Blood-Glucose Regulation in an Estuarine Crab, Chasmagnathus-Granulata (Dana, 1851) Exposed to Different Salinities (original) (raw)
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Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology, 2017
We studied the existence, biochemical characteristics and response to different environmental salinities of amylase, maltase and sucrase activity in the intertidal euryhaline crab Cyrtograpsus angulatus (Dana, 1852) along with the response to distinct salinities of glycogen and free glucose content in storage organs. Amylase, maltase and sucrase activities were kept over a broad range of pH and temperature and exhibited Michaelis-Menten kinetics. Zymography showed the existence of two amylase forms in crabs exposed to 35 (osmoconformation) and low (6-10psu; hyper-regulation) or high (40psu) (hypo-regulation) salinities. Carbohydrases activity in the hepatopancreas and glycemia were not affected in crab exposed to different environmental salinities. In 6 and 40psu, the glycogen content in anterior gills was lower than in 35psu. In 6, 10 and 40psu, glycogen concentration in hepatopancreas, muscle and posterior gills were similar to that in 35psu. Free glucose concentration in chela mu...
Marine Biology, 2010
Adult Cancer magister make forays into hyposaline estuarine habitats during times of high food abundance. However, as weak osmoregulators, they are poorly equipped to deal with the concurrent demands of osmoregulation and digestion. Therefore, the potential interaction between nutritional status and feeding in a physiologically challenging environment was investigated. Changes in the proportion of crabs feeding, the amount of food consumed, the time spent feeding, and the efficiency with which a meal was consumed were examined in response to the length and severity of hyposaline exposure, and the duration of starvation. Reductions in the (a) number of animals feeding, (b) the amount of food consumed, and (c) the time spent feeding were observed in salinities where C. magister actively osmoregulates the concentration of its internal fluids. Although this reduction in feeding was likely a stress response, the crabs were able evaluate the level of salinity stress: there was a dose-dependent reduction in feeding, and they were able to discriminate between salinities separated by as little as 3.5%. The likelihood that animals would feed in low salinity increased with starvation. Thus, the aversion to food uptake in physiologically stressful conditions may be overridden by the need to procure nutrients. In the natural environment, we suggest that C. magister are employing an 'eat and run' strategy, moving into the estuary, consuming a meal, and retreating to higher salinities to digest.
Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2008
Neohelice granulata (Chasmagnathus granulatus) is an intertidal crab species living in salt marshes from estuaries and lagoons along the Atlantic coast of South America. It is a key species in these environments because it is responsible for energy transfer from producers to consumers. In order to deal with the extremely marked environmental salinity changes occurring in salt marshes, N. granulata
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The specific metabolic rate (SMR) and haemolymph osmolality (HO) of the mud crab Rhithropanopeus harrisii Gould, 1841 from Baltic brackish waters were measured at a habitat salinity of 7 psu (T = 15°C, full air saturation) and after step-wise acclimation to a salinity range of 3-27 psu. Values of SMR at 7 psu varied between 0.40 and 3.89 J g − 1 WW h − 1 (n = 25, wet weight range 0.051-1.142 g) and were significantly ( p b 0.05) related to the specimen's wet weight (WW) according to the power regression SMR = 0.94 WW − 0.41 (R 2 = 0.68). The SMR of females did not differ significantly ( p N 0.05) from those of males. When exposed to higher salinities, the SMR of R. harrisii decreased significantly ( p b 0.05) and reached a minimum value at 23 psu (0.55 ± 0.05 J g − 1 WW h − 1 , n = 6). Mean haemolymph osmolality at 7 psu amounted to 581 ± 26 mOsm kg − 1 (n = 5) and was 2.9 times higher than that of the external medium. R. harrisii hyperosmoregulated its body fluids up to 24 psu (727 mOsm kg − 1 ) at which salinity the isosmotic point was reached.
Acute response of the estuarine crab Eurypanopeus depressus to salinity and desiccation stress
Hemolymph osmolality changes following exposure to abrupt salinity change in the range of 5–40 ppt (T = 26°C, full air saturation) and upon exposure to air (T = 23°C, r.h. = 30%) were investigated in the flatback mud crab Eurypanopeus depressus (Smith, 1869), a dominant species on oyster reefs in Southwest Florida. During salinity trials, hemolymph osmolality of E. depressus ranged from 751 ± 123 mOsmol kg−1 at 5 ppt (214 ± 32 mOsmol kg−1) to 1188 ± 81 mOsmol kg−1 at 40 ppt (1188 ± 29 mOsmol kg−1). In the salinity range of 5–15 ppt E. depressus exhibited a hyperosmotic pattern of osmoregulation while at 30 and 40 ppt it conformed. In all cases stable hemolymph osmotic concentration was reached in less than 24 h. During desiccation trials, hemolymph osmolality of E. depressus ranged from 971 ± 121 mOsmol kg−1 for unexposed crabs to 1132 ± 169 mOsmol kg−1 after 90 min of exposure. The information obtained from this study adds to knowledge of crustacean stress physiology and may give a clearer picture of the important factors involved in population distribution and the consequences of multiple stressors that may affect the crabs or their oyster-reef habitat.
