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1. Increased physical activity is not related to markers of cardiometabolic health in two lemur species

   https://doi.org/10.1002/ajp.23564  

   Rimbach, Rebecca; Pontzer, Herman (January 2024, American Journal of Primatology)

   Abstract Insufficient physical activity is a major risk factor for cardiometabolic disease (i.e., unhealthy weight gain, heart disease, and diabetes) in humans and may also negatively affect health of primates in human care. Effects of physical activity on energy expenditure and cardiometabolic health are virtually unstudied in nonhuman primates. We investigated physical activity and metabolic markers in 15 adult ring‐tailed lemurs (Lemur catta) and 11 Coquerel's sifakas (Propithecus coquereli) at the Duke Lemur Center during a period of low activity in winter when the animals were housed in buildings (with outdoor access) and a period of high activity when individuals were free‐ranging in large, outdoor, forested enclosures. We compared body mass, blood glucose, triglycerides, HDL‐ and LDL‐cholesterol, physical activity via accelerometry, and total energy expenditure (TEE) via the doubly labeled water method (in ring‐tailed lemurs only) between both conditions. Both species were more active and had a lower body mass in summer. Ring‐tailed lemurs had a higher TEE and lower triglyceride levels in summer, whereas sifaka had higher triglyceride levels in summer. Individuals that increased their activity more, also lost more body mass. Individuals that lost more body mass, also had a positive change in HDL‐cholesterol (i.e., higher values in summer). Changes in activity were not associated with changes in markers of metabolic health, body fat percentage and TEE (both unadjusted and adjusted for body composition). Older age was associated with lower activity in both species, and decreased glucose in ring‐tailed lemurs, but was otherwise unrelated to metabolic markers and, for ring‐tailed lemurs, adjusted TEE. Overall, body mass was lower during summer but the increase in physical activity did not strongly influence metabolic health or TEE in these populations. 

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2. Total energy expenditure is repeatable in adults but not associated with short-term changes in body composition

   https://doi.org/10.1038/s41467-021-27246-z  

   Rimbach, Rebecca; Yamada, Yosuke; Sagayama, Hiroyuki; Ainslie, Philip N.; Anderson, Lene F.; Anderson, Liam J.; Arab, Lenore; Baddou, Issaad; Bedu-Addo, Kweku; Blaak, Ellen E.; et al (January 2022, Nature Communications)

   Abstract Low total energy expenditure (TEE, MJ/d) has been a hypothesized risk factor for weight gain, but repeatability of TEE, a critical variable in longitudinal studies of energy balance, is understudied. We examine repeated doubly labeled water (DLW) measurements of TEE in 348 adults and 47 children from the IAEA DLW Database (mean ± SD time interval: 1.9 ± 2.9 y) to assess repeatability of TEE, and to examine if TEE adjusted for age, sex, fat-free mass, and fat mass is associated with changes in weight or body composition. Here, we report that repeatability of TEE is high for adults, but not children. Bivariate Bayesian mixed models show no among or within-individual correlation between body composition (fat mass or percentage) and unadjusted TEE in adults. For adults aged 20–60 y (N = 267; time interval: 7.4 ± 12.2 weeks), increases in adjusted TEE are associated with weight gain but not with changes in body composition; results are similar for subjects with intervals >4 weeks (N = 53; 29.1 ± 12.8 weeks). This suggests low TEE is not a risk factor for, and high TEE is not protective against, weight or body fat gain over the time intervals tested. 

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3. Total daily energy expenditure and elevated water turnover in a small-scale semi-nomadic pastoralist society from Northern Kenya

   https://doi.org/10.1080/03014460.2024.2310724  

   McGrosky, Amanda; Swanson, Zane S; Rimbach, Rebecca; Bethancourt, Hilary; Ndiema, Emmanuel; Nzunza, Rosemary; Braun, David R; Rosinger, Asher Y; Pontzer, Herman (January 2024, Annals of Human Biology)

   Background: Pastoralists live in challenging environments, which may be accompanied by unique activity, energy, and water requirements. Aim: Few studies have examined whether the demands of pastoralism contribute to differences in total energy expenditure (TEE) and water turnover (WT) compared to other lifestyles. Subjects and methods: Accelerometer-derived physical activity, doubly labelled water-derived TEE and WT, and anthropometric data were collected for 34 semi-nomadic Daasanach adults from three northern Kenyan communities with different levels of pastoralist activity. Daasanach TEEs and WTs were compared to those of other small-scale and industrialised populations. Results: When modelled as a function of fat-free-mass, fat-mass, age, and sex, TEE did not differ between Daasanach communities. Daasanach TEE (1564–4172 kcal/day) was not significantly correlated with activity and 91% of TEEs were within the range expected for individuals from comparison populations. Mean WT did not differ between Daasanach communities; Daasanach absolute (7.54 litres/day men; 7.46 litres/day women), mass-adjusted, and TEE-adjusted WT was higher than most populations worldwide. Conclusions: The similar mass-adjusted TEE of Daasanach and industrialised populations supports the hypothesis that habitual TEE is constrained, with physically demanding lifestyles necessitating trade-offs in energy allocation. Elevated WT in the absence of elevated TEE likely reflects a demanding active lifestyle in a hot, arid climate. 

