Potential of intestinal electrical stimulation for obesity: a preliminary canine study

Objective: The aims of this study were to investigate the therapeutic potential of intestinal electrical stimulation (IES) for obesity. Experiments were performed to investigate the effects of IES on food intake, gastric tone, gastric accommodation, and its possible pathway. Research Methods and Procedures: Ten normal dogs and six dogs with truncal vagotomy were used in this study. Each dog was equipped with a gastric cannula for the measurement of gastric tone and accommodation by barostat and one pair of duodenal serosal electrodes for IES. The experiment on food intake was composed of both control session without IES and IES session after a 28‐hour fast. The experiment on gastric tone and accommodation was performed in the fasting and fed states and composed of three sessions: control, IES, and IES with N^G‐nitro‐l ‐arginine. Results: IES significantly reduced food intake in the normal dogs (459.0 vs. 312.6 grams, p < 0.001). The food intake was negatively correlated with the fasting gastric volume during IES. IES significantly decreased fasting gastric tone in the normal dogs reflected as a decrease in gastric volume (89.1 vs. 261.3 mL, p < 0.01), which was abolished by vagotomy and N^G‐nitro‐l ‐arginine. Discussion: IES reduces food intake and inhibits gastric tone in the fasting state. The inhibitory effect of IES on gastric tone is mediated by both vagal and nitrergic pathway.     

Effects of age on children's intake of large and self-selected food portions

Objective: Whether developmental periods exist in which children become particularly sensitive to environmental influences on eating is unclear. This research evaluated the effects of age on intake of large and self‐selected portions among children 2 to 9 years of age. Research Methods and Procedures: Seventy‐five non‐Hispanic white children 2 to 3, 5 to 6, and 8 to 9 years of age were seen at a dinner meal in reference, large, and self‐selected portion size conditions in which the size of an entrée was age‐appropriate, doubled, and determined by the child, respectively. Weighed food intake data were collected. Entrée bite size and bite frequency were assessed. Height and weight measurements were obtained. Results: The effect of age on children's intake of the large portion was not significant. Entrée consumption was 29% greater (p < 0.001) and meal energy intake was 13% greater (p < 0.01) in the large portion condition than in the reference condition. Increases in entrée consumption were attributable to increases in average bite size (p < 0.001). Neither child weight nor maternal weight predicted children's intake of large portions. Self‐selection resulted in decreased entrée (p < 0.05) and meal energy (p < 0.01) only among those children who ate more when served the large portion. Discussion: The results of this research confirm that serving large entrée portions promotes increased intake at meals among 2‐ to 9‐year‐old children. These findings suggest that any age‐related differences in children's response to large portions are likely to be smaller than previously suspected.     

Heritability of hyperphagic eating behavior and appetite-related hormones among Hispanic children

Objective: Eating in the absence of hunger (EAH) may be a genetically influenced phenotype of overweight children, but evidence is limited. This research evaluated the heritability (h²) of EAH and its association with overweight among Hispanic children 5 to 18 years old. Genetic and environmental associations of EAH with overweight, fat mass, and key hormonal regulators of food intake were also evaluated. Research Methods and Procedures: A family design was used to study 801 children from 300 Hispanic families. Weighed food intakes were used to measure EAH after an ad libitum dinner providing 50% of estimated energy needs. Fasting ghrelin, amylin, insulin, and leptin were measured by immunoassays. Measured heights, weights, and fat mass (using DXA) were obtained. Total energy expenditure (TEE) was measured by room respiration calorimetry. Results: On average, children consumed 41% of TEE at the dinner meal, followed by an additional 19% of TEE in the absence of hunger. Overweight children consumed 6.5% more energy at dinner (p < 0.001) and 14% more energy in the absence of hunger (p < 0.001) than non‐overweight children. Significant heritabilities were seen for EAH (h² = 0.51) and dinner intake (h² = 0.52) and for fasting levels of ghrelin (h² = 0.67), amylin (h² = 0.37), insulin (h² = 0.37), and leptin (h² = 0.34). Genetic correlations were seen between eating behavior and fasting hormones, suggesting common underlying genes affecting their expression. Discussion: This research provides new evidence that overweight Hispanic children exhibit elevated levels of hyperphagic eating behaviors that are influenced by genetic endowment.     

