Effects of swimming on metabolic recovery from anoxia in the painted turtle

Abstract

Anoxic submergence in the Western painted turtle results in a severe metabolic acidosis characterized by high plasma lactate and depressed arterial pH, a response similar to that seen in other vertebrates following exhaustive exercise. We tested the hypothesis that 1 or 2·h of aerobic swimming following anoxic submergence would enhance the rate of lactate disappearance from the blood just as sustained aerobic exercise does in mammals and fishes following strenuous exercise. Following 2·h of anoxic submergence at 25°C and 1·h of recovery, the pattern of plasma lactate disappearance in turtles previously trained to swim in a flume and swum aerobically (2-3؋ resting VO∑) for 1 or 2·h did not differ significantly from that in trained and untrained non-swimming turtles. Turtles were fully recovered by 7-10·h post-anoxia. The response patterns also did not differ between treatments for arterial PO∑, PCO∑, pH, and plasma glucose and HCO3 -. Blood pH and plasma HCO3 -recovered by 1 and 4·h, respectively. Despite the large lactate load, painted turtles are able to sustain periods of continuous swimming for at least 2·h without compromising metabolic recovery. Although this activity did not consistently enhance recovery, the rate of lactate disappearance was positively correlated with oxygen consumption rate in actively and passively recovering turtles. We suggest that active recovery was not a more important enhancer of recovery either because swimming may have had an inhibitory effect on hepatic gluconeogenesis or that there is variation in fuel utilization during the swimming period.

A breath of fresh air: avoiding anoxia and mortality of freshwater turtles in fyke nets by the use of floats

“…In the controlled experiment, painted turtles in submerged nets had significantly higher blood lactate levels and significantly lower blood pH than both surfaced nets and nets with floats, thus indicating that turtles in submerged nets were experiencing anoxia. Previous studies of anoxic painted turtles at 20–22 °C (Keiver et al ., ; Warren and Jackson, ) yielded lactate and blood pH values that were consistent with the values observed here when turtles were sampled from submerged nets without air spaces, thus confirming that turtles in the submerged net treatment did indeed experience anoxia. Given that baseline lactate and pH levels for painted turtles are typically ~1.5 mmol L ‐1 and ~7.8 pH, respectively (Keiver et al ., 1992a, b; Warren and Jackson, ), the results here indicate that turtles were using the air space in both the surfaced net and the net with floats to breathe, and were not experiencing anoxia.…”

“…Previous studies of anoxic painted turtles at 20–22 °C (Keiver et al ., ; Warren and Jackson, ) yielded lactate and blood pH values that were consistent with the values observed here when turtles were sampled from submerged nets without air spaces, thus confirming that turtles in the submerged net treatment did indeed experience anoxia. Given that baseline lactate and pH levels for painted turtles are typically ~1.5 mmol L ‐1 and ~7.8 pH, respectively (Keiver et al ., 1992a, b; Warren and Jackson, ), the results here indicate that turtles were using the air space in both the surfaced net and the net with floats to breathe, and were not experiencing anoxia. Turtles in nets with floats had slightly (yet significantly) higher lactate levels and lower blood pH than turtles in surfaced nets, so it appears that turtles in nets with floats had more difficulty obtaining air.…”

The metabolic consequences of repeated anoxic stress in the western painted turtle, Chrysemys picta bellii

“…The next day, they were fed Turtle Brittle ad libitum. This dive protocol was chosen because it is known that painted turtles require 10-12 hours to achieve full metabolic recovery from 2 hours of anoxic stress at 25°C (Warren and Jackson, 2004) and to insure they had one full day to eat and bask between dive days. A second group of control turtles (N=32), were treated in the same way except they were not placed in containers and submerged.…”

“…The remaining turtles in each treatment (N = 48 total, 24 submerged and 24 controls) were cannulated in the left subclavian artery one day after the End-Treatment turtles were sampled (48 hours after the final submergence) according to previously published methods (Warren and Jackson, 2004). While the turtle was maintained under isoflurane anesthesia using a Hallowell Anesthesia Workstation and precision veterinary vaporizer (5% induction, 2% maintenance, 20-25 ml tidal volume, 10 breaths min -1 ), a 2.5 cm hole was cut in the plastron through the left pectoral scute with a trephine and the vessel isolated and occlusively cannulated with an Intramedic PE90 catheter (Becton Dickinson, Sparks, MD, USA) that was flushed and filled with 20 IU ml -1 heparinized 0.8% NaCl saline and led out of a hole pierced in the skin of the neck.…”

Swimming ability in sea turtle hatchlings: a comparison between species

“…Physiological energy in the form of adenosine triphosphate (ATP) can be generated by two sources: aerobic metabolism and anaerobic metabolism Warren and Jackson, 2004). Aerobic metabolism yields ATP through the oxidation of foodstuffs.…”