Oxygen consumption, ammonia excretion and osmoregulation of Callinectes similis juveniles (Crustacea: Portunidae) exposed to fluctuating salinities

Autor: C. Rosas-Vázquez, F. Díaz-Herrera, A. Tapia-Gamas, E. Pérez-Cruz, J. Luna-Figueroa
Předmět:
Zdroj: Scopus-Elsevier
CIÊNCIAVITAE
Popis: The oxygen consumption of Callinectes similis was determined under salinity fluctuations. The metabolic rate remained unchanged (P > 0.05) and within a metabolic range of 1.23 to 2.08 mg O2.h–l.g–l D.W., exhibiting a type IV response according to Kinne (1971). Ammonia excretion rose significantly to 0.028 mg N-NH4.h–l.g–l D.W. (P < 0.05) as the salinity decreased from 35 to 24‰; in a salinity range of 18-12-18‰ it remained unchanged at 0.021 mg N-NH4.h–l.g–l D.W. It increased at 26‰to 0.029 mg N-NH4.h–l.g–l D.W. and there was a minimum value of 0.012 mg N-NH4.h–l.g–l D.W. at 35‰. The O:N atomic ratio calculated for C. similis indicates that the crabs were not significantly affected (P > 0.05) by osmotic stress. In high salinities catabolism is based on carbohydrates and in lower salinities on a mixture of lipids and carbohydrates. The osmoregulatory pattern exhibited by C. similis is of an osmoconforming organism, the hemolymph was only slightly hyperosmotic in higher and isosmotic in lower salinities.
Databáze: OpenAIRE