High Metabolic Rate Research Articles

MECHANISMS OF ACTION OF PROTEIN SHAKES IN NORMALIZING METABOLIC PROCESSES, THEIR ROLE IN IMPROVING GLYCEMIC CONTROL IN PATIENTS WITH TYPE 2 DIABETES, AND IN PREVENTING CARDIOVASCULAR DISEASES

This review article delves into the significance of protein shakes, particularly whey protein, in various health and fitness contexts. The primary focus is on their biochemical properties, metabolic benefits, and their role in supporting muscle mass, weight loss, and metabolic health. The article synthesizes findings from multiple studies to highlight the potential of protein shakes in improving glycemic control, reducing inflammation, and enhancing overall health, particularly for individuals with type 2 diabetes, obesity, and sarcopenia. The review also explores the effectiveness of protein shakes in athletic performance and recovery, as well as their impact on glucose metabolism and homeostasis. It underscores the necessity for further research to optimize the use and dosage of protein shakes for diverse populations to fully harness their benefits. Whey proteins are rich in essential amino acids, particularly leucine, which stimulates muscle protein synthesis via the mTOR pathway. This makes them highly effective in muscle building and recovery. Whey protein consumption enhances glycemic control by increasing insulin secretion and improving insulin sensitivity. Studies have shown significant reductions in fasting glucose levels and HbA1c in patients with type 2 diabetes. Protein shakes aid in weight loss by promoting satiety and increasing thermogenesis. They help maintain muscle mass during weight loss, which is crucial for sustaining metabolic rate. Clinical trials have demonstrated their efficacy in reducing body fat and improving metabolic markers. Whey protein, combined with resistance training, significantly improves muscle mass and strength in older adults, helping to prevent sarcopenia. This is essential for maintaining physical functionality and reducing the risk of falls and fractures. In the rehabilitation of patients with severe obesity, protein shakes are effective in reducing body weight, improving metabolic health, and maintaining muscle mass. They play a crucial role in comprehensive rehabilitation programs that include diet and physical exercise. Protein shakes support metabolic adaptations by preserving muscle mass and enhancing thermogenesis, which helps maintain a high metabolic rate and prevent weight regain. Whey proteins enhance muscle mass and strength, speed up recovery after training, and boost endurance. They also support the immune system and reduce oxidative stress, contributing to better overall athletic performance . Proteins shakes aid in regulating blood glucose levels and improving insulin sensitivity, which is crucial for preventing and managing diabetes. Their antioxidant and anti-inflammatory properties further enhance metabolic health.

The Effects of an 8-Month Multicomponent Training Program in Body Composition, Functional Fitness, and Sleep Quality in Aged People: A Randomized Controlled Trial.

Background/Objectives: This study examined the effects of an intervention on anthropometrics, body composition, physical fitness, and sleep quality in aged individuals, comparing a control group (N = 11) and an experimental group (N = 13) across two measurement points. Methods: A multicomponent training program of 8 months was adopted as the intervention group. A bioimpedance balance, functional fitness test, and Pittsburgh Sleep Quality Index measured body composition, functional fitness, and sleep quality. Results: Both groups showed minimal changes in body mass and hand grip strength. However, the experimental group experienced significant improvements in physical fitness, including a 26% increase in arm curl repetitions, an 18% reduction in 5 times sit-to-stand (5TSTS) completion time, and a 29% rise in 2-min step test (2MST) steps, indicating enhanced muscle endurance and cardiovascular fitness. Flexibility decreased significantly in the experimental group, while body fat percentage was reduced by 10%. Sleep quality improved by 47% in the experimental group but declined by 14% in the control group. Correlational analysis revealed that better sleep quality was linked to improved fitness performance and reduced body fat in the experimental group, with post-intervention results further confirming the connection between sleep and fat reduction. In the control group, improved sleep quality was associated with higher metabolic rates after 8 months. Conclusions: These findings suggest that the intervention positively impacted physical fitness and sleep quality, with potential benefits for overall health.