Growth and immunological profile of gercacinid crab at different sublethal salinity regimes
Bio-Research
Salinity is the most variable ecological parameter in the lagoon with daily and seasonal variations. The changes in growth, serum biochemistry and antioxidant enzymes activities of Cardisoma armatum were examined during 84-day exposure to five different sublethal salinities (0, 5, 10, 15 and 20 ppt). At the start of the trial, the crab initial average body weight was not significantly different (P > 0.05). The highest weight gain was recorded in 15 ppt (47.40±1.01 g), followed by 20 ppt, 10 ppt and 5 ppt with no significant differences between them. At the end of 84 days experiment, the crab exhibited the lowest body weight growth (48.29 %) at 0 ppt and the highest (81.04±1.08%) at 10 ppt. The 10 ppt treatment had the highest specific growth rates (0.31±0.11 %/day), followed by 5 ppt, 20 ppt, 15 ppt, and then 0 ppt treatments. Aspartate and alanine aminotransferases significantly decreased after 0 ppt, but mean serum protein value increased with salinity increase. Greater activit...
Journal of Experimental Zoology Part a-Ecological Genetics and Physiology, 2003
Lipids seem to be the major energy store in crustaceans. Moreover, they are extremely important in maintaining structural and physiological integrity of cellular and sub cellular membranes. During salinity adaptation, energy-demanding mechanisms for hemolymph osmotic and ionic regulation are activated. Thus, the main goal of this work was to verify the possible involvement of lipids as an energy source in the osmotic adaptation process. The estuarine crab Chasmagnathus granulata was captured and acclimated to salt water at 20% salinity and 20 7 21C, for 30 days. After acclimation, crabs were divided into groups of ten and transferred to fresh water (0%), salt water at 40% salinity, or maintained in salt water at 20% salinity (control group), without feeding. Before and seven days after the salinity change, wet weight and lipid concentration in gills, muscle, hepatopancreas, and hemolymph were determined according to the colorimetric assay of sulphophosphovanilin. Results show that hepatopancreas lipids were not mobilized during osmotic stress regulation. Gill and muscle lipids were significantly lower in crabs subjected to hypo-osmotic stress than those subjected to the hyper-osmotic stress or maintained at the control salinity. Our results point to the occurrence of lipid mobilization and involvement of these compounds in the osmotic acclimation process in C. granulata, but with differences between tissues and the osmotic shock (hypo or hyper) considered.
Behavioral Physiology of Four Crab Species in Low Salinity
Biological Bulletin, 1999
Reports focusing on the behavioral responses of crabs to exposure to low salinity have involved choice chamber experiments or quantification of changes in activity. In addition to describing changes in locomotor activity in four species of crabs of differing osmoregulatory ability, the present study describes six behaviors: increased movement of the mouthparts, cleaning of the mouthparts with the chelae, cleaning of the antennae and antennules with the maxillipeds, flicking of the antennae, retraction of the antennules, and extension of the abdomen. Callinectes sapidus and Carcinus maenas are classed as efficient osmoregulators, and in general, showed an increase in these behaviors with decreasing salinity. Cancer magister, a weak regulator, and Libinia emarginata, an osmoconformer, exhibited these behaviors to a lesser degree and became inactive in the lower salinities, tending to adopt an isolation-type response. The differences in behaviors between the species correlated closely with previously reported changes in cardiovascular function and hemolymph flow. These overt reactions are discussed in relation to the osmoregulatory physiology and ecology of each crab species.
Journal of The Marine Biological Association of The United Kingdom, 2010
Hemigrapsus crenulatus is an abundant and frequent decapod crustacean inhabiting estuarine environments, where it must tolerate large shifts in salinity. The present study evaluates the effect of salinity (5, 13, 21 and 30 psu) on the adult physiological processes related to the energy balance. The growth potential (SFG) and the respired oxygen:excreted nitrogen ratio were used as indices of stress. Ingestion, excretion and respiration rates showed a significant dependence on salinity, being higher at low salinities. The assimilation efficiency remained constant along the studied salinity gradient. The assimilation and ingestion rates were inversely related with the salinity. Given this scenario, the growth potential remained constant within the studied salinity gradient, as did the oxygen:nitrogen ratio. The results suggest that the increased energy losses at low salinity due to respiration and excretion are compensated by an increment in the ingestion rate, contributing to the success of H. crenulatus in dynamic habitats such as estuaries.
PLOS ONE, 2019
The Chinese mitten crab (Eriocheir sinensis) is an euryhaline crustacean, whose adults migrate downstream to estuaries for reproduction. Lipids are believed to be involved in salinity adaptation during migration. This study investigated the effects of different salinities (0, 6, 12, and 18‰) on the total lipids, neutral lipids, and polar lipids contents, and fatty acid profiles in the gonads, hepatopancreas, and muscles of adult E. sinensis after 40 days of salinity adaptation. The results showed that the males and females from 12‰ treatment had the highest contents of total lipids and neutral lipids in their hepatopancreas and total lipids in the muscles. Notably, salinity had a greater effect on the fatty acid profiles in the hepatopancreas compared to that in the gonads and muscles. The male hepatopancreas treated with 18‰ salinity had the highest percentage of total n-6 polyunsaturated fatty acid (∑n-6PUFA) in both neutral lipids and polar lipids, while the percentage of total n-3 polyunsaturated fatty acid (∑n-3PUFA) in neutral lipids and polar lipids decreased significantly with increasing salinity in males. In females, the 0‰ treatment had the highest percentages of total saturated fatty acids in neutral lipids and polar lipids in the hepatopancreas, while the highest ∑n-3PUFA and ∑n-6PUFA in neutral lipids and polar lipids were detected in the 12‰ treatment group. In conclusion, brackish water could promote the accumulations of total lipids and neutral lipids in the hepatopancreas and change the fatty acid profiles of adult E. sinensis, particularly in the hepatopancreas after long-term salinity adaptation.