Daily frequency of water changes in flooded pens during initial bullfrog rearing

Abstract

The flooded pens represent ease of handling when compared to other systems and allow the use of higher stocking densities, which results in an increase in productivity by area. However, information on management in this type of system are scarce in the literature. The objective was to evaluate the effect of the daily frequency of water changes on the performance of bullfrog froglets (Lithobates catesbeianus) reared in flooded pens, for a period of 30 days. A total of 360 froglets with 8.13 ± 0.22 g and 4.85 ± 0.81 cm was randomly distributed in twelve flooded pens (0.48 m2) in a density of 30 animals/ pen. A completely randomized design with four treatments and three replications was used, the pen being the experimental unit. The treatments were the total replacement of the water in the pens performed once, twice and three times a day and a treatment with continuous water flow. The frogs were fed, ad libitum, three times a day. The average survival rate was high (96.75%) and did not differ between treatments. Higher feed intake was observed in the treatment of one and two daily water changes and continuous water flow. The continuous water flow treatment showed a higher percentage of animals over 30 g. The other variables of productive performance were not significant. Total ammonia was lower in the continuous water flow treatment. Therefore, prioritizing well-being, the use of a continuous water flow for the creation of froglets in flooded pens is the most suitable. As flooded pens is the most used system in frogs farming, is important to continue studies on management in flooded pens, especially in relation to the reuse of water resources.