Comparison of Aerobic Scope for Metabolic Activity in Aquatic Ectotherms With Temperature Related Metabolic Stimulation: A Novel Approach for Aerobic Power Budget

Considering that swim-flume or chasing methods fail in the estimation of maximum metabolic rate and in the estimation of Aerobic Scope (AS) of sedentary or sluggish aquatic ectotherms, we propose a novel conceptual approach in which high metabolic rates can be obtained through stimulation of organism metabolic activity using high and low non-lethal temperatures that induce high (HMR) and low metabolic rates (LMR), This method was defined as TIMR: Temperature Induced Metabolic Rate, designed to obtain an aerobic power budget based on temperature-induced metabolic scope which may mirror thermal metabolic scope (TMS = HMR—LMR). Prior to use, the researcher should know the critical thermal maximum (CT max) and minimum (CT min) of animals, and calculate temperature TIMR max (at temperatures −5–10% below CT max) and TIMR min (at temperatures +5–10% above CT min), or choose a high and low non-lethal temperature that provoke a higher and lower metabolic rate than observed in routine conditions. Two sets of experiments were carried out. The first compared swim-flume open respirometry and the TIMR protocol using Centropomus undecimalis (snook), an endurance swimmer, acclimated at different temperatures. Results showed that independent of the method used and of the magnitude of the metabolic response, a similar relationship between maximum metabolic budget and acclimation temperature was observed, demonstrating that the TIMR method allows the identification of TMS. The second evaluated the effect of acclimation temperature in snook, semi-sedentary yellow tail (Ocyurus chrysurus), and sedentary clownfish (Amphiprion ocellaris), using TIMR and the chasing method. Both methods produced similar maximum metabolic rates in snook and yellowtail fish, but strong differences became visible in clownfish. In clownfish, the TIMR method led to a significantly higher TMS than the chasing method indicating that chasing may not fully exploit the aerobic power budget in sedentary species. Thus, the TIMR method provides an alternative way to estimate the difference between high and low metabolic activity under different acclimation conditions that, although not equivalent to AS may allow the standardized estimation of TMS that is relevant for sedentary species where measurement of AS via maximal swimming is inappropriate

Maturation trade-offs in octopus females and their progeny: energy, digestion and defence indicators

Sexual maturation and reproduction influence the status of a number of physiological processes and consequently the ecology and behaviour of cephalopods. Using Octopus mimus as a study model, the present work was focused in the changes in biochemical compound and activity that take place during gonadal maturation of females and its consequences in embryo and hatchlings characteristics. To do that, a total of 31 adult females of O. mimus were sampled to follow metabolites (ovaries and digestive gland) and digestive enzyme activities (alkaline and acidic proteases) during physiological and functional maturation. Levels of protein (Prot), triacylglyceride (TG), cholesterol (Chol), glucose (Glu), and glycogen (Gly) were evaluated. Groups of eggs coming from mature females were also sampled along development and after hatching (paralarvae of 1 and 3 days old) to track metabolites (Prot, TG, Glu, Gly, TG, Chol), digestive enzymes activity (Lipase, alkaline proteases, and acidic proteases), and antioxidant/detoxification defence indicators with embryos development. Based on the data obtained, we hypothesized that immature females store Chol in their ovaries, probably from the food they ingested, but switch to TG reserves at the beginning of the maturation processes. At the same time, results suggest that these processes were energetically supported by Glu, obtained probably from Gly breakdown by gluconeogenic pathways. Also, was observed that embryos metabolites and enzyme activities (digestive and antioxidant/detoxification enzymes) where maintained without significant changes and in a low activity during the whole organogenesis, meaning that organogenesis is relatively not energetically costly. In contrast, after organogenesis, a mobilization of nutrients and activation of the metabolic and digestive enzymes was observed, together with increments in consumption of yolk and Gly, and reduction in lipid peroxidation. Derived from our results, we also have the hypothesis that reactive oxygen species (ROS) were produced during the metabolic processes that occurs in ovarian maturation. Those ROS may be in part transferred to the egg provoking a ROS charge to the embryos. The elimination of ROS in embryos started when the activity of the heart and the absorption of the yolk around stages XIV and XV were evident. Altogether, these processes allowed the paralarvae to hatch with buffered levels of ROS and with the antioxidant defence mechanisms ready to support further ROS production derived from paralarvae higher life stage requirements (feeding and metabolic demands)

Comparison of aerobic scope for metabolic activity in aquatic ectotherms with temperature related metabolic stimulation: a novel approach for aerobic power budget