Heat stress and bleaching in corals: a bioenergetic model

AbstractThe coral-dinoflagellate endosymbiosis is based on nutrient exchanges that impact holobiont energetics. Of particular concern is the breakdown or dysbiosis of this partnership that is seen in response to elevated temperatures, where loss of symbionts through coral bleaching can lead to starvation and mortality. Here we extend a dynamic bioenergetic model of coral symbioses to explore the mechanisms by which temperature impacts various processes in the symbiosis and to enable simulational analysis of thermal bleaching. Our model tests the effects of two distinct mechanisms for how increased temperature impacts the symbiosis: 1) accelerated metabolic rates due to thermodynamics and 2) damage to the photosynthetic machinery of the symbiont caused by heat stress. Model simulations show that the model can capture key biological responses to different levels of increased temperatures. Moderately increased temperatures increase metabolic rates and slightly decrease photosynthesis. The slightly decreased photosynthesis rates cause the host to receive less carbon and share more nitrogen with the symbiont. This results in temporarily increased symbiont growth and a higher symbiont/host ratio. In contrast, higher temperatures cause a breakdown of the symbiosis due to escalating feedback that involves further reduction in photosynthesis and insufficient energy supply for $$\hbox {CO}_2$$ CO 2 concentration by the host. This leads to the accumulation of excess light energy and the generation of reactive oxygen species, eventually triggering symbiont expulsion and coral bleaching. Importantly, bleaching does not result from accelerated metabolic rates alone; it only occurs as a result of the photodamage mechanism due to its effect on nutrient cycling. Both higher light intensities and higher levels of DIN render corals more susceptible to heat stress. Conversely, heterotrophic feeding can increase the maximal temperature that can be tolerated by the coral. Collectively these results show that a bioenergetics model can capture many observed patterns of heat stress in corals, such as higher metabolic rates and higher symbiont/host ratios at moderately increased temperatures and symbiont expulsion at strongly increased temperatures.

Physiological and biochemical assessment of a new three-breed carp cross

The article presents data about the physiological and biochemical assessment of a new three-breed carp cross. The basis for the creation of the cross was the theory of heterosis and the high combinational ability of both parent forms. The effect of heterosis was noted for a number of zootechnical indicators: body weight, head index, number of stamens on the anterior gill arch. The results of a comparative analysis of biochemical parameters such as alanine aminotransferase activity, glucose and total protein content are presented, which allowed us to conclude about the physiological state of the new three-breed cross, about the balance of its carbohydrate metabolism and high rates of protein metabolism, low level of hepatocyte destruction, high immune status and cellular immunity. The new cross is characterized by intensive metabolism of a greater proportion of mature neutrophils and a high level of cellular immunity according to the cytochemical coefficient of lysosomal cationic protein. When obtaining a new three-breed cross, the method of reciprocal hybridization of different carp breeds was used and the choice of an acceptable option with a pronounced effect of heterosis in terms of productivity and vitality was used. The article presents the results of immunological, hematological and biochemical blood tests of the new cross. Also, the article demonstrates the results of studies of the phagocytic activity of neutrophils and determines the content of non-enzymatic cationic protein in them. According to the results of the biochemical assessment, the new three-breed cross showed a high combination of its parent forms with the expected level of the heterosis effect.

Evidence of Intraspecific Adaptive Variation in the American Pika (Ochotona princeps) on a Continental Scale Using a Target Enrichment and Mitochondrial Genome Skimming Approach.

