Effects of temperature on metabolic scaling in silver carp

Abstract

The association between temperature and metabolic scaling varies among species, which could be due to variation in the surface area and its scaling. This study aims to examine the effect of temperature on metabolic scaling and to verify the links between metabolic scaling and surface area scaling at both the whole body and the cell levels. The routine metabolic rate (RMR), gill surface area (GSA), ventilation frequency (VF), red blood cell surface area (SRBC), and metabolic rate (MRRBC) were determined in silver carp, and their mass‐scaling exponents were analyzed at 10 and 25°C. These results showed that body mass and temperature independently affected the RMR, GSA, and VF, suggesting constant scaling exponents of RMR (0.772), GSA (0.912), and VF (−0.282) with changing temperature. The RMR at 25°C was 2.29 times higher than that at 10°C, suggesting increased metabolic demand at a higher temperature. The results showed that the RMR increased, while the scaling exponents of RMR, GSA, and VF remained unchanged with increasing temperature. These results support the view that the scaling of oxygen supply capacity importantly affects metabolic scaling. The SRBC did not change with either temperature or body mass. However, the MRRBC increased by 5.48 times from 10 to 25°C but did not change with body mass. As the scaling exponents of RMR did not change between temperatures, the results indicate that no obvious link exists between the scaling of both the cell size and cell metabolic rate and the metabolic scaling of silver carp.

How Metabolic Rate Relates to Cell Size

“…Since cell size for a given tissue type tends to vary less within than among species, predicted cell-size effects may be more difficult to detect within species because they are more easily obscured by the effects of other extraneous factors. However, intraspecific studies of temperature effects largely support cell SA theory, because increasing temperature tends to cause both an increase in metabolic rate and a decrease in cell size (thus increasing cellular SA/V ratios that can better accommodate an increasing metabolic demand) (reviewed in [ 56 ]; but see [ 70 ]), as predicted.…”