Energy imbalance underlying the development of childhood obesity

Objective: To develop a model based on empirical data and human energetics to predict the total energy cost of weight gain and obligatory increase in energy intake and/or decrease in physical activity level associated with weight gain in children and adolescents. Research Methods and Procedures: One‐year changes in weight and body composition and basal metabolic rate (BMR) were measured in 488 Hispanic children and adolescents. Fat‐free mass (FFM) and fat mass (FM) were measured by DXA and BMR by calorimetry. Model specifications include the following: body mass (BM) = FFM + FM, each with a specific energy content, cff (1.07 kcal/g FFM) and cf (9.25 kcal/g FM), basal energy expenditure (EE), kff and kf, and energetic conversion efficiency, eff (0.42) for FFM and ef (0.85) for FM. Total energy cost of weight gain is equal to the sum of energy storage, EE associated with increased BM, conversion energy (CE), and diet‐induced EE (DIEE). Results: Sex‐ and Tanner stage–specific values are indicated for the basal EE of FFM (kff) and the fat fraction in added tissue (fr). Total energy cost of weight gain is partitioned into energy storage (24% to 36%), increase in EE (40% to 57%), CE (8% to 13%), and DIEE (10%). Observed median (10th to 90th percentile) weight gain of 6.1 kg/yr (2.4 to 11.4 kg/yr) corresponds at physical activity level (PAL) = 1.5, 1.75, and 2.0 to a total energy cost of weight gain of 244 (93 to 448 kcal/d), 267 (101 to 485 kcal/d), and 290 kcal/d (110 to 527 kcal/d), respectively, and to a total energy intake of 2695 (1890 to 3730), 3127 (2191 to 4335), and 3551 (2487 to 4930) kcal/d, respectively. If weight gain is caused by a change in PAL alone and PAL₀ = 1.5 at baseline t = 0, the model indicates a drop in PAL of 0.22 (0.08 to 0.34) units, which is equivalent to 60 (18 to 105) min/d of walking at 2.5 mph. Discussion: Halting the development or progression of childhood obesity, as observed in these Hispanic children and adolescents, by counteracting its total energy costs will require a sizable decrease in energy intake and/or reciprocal increase in physical activity.     

四川卧龙国家级自然保护区三种高山同域鸡形目鸟类的时空生态位比较

高海拔山区气候条件恶劣, 资源匮乏, 探究同域分布的近缘物种如何利用有限的资源以实现稳定共存, 对于了解高山生态系统生物多样性格局的形成和维持机制具有重要意义。鸡形目鸟类飞行能力弱, 属于典型的地栖物种, 生态位空间相对狭窄, 可能面临更高的种间竞争压力。本研究旨在比较几种同域分布的鸡形目鸟类的时空生态位, 为了解高山生态系统同域物种的共存机制提供新的研究案例。2020年4-9月, 研究人员在四川卧龙国家级自然保护区海拔3,300-4,200 m的高山区域进行了野外调查, 通过样线法和样方法对鸡形目鸟类群落优势物种绿尾虹雉(Lophophorus lhuysii)、雉鹑(Tetraophasis obscurus)和雪鹑(Lerwa lerwa)繁殖期的微生境进行调查, 使用红外相机对其活动节律进行监测, 并运用核密度估计法从微生境利用和日活动节律两个生态维度进行了种间生态位比较。结果显示, 雪鹑在微生境利用和日活动节律上均与其他两个物种存在显著差异。绿尾虹雉与雉鹑在微生境的利用上具有相似偏好; 但绿尾虹雉的早活动高峰晚于雉鹑, 晚活动高峰早于雉鹑, 表现出显著的种间日活动节律差异; 然而, 整合两个维度后, 绿尾虹雉和雉鹑的整体生态位仍然高度重叠, 没有显著分化。本研究表明高山鸡形目物种间的生态位分化体现于多个不同的生态维度, 并且不同物种之间的分化方式有所差异。在空间和时间生态位上的显著分化使雪鹑与同域物种间的竞争压力相对较小, 有利于其实现稳定共存。而绿尾虹雉与雉鹑的整体生态位高度重叠, 建议进一步对其食性开展研究, 探讨营养生态位上的潜在种间分化。     

