Age and gender influence the cardiorespiratory function and metabolic rate of broiler chicks during normocapnia and hypercapnia

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Steelhead trout Oncorhynchus mykiss metabolic rate is affected by dietary Aloe vera inclusion but not by mounting an immune response against formalin-killed Aeromonas salmonicida

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The Influence of Baseline Metabolic Rate and Exercise Training on Cardio-Respiratory Dynamics

Speeding the VO2 kinetics results in a reduction of the O2 deficit. Two factors might determine VO2 kinetics: oxygen delivery to muscle (Tschakovsky and Hughson 1999) and a muscle 'metabolic inertia' (Grassi et al. 1996). Therefore, in study 1 we investigated VO2 kinetics and cardiovascular system adaptations during step exercise transitions in different regions of the moderate domain. In study 2 we investigated muscle oxygenation and cardio-pulmonary adaptations during step exercise tests before, after and over a period of training. Study 1 methods: Seven subjects (26 ± 8 yr; 176 ± 5 cm; 69 ± 6 kg) performed 4 types of step transition from rest (0-50W; 0-100W) or elevate baseline (25-75W; 25-125W). GET and VO2max were assessed before testing. O2 uptake and were measured during testing. Study 2 methods: 10 subjects (25 ± 4 yr; 175 ± 9 cm; 71 ± 12 kg) performed a step transition test (0 to 100 W) before, after and during 4 weeks of endurance training (ET). VO2max and GET were assessed before and after of ET (40 minutes, 3 times a week, 60% O2max). VO2 uptake, Q and deoxyheamoglobin were measured during testing. Study 1 results: VO2 τ and the functional gain were slower in the upper regions of the moderate domain. Q increased more abruptly during rest to work condition. Q τ was faster than VO2 τ for each exercise step. Study 2 results: VO2 τ became faster after ET (25%) and particularly after 1 training session (4%). Q kinetics changed after 4 training sessions nevertheless it was always faster than VO2 τ. An attenuation in ∆[HHb] /∆VO2 was detectible. Conclusion: these investigations suggest that muscle fibres recruitment exerts a influence on the VO2 response within the moderate domain either during different forms of step transition or following ET.

Perinatal adaptation in mammals: the impact of metabolic rate

Mammalian birth is accompanied by profound changes in metabolic rate that can be described in terms of body size relationship (Kleiber's rule). Whereas the fetus, probably as an adaptation to the low intrauterine pO2, exhibits an "inappropriately" low, adult-like specific metabolic rate, the term neonate undergoes a rapid metabolic increase up to the level to be expected from body size. A similar, albeit slowed, "switching-on" of metabolic size allometry is found in human preterm neonates whereas animals that are normally born in a very immature state are able to retard or even suppress the postnatal metabolic increase in favor of weight gain and O2 supply. Moreover, small immature mammalian neonates exhibit a temporary oxyconforming behavior which enhances their hypoxia tolerance, yet is lost to the extent by which the size-adjusted metabolic rate is "locked" by increasing mitochondrial density. Beyond the perinatal period, there are no other deviations from metabolic size allometry among mammals except in hibernation where the temporary "switching-off" of Kleiber's rule is accompanied by a deep reduction in tissue pO2. This gives support to the hypothesis that the postnatal metabolic increase represents an "escape from oxygen" similar to the evolutionary roots of mitochondrial respiration, and that the overall increase in specific metabolic rate with decreasing size might contribute to prevent tissues from O2 toxicity.

[Calculating the basal metabolic rate and severe and morbid obesity]

The aim of this study was to evaluate the currently available predictive equations for basal metabolic rate (BMR) in subjects with obesity class II and III, and to assess the contribution by the components of a two-compartment model of body composition, namely the lean body mass (LBM) and the fat mass (FM) to the prediction. A second objective was to examine the reliability of the Harris Benedict equation in obese subjects, especially with a weight > or = 120 kg.

Association between cerebral oxygen metabolic rate and the incidence of nosocomial pneumonia in head injury patients

The development of nosocomial pneumonia was monitored in 96 head-trauma patients requiring mechanical ventilation for up to 10 days. Pneumonia occurred in 28 patients (29.2%) or 53.9 cases per 1,000 admission days. The incidence of nosocomial pneumonia was negatively correlated with cerebral oxygen metabolic rate (CMRO$\sb2$) measured during the first five days. The relative risk of nosocomial pneumonia for patients with CMRO$\sb2$ less than 0.6 umol/gm/min is 2.08 (1.09$-$3.98) times those patients with CMRO$\sb2$ greater than 0.6 umol/gm/min. The association between cerebral oxygen metabolic rate and nosocomial pneumonia was not affected by adjustment of potential confounding factors including age, cimetidine and other infections. These findings provide evidences underlying the CNS-immune system interaction. ^

Seawater carbonate chemistry and length, weight, survival rate, metabolic rate of coral reef fish Amphiprion melanopus in a laboratory experiment

Carbon dioxide concentrations in the surface ocean are increasing owing to rising CO2 concentrations in the atmosphere. Higher CO2 levels are predicted to affect essential physiological processes of many aquatic organisms, leading to widespread impacts on marine diversity and ecosystem function, especially when combined with the effects of global warming. Yet the ability for marine species to adjust to increasing CO2 levels over many generations is an unresolved issue. Here we show that ocean conditions projected for the end of the century (approximately 1,000 µatm CO2 and a temperature rise of 1.5-3.0 °C) cause an increase in metabolic rate and decreases in length, weight, condition and survival of juvenile fish. However, these effects are absent or reversed when parents also experience high CO2 concentrations. Our results show that non-genetic parental effects can dramatically alter the response of marine organisms to increasing CO2 and demonstrate that some species have more capacity to acclimate to ocean acidification than previously thought.