Effects of temperature and salinity on oxygen consumption and ammonia excretion of juvenile miiuy croaker, Miichthys miiuy (Basilewsky)

Abstract

The metabolic responses of the juvenile Miichthys miiuy in terms of oxygen consumption and ammonia excretion to changes in temperature (6-25°C) and salinity (16-31 ppt) were investigated. At a constant salinity of 26 ppt, the oxygen consumption rate (OCR) of the fish increased with an increase in temperature and ranged between 133.38 and 594.96 lg O 2 h -1 g -1 DW. The effect of temperature on OCR was significant (P \ 0.01). Q 10 coefficients were 6.80, 1.41, 1.29 and 2.36 at temperatures of 6-10, 10-15, 15-20 and 20-25°C, respectively, suggesting that the juveniles of M. miiuy will be well adapted to the field temperature in the summer, but not in the winter. The ammonium excretion rates (AER) of the fish were also affected significantly by temperature (P \ 0.01). The O:N ratio at temperatures of 6, 10, 15 and 20°C ranged from 13.12 to 20.91, which was indicative of a protein-dominated metabolism, whereas the O:N at a temperature of 25°C was 51.37, suggesting that protein-lipids were used as an energy substrate. At a constant temperature of 15°C, the OCRs of the fish ranged between 334.14 (at 31 ppt) and 409.68 (at 16 ppt) lg O 2 h -1 g -1 DW. No significant differences were observed in the OCR and AER of the juveniles between salinities of 26 and 31 ppt (P [ 0.05). The OCR and AER at 16 ppt were, however, significantly higher than those at 26 and 31 ppt (P \ 0.05), indicating salinity lower than 16 ppt is presumably stressful to M. miiuy juveniles.

Effects of temperature and salinity on oxygen consumption of tawny puffer Takifugu flavidus juvenile

“…It may be hypothesized that the experimental temperatures (20–29 °C) were in the suitable range for tawny puffer juvenile. Similar results have been obtained in many teleosts, for example, the leopard shark T. semifasciata (Miklos et al 2003), the carp Labeo rohita (Das, Pal, Chakraborty, Manush, Sahu & Mukherjee 2005), the largemouth bass M. salmoides (Lacépède) (Díaz et al 2007) and the miiuy croaker Miichthys miiuy (Basilewsky) (Zheng et al 2008).…”

“…Closed‐chamber respiration methods were used to determine OCR (Zheng, Jin, Li, Bai & Dong 2008). The chamber was a 1.5 L transparent plastic cylindrical bottle.…”

“…Oxygen uptake was measured using a polarographic oxygen electrode (YSI‐58 with stirrer). To minimize the possible influence on oxygen consumption caused by oxygen saturation, each measurement lasted for 1–3 h until oxygen saturation reached about 60% (Meade et al 2002; Zheng et al 2008). To ensure oxygen saturation before taking physiological measurements, seawater was fully aerated for at least 1 h in a 100 L tank before filling the experimental chambers.…”

“…Data were used to determine the OCR, based on the following equation (Saucedo, Ocampo, Monteforte & Bervera 2004; Zheng et al 2008): where R is the OCR and expressed as the fresh weight‐specific rate (mg O 2 g −1 h −1 ), t 0 and t 1 are the start and the finish times (h) of the measurement period, C t is the oxygen concentration in water (mg O 2 L −1 ) at time t, W is the body weight of the juveniles (g fresh weight) and V is the volume of the respiratory chamber (L).…”

Effects of temperature and salinity on metabolic rate of the Asiatic clam Corbicula fluminea (Müller, 1774)

“…The Q 10 coefficient has been identified as an index relating to enzymatic and physiological requirements for energy, when a 10°C temperature increases within an organism’s tolerance range (Zheng et al 2008). In this study, Q 10 values for OCR were calculated at the 7°C intervals for small C. fluminea .…”