Effects of myeloid sirtuin 1 deficiency on hypothalamic neurogranin in mice fed a high-fat diet

Hypothalamic inflammation has been known as a contributor to high-fat diet (HFD)-induced insulin resistance and obesity. Myeloid-specific sirtuin 1 (SIRT1) deletion aggravates insulin resistance and hypothalamic inflammation in HFD-fed mice. Neurogranin, a calmodulin-binding protein, is expressed in the hypothalamus. However, the effects of myeloid SIRT1 deletion on hypothalamic neurogranin has not been fully clarified. To investigate the effect of myeloid SIRT1 deletion on food intake and hypothalamic neurogranin expression, mice were fed a HFD for 20 weeks. Myeloid SIRT1 knockout (KO) mice exhibited higher food intake, weight gain, and lower expression of anorexigenic proopiomelanocortin in the arcuate nucleus than WT mice. In particular, KO mice had lower ventromedial hypothalamus (VMH)-specific neurogranin expression. However, SIRT1 deletion reduced HFD-induced hypothalamic neurogranin. Furthermore, hypothalamic phosphorylated AMPK and parvalbumin protein levels were also lower in HFD-fed KO mice than in HFD-fed WT mice. Thus, these findings suggest that myeloid SIRT1 deletion affects food intake through VMH-specific neurogranin-mediated AMPK signaling and hypothalamic inflammation in mice fed a HFD.     

Daily growth increments in otoliths of wild-caught honmoroko Gnathopogon caerulescens

Otolith growth increments in wild-caught alizarin complex one (ALC)-marked honmoroko Gnathopogon caerulescens were examined to verify the veracity of the age determination method in cyprinids. ALC-marked G. caerulescens recaptured from their natural environment had lapilli increment counts outside the ALC ring mark that had formed on a daily basis during the juvenile stage. This apparently being the first direct evidence of daily periodicity of otolith increment formation in wild-caught cyprinids.     

The omnivorous triggerfish Melichthys niger is a functional herbivore on an isolated Atlantic oceanic island

This study evaluated the functional role of the highly generalist omnivore Melichthys niger in the remote St. Peter and St Paul's Archipelago (SPSPA), Brazil, where grazing herbivorous fishes are very scarce. We analysed patterns of distribution from zero to 30 m deep during three time intervals during the day and sampled different aspects of their feeding behaviour, including diel feeding rate, feeding substrate and diet. The density of M. niger increased with depth (26–30 m) and decreased by the end of the day. Although M. niger did not present a typical herbivore diel feeding pattern, they targeted the epilithic algal matrix as their primary feeding substrate, ingesting predominantly algae and detritus. The characteristic Caulerpa racemosa var. peltata from SPSPA was ingested only as detached fronds. We suggest that in the isolated SPSPA, the single species M. niger may perform a unique role as a link between benthic primary production and higher levels. Further studies on the trophic ecology of omnivorous species are necessary to better understand their roles in a reef system, especially in impoverished areas where they are likely to play a crucial role.     

Dietary intake of selenium and its concentration in breast milk

Selenium concentration was measured in the breast milk of 30 mothers at different stages of lactation and various body mass indices (BMI). For a maternal mean selenium intake meeting 100% of the Recommended Daily Allowance, mean milk selenium concentration was 14.06 ng/mL (range: 10.0–24.7 ng/mL). No significant correlation was found between the concentration of milk selenium with the stage of lactation, BMI, or dietary selenium intake.