The effect of exercise training on the metabolic interaction between feeding and locomotion in the juvenile southern catfish (Silurus meridionalis Chen)

Abstract

The southern catfish exhibits the largest decrease in critical swimming speeds (U(crit)) during digestion among the fish species that have been investigated. To test whether the maximum metabolic capacity of the southern catfish was improved after exercise training to alleviate the competitive interaction between digestion and swimming, we measured postprandial metabolic responses, U(crit) and oxygen consumption rates (MO(2)) during swimming in both fasting and digesting fish. Twenty-one days of training (50 min swimming at 60% U(crit) followed by 10 min chasing) did not produce significant differences in resting MO(2) (MO(2rest)) or postprandial peak MO(2) (MO(2peak)). However, it did result in a significant decrease in energy expenditure during digestion. Feeding caused a significant decrease in U(crit) and an increase in active MO(2) (MO(2active)), whereas training caused a significant increase in U(crit) but no significant change in MO(2active). Neither digestion nor training had a significant effect on metabolic scope (MO(2active)-MO(2rest)). Training had no interactive effect on postprandial changes in any measured variable, so we conclude that training did not alleviate the competitive interaction between digestion and swimming. Our results suggest that: (1) the metabolic capacity of nontrained fish cannot support the metabolic demands of both digestion and locomotion simultaneously, and swimming metabolism, therefore, is sacrificed to sustain digestion when feeding and locomotion are combined (digestion-prioritization mode); (2) the metabolic capacity and metabolic mode of competition did not change after training, but trained fish did exhibit improved swimming performance, possibly due to their increased rate of O(2) extraction.

Effects of prolonged exercise training and exhaustive chasing training on the swimming performance of an endangered bream Megalobrama pellegrini

“…U crit was measured by a Blakza-type swimming tunnel respirometer (total volume 3.5 l; for details, see Li et al 2010a, Pang et al 2011. Eight fish from each group were individually transferred into the swim tunnel after 24 h of fasting and allowed to recover for 6 h at a water speed of 6 cm s −1 (Peng et al 2014).…”

“…Survival, growth and reproduction in fish depend heavily on swimming ability (Brett 1964, Blake 2004, Graham et al 2004, Kieffer 2010, Cai et al 2014. The swimming ability of fish is complex and varied, and it is often evaluated through many different indicators, such as critical swimming speed (U crit ) and burst swimming speed (Colavecchia et al 1998, Liu et al 2009, Li et al 2010a. U crit is not only a widely accepted evaluation index of aerobic swimming performance, but also reflects an anaerobic metabolism from approximately 60% U crit onward in fish (Nelson et al 1996, Gregory & Wood 1998, Plaut 2001, Lee et al 2003a.…”

Complete mitochondrial genome of the Southern catfish (Silurus meridionalis Chen) and Chinese catfish (S. asotus Linnaeus): Structure, phylogeny, and intraspecific variation

“…To improve the culture of both species, several studies have focused on reproduction (Wei and Luo, 1998), cell biology (Hong and Liu, 1998), and biochemistry (Shirai et al, 2006;Li et al, 2010;Zhang et al, 2010).…”

Effects of temperature and digestion on the swimming performance of juvenile Chinese bream

“…) and force-fed with approximately 3% body-mass, meal-sized diets (satiated feeding) by a gavage protocol (Altimiras et al 2008, Li et al 2010). The fed fish were then transferred to the swimming chamber and allowed to recover for 2 h; following recovery, U crit was measured in the same manner as for the fasting groups.…”

“…A Brett-type swim tunnel respirometer was used to measure fish U crit and MO 2 as a function of swimming speed (for details of the respirometer, see Li et al 2010 andPang et al 2011). Fish were placed downstream of the propeller in a swimming chamber with an area of approximately 20 cm 2 .…”