Feed digestibility and productive performance of bullfrogs raised in cages and fed in different periods and high frequency

Abstract

Abstract Three feeding frequencies (24, 48 and 96 meals/day) and three feeding periods (daytime, nighttime and daytime/nighttime) were evaluated in this experiment. Bullfrogs ( Lithobates catesbeianus ), with average weight of 78.6 ± 15.7 g, were distributed in 36 pens at a density of 88 frogs/m 2 . The pens, made of polypropylene and screened floor, were installed inside cages, linearly distributed in a 2000 m 2 pond with 5% water renewal. The frogs were fed daily by automatic feeders with extruded commercial feed for carnivore fish. The experiment lasted 90 days, corresponding to the autumn and winter seasons. Feeding frequency and period interacted on the frogs’ average weight (AW) values. At the end of the experiment, in the daytime and daytime/nighttime periods, there was no difference of the AW values between the evaluated feeding frequencies; however, in the nighttime period, the frogs’ AW was greater for the frequency of 48 meals/day. Separately, the feeding frequency and period influenced the result of apparent feed conversion ratio (FCR) which was better with the frequency of 96 meals/day with average value of 2.13, and average value of 2.23 at nighttime. There was no difference between the treatments regarding the coefficient of apparent digestibility of dry matter, crude protein and crude energy. The coefficients of apparent availability of calcium and phosphorus were higher with the feeding frequency of 48 meals/day, regardless of the feeding period. The results showed that bullfrogs can be fed at daytime as well as at nighttime and that the highest feeding frequencies improved FCR in the production of this species. For bullfrog rearing in cages, it is recommended feeding frequency of 96 meals/day at daytime and daytime/nighttime periods and 48 meals/day at nighttime.