Habitat and climate shape growth patterns in a mountain ungulate

Uptake and use of energy are of key importance for animals living in temperate environments that undergo strong seasonal changes in forage quality and quantity. In ungulates, energy intake strongly affects body mass gain, an important component of individual fitness. Energy allocation among life‐history traits can be affected by internal and external factors. Here, we investigate large‐scale variation in body growth patterns of Alpine chamois Rupicapra rupicapra rupicapra, in relation to sex, age, temperature, and habitat variations across 31 (sub)populations in the Central European Alps. Taking advantage of an exceptionally large dataset (n = 178,175) of chamois hunted over 27 consecutive years between 1993 and 2019 in mountain ranges with different proportions of forest cover, we found that (i) patterns of body mass growth differ between mountain ranges, with lower body mass but faster mass growth with increasing proportion of forest cover and that (ii) the effect of spring and summer temperatures on changes in body growth patterns are larger in mountain ranges with lower forest cover compared to mountain ranges with higher forest cover. Our results show that patterns of body mass growth within a species are more plastic than expected and depend on environmental and climatic conditions. The recent decline in body mass observed in Alpine chamois populations may have greater impacts on populations living above the treeline than in forests, which may buffer against the effects of increasing temperatures on life‐history traits.     

Disruptores endocrinos y obesidad: obesógenos

Incidence and prevalence of owerweight and obesity have greatly increased over the past three decades in almost all countries around the world. This phenomenon is not easily explained by lifestyle changes in populations with very different initial habits. This has led to consider the influence of other factors, the so-called endocrine disruptors, and more specifically obesogens. This study reviewed the available evidence about polluting chemical substances which may potentially be obesogens in humans: DES, genistein, bisphenol A, organotins (TBT, TPT), and phthalates. The first three groups of substances mainly act upon estrogen receptors, while organotins and phthalates activate PPARγ. It was concluded that evidence exists of the obesogenic effect of these chemical substances in tissues and experimental animals, but few data are available in humans.     

How Humans Differ from Other Animals in Their Levels of Morphological Variation

Animal species come in many shapes and sizes, as do the individuals and populations that make up each species. To us, humans might seem to show particularly high levels of morphological variation, but perhaps this perception is simply based on enhanced recognition of individual conspecifics relative to individual heterospecifics. We here more objectively ask how humans compare to other animals in terms of body size variation. We quantitatively compare levels of variation in body length (height) and mass within and among 99 human populations and 848 animal populations (210 species). We find that humans show low levels of within-population body height variation in comparison to body length variation in other animals. Humans do not, however, show distinctive levels of within-population body mass variation, nor of among-population body height or mass variation. These results are consistent with the idea that natural and sexual selection have reduced human height variation within populations, while maintaining it among populations. We therefore hypothesize that humans have evolved on a rugged adaptive landscape with strong selection for body height optima that differ among locations.     

Prevention of Obesity in Middle-Aged Monkeys: Food Intake During Body Weight Clamp

Prevention of obesity and increase in longevity in obesity-prone rodents can be achieved by long-term moderate dietary restriction. In order to examine the likelihood that caloric restriction could have similar salutary effects in humans, rhesus monkeys, after reaching mature adult stature, were placed on a protocol to clamp or stabilize body weight by weekly caloric adjustment Further weight gain was prevented by this caloric titration procedure, and thus middle-age onset obesity, which is very common in this species, was prevented. The present study analyzed daily food intake for six weight-clamped monkeys and six ad libitum fed age-matched animals over a 3- year period, ages 18.5 to 21.5 years. After approximately 9 years of caloric restriction the daily calorie load to maintain stable adult body weight proved to be 40% less than the amount ingested by ad libitum fed animals. Calories per kg body weight did not differ significantly between the groups although the ad libitum fed animals were significantly fatter than the weight-clamped group. Prevention of obesity using this weight clamp protocol has also maintained lower insulin levels and higher glucose tolerance in the restricted animals.     

