Oxygen consumption and feeding rates of gilthead sea bream (Sparus aurata) reveal lack of acclimation to cold

Abstract

Low temperature has been implicated in inducing outbreaks of 'winter syndrome' or 'winter disease' in farmed gilthead sea bream (Sparus aurata). The responses of gilthead sea bream to reduced temperature followed by maintenance at low temperature were studied. In a first experiment, oxygen consumption was measured when water temperature was reduced from 18 • C to 8 • C at either a rate of 1 • C · day −1 or as two 'sharp drops' (from 18 • C to 12 • C, and from 12 • C to 8 • C). In a second experiment, the water temperature was reduced from 16 • C to 8 • C or 12 • C and then maintained for 20 days to study the fish acclimation to these temperatures. In both experiments, fish stopped feeding below 13 • C and did not resume feeding when maintained at low temperatures. The decrease in metabolic activity, expressed by the oxygen consumption rate, was directly related to the fall in water temperature: the Q 10(18 • C−8 • C) values were between 2.2-2.5, independently of the descend rate in water temperature. However, we observed a more reduced metabolic rate when the water temperature was below 12 • C. Fish maintained at low temperatures showed only a partial recovery in oxygen consumption (15% at 8 • C and 20% at 12 • C) after 20 days. A higher metabolic rate together with a fasting-temperature condition meant that maintenance at 12 • C was more aggressive than at 8 • C, as revealed by the condition factor and energy needs. Data suggest that 12 • C could be a threshold temperature for the metabolic activity of gilthead sea bream. The relationship between low temperatures and their possible implication in the appearance of 'winter disease' in gilthead sea bream is also discussed.

Effect of temperature on the metabolism, behaviour and oxygen requirements of Sparus aurata

“…As expected, MO 2 increased with temperature (Guinea & Fernandez 1997, Ibarz et al 2003, Libralato & Solidoro 2008. As temperature increases, biochemical reactions proceed faster (Angilletta et al 2002), and the metabolic cost of maintenance increases (Fry 1947(Fry , 1971.…”

“…The capacity for feeding and growth increases with temperature until the thermal optimum is reached, and decreases thereafter (reviewed by Fry 1947, 1971, Farrell 2009, Pörtner 2010. The low feed intake and RMR observed at 12°C is in line with suggestions by Ibarz et al (2003) that this temperature represents a lower limit for suitable temperatures in S. aurata aquaculture. The highest temperature used in the present study (20°C) can be expected to be close to the optimal temperature for growth.…”

Low-temperature challenges to gilthead sea bream culture: review of cold-induced alterations and ‘Winter Syndrome’

“…The reduction in food intake at low temperatures has also been observed under laboratory-controlled conditions. Tort et al (2004) reported that a gradual decrease in water temperature led to a reduction in the ration proposed by commercial diets (Petridis and Rogdakis 1996), while Ibarz et al (2003) showed that below 13°C sea bream stop feeding altogether. This reluctance to feed did not depend on the rate of temperature drop , and feeding did not recover during extended periods at constant low temperatures such as 20 days at 12°C or 35 days at 8°C (Ibarz et al 2007a, b).…”

“…Experiment 3: acute and chronic values correspond to 3-7 and 30-35 days of experimental conditions (fromIbarz et al 2007b) b Daily requirements were calculated as 1 mg of oxygen consumed corresponding to 13.6 Jouls in energy equivalents(Brafield and Salomon 1972) c Food intake ration corresponds to food supply during trials as % of body weight. At 11-12°C Tort et al (2004) reported low food intake whereasIbarz et al (2003) showed fasting. In fluctuating conditions at 16°C, food intake rose from 0.3 to 1% during warm-…”

“…Experiment 2: acute and maintenance values correspond to 3-7 and 15-20 days of temperature maintenance (fromIbarz et al 2003). Experiment 3: acute and chronic values correspond to 3-7 and 30-35 days of experimental conditions (fromIbarz et al 2007b) b Daily requirements were calculated as 1 mg of oxygen consumed corresponding to 13.6 Jouls in energy equivalents(Brafield and Salomon 1972) c Food intake ration corresponds to food supply during trials as % of body weight.…”