Montane landscapes present an array of abiotic challenges that drive adaptive evolution amongst organisms. These adaptations can promote habitat specialisation, which may heighten the risk of extirpation from environmental change. For example, higher metabolic rates in an endothermic species may contribute to heightened cold tolerance, whilst simultaneously limiting heat tolerance. Here, using the climate-sensitive American pika (Ochotona princeps), we test for evidence of intraspecific adaptive variation amongst environmental gradients across the Intermountain West of North America. We leveraged results from previous studies on pika adaptation to generate a custom nuclear target enrichment design to sequence several hundred candidate genes related to cold, hypoxia and dietary detoxification. We also applied a 'genome skimming' approach to sequence mitochondrial DNA. Using genotype-environment association tests, we identified rare genomic variants associated with elevation and temperature variation amongst populations. Amongst mitochondrial genes, we identified intraspecific variation in selective signals and significant changes to the amino acid property equilibrium constant, which may relate to electron transport chain efficiency. These results illustrate a complex dynamic of adaptive variation amongst O. princeps where lineages and populations have adapted to unique regional conditions. Some of the clearest signals of selection were in a genetic lineage that includes pikas of the Great Basin region, which is also where recent localised extirpations have taken place and highlights the risk of losing adaptive alleles during environmental change.

Microwave Ablation Therapy for Hepatocellular Carcinoma: The Effect of Metabolic Heat on Temperature Distribution

Hepatocellular carcinoma is the main cause of liver cancer and one of the most occurring cancers worldwide. Microwave Ablation (MWA) is a method to destroy cancer cells by heating tumours above 50°C. Cancerous tissues can have high metabolic heat rates and affect temperature gain and distribution in thermal therapies. This research clarifies the metabolic heat effects in MWA therapy of liver cancer. Using Pennes Bioheat transfer equation with finite element numerical method, this research simulates temperature distribution with metabolic heat value ranging from 368,1 W/m3 to 29000 W/m3. The heat generated by metabolic heat is lower than the MWA heat source. However, the temperature increase should be considered as it can increase healthy surrounding tissue temperature to dangerous levels.

Metabolic Rate and Oxidative Stress as a Risk Factors in the Development of Colorectal Cancer.

There is growing evidence that the body's energy expenditures constitute a significant risk factor for the development of most deadly diseases, including cancer. Our aim was to investigate the impact of basal metabolic rate (BMR) on the growth and progression of colorectal cancer (CRC). To do so, we used a unique model consisting of three lines of laboratory mice (Mus musculus) artificially selected for high (HBMR) and low (LBMR) basal metabolic rate and randomly bred individuals (non-selected, NSBMR). The experimental individuals were implanted with human colorectal cancer cells DLD-1. The variation in BMR between the lines allowed for testing the impact of whole-body metabolism on oxidative and antioxidant parameters in the liver throughout the cancerogenesis process. We investigated the dependence between metabolic values, reactive oxygen species (ROS) levels, and Kelch-like ECH-associated protein 1-based E3 ligase complexes (Keap1) gene activity in these animals. We found that the HBMR strain had a higher concentration of oxidative enzymes compared to the LBMR and NSBMR. Furthermore, the growth rate of CRC tumors was associated with alterations in the levels of oxidative stress enzymes and Keap1 expression in animals with a high metabolic rate. Our results indicate that a faster growth and development of CRC line DLD-1 is associated with enzymatic redox imbalance in animals with a high BMR.

8538 Pancreatic Islet Adaptations to Hyperglycemia Are Prevented by Glycolytic Inhibition and Amplified by Inhibiting Membrane Depolarization