Considering that swim-flume or chasing methods fail in the estimation of maximum metabolic rate and in the estimation of Aerobic Scope (AS) of sedentary or sluggish aquatic ectotherms, we propose a novel conceptual approach in which high metabolic rates can be obtained through stimulation of organism metabolic activity using high and low non-lethal temperatures that induce high (HMR) and low metabolic rates (LMR), This method was defined as TIMR: Temperature Induced Metabolic Rate, designed to obtain an aerobic power budget based on temperature-induced metabolic scope which may mirror thermal metabolic scope (TMS = HMR—LMR). Prior to use, the researcher should know the critical thermal maximum (CT max) and minimum (CT min) of animals, and calculate temperature TIMR max (at temperatures −5–10% below CT max) and TIMR min (at temperatures +5–10% above CT min), or choose a high and low non-lethal temperature that provoke a higher and lower metabolic rate than observed in routine conditions. Two sets of experiments were carried out. The first compared swim-flume open respirometry and the TIMR protocol using Centropomus undecimalis (snook), an endurance swimmer, acclimated at different temperatures. Results showed that independent of the method used and of the magnitude of the metabolic response, a similar relationship between maximum metabolic budget and acclimation temperature was observed, demonstrating that the TIMR method allows the identification of TMS. The second evaluated the effect of acclimation temperature in snook, semi-sedentary yellow tail (Ocyurus chrysurus), and sedentary clownfish (Amphiprion ocellaris), using TIMR and the chasing method. Both methods produced similar maximum metabolic rates in snook and yellowtail fish, but strong differences became visible in clownfish. In clownfish, the TIMR method led to a significantly higher TMS than the chasing method indicating that chasing may not fully exploit the aerobic power budget in sedentary species. Thus, the TIMR method provides an alternative way to estimate the difference between high and low metabolic activity under different acclimation conditions that, although not equivalent to AS may allow the standardized estimation of TMS that is relevant for sedentary species where measurement of AS via maximal swimming is inappropriate

Capacitación sobre crustáceos de alta calidad nutricional en un contexto de cambio global para pequeños productores de Latinoamérica: hacia una mejor salud, equidad y empleo digno (CRUSLAC)

Los crustáceos constituyen un taxón mayoritariamente acuático que integran complejas tramas tróficas en agua dulce, marismas y ambientes marinos. Sostienen además importantes actividades económicas como la acuicultura y pesquería. Como ectotermos, su fisiología está fuertemente modulada por la temperatura impactando en el metabolismo global en cada etapa de su ciclo de vida y en particular en la relación dinámica entre dos procesos de relevante asignación de energía como la reproducción y el crecimiento. Estas características los convierten en excelentes modelos para evaluar el impacto del cambio climático. El análisis en algunas especies de crustáceos decápodos muestran que el incremento de temperatura produce: alteraciones en la maduración gonadal, la fecundidad, el tiempo de incubación, la cronología de las etapas del desarrollo embrionario y el crecimiento (alteraciones en los patrones de muda). Los resultados (Proyecto CRUSLAC) obtenidos en juveniles de Litopenaeus vannamei, la especie de camarón más cultivada del mundo, mostraron que la combinación de alta temperatura (31°C) y baja salinidad (5 UPS) favorece el potencial respiratorio (0.71 mgO2 h-1 g-1), lo que sugiere que en esas condiciones los animales tendrán una mayor cantidad de energía útil disponible, que la que tendrían en alta temperatura (31°C) y alta salinidad (34 UPS) (0.52 mgO2 h-1 g-1). Los resultados del análisis del sistema antioxidante mostraron que hay un efecto significativo en la condición fisiológica de los camarones la cual es favorecida por la combinación baja salinidad y alta temperatura. Estos resultados se discutirán en función de los mecanismos de adaptación a la salinidad que esta especie tiene y los mecanismos involucrados que los camarones despliegan para aprovechar las altas temperaturas en beneficio de la obtención de energía fisiológicamente úti

Measurement of aerobic scope during the whole embryonic development of a cephalopod

In the context of global warming, the present study aimed to identify at which stages the embryos of the holobenthic species Octopus maya are the most sensitive to temperature. We used temperature as a tool to induce minimum (TIMR-min: 11°C) and maximum metabolic rates (TIMR-max: 30°C) on embryos that came from three wild females caught off Sisal harbor (21°10'N, 90°02'W; Yucatán, Mexico) in March 2016. Higher metabolic rate values were recorded at stages XV and XVI, when the three hearts start beating, compared to stage X, when organogenesis begins. The factorial metabolic scope (FMS = TIMR-max ? TIMR-min) was higher at stages XV and XVI than the more mature stages, establishing stage XVII as the most vulnerable. High temperature exposure applied only during the earliest developmental stages (until stage XV) could have adaptive advantages if spawning occurs during hot waves in tropical coastal zones where the embryos are incubated or used for aquaculture purposes by shortening the time before hatching without physiological costs

Effects of maternal diet on reproductive performance of O. maya and its consequences on biochemical characteristics of the yolk, morphology of embryos and hatchling quality

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Anti-oxidant defence mechanisms and oxidant damage indicators measured in adults of Octopus maya exposed at optimal (24°C) and high (30°C) temperatures