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4. Body composition profiling at 0.55T: Feasibility and precision

   https://doi.org/10.1002/mrm.29682  

   Nayak, Krishna S; Cui, Sophia X; Tasdelen, Bilal; Yagiz, Ecrin; Weston, Sarah; Zhong, Xiaodong; Ahlgren, André (September 2023, Magnetic Resonance in Medicine)

   PurposeBody composition MRI captures the distribution of fat and lean tissues throughout the body, and provides valuable biomarkers of obesity, metabolic disease, and muscle disorders, as well as risk assessment. Highly reproducible protocols have been developed for 1.5T and 3T MRI. The purpose of this work was to demonstrate the feasibility and test–retest repeatability of MRI body composition profiling on a 0.55T whole‐body system. MethodsHealthy adult volunteers were scanned on a whole‐body 0.55T MRI system using the integrated body RF coil. Experiments were performed to refine parameter settings such as TEs, resolution, flip angle, bandwidth, acceleration, and oversampling factors. The final protocol was evaluated using a test–retest study with subject removal and replacement in 10 adult volunteers (5 M/5F, age 25–60, body mass index 20–30). ResultsCompared to 1.5T and 3T, the optimal flip angle at 0.55T was higher (15°), due to the shorter T1 times, and the optimal echo spacing was larger, due to smaller chemical shift between water and fat. Overall image quality was comparable to conventional field strengths, with no significant issues with fat/water swapping or inadequate SNR. Repeatability coefficient of visceral fat, subcutaneous fat, total thigh muscle volume, muscle fat infiltration, and liver fat were 11.8 cL (2.2%), 46.9 cL (1.9%), 14.6 cL (0.5%), 0.1 pp (2%), and 0.2 pp (5%), respectively (coefficient of variation in parenthesis). ConclusionsWe demonstrate that 0.55T body composition MRI is feasible and present optimized scan parameters. The resulting images provide satisfactory quality for automated post‐processing and produce repeatable results. 

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5. Diet and Temperature Effects on the Survival of Larval Red Deep-Sea Crabs, Chaceon quinquedens (Smith, 1879), under Laboratory Conditions

   https://doi.org/10.3390/jmse11051064  

   Pérez-Pérez, Nivette M.; Poach, Matthew; Stevens, Bradley; Smith, Stacy L.; Ozbay, Gulnihal (May 2023, Journal of Marine Science and Engineering)

   Declines in commercial crustacean species (such as lobsters, king crab, etc.) have caused an increased interest in the harvest of the red deep-sea crab Chaceon quinquedens. The red deep-sea crab is a federally managed fishery; however, little is known about the species’ general biology, especially the conditions required for larval survival. We aimed to answer two main questions about the life history of the red deep-sea crab. First, is there a common larval hatching pattern between adult female crabs? Specifically, our inquiries are about the duration of the hatching process, daily peak hatching time, and the relationship between female morphometry and the total larvae hatched. Second, which are the factors affecting the survival and development of larval red deep-sea crabs? In order to answer these research questions, we studied the effects of diet (rotifers, Artemia sp., algae, and unfed), temperature (9 °C, 15 °C, and 20 °C), and aquaculture settings. Ovigerous females were obtained from commercial traps and transported to the NOAA James J. Howard Laboratory, NJ. They were placed in the Females Husbandry and Hatching Collection System (FHCS), where the larvae hatched. Hatching of adult females was monitored and measured by volume. A simple linear regression (SLR) was calculated to predict the number of larvae hatched based on the measured volumes, and it was significant (F = 1196; df = 1, 13; R2 = 0.9892, p = 3.498 × 10−14). Duration of hatching period showed an approximate 30 days for adult females red deep-sea crabs, with a common daily maximum hatching time at 22:00 hrs (hatching time seem to follow the sun cycle and the first hours after sunset, Perez, pers. observation). Linear polynomial quadratic regressions were conducted for both years with an interaction term for the two continuous variables (diet and temperature), and were used to model the proportion of larval survival through time. In both years, a highly significant difference was obtained (F = 56.15; df = 4, 2134; R2 = 0.09353; p = < 2.2 × 10−16). There is an effect of diet and temperature in the survival of red deep-sea crabs, but not a combined effect of them. 

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