, mustached guenons; HYB, guenon hybrids (present study); AGM, African green monkeys [Liddie et al., 2010]; MAC, bonnet macaques [Pierre et al., 2011]; LEM, red ruffed lemurs [Dutton et al., 2008]; CPZ, chimpanzees [Loeb, 1986]; GOR, gorillas [Loeb, 1986]; HUM, humans [Kratz et al., 2004]. Vertical bars represent mean and 2× standard deviation (SD) for high and low range. (ASAT) in old individuals (P < 0.05 in all cases; Table III). Old individuals also exhibited lower albumin levels than the other age classes, and lower ALAT than their immature counterparts (P < 0.05 in both cases). Interspecific Comparisons The biochemical and hematological values obtained for the mustached guenons and the hybrid guenons are presented in Figures 1 and 2. Am. J. Primatol. DISCUSSION The main purpose of the present study was to establish reference values for biochemical and hematological parameters in the sun-tailed monkey, one of the most poorly known nonhuman primate species, within its geographical range in Gabon. Complementary data on two sympatric guenon species are also provided for comparison purposes. The results show that age and sex significantly affect a number of biochemical and hematological parameters in the study species, contributing to individual variation. Many of our findings converge Blood Parameters of Sun-Tailed Monkeys / 243 Fig. 2. Blood chemical reference values for the sun-tailed monkeys, mustached guenons, and guenon hybrids of the CIRMF colony as compared to other primate species. SOL, sun-tailed monkeys; CEP, mustached guenons; HYB, guenon hybrids (present study); AGM, African green monkeys [Hambleton et al., 1979; Liddie et al., 2010]; MAC, bonnet macaques [Pierre et al., 2011]; LEM, red ruffed lemurs [Dutton et al., 2008]; CPZ, chimpanzees [Hambleton et al., 1979; Herdon and Tigges, 2001; Loeb, 1986]; GOR, gorillas [Loeb, 1986]; HUM, humans [Kratz et al., 2004]. Vertical bars represent mean and 2× standard deviation (SD) for high and low range. Am. J. Primatol. 244 / Motsch et al. with the patterns of gender- and age-related differences reported in other primate species. For instance, hematological analyses demonstrated significant differences in RBC, HB, and HT, with males showing greater values than females. This is consistent with previous reports in African green monkeys (Chlorocebus sabaeus) [Kagira et al., 2007], cynomolgus macaques (Macaca fascicularis) [Andrade et al., 2004; Schuurman and Smith, 2005], bonnet macaques (M. radiata) [Pierre et al., 2011], tonkean macaques (M. tonkeana) [Thierry et al., 2000], tufted capuchin monkeys (Cebus apella) [Samonds et al., 1974], owl monkeys (Aotus azarai infulatus) [Takeshita et al., 2011], mandrills (Mandrillus sphinx) [Setchell et al., 2006], chimpanzees (Pan troglodytes) [Loeb, 1986], and humans (Homo sapiens) [Kratz et al., 2004]. Differences in hormonal status and muscular mass between genders, as well as menstrual blood loss, have been proposed as explanatory factors [Dacie and Lewis, 1984; Jain, 1986]. In contrast, neutrophil counts were greater in females, as previously reported in African green monkeys [Liddie et al., 2010], mandrills [Setchell et al., 2006], and hamadryas baboons (Papio hamadryas) [Harewood et al., 1999; Havill et al., 2003] but not in macaques [Andrade et al., 2004] and humans [Kratz et al., 2004]. Such sex differences in white blood cell counts have been attributed to the level of female sexual promiscuity [Anderson et al., 2004; Nunn, 2002]. Females also displayed greater cholesterol than males, as previously reported in red ruffed lemurs (Varecia rubraga) [Dutton et al., 2008] and African green monkeys [Liddie et al., 2010], and greater ALAT levels, which has been elsewhere attributed to greater levels of parasitic infections rather than sex-related differences [Monteiro et al., 2009; Takeshita et al., 2011]. Age also markedly affected biochemical and hematological parameters. For instance, we detected an ontogenetic effect for HB and HT increasing with age in males, as well as eosinophil and monocyte relative counts in both sexes. In contrast, lymphocytes significantly decreased with age. These results are consistent with a previous report on mandrills [Setchell et al., 2006]. Furthermore, the increase in blood urea in old individuals may suggest a declining kidney function as commonly described in elderly humans [Tietz et al., 1992] and aging chimpanzees [Videan et al., 2008]. Increase in ASAT coupled with decrease in albumin in old individuals may also suggest a decrease in liver function with age, as reported in rhesus macaques, chimpanzees, and humans [Smucny et al., 