Characterization of Obese Phenotypes in a Small Nonhuman Primate,the Common Marmoset (Callithrix jacchus)

This report explores aspects of developing obesity in two captive populations of common marmosets (Callithrix jacchus), a small primate with a short lifespan that may be of value in modeling chronic aspects of obesity acquisition and its lifetime effects. Two populations were examined. In study 1, body composition, lipid parameters, and glucose metabolic parameters were measured in a population of 64 adult animals. Animals classified as obese (>80th percentile relative fat based on sex) displayed both dyslipidemia (higher triglyceride and very low–density lipoprotein (VLDL)) and altered glucose metabolism (higher fasting glucose and HbA_1c). Using operational definitions of atypical values for factors associated with metabolic syndrome in humans, five subjects (7.8%) had at least three atypical factors and five others had two atypical factors. A previously unreported finding in these normally sexually monomorphic primates was higher body weight, fat weights, and percent fat in females compared to males. In a second study, longitudinal weight data for a larger population (n = 210) were analyzed to evaluate the development of high weight animals. Differences in weights for animals that would exceed the 90th percentile in early adulthood were evident from infancy, with a 15% difference in weight between future‐large weight vs. their future‐normal weight litter mates as early as 4–6 months of age. The marmoset, therefore, demonstrates similar suites of obesity‐related alterations to those seen in other primates, including humans, suggesting that this species is worthy of consideration for obesity studies in which its fast maturity, high fertility, relatively short lifespan, and small size may be of advantage.     

Obesity-inducing lesions of the central nervous system alter leptin uptake by the blood-brain barrier.

Leptin regulates body adiposity by decreasing feeding and increasing thermogenesis. Obese humans and some obese rodents are resistant to peripherally administered leptin, suggesting a defect in the transport of leptin across the blood-brain barrier (BBB). Defective transport of exogenous leptin occurs in some models of obesity, but in other models transport is normal. This shows that factors other than obesity are associated with impairment of leptin transport across the BBB. In order to further investigate these factors, we determined leptin transport in rats made obese by lesioning of the ventromedial hypothalamus (VMH), paraventricular nucleus (PVN), or posterodorsal amygdala (PDA). These regions all contain leptin receptors and lesions there induce obesity and hyperleptinemia and alter the levels of many feeding hormones which might participate in leptin transporter regulation. We measured the uptake of radioactively labeled leptin by the BBB by multiple-time regression analysis which divides uptake into a reversible phase (Vi, e.g., receptor/transporter binding to the brain endothelial cell) and an irreversible phase (Ki, complete transport across the BBB). Leptin uptake was not affected in rats with VMH lesions. No significant change occurred in the entry rate (Ki) for any group, although Ki declined by over 35% in rats with PVN lesions. Decreased uptake was observed in rats with PVN lesions and with PDA lesions. This was primarily due to a reduced Vi (about 21% for the PDA). This decreased uptake is most likely explained by decreased binding of leptin to the brain endothelial cell, which could be because of decreased binding by either receptors or transporters. This suggests that some of the feeding hormones controlled by the PVN and PDA may participate in regulating leptin uptake by the BBB.     

The body fat-lowering effect of conjugated linoleic acid: a comparison between animal and human studies

Different reasons which justify differences between rodents and humans in body fat reduction produced by conjugated linoleic acid (CLA) could be proposed. The doses used in humans are lower than those used in rodents. Human experiments have been performed with CLA isomer mixtures instead of isolated isomers. The variable dilution of t-10, c-12, the active isomer, among different preparations might explain the reduced responsiveness in humans. Diet composition may modulate CLA effects on body fat accumulation. As far as human studies are concerned, a specific dietary pattern has not been established. As a result differences among studies and also among subjects in the same study are likely. In rodents, the effects of CLA vary with genotype, suggesting that genetic predisposition to fat accumulation can play an important role in the effectiveness of CLA. Human volunteers with different body mass index have participated in the published studies and even in the same experiment. So, differences in lipid metabolism among subjects could help to explain the discrepancies observed in the literature. Age and maturity may also be crucial. Experiments using rodents have been conducted with growing animals and there is little evidence of CLA effectiveness in adult animals. By contrast, human studies have been performed with adults. Inhibition of lipogenesis in white adipose tissue is one of the mechanisms which have been proposed to explain the body-fat lowering effect of CLA, but lipogenesis in this tissue is very low in humans. Another mechanism suggested is increased fatty acid oxidation in the liver associated with peroxisome proliferation, but humans are relatively insensitive to this effect.     