Abstract Disclosure: N.B. Whitticar: None. B.P. List: None. N. Bruce: None. R. Bertram: None. C.S. Nunemaker: None. Long before type 2 diabetes ensues, pancreatic islets undergo functional changes to compensate for increasing insulin resistance. Primarily, the islets increase their ability to secrete insulin by augmenting the glucose-stimulated insulin secretion (GSIS) pathway. As metabolic syndrome worsens, islets become functionally exhausted, leading to cellular dysfunction and apoptosis. To avoid the negative consequences of this compensatory response, various steps of the GSIS pathway can be attenuated to restore normal functional levels before the islets fail. Determining which inhibitors can prevent the earliest adaptations to hyperglycemia may reveal the processes that play a causal role in islet failure. The chemicals mannoheptulose (MH), diazoxide (DZ), and nifedipine (NP) were chosen to inhibit the glucokinase enzyme, KATP-channel closure, and voltage-gated calcium channels, respectively. CD-1 mouse islets were placed in 20 mM glucose to simulate hyperglycemia along with a concentration of each inhibitory drug that reduced insulin secretion by 30-40%. After 48-hour treatment, glucose-stimulated calcium tests were performed to determine if the treatments could prevent the negative adaptation to hyperglycemia. Only islets treated with MH to reduce glycolytic activity maintained a normal calcium response. Islets in the MH group also retained a strong insulin response to glucose and were not depleted of insulin content. Unexpectedly, inhibition of calcium influx and insulin secretion with DZ or NF caused a substantial increase in basal insulin secretion compared to islets in standard culture (P<0.01, n=6; P=0.06, n=6, respectively). These results indicate that the signaling pathway that causes the adaptation to hyperglycemia lies upstream of KATP channels and downstream of glucokinase. Mathematical modeling using the Integrated Oscillator Model was able to replicate our results and suggests that high rates of glycolytic and mitochondrial metabolism are associated with the signal that adapts islets to hyperglycemia, and that reducing intracellular calcium in the face of high glucose further increases basal insulin secretion. Ongoing studies will determine if metabolic acceleration or altered membrane conductance are responsible for the earliest islet adaptations to hyperglycemia. Our results suggest that reducing metabolic activity, but not calcium influx, prevents adaptations to hyperglycemia in mouse islets. These findings can be applied to potentially prevent the progression of obesity and hyperinsulinemia into type 2 diabetes. Presentation: 6/2/2024

The role of oxidative stress in retinal diseases

Oxidative stress plays a key role in the pathogenesis of many diseases associated with aging, including atherosclerosis, neurodegenerative diseases, diabetes, and retinal diseases. The retina is a tissue that is particularly susceptible to the adverse effects of oxidative stress, as it is characterized by high metabolic rate and high oxygen consumption compared to other body tissues. This review article discusses the relationship between the cellular mechanisms of impaired prooxidant-antioxidant homeostasis and the development of age-related macular degeneration and diabetic retinopathy. Natural defense mechanisms of maintaining redox homeostasis and therapeutic strategies based on the use of antioxidants are also described.

High metabolic rates drive tiny genomes in plants (and birds): a commentary on 'The smallest angiosperm genomes may be the price for effective traps of bladderworts'.

High metabolic rates drive tiny genomes in plants (and birds): a commentary on 'The smallest angiosperm genomes may be the price for effective traps of bladderworts'.

When the Going Gets Tough, the Females Get Going: Sex-Specific Physiological Responses to Simultaneous Exposure to Hypoxia and Marine Heatwave Events in a Ubiquitous Copepod.

The existence of sex-specific differences in phenotypic traits is widely recognized. Yet they are often ignored in studies looking at the impact of global changes on marine organisms, particularly within the context of combined drivers that are known to elicit complex interactions. We tested sex-specific physiological responses of the cosmopolitan and ecologically important marine copepod Acartia tonsa exposed to combined hypoxia and marine heatwave (MHW) conditions, both of which individually strongly affect marine ectotherms. Females and males were acutely exposed for 5 days to a combination of either control (18°C) or a high temperature mimicking a MHW (25°C), and normoxia (100% O2 sat.) or mild hypoxia (35% O2 sat.). Life-history traits, as well as sex-specific survival and physiological traits, were measured. Females had overall higher thermal tolerance levels and responded differently than males when exposed to the combined global change drivers investigated. Females also showed lower metabolic thermal sensitivity when compared to males. Additionally, the MHW exerted a dominant effect on the traits investigated, causing a lower survival and higher metabolic rate at 25°C. However, egg production rates appeared unaffected by hypoxia and MHW conditions. Our results showed that MHWs could strongly affect copepods' survival, that combined exposure to hypoxia and MHW exerted an interactive effect only on CTmax, and that sex-specific vulnerability to these global change drivers could have major implications for population dynamics. Our results highlight the importance of considering the differences in the responses of females and males to rapid environmental changes to improve the implementation of climate-smart conservation approaches.

