Estufas Climatizadas para Experimentos Ambientais com Rãs, em Gaiolas

Abstract

Six acclimatized incubators were initially installed in the Experimental Frog Farm of the Federal University of Viçosa and later in Experimental Frog Farm of the Federal University of Rio Grande, with the objective of accomplishing experiments to evaluate the effects of the environment on frogs performance in cages of fiber glass. Environments with temperatures of 25°C and photoperiod of 12/12 hours of light/hours of darkness (h L/D) were available to frogs adaptation during 15 days before each experiment. The treatments consisted to simulate environments with temperatures varying from 20 to 35°C and photoperiods of 8/16, 12/12 and 16/8 h L/D. They were accomplished experiments with bullfrog (Rana catesbeiana Shaw, 1802) and with butterfrog (Leptodactylus ocellatus Linnaeus, 1758). In these incubators it was possible to estimate that: a) the highest weight gain of bullfrog was obtained between 27.6 and 29.7°C, with better growth between 28.2 and 30.1°C; for butterfrog the best gain and alimentary conversion were verified at 28.6 and 28°C, respectively; b) temperature interact with photoperiod affecting the frogs performance and gonadal development; c) at 27.7°C (temperature of thermal comfort) there will be less frogs inside of water; d) the highest cloacal temperature: 32.1°C, in the dry part, and 33.8°C, inside of water, at 35°C, evidenced the bullfrog thermoregulation; e) the tetraiodotironine (T4) level in the plasm decreases in the temperature of thermal comfort; f) butterfrog was conditioned to the routine handling, coming around feeder at eater time.