Efficacy and safety of dietary supplements containing CLA for the treatment of obesity: evidence from animal and human studies

Dietary supplements containing conjugated linoleic acid (CLA) are widely promoted as weight loss agents available over the counter and via the Internet. In this review, we evaluate the efficacy and safety of CLA supplementation based on peer-reviewed published results from randomized, placebo-controlled, human intervention trials lasting more than 4 weeks. We also review findings from experimental studies in animals and studies performed in vitro. CLA appears to produce loss of fat mass and increase of lean tissue mass in rodents, but the results from 13 randomized, controlled, short-term (<6 months) trials in humans find little evidence to support that CLA reduces body weight or promotes repartitioning of body fat and fat-free mass in man. However, there is increasing evidence from mice and human studies that the CLA isomer trans-10, cis-12 may produce liver hypertrophy and insulin resistance via a redistribution of fat deposition that resembles lipodystrophy. CLA also decreases the fat content of both human and bovine milk. In conclusion, although CLA appears to attenuate increases in body weight and body fat in several animal models, CLA isomers sold as dietary supplements are not effective as weight loss agents in humans and may actually have adverse effects on human health.     

Three Months of High-Fructose Feeding Fails to Induce Excessive Weight Gain or Leptin Resistance in Mice

High-fructose diets have been implicated in obesity via impairment of leptin signaling in humans and rodents. We investigated whether fructose-induced leptin resistance in mice could be used to study the metabolic consequences of fructose consumption in humans, particularly in children and adolescents. Male C57Bl/6 mice were weaned to a randomly assigned diet: high fructose, high sucrose, high fat, or control (sugar-free, low-fat). Mice were maintained on their diets for at least 14 weeks. While fructose-fed mice regularly consumed more kcal and expended more energy, there was no difference in body weight compared to control by the end of the study. Additionally, after 14 weeks, both fructose-fed and control mice displayed similar leptin sensitivity. Fructose-feeding also did not change circulating glucose, triglycerides, or free fatty acids. Though fructose has been linked to obesity in several animal models, our data fail to support a role for fructose intake through food lasting 3 months in altering of body weight and leptin signaling in mice. The lack of impact of fructose in the food of growing mice on either body weight or leptin sensitivity over this time frame was surprising, and important information for researchers interested in fructose and body weight regulation.     

The Baboon as a Nonhuman Primate Model for the Study of the Genetics of Obesity

Objective: At present, rodents represent the most common animal model for research in obesity and its comorbidities (e.g., type 2 diabetes and coronary heart disease), however, there are several physiological and developmental differences between rodents and humans reflective of their relatively ancient evolutionary divergence (approximately 65 to 75 million years ago). Therefore, we are currently developing the baboon as a nonhuman primate model for the study of the genetics of obesity. Research Methods and Procedures: At present, we are collecting extensive phenotypic data in a large pedigreed colony (N > 2000) of baboons housed at the Southwest Foundation for Biomedical Research in San Antonio, Texas. The long‐term goal of this project is to identify genes influencing adiposity‐related phenotypes and to test hypotheses regarding their pleiotropic effects on other phenotypes related to increased risk for a variety of common diseases (e.g., coronary heart disease and type 2 diabetes). Results: To date we have obtained various adipose‐specific endocrine measures, adipose tissue biopsies, and estimates of body composition on a substantial portion of our pedigreed colony. The pattern of adipose tissue accumulation follows closely that seen in humans, and we have detected significant additive genetic heritabilities for these obesity‐related phenotypes. Discussion: Given the physiological and developmental similarities between humans and baboons, along with the ability to collect data under well‐controlled situations and the extensive pedigree data available in our colony, the baboon offers an extremely valuable nonhuman primate model for the study of obesity and its comorbidities.     

