Is digestive capacity limiting growth at low temperatures in roach?

Abstract

In roach Rutilus rutilus growth ceases below a temperature threshold of 12° C. This cessation of growth is accompanied by a reduction in feeding. Do roach decrease feeding in the cold because of reduced energy demand, caused by the decelerating effect of low temperature on metabolism and growth, or is feeding directly limited by low temperatures, leading to reduced growth rates? It was found that at low temperatures the intake and digestion of food may be limited by reduced activities of digestive enzymes. Trypsin, amylase and γ‐glutamyl transferase showed a negative compensation with respect to temperature, resulting in very low activities at acclimation temperatures of ≤12° C. Trypsin activity, falling from 400·5 ± 131·2 U g−1 fresh mass of the gut at 27° C to 12·5 U g−1 fresh mass at 4° C, displayed the strongest linear correlation with growth rates, suggesting that trypsin activities may set a limit to growth in the low temperature range. If protein digestion is limiting at low temperatures, this should be reflected in reduced concentrations of amino acid in the white muscle. The size of the total amino acid pool was not affected by temperature acclimation and ranged between 19·2 ± 6·2 and 25·2 ± 3·6 µmol g−1 fresh mass of the white muscle. A decrease, however, was found of several amino acids, mainly of threonine and glutamine, in the low temperature range. Low concentrations of the essential amino acid threonine (0·14 ± 0·03 µmol g−1 fresh mass at 12° C and 0·12 ± 0·05 µmol g−1 fresh mass at 4° C) were probably due to nutritional or digestional limitations and may therefore have resulted from reduced trypsin activity in the cold. The non‐essential amino acid glutamine, however, can be endogenously synthesized and its low level observed at 4° C (0·16 ± 0·09 µmol g−1 fresh mass) was not necessarily a result of low trypsin activities. It is more likely that low temperatures impair glutamine synthesis. The possibility that glutamine concentrations may be down regulated under conditions when anabolic processes are not advantageous is discussed.

Behavior of juveniles of roach Rutilus rutilus (cyprinidae), produced by breeders from a tributary of the Rybinsk Reservoir and from a nonfreezing area of the Moskva River at variable temperatures

“…Sharp changes in the values of most behavioral parameters were observed at temperatures below 12°С: e.g., no changes in feeding intensity were observed until the temperature reached 7.6°С, and the value of this parameter at 5.4°C was only 8% of its initial value, observed in the experiment with stable temperature. Similar results were obtained in experiments with the roach from natural waterbodies of Germany and southern Sweden, where the feeding intensity of the fish also decreased at temperatures below 12°C (Van Dijk et al, 2002: Hardewig and Van Dijk, 2003: Linlokken et al, 2010. This was explained by the decreasing activity of enzymes at these temperatures, especially of trypsin (Hardewig and Van Dijk, 2003).…”

“…Similar results were obtained in experiments with the roach from natural waterbodies of Germany and southern Sweden, where the feeding intensity of the fish also decreased at temperatures below 12°C (Van Dijk et al, 2002: Hardewig and Van Dijk, 2003: Linlokken et al, 2010. This was explained by the decreasing activity of enzymes at these temperatures, especially of trypsin (Hardewig and Van Dijk, 2003).…”

Effect of temperature and roach Rutilus rutilus group size on swimming speed and prey capture rate of perch Perca fluviatilis and R. rutilus

“…The growth of perch Perca fluviatilis L., for example, is positively correlated to temperature (< 24° C) in natural waters (LeCren, 1958; Tolonen et al , 2003), and its metabolism is positively related to temperature below its optimum for growth (23° C) (Mélard et al , 1996) and fells sharply at temperatures < 12° C (Karås & Thoresson, 1992). The growth of roach Rutilus rutilus (L.) is also temperature dependent (Müller & Meng, 1986) and Hardewig & Van Dijk (2003) showed that feeding and growth of R. rutilus was reduced at temperatures < 12° C. They explained this reduction with reduced activity of enzymes, especially trypsin. Experiments have also shown that R. rutilus has an optimal temperature range for growth of 20–27° C, and that starvation, at temperatures < 12° C, leads to increased food uptake when food becomes available, compared to fed control animals (Van Dijk et al , 2002).…”

Predicting the habitat expansion of the invasive roach Rutilus rutilus (Actinopterygii, Cyprinidae), in Great Britain

“…The eurythermal characteristics of roach allow it to survive a broad range of water temperatures (4 to [30°C; Cocking, 1959;Graham & Harrod, 2009) but with a distinct preference for warmer temperatures: growth occurs only above 12°C (van Dijk et al, 2002) and juvenile growth is maximal between 20-27°C (Hardewig & van Dijk, 2003). Furthermore, spawning is observed only at temperatures above 12-16°C (Graham & Harrod, 2009) illustrating that population recruitment of the species is also tightly linked to higher water temperatures.…”