Metabolic recovery in Atlantic salmon fry and parr following forced activity

Abstract

Atlantic salmon Salmo salar fry and parr were subjected to 5 min of forced activity and the subsequent changes in oxygen consumption and ammonia excretion rates were evaluated over a 24 h period. In a second experiment, individual Atlantic salmon fry and parr were freeze-clamped in liquid nitrogen, before, immediately following a 5 min activity period, or after periods of recovery up to 2 h. Samples were analysed for whole body phosphocreatine (PCr), ATP and lactate. Five minutes of forced activity resulted in significant increases in both oxygen consumption and ammonia excretion rates. Changes in the oxygen consumption rates were greater in the parr compared with the fry. In contrast, the post-exercise ammonia excretion rates were nearly twice as high for the fry compared with the parr. Exercise also caused a marked decrease in PCr levels (c. 47 and 65% in fry and parr, respectively), no change in ATP levels and a significant increase in lactate levels in Atlantic salmon fry and parr. Recovery of PCr occurred quickly (between 15 and 30 min) in fry and parr. Although the post-activity levels of lactate were lower in fry (c. 3 mmol g À1 ) compared with parr (c. 14 mmol g À1 ), lactate levels returned to control levels within 60 min in fry, but it took >2 h for this metabolite to recover in parr. Compared with parr, these findings show that Atlantic salmon fry possess a reduced anaerobic capacity, and these results are consistent with the theoretical and experimental evidence that smaller fish support burst swimming through aerobic processes. # 2004 The Fisheries Society of the British Isles

The influence of environmental temperature and oxygen concentration on the recovery of largemouth bass from exercise: implications for live–release angling tournaments

“…While a 50% reduction in environmental oxygen does not appear to initiate anaerobic metabolism in resting largemouth bass (Furimsky et al ., 2003), this level of hypoxia does impede recovery of the metabolic disturbance in this species following exhaustive exercise. This is probably due to the fact that the oxygen requirements of fishes are greatly elevated following the cessation of exercise (Scarabello et al ., 1991; Wakefield et al ., 2004). It has also been shown that the energy required to fuel recovery of the post‐exercise metabolic disturbance must be derived aerobically (Moyes et al ., 1992; Richards et al ., 2002).…”

Resource allocation in yolk-feeding fish

“…Yolk-feeding larvae of Salmo salar have reduced anaerobic performance as compared to parr, their swimming is fuelled aerobically (Wakefield et al 2004).…”

The effect of body size on post-exercise physiology in largemouth bass

“…As reviewed in Boeuf and Payan (2001), osmotic regulation accounts for 20 to [50% of the resting energy expenditure of several freshwater fishes, indicating a relatively large energetic cost to correct altered ionic status. Accelerated recovery rates of metabolites in smaller fish have previously been attributed to smaller individuals having a greater per gram metabolic rate than larger individuals, or else an increased reliance on aerobic processes during burst swimming, thereby resulting in accelerated returns to homeostasis (Wakefield et al 2004;Ohlberger et al 2005). An alternative explanation, however, is that smaller fishes have a smaller diameter of muscle fibers relative to larger individuals resulting in a greater surface area per unit length for the muscle fibers, permitting facilitated metabolic exchange of nutrients and accelerated clearance of waste products (Weatherly 1990).…”

“…Both large and small largemouth bass consumed similar relative amounts of muscle PCr and ATP following exercise and had similar concentrations of LDH in plasma following exercise. Previous studies investigating forced exercise in salmonid fishes [Atlantic salmon (Salmo Salar) (Wakefield et al 2004), brook trout (Salvelinus fontinalis) (Kieffer et al 1996), and rainbow trout (Goolish 1989)] noted that PCr consumption was greater in larger individuals compared with smaller individuals, that larger individuals experienced a greater acid-base disturbance relative to smaller individuals, and that larger fish also had elevated lactate production relative to smaller conspecifics. These differences in metabolic disturbances across size classes of salmonid fishes were attributed to either an elevated cost of swimming (i.e., increased power requirement) (Schmidt-Nielsen 1972;Goolish 1991), increased anaerobic enzyme activity (increases in lactate dehydrogenase and creatine phosphokinase), and/or decreased aerobic potential (citrate synthase activity) (Ferguson and Tufts 1992) for larger individuals.…”

“…For example, previous studies of exercise, stress, and disturbance in rainbow trout by Pagnotta and Milligan (1991) used fish that ranged from 100 to 250 g. Similar work by Primmett et al (1986) used rainbow trout that ranged from 200 to 300 g, while Wood et al (1983) used rainbow trout that ranged from 200 to 400 g. By comparison, largemouth bass in this study ranged from 93 to 1,441 g across both size classes. In many of these earlier studies, a narrow size range of fish was likely used intentionally to control for allometric differences in physiological responses (e.g., Wakefield et al 2004). Results, however, are often then applied across a broad range of fish sizes and even across different fish species with different ecological roles and lifestyles (i.e., sedentary vs. active, migratory vs. non-migratory, etc.…”