Obesity in rhesus and cynomolgus macaques: a comparative review of the condition and its implications for research

Obesity is an increasingly important health issue in both humans and animals and has been highly correlated as a risk factor for hyperglycemic conditions in humans. Naturally occurring obesity has been extensively studied in nonhuman primates with a focus on the development of biomarkers for characterizing overweight individuals and tracking the progression of obesity to conditions such as type 2 diabetes mellitus. Animal models have provided a basic understanding of metabolism and carbohydrate physiology, and continue to contribute to ongoing research of obesity and its adverse health effects. This review focuses on spontaneous obesity in rhesus and cynomolgus macaques as a model for human obesity and type 2 diabetes mellitus, including associated risk factors for the development of obesity and obesity-related health conditions. Little is known about preventive measures to minimize obesity while maintaining a healthy colony of macaques, and numerous complexities such as social status, feeding behaviors, timing of feeding, food distribution, and stress have been identified as contributing factors to overweight body condition in both single and group housed nonhuman primates. As in humans, increased body weight and obesity in macaques affect their overall health status. These conditions may interfere with the suitability of some animals in various studies unrelated to obesity.     

Growth and Body Mass Index of Brazilians Ages 9 Through 17 Years

Obesity during adolescence is considered a strong predictor of adult obesity, and obesity and overweight have been increasing among Brazilian adults. To gauge the relative frequency of overweight among adolescents in Brazil, we compared the distributions of body mass index (kg/m²) and stature in national population based samples of the U.S. and Brazil. U.S. adolescents were on average about 10 cm taller than Brazilians, although growth spurts occurred at the same age for both populations. Brazilian adolescents were leaner than their U.S. counterparts. This difference was reduced among girls in the postpubertal period. At age 17 years, U.S. boys were about 10 kg heavier than Brazilian boys, but the difference among girls was only 2 kg. In families above the poverty level in the more developed South region, body mass index distribution for boys was closer to that of the U.S., and older girls tended to have higher body mass index than U.S. girls. Within Brazil, body mass index varied by ethnicity with Mulattos, but not Blacks, of both sexes having lower body mass index than Whites of the same age. Urban adolescents had higher body mass index than those living in rural areas. In general, the patterns seen among Brazilian adults were found among children. Among girls, in particular, overweight has become an identifiable problem during adolescence.     

The Pig as a Model for the Study of Obesity and of Control of Food Intake: A Review

The use of the pig for studies of food intake and obesity is reviewed. Effects of ambient temperature and taste on food intake as well as satiety factors impicating both neural and hormonal mechanisms originating in the gastrointestinal tract are considered; the integration of information in the central nervous system for both internal and external sources is hypothesized. Special concerns of food intake controls in the neonate are discussed, including effects of neonate sweet preference on food intake, gastrointestinal satiety factors, and hypoglycemia as a stimulus for food ingestion.For obesity studies, pigs offer several advantages, including their general physiological similarity to humans, similar fat cell size, and body fat distribution. Lipogenesis, lipolysis, and lipid mobilization are under intensive study in swine and the information obtained may have important application in studies of human obesity. The voluminous literature on metabolic differences between genetically lean versus obese populations of pigs suggests possibilities for application in humans. Greater characterization of differences and similarities between pigs and humans in important metabolic parameters related to regulation of food intake and obesity should facilitate better understanding and control of human obesity.     

Determinants of uncertainty in wildlife responses to human disturbance

Outdoor recreation is increasing in intensity and space. Areas previously inaccessible are now being visited by ever‐growing numbers of people, which increases human–wildlife encounters across habitats. This has raised concern among researchers and conservationists as, even in non‐aggressive encounters, animals often perceive humans as predators and mount physiological and behavioural responses that can have negative consequences. However, despite all the research in recent decades, not many general patterns have emerged, especially at the level of populations, and many studies have yielded seemingly contradictory or inconclusive results. We argue that this is partly due to incomplete knowledge of the number and complexity of factors that may modulate the responses of animals. Thus, we aim to provide a conceptual approach intended to highlight the reasons that make it difficult to detect general patterns. We present a comprehensive compilation of factors modulating animal responses to humans at increasing levels (from sensory detection and immediate behavioural and physiological reactions, to changes in fitness and population trends), which may help understanding the uncertainty in the patterns. We observed that there are many modulating factors, which can be categorized as reflecting characteristics of the recreational activity itself (e.g. intensity of human presence), of the animals concerned (e.g. age or antipredatory strategy), and of the spatio‐temporal context (e.g. habitat or timing of the encounter). Some factors appear to have non‐linear and complex effects, which, if not considered, may lead to erroneous conclusions. Finally, we conclude that the difficulty in finding general patterns will be amplified at higher levels (i.e. at the level of populations), since as we proceed from one level to the next, the number of potential modulating factors accumulates, adding noise and obscuring direct associations between recreation and wildlife. More comprehensive knowledge about which (and how) factors affect animal responses across levels will certainly improve future research design and interpretation, and thus, our understanding of human recreational impacts on wildlife.     

