Feeding rates for bullfrogs with automated feed management and high feeding frequency

Three feeding rates (3, 4 and 5% of body weight/day - BW/day) with automated feed management and high feeding frequency (24 meals/day) for bullfrogs (Lithobates catesbeianus) under wet systems were evaluated in this 60-day experiment. Bullfrogs with an average weight of 31.91±0.97 g, were distributed into twelve 20 m2 wet pens at a density of 60 frogs/m2. Commercial extruded feed for carnivorous fish was supplied directly onto water surface by automatic feeders. At 20 and 40 days of the experiment, the best growth was observed in frogs treated with a feeding rate of 5% BW/day. The frogs reached an average weight of 100.2 g at the end of the experiment but there was no difference among the feeding rates. At the end of the experiment, feeding rates of 3, 4 and 5% BW/day resulted in apparent feed conversion values of 1.08, 1.56 and 1.52, respectively, which are considered excellent for frog rearing. Bullfrogs reared at ideal temperature and with an average weight of 31.9 to 87.6 g can be fed at a high feeding rate (5% BW/day) for a greater growth. When temperature is lower than 25°C, feeding rate of 3% BW/day could be considered the most suitable for bullfrog weighing from 87.6 to 100.2 g, because the feed conversion ratio was numerically better and reduced feed leftovers.Três taxas de alimentação (3, 4 e 5% do peso vivo/dia – PV/dia) com manejo alimentar automatizado e alta frequência alimentar (24 refeições/dia) para rã-touro (Lithobates catesbeianus) em sistema inundado foram avaliadas em 60 dias de experimento. Rãs-touro, com peso médio de 31,91±0,97 g, foram distribuídas em 12 baias inundadas de 20 m2 com densidade de 60 rãs/m2. Ração comercial extrusada para peixes carnívoros foi fornecida diretamente sobre a superfície da água por meio de alimentadores automáticos. O melhor crescimento das rãs, aos 20 e 40 dias de experimento, foi observado com as rãs alimentadas com taxa alimentar de 5% PV/dia, e ao final do experimento as rãs atingiram peso médio de 100,2 g, entretanto não houve diferença entre as taxas de alimentação. As taxas alimentares de 3, 4 e 5% PV/dia proporcionaram ao final do experimento conversão alimentar aparente de 1.08, 1.56 e 1.52, respectivamente, considerados excelente na criação de rãs. Rãs-touro criadas em temperatura ideal, com peso médio de 31,9 a 87,6 g, podem ser alimentadas com alta taxa alimentar (5% PV/dia) para maior crescimento. Quando a temperatura é menor que 25°C, a taxa alimentar de 3% PV/dia pode ser considerada mais adequada para rãs-touro pesando 87,6 a 100,2 g, pois apresentou taxa de conversão alimentar numericamente melhor, diminuindo os desperdícios de ração