There is the raw data of the evaluations of effects of temperature on males and females of Octopus maya acclimated for 30 d at 24 and 30°C. Data here are: 1. Routine metabolic rates measured in open respirometers during 24h, (RMR24h), without values, used to LMR data 2. The low oxygen consumption data (LMR) obtained from 20% lower quartile data distribution of the RMR 24h 3. High metabolic rate (HMR) measured in animals exposed to 35°C for 5 min in an intermittent respirometer. 4. Values of Q10 calculated with LMR, RMR 24h and HMR data 5. Data of activities of Catalase (CAT), superoxide dismutase (SOD), total glutathione (GSH), lipoperoxidation (LPO), Carbonylation (PO), total protein, acetyl-cholinesterase (AChE), and carboxylesterase (CbE) of hearts and muscle of males and females of O. maya. Abstract Since thermal stress enhances the energy demands, it is possible to hypothesize that the harmful effects of high temperatures observed in cephalopods are the result of the limited capacity of adults to channel more energy than those that the reproductive activity demands. In this sense, the present study was designed to know how thermal stress modulates the energy physiology of Octopus maya adults, evaluated through the relationship between temperature, respiratory metabolism (measured as thermal metabolic scope: TMS), antioxidant defence mechanisms (ANTIOX) and oxidant damage indicators (ODI). Sixty-seven males and females of O. maya were individually distributed in two different temperatures of 24, and 30°C. TMS resulted lower in females and males acclimated to 30°C than in animals maintained at 24°C. At the same time, higher values of ANTIOX and ODI were registered in the branchial hearts than in muscle arms and both octopus males and females acclimated at 30 than 24°C. Octopus Carboxyl-esterase (CbE) and acetylcholinesterase (AChE) were not affected by the acclimation temperature and by sex; however higher values in the branchial hearts than the muscle of those enzymes were observed. Results obtained in the present study demonstrated in adults of O. maya that 30°C is a temperature where animals are in a limit of energy production, probably as a result of the incapacity of animals to transport oxygen to mitochondria. Although the animals are adapted to satisfy their basic energy requirements at 30 °C, it is not enough to cover all the demands energy needed of reproduction. At 30°C, oxidative stress is present explaining the reduction in the production of eggs, viable sperm and therefore in the quality of the progeny

Thermal metabolic scope measured in adults of Octopus maya exposed at optimal (24°C) and high (30°C) temperatures

There is the raw data of the evaluations of effects of temperature on males and females of Octopus maya acclimated for 30 d at 24 and 30°C. Data here are: 1. Routine metabolic rates measured in open respirometers during 24h, (RMR24h), without values, used to LMR data 2. The low oxygen consumption data (LMR) obtained from 20% lower quartile data distribution of the RMR 24h 3. High metabolic rate (HMR) measured in animals exposed to 35°C for 5 min in an intermittent respirometer. 4. Values of Q10 calculated with LMR, RMR 24h and HMR data 5. Data of activities of Catalase (CAT), superoxide dismutase (SOD), total glutathione (GSH), lipoperoxidation (LPO), Carbonylation (PO), total protein, acetyl-cholinesterase (AChE), and carboxylesterase (CbE) of hearts and muscle of males and females of O. maya. Abstract Since thermal stress enhances the energy demands, it is possible to hypothesize that the harmful effects of high temperatures observed in cephalopods are the result of the limited capacity of adults to channel more energy than those that the reproductive activity demands. In this sense, the present study was designed to know how thermal stress modulates the energy physiology of Octopus maya adults, evaluated through the relationship between temperature, respiratory metabolism (measured as thermal metabolic scope: TMS), antioxidant defence mechanisms (ANTIOX) and oxidant damage indicators (ODI). Sixty-seven males and females of O. maya were individually distributed in two different temperatures of 24, and 30°C. TMS resulted lower in females and males acclimated to 30°C than in animals maintained at 24°C. At the same time, higher values of ANTIOX and ODI were registered in the branchial hearts than in muscle arms and both octopus males and females acclimated at 30 than 24°C. Octopus Carboxyl-esterase (CbE) and acetylcholinesterase (AChE) were not affected by the acclimation temperature and by sex; however higher values in the branchial hearts than the muscle of those enzymes were observed. Results obtained in the present study demonstrated in adults of O. maya that 30°C is a temperature where animals are in a limit of energy production, probably as a result of the incapacity of animals to transport oxygen to mitochondria. Although the animals are adapted to satisfy their basic energy requirements at 30 °C, it is not enough to cover all the demands energy needed of reproduction. At 30°C, oxidative stress is present explaining the reduction in the production of eggs, viable sperm and therefore in the quality of the progeny

Energetic metabolites, digestive enzymes, detoxification and oxidative stress indicators of Octopus mimus females and embryos

Morphological changes of Octopus mimus females were evaluated during ovarian development. Digestive gland (DG) and ovaries wet weight were assessed to obtain gonadosomatic and hepatosomatic indices. Obtained from a group of females placed in tanks until spawn, embryos were incubated and sampled during development. Females (DG and ovaries), embryos (at different stages of development) and paralarvae (one and three days old) were preserved for energetic metabolites (glucose, glycogen, cholesterol, triacylglycerides, and protein concentrations), digestive enzyme activities (acidic proteases, alkaline proteases, trypsin and lipases), detoxification (acetylcholinesterase and carboxylesterase activities), and oxidative stress indicators (catalase activity, glutathione-s-transferase activity, superoxide dismutase activity, redox potential, total glutathione and lipid peroxidation)