Dietary macronutrient composition and partial soybean meal replacement with slow-release urea: Effects on performance, digestibility, rumen fermentation, and nitrogen metabolism in dairy cows

A 2 × 2 factorial arrangement of treatments was used to investigate the interactive effects of dietary macronutrient composition [high-starch, low-fat, low-fiber (HsLFF) than low-starch, high-fat, high-fiber (LsHFF)] and N source [soybean meal (SBM) or partially replaced by slow-release urea (SRU)] on lactation performance, rumen fermentation, N utilization efficiency, nutrient digestibility, blood metabolites, and feeding behavior in cows. A replicated 4 × 4 Latin square design was used involving 12 multiparous Holstein cows (milk yield of 40.5 ± 5.6 kg/d, BW of 590 ± 20 kg; 81 ± 12 d in milk). The HsLFF diet contained 300 g/kg starch, 31.3 g/kg fat, and 301 g/kg NDF, without straw or additional fat. In contrast, the LsHFF diet contained 195.5 g/kg starch, 60.8 g/kg fat, and 367.5 g/kg NDF, enriched with wheat straw (100 g/kg), and additional fat (34 g/kg). The diets were formulated to be iso-nitrogenous and isocaloric. Cows fed the HsLFF diet had greater DM intake, digestibility of DM and CP, milk yield and milk protein %, but lower intakes of NDF, and physically effective NDF, and milk fat % than cows fed the LsHFF diet. Replacing SBM with SRU significantly increased milk solids yield without affecting other lactation performance or BW. Cows fed the LsHFF diet had higher ruminal pH and branched-chain VFA proportions but lower total VFA concentrations compared with the HsLFF diet, while those on the LsHFF-SRU diet had the highest ruminal ammonia levels. Compared with the HsLFF diet, cows fed LsHFF had lower NE intake, milk energy output and energy requirement for maintenance, although energy balances were similar among groups. The HsLFF diet improved N utilization, resulting in higher N content in milk and lower N excretion in feces. Blood metabolite studies showed significant interactions between the main factors, particularly for blood glucose and creatinine, with the lowest levels in cows fed the LsHFF-SRU and LsHFF-SBM diets. In addition, alanine aminotransferase levels were higher in cows fed the LsHFF diet than in cows fed the HsLFF diet. This could indicate early-stage liver stress due to the metabolic imbalance caused by a high-fat, low-starch diet, which can alter energy metabolism. Cows on the HsLFF-SRU diet had the highest glucose levels, indicating possible changes in carbohydrate metabolism or a higher metabolic rate. The concentration of BUN increased steadily after feeding in the LsHFF diet and peaked after 4 h in the LsHFF-SRU diet, with no difference between N sources in the HsLFF diet. Partial replacement of SRU with SBM had no effect on BUN. The interaction between the main factors had a significant effect on MUN content, which was highest in LsHFF-SRU and lowest in HsLFF-SRU, with no difference between the N sources in the HsLFF diets. Overall, while diets with reduced starch and increased fiber and fat compromised lactation performance, partially substituting SRU with SBM helped maintain milk production and milk nitrogen efficiency. However, the LsHFF-SRU diet was less efficient in N utilization, as shown by higher levels of ruminal ammonia, BUN and MUN.

