Recria e engorda de rã-touro (lithobates catesbeianus) em sistema de produção semi-inundado e inundado

Abstract

The present study aimed to evaluate the productive performance and the welfare of the bullfrog (Lithobates catesbeianus) in two production systems, semi-flooded and flooded, during the rearing and fattening phases. Experiment I lasted 30 days and 600 bullfrog froglets (5.48 ± 0.57 g) were used, randomly distributed in six pens of 1.22 m², three pens in a flooded system and three pens in a semi-flooded system, at a stocking density of 100 froglets/pen. Experiment II lasted 120 days and 204 bullfrogs (37.85 ± 1.55 g) were used, randomly distributed in six 1.22 m² pens, three in a flooded system and three in a semi-flooded system, in stocking density of 34 frogs/pen. In experiment I, both the zootechnical performance and the proportion of animals per size range were statistically equal (p>0.05) between the two systems. In experiment II, frogs reared in a flooded system had greater weight gain, specific growth rate, protein efficiency rate and better feed conversion (p<0.05). The animals raised in flooded pens had a higher (p<0.05) percentage of medium animals – 150 to 250 g, while the semi-flooded system had a higher (p<0.05) percentage of small animals – <150 g. There was no difference (p>0.05) between the types of pens on the percentage of large animals – >250 g. There was no interaction (p>0.05) between the type of pen and the sex of the animals on any of the performance variables evaluated. Regardless of sex, animals raised in flooded pens had a higher (p<0.05) liposomal index. On the other hand, only females reared in flooded pens had a higher (p<0.05) gonadosomatic index. Regardless of the system, females had higher (p<0.05) viscerosomatic index. Males had higher (p<0.05) carcass and legs yields. There was no influence (p>0.05) of the type of pen on the erythrogram and white blood cell count of the frogs. Frogs reared in flooded pens showed higher levels of triglycerides and total cholesterol (p<0.05). On the other hand, the type of pen did not influence (p>0.05) the levels of glucose, lactate, total proteins, albumin, globulins and the albumin/globulins. Therefore, although the type of pen did not influence the growth of froglets during the rearing phase, it is recommended that bullfrogs be fattened in a flooded pen, as the animals raised in this type of system presented better productive performance and did not have their homeostasis altered.