Central obesity and health-related factors among middle-aged men: a comparison among native Japanese and Japanese-Brazilians residing in Brazil and Japan

The objective of this study was to investigate the influence of different cultural environments on the development of obesity by examining the association of central obesity, lifestyle, and selected coronary risk factors among people with identical Japanese genetic backgrounds living in Japan and Brazil. One hundred and four native Japanese and 286 Japanese-Brazilians residing in Brazil and Japan aged 35 years or over were studied. Obesity, metabolic risk factors for coronary disease, and history of regular sports activity, daily physical activity, and eating habits were assessed. The results showed Japanese-Brazilians residing in Brazil with significantly higher waist circumference values, and greater prevalence of central obesity compared to native Japanese and Japanese-Brazilians residing in Japan. The risk of developing central obesity was found to be 2.8 times higher among Japanese-Brazilians residing in Brazil. However, this association was no longer found to be significant after adjusting for lifestyle factors in the logistic model. Additionally, waist circumference was found to be significantly associated with metabolic risk factors for coronary disease. These findings suggest substantial variation in measures of central obesity among the three groups of Japanese ancestry, and underscore the heterogeneity of risk factors among communities of Japanese ancestry living in different cultural environments. The results also suggest that immigrant men exposed to the Brazilian cultural environment are more susceptible to the development of central obesity, and it seems to be associated with various lifestyle items and metabolic risk factors for coronary disease.     

Preliminary observations on the spawning conditions of the European amphioxus (Branchiostoma lanceolatum) in captivity

Members of the subphylum Cephalochordata, which include the genus Branchiostoma (i.e. amphioxus), represent the closest living invertebrate relatives of the vertebrates. To date, developmental studies have been carried out on three amphioxus species (the European Branchiostoma lanceolatum, the East Asian B. belcheri, and Floridian-Caribbean B. floridae). In most instances, adult animals have been collected from the field during their ripe season and allowed (or stimulated) to spawn in the laboratory. In any given year, dates of laboratory pawning have been limited by two factors. First, natural populations of these three most studied species of amphioxus are ripe, at most, for only a couple of months each year and, second, even when apparently ripe, animals spawn only at unpredictable intervals of every several days. This limited supply of living material hinders the development of amphioxus as a model system because this limitation makes it more difficult to work out protocols for new laboratory techniques. Therefore we are developing laboratory methods for increasing the number of amphioxus spawning dates per year. The present study found that a Mediterranean population of B. lanceolatum living near the Franco-Spanish border spawned naturally at the end of May and again at the end of June in 2003. Re-feeding experiments in the laboratory demonstrated that the gonads emptied at the end of May refilled with gametes by the end of June. We also found that animals with large gonads (both, obtained from the field and kept and fed at the laboratory during several weeks) could be induced to spawn in the laboratory out of phase with the field population if they were temperature shocked (spawning occurred 36 hours after a sustained increase in water temperature from 19 degrees C to 25 degrees C).     

Anti-obesity effects of resveratrol: comparison between animal models and humans

The prevalence of obesity has increased rapidly during recent years and has reached epidemic proportions. As a result, the scientific community is interested in active biomolecules which are naturally present in plants and foodstuffs and may be useful in body weight management. In recent years, polyphenols have made up one of the most frequently studied groups among these molecules. Numerous studies have been carried out on animals to analyse the potential anti-obesity effects of resveratrol, a non-flavonoid polyphenol, and a general consensus concerning the body-fat-lowering effect of this compound exists. By contrast, studies in humans have been few so far. Moreover, in these studies, the effectiveness of resveratrol is low. The aims of the present review are to summarize the results reported so far on this topic and to justify the differences observed between animals and humans. It seems that the reduced response to resveratrol in humans cannot be attributed to the use of lower doses in humans because the doses that induce body-fat-lowering effects in rodents are in the same range as those used in human studies. With regard to the experimental period length, treatments were longer in animal studies than in human studies. This can be one of the reasons contributing to the reduced responses observed in humans. Moreover, animals used in the reported studies are young while volunteers participating in human studies are adults, suggesting that resveratrol may be more efficient in young individuals. In addition to differences in the experimental designs, metabolic differences between animals and human cannot be discarded.     