Early detection of thermal image based T1 breast cancer using enhanced multiwavelet denoised convolution neural network with region based analysis

Medical Thermography image is used for the detection of breast cancer at an earlier stage. Thermography image shows the temperature change in the body due to cells. The metabolic rate of cancer cells is high compared to normal cells. A high metabolic rate increases the blood flow in cancer cells. High blood leads to changes in body temperature. The change in body temperature is used for cancer cell detection at an earlier stage. However, T1-stage cancer cells are smaller and have small temperature differences undetected with thermography. In this paper, a T1-stage cancer cell is heated by an external source; then, thermal images are acquired for earlier detection of small-size cancer cells. External heat source amplifies T1 stage cancer cell temperature. Amplified cancer cell images are analyzed using the proposed Multiwavelet-Deep Denoised Convolutional Neural Network (MWTDnCNN) algorithm for T1 cancer cell detection. Amplified T1 stage cancer cell has higher thermal conductivity (k) and heat capacity (Cp), which helps to detect T1 cancer cell tissue due to the enhanced pixel feature. The proposed MWTDnCNN algorithm has a T1-stage cancer cell detection accuracy of about 98% compared with traditional algorithms. The proposed MWTDnCNN algorithm detects T1-stage cancer of size 1.29 mm.

The hydroperiod gradient drives species sorting in pace-of-life strategies but not in stressor sensitivity in Lestes damselfly larvae

Many species sort along environmental gradients, whereby species traits are predicted to shift as integrated sets of life-history, behavioural and physiological traits thereby making up a fast-to-slow pace-of-life continuum. This has also been predicted to cause species differences in stressor sensitivity along such gradients with a faster pace-of-life causing a higher sensitivity. We tested for predictable differences in pace-of-life and in stressor sensitivity for a set of four Lestes damselfly species that separate along the hydroperiod gradient. We reared in a common-garden experiment, larvae of two vernal pond specialists, L. dryas and L. barbarus, and two hydroperiod generalists, L. sponsa and L. virens, and exposed them to transient food deprivation and pesticide exposure, and monitored a set of life-history, behavioural and physiological traits both in the larvae and in the adults. Consistent with the time constraints imposed by the shorter hydroperiod of their habitat, the vernal pond specialists showed a faster pace-of-life (faster growth and development, and higher activity levels) than the hydroperiod generalists. Yet, in contrast with theory, this was not associated with a higher metabolic rate and a lower energy budget, neither with a higher oxidative damage to lipids. Both food deprivation and pesticide exposure were experienced as stressors, and species showed compensatory responses to cope with the transient food deprivation, including compensatory growth and delayed development. Nevertheless, the sensitivity to these stressors could not be predicted based on the difference in pace-of-life strategy between the vernal pond specialists and the hydroperiod generalists because of a decoupling of life-history and physiological traits. Our study indicates that while pace-of-life strategies change largely predictably along the hydroperiod gradient, these are not reliable predictors of species sensitivity to stressors. This highlights the need to consider also physiological traits to arrive at a generalizable predictive framework of species sensitivity to global change.

Mitophagy Regulates Kidney Diseases

Background: Mitophagy is a crucial process involved in maintaining cellular homeostasis by selectively eliminating damaged or surplus mitochondria. As the kidney is an organ with a high dynamic metabolic rate and abundant mitochondria, it is particularly crucial to control mitochondrial quality through mitophagy. Dysregulation of mitophagy has been associated with various renal diseases, including acute and chronic kidney diseases, and therefore a better understanding of the links between mitophagy and these diseases may present new opportunities for therapeutic interventions. Summary: Mitophagy plays a pivotal role in the development of kidney diseases. Upregulation and downregulation of mitophagy have been observed in various kidney diseases, such as renal ischemia-reperfusion injury, contrast-induced acute kidney injury, diabetic nephropathy, kidney fibrosis, and several inherited renal diseases. A growing body of research has suggested that PINK1 and Parkin, the main mitophagy regulatory proteins, represent promising potential therapeutic targets for kidney diseases. In this review, we summarize the latest insights into how the progression of renal diseases can be mitigated through the regulation of mitophagy, while highlighting their performance in clinical trials. Key Message: This review comprehensively outlines the mechanisms of mitophagy and its role in numerous kidney diseases. While early research holds promise, most mitophagy-centered therapeutic approaches have yet to reach the clinical application stage.

