Aerobic and Anaerobic Scope for Activity in the Giant Toad, Bufo marinus

Abstract

Maximum rates of oxygen consumption and lactate accumulation in hind limb muscles of Bufo marinus acclimated at 15 C or 25 C and LD 12:12 were determined in an experiment designed to test the relative effectiveness of electric shocks and mechanical rotation in eliciting burst-activity metabolism; no differences in oxygen consumption or in lactate production due to the method of stimulation were found. Mean max for toads at 15 C (mean mass = 359 g) was 0.60 ± 0.069 ml O₂ g⁻¹ h⁻¹ and for toads at 25 C (mean mass = 266 g), 1.44 ± 0.098 ml O₂ g⁻¹ h⁻¹. At 15 C toads had 0.36 ± 0.067 mg lactate g⁻¹ muscle and at 25 C, 0.69 ± 0.109 mg lactate g⁻¹ muscle following 3 min forced activity. At both 25 C and 15 C, oxygen consumption accounted for more than 85% of the total ATP produced during a 3-min bout of activity.