Body condition and adrenal glucocorticoid activity affects metabolic marker and lipid profiles in captive female elephants in Thailand

Abstract

Studies in western zoo elephants have found relationships between body condition and physiological function, and identified mitigating management strategies to optimize health and welfare. A similar methodological approach was used in this study, which evaluated a body condition score (BCS; 1 = thinnest, 5 = fattest) every other month and fecal glucocorticoid metabolite (FGM) concentrations twice monthly in 33 tourist camp elephants in Thailand for a 1-year period to assess seasonal variations, and determine how lipid profiles [total cholesterol (TC), low density lipoproteins (LDL), high density lipoproteins (HDL), triglycerides (TG)] and metabolic parameters [insulin, glucose, fructosamine, glucose to insulin ratio (G:I)] related to measures of body condition and adrenal function. The most prevalent BCS was 3–3.5 (60.6%), with 27.3% at BCS = 4 (overweight) and 12.1% at BCS = 4.5–5 (very overweight); no elephants had a BCS <2. BCSs were higher in rainy and winter seasons compared to summer, with FGM, TG, HDL, LDL, and insulin also higher in the rainy and/or winter seasons (p<0.05). By contrast, TC and glucose were lowest in the rainy season. FGM measures were negatively associated with two environmental factors: temperature and rainfall, but not humidity. Positive correlations were found between BCS and TC, LDL, and HDL, and between FGM and TC, HDL, glucose, and insulin (p<0.05), whereas BCS and FGM were both negatively associated with the G:I (p<0.05). However, there was no relationship between BCS and FGM among the camp elephants. Using BCS and FGM measures as outcome variables in separate regression models, this study found high BCS and elevated FGM concentrations were associated with altered lipid profiles and metabolic status in elephants. Furthermore, more work hours/day was associated with better body condition and health measures. Thus, being overweight and exposed to factors that increase adrenal activity could adversely affect health status, requiring alterations in management for some individuals, whereas exercise appears to have a protective effect.

Influence of season, tourist activities and camp management on body condition, testicular and adrenal steroids, lipid profiles, and metabolic status in captive bull elephants in Thailand

“…This could be due to higher amounts of exercise, with tourist elephants engaged in many activities, including trekking, bathing, shows or walking with tourists [34], so inactivity is less of a concern. This result is consistent with a study of female 295 Asian elephants in Thailand where most (~60%) had a BCS = 3 [11], although compared to males, females had on average higher BCSs than males (3.50  0.02 vs 2.80  0.04; GEE, p<0.001). In the U.S., elephants that walked more than 14 hours/week had a decreased risk of BCS = 4 or 5 [35].…”

“…Thus, increased exercise associated with tourist activities likely helps elephants maintain better body condition. From a previous study, female elephants that worked 300 more hours per day in the form of saddle or bareback riding were found to have better BCSs and metabolic health [11].…”

“…135 5 = fattest) in 0.5-point increments as described by Norkaew et al [11]. All photos were evaluated by three experienced elephant veterinarians, and the scores averaged.…”

“…Metabolic and lipid markers were analyzed as described by Norkaew et al [11]. Serum glucose was measured using an automated glucose analyzer (Glucinet T01-149, Bayer, Barcelona, Spain), serum fructosamine was measured by a colorimetric method in a Biosystems BA400 150 clinical chemistry analyzer (©Biosystems S.A., Barcelona, Spain), and a validated solid-phase, two-site bovine insulin enzyme immunoassay (EIA; Cat.…”

“…Fecal samples were collected immediately after defecation, and about 50 g of well-mixed sub 160 aliquots were placed in plastic ziplock bags, and stored on ice until transported to freezers at the Chiang Mai University. The fecal extraction technique is described in Norkaew et al [11].…”