Analysis of Genetic Risk Factors Associated with Charcot Foot Based on the FinnGen Study R9 Data: A Wide-angle Mendelian Randomization Study.

Charcot foot or Charcot neuropathic joint disease (CN) is a rare and complex foot disease with unknown pathogenesis, hindering early identification and intervention. The study aimed to clarify the causal association between all predominant risk factors and CN. Two-sample Mendelian Randomization (MR), Multivariate MR, and Bidirectional MR analyses investigated the causal association between 36 modifiable risk factors and CN. The causal relationship between CN and Inflammatory cytokine and immune cells was also analyzed. Genetic factors associated with obesity and genetic susceptibility to various autoimmune diseases and non-cancerous thyroid diseases increased the risk of CN (P < .05), genetically associated high basal metabolic rate and high total cholesterol decreased the risk of CN (P < .05). In addition, we found a bi-directional causal relationship between CN and diabetes. In further immune cell analysis, we found 8 CN related immune cells, and in inflammatory cytokine analysis, we found 2 CN related inflammatory cytokines. This comprehensive MR Study supports the causal role of Obesity-related factors, diabetes, autoimmune-related factors, and smoking in the development and progression of CN. This study identifies a potential cause of CN that has not been identified in previous studies and provides a new direction for further research.

230 The relationship between hormone status and the metabolism of androstenone and skatole in isolated porcine hepatocytes

Abstract Surgical castration is a significant welfare concern within the swine industry; however, it is currently the most effective method to prevent boar taint, which is a meat quality issue that develops in entire male pigs due to the accumulation of androstenone and skatole in the fat. Metabolism of the boar taint compounds occurs within the liver and promotes their excretion, ultimately reducing the extent of their accumulation in the fat. Previous research has demonstrated that plasma concentrations of estrone sulfate (E1S), which are indicative of steroid hormone status in the boar, are highly variable between individual animals of similar live body weights at slaughter. Testicular steroids are known to influence the activity and expression of some enzymes regulating the metabolism of skatole, but the effect of hormone concentrations on the entire expression profile of enzymes responsible for boar taint metabolism has not been characterized. Therefore, the objective of this study was to relate plasma E1S concentrations at slaughter to expression levels of genes regulating the metabolism of androstenone and skatole and their respective metabolite profiles in isolated hepatocytes, to further characterize the relationship between hormone status and boar taint metabolism. Blood and liver samples were collected from 5-mo-old crossbred [(Yorkshire x Landrace) x Duroc] boars (n = 8)] at slaughter. Plasma E1S concentrations were quantified using a radioimmunoassay and gene expression in the liver was evaluated by RT-qPCR. Hepatocytes were also isolated and incubated with androstenone or skatole, with metabolite concentrations in the incubation media quantified by high-performance liquid chromatography. Statistical analysis was performed using Pearson correlation. Plasma E1S concentrations at slaughter ranged from 2.2-108.5 ng/mL and were positively correlated with overall skatole metabolism (r = 0.77, P = 0.0265), the production of the Phase I skatole metabolites 3-methyloxindole (3MOI; r = 0.80, P = 0.0183), and 3-hydroxy-3-methyloxindole (HMOI; r = 0.73, P = 0.0413), as well as expression levels of CYP2C33 (r = 0.88, P = 0.0042), CYP2C49 (r = 0.78, P = 0.0221), and CYB5R1 (r = 0.80, P = 0.0165), which regulate skatole metabolism. A strong positive relationship was also identified between overall skatole metabolism and the production of 3MOI (r = 0.96, P = 0.0001) and HMOI (r = 0.93, P = 0.001). Androstenone metabolism primarily resulted in the production of Phase II glucuronide metabolites, but the levels produced were not related to E1S concentrations or gene expression levels. Taken together, these results demonstrate that plasma E1S concentrations are related to the rate of skatole, but not androstenone, metabolism in mature boars. Additional research is required to assess the potential of E1S concentrations as a biomarker for the rate of skatole metabolism in vivo and establish thresholds that could be used to identify boars with high and low rates of metabolism. This may provide an opportunity to develop targeted treatments for boar taint based on the metabolic status of the animal.

