Heterogeneous growth of bullfrog tadpoles fed with different diets

This work tested the performance and growth variability (heterogeneous growth) of Rana catesbeiana tadpoles fed with isocaloric food constituted of four levels of crude protein: three experimental levels (33.6%, 26.6% and 22.5%), and one commercial feed (46.5%). The tadpoles were kept, during three months, in containers with capacity for 1,000 L supplied with running water at density of one tadpole U. The tadpoles were fed twice a day with ad libitum portions, and submitted to the body weight records every fifteen days. The group fed with commercial food (46.5% crude protein) showed better biomassa performance, however the heterogeneous growth was elevated, with body member's deformations in some individuals (27% of tadpoles of the total tadpole-initiated metamorphosis, and 5% at the end). Tadpoles fed with 33.6% and 26.6% of crude protein had similar growth, less heterogeneous growth and did not show body deformations, indicating that these protein concentration might be more adequate than the commercial one. Food with 22.5% of crude protein showed to be inadequate for the nutritional needing of the tadpoles, so it was excluded from the experiment, in order to preserve the animals from injury and death.