Shifts in morphology and diet of non-native sticklebacks introduced into Japanese crater lakes

An increasing number of exotic animals are causing ecological problems. Therefore, for better ecosystem management, it is important to understand how exotic species colonize and adapt to novel environments. The threespine sticklebacks (Gasterosteus aculeatus) can be a good vertebrate model system to explore the ecological and genetic mechanisms of adaptation not only in natural populations, but also in non-native populations. Although morphological changes have been documented in several introduced populations of stickleback, little is known about the dietary changes during colonization into novel environments. Here, we investigated the morphological and dietary changes of exotic threespine stickleback populations introduced into three Japanese crater lakes (Lake Towada, Lake Kussharo, and Lake Shikotsu). Sticklebacks were introduced into the crater lakes likely along with salmonids transplanted for aquaculture. The stickleback population in Lake Kussharo had multiple mitochondrial haplotypes and had larger phenotypic variances than other crater lake stickleback populations that had only one mitochondrial haplotype. Compilation of historical data on the morphology and stomach contents of the Lake Towada stickleback population showed that substantial shifts in body size and stomach contents occurred after colonization. Some of these changes may be related to an outbreak of the Schistocephalus parasite. These results suggest that sticklebacks can change their morphology and trophic ecology when they colonize novel environments. Therefore, extreme care should be taken when salmonids are transported between watersheds for aquaculture and that long-term monitoring of exotic species is essential for ecosystem management. In addition, further genetic studies on phenotypic changes in crater lake sticklebacks would help elucidate the genetic mechanisms underlying the adaptation of exotic fishes to novel environments.     

Urban Environments and Obesity in Southeast Asia: A Systematic Review,Meta-Analysis and Meta-Regression

Many environmental factors contribute to the rise in prevalence of obesity in populations but one key driver is urbanization. Countries in Southeast (SE) Asia have undergone rapid changes in urbanization in recent decades. The aim of this study is to provide a systematic review of studies exploring the relationship between living in an urban or rural environment (urbanicity) and obesity in Southeast Asia. In particular, the review will investigate whether the associations are uniform across countries and ages, and by sex. The literature search was conducted up to June 2014 using five databases: EMBASE, PubMed, GlobalHealth, DigitalJournal and Open Grey. Forty-five articles representing eight of the eleven countries in SE Asia were included in the review. The review found a consistent positive association between urbanicity and obesity in countries of Southeast Asia, in all age groups and both genders. Regional differences between the associations are partly explained by gross national income (GNI). In countries with lower GNI per capita, the association between urbanicity and obesity was greater. Such findings have implications for policy makers. They imply that population level interventions need to be country or region specific, tailored to suit the current stage of economic development. In addition, less developed countries might be more vulnerable to the negative health impact of urbanization than more developed countries.     

The emergence of obesity among indigenous Siberians

Once considered a disease of affluence and confined to industrialized nations, obesity is currently emerging as a major health concern in nearly every country in the world. Available data suggest that the prevalence rate of obesity has reached unprecedented levels in most developing countries, and is increasing at a rate that far outpaces that of developed nations. This increase in obesity has also been documented among North American circumpolar populations and is associated with lifestyle changes related to economic development. While obesity has not been well studied among indigenous Siberians, recent anthropological studies indicate that obesity and its associated comorbidities are important health problems.The present study examines recent adult body composition data from four indigenous Siberian populations (Evenki, Ket, Buriat, and Yakut) with two main objectives: 1) to determine the prevalence of overweight and obesity among these groups, and 2) to assess the influence of lifestyle and socioeconomic factors on the development of excess body fat. The results of this study indicate that obesity has emerged as an important health issue among indigenous Siberians, and especially for women, whose obesity rates are considerably higher than those of men (12% vs. 7%). The present study investigated the association between lifestyle and body composition among the Yakut, and documented substantial sex differences in lifestyle correlates of obesity. Yakut men with higher incomes and who owned more luxury consumer goods were more likely to have excess body fat while, among Yakut women, affluence was not strongly associated with overweight and obesity.