On the function and origin of the avian renal portal shunt and its potential significance throughout evolution.

All birds possess a unique venous architecture surrounding the kidneys known as the renal portal system. In veterinary medicine, this system is well known for causing a first-pass effect when medication is administered parenterally via the leg veins, that is venous blood from the leg is filtered before entering general circulation, thus possibly compromising adequate dosage. Additionally, bilateral valves are present in these veins, and it has been hypothesized that they play a crucial role in regulating flow through the kidneys to protect them against increases in blood pressure. While this hypothesis has been acknowledged, it has not been thoroughly explored. We propose that the function of the renal portal valve extends beyond its significance for kidney function, potentially impacting general hemodynamics. Examining anatomical similarities with extant non-avian reptiles, which lack the renal portal shunt with valve, could reveal additional functionalities of this system in birds. Given the endothermic metabolism and the energetically expensive locomotor activity of birds, the resistance of the hepatic and renal portal system might constrain the blood flow from splanchnic to non-splanchnic blood vessels necessary for (sustained) peak performance. Therefore, diverting blood from the renal portal system using the renal portal valve as a regulatory structure might represent a key adaptation to facilitate sustained peak performance. In addition, we hypothesize that this shunt and valve represents a very early adaptation in amniotes, possibly lost in extant non-avian reptiles but enhanced in birds, with a pivotal role in maintaining hemodynamic homeostasis to support the high metabolic rates characteristic of birds.

Brain energy metabolism as an underlying basis of slow and fast cognitive phenotypes in honeybees.

In the context of slow-fast behavioral variation, fast individuals are hypothesized to be those who prioritize speed over accuracy while slow individuals are those which do the opposite. Since energy metabolism is a critical component of neural and cognitive functioning, this predicts such differences in cognitive style to be reflected at the level of the brain. We tested this idea in honeybees by first classifying individuals into slow and fast cognitive phenotypes based on a learning assay and then measuring their brain respiration with high-resolution respirometry. Our results broadly show that inter-individual differences in cognition are reflected in differences in brain mass and accompanying energy use at the level of the brain and the whole animal. Larger brains had lower mass-specific energy usage and bees with larger brains had a higher metabolic rate. These differences in brain respiration and brain mass were, in turn, associated with cognitive differences, such that bees with larger brains were fast cognitive phenotypes whereas those with smaller brains were slow cognitive phenotypes. We discuss these results in the context of the role of energy in brain functioning and slow-fast decision making and speed accuracy trade-off.

Highly virulent avian brood-parasitic species show elevated embryonic metabolic rates at specific incubation stages compared to less virulent and non-parasitic species.

As the avian embryo grows and develops within the egg, its metabolic rate gradually increases. Obligate avian brood-parasitic birds lay their eggs in the nests of other species to avoid the costs of parental care, and all but one of these brood-parasitic species are altricial at hatching. Yet the chicks of some altricial brood-parasitic species perform the physically demanding task of evicting, stabbing or otherwise killing host progeny within days of hatching. This implies a need for high metabolic rates in the embryo, just as precocial species require. Using flow-through respirometry in situ, we investigated embryonic metabolic rates in diverse avian brood parasite lineages which either kill host offspring (high virulence) or share the nest with host young (low virulence). High-virulence brood parasite embryos exhibited higher overall metabolic rates than both non-parasitic (parental) species and low-virulence parasites. This was driven by significantly elevated metabolic rates around the halfway point of incubation. Additionally, a fine-scale analysis of the embryos of a host-parasitic pair showed faster increases in metabolic rates in the parasite. Together these results suggest that the metabolic patterns of the embryos of high-virulence parasites facilitate their early-life demands.