2001; Tietz et al., 1992; Videan et al., 2008]. In addition to indicating a loss of liver function, the significant decrease in albumin may also indicate a decrease in muscle strength [Schalk et al., 2005]. Although most hematological and biochemical parameters were broadly consistent with previous Am. J. Primatol. reports in a number of primate species (Figs 1 & 2), as well as most of the trends in sex- and age-related differences, some parameters measured in the present study tended to be outside the reference value ranges commonly reported for other species. Lymphocyte counts were particularly low in the CIRMF mustached and hybrid guenons (18–20% vs. 35–45%), and monocyte counts relatively elevated in both suntailed monkeys (10%) and the two other guenon species (16–18% vs. 5%) in comparison to other selected primates (Fig. 1). In addition, the present study reported elevated values for blood creatinine, total bilirubin and ASAT, and reduced blood urea as compared to other primate species (Fig. 2). Whether this reflects actual interspecies differences is hard to determine. For instance, stress response is one of the processes that can decrease lymphocytes and increase monocyte counts [Davis et al., 2008]. The semifree-ranging conditions and relatively low level of habituation to humans at the CIRMF Cercopithecus colony could be responsible for a greater level of stress during manipulation as compared to captive and zoo populations of primates. Maintained physical activity and natural foraging within the forest enclosure could also account for the differences observed in blood metabolites. Several studies have discussed the effect of captivity on biological parameters in wildlife. A comparison between captive and free-ranging red ruffed lemurs showed differences associated with physiological state, hydration, and diet between the two populations [Dutton et al., 2008]. In particular, the lower hematocrit, plasma concentrations of total proteins, albumin, and cholesterol found in the freeranging cohort have been interpreted as a consequence of the lower protein, and trace mineraldeficient diet in wild animals. In contrast, levels of ASAT, ALAT, and triglycerides were lower in captive ruffed lemurs. Similarly, Liddie et al.  showed that captivity increases a number of biological parameters in African green monkeys (total proteins, albumin, total bilirubin, alkaline phosphatase, phosphorus, and sodium) depending on the time spent in captivity, while RBC and platelets fluctuate over the course of captivity. Correspondingly, Kagira et al.  highlighted the need for a long adaptation period and individual baseline measures before experimental use in nonhuman primates. However, obtaining blood samples from wild nonhuman primates can prove extremely challenging, as well as ethically questionable. Indeed, nonhuman primates very often inhabit inaccessible areas, display cryptic behaviors, and prove difficult to follow and/or habituate in the wild. This is particularly true in the case of the sun-tailed monkey that was first described only 27 years ago due to the difficulty to observe it in its habitat [Brugière and Gautier, 1999; Harrison, 1988]. In addition, wild animals may experience greater individual variation in the Blood Parameters of Sun-Tailed Monkeys / 245 factors that influence biological parameters of significance (due, for instance, to greater energetic demands, less balanced diets, more variation in food intake, and exposure to a potentially wider array of parasites and pathogens) [Nunn, 2002], and thus the establishment of reference values may require a much larger sample size. In homogeneous captive cohorts kept in controlled conditions and of known medical history, interindividual variation is likely to be less substantial. In the present study, the fact that the CIRMF sun-tailed monkeys are kept within their geographical range, in a semifree-ranging setting, where they move and forage freely might reduce the effects linked to environmental conditions such as climate and artificial housing, as well as the diet-related bias. This unique setting might indeed represent an ideal compromise between natural free-ranging populations that are difficult to study, and captive colonies, which preclude any investigation on natural processes. Hence, data emanating from this colony, including the clinical biochemistry and hematology data presented here, will be useful in the further ecological, parasitological, and virological studies to be conducted in both CIRMF and free-ranging populations of sun-tailed monkeys in Gabon. 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