Growth and survival of the axolotl (Ambystoma mexicanum), fed with the probiotic PROBION-forte©, under laboratory conditions.

Abstract
For the present study, the growth and survival of 30 juvenile axolotls of the Ambystoma mexicanum species fed with a probiotic were evaluated. At the beginning of the investigation, the specimens had an average size and weight of 4 ± 0.5 (cm) and 2 ± 0.3 (g) respectively. Throughout the study the organisms were kept in six aquariums with 40 L of fresh water, at a temperature of 15 ± 1 °C, with a natural photoperiod and with 5 axolotls each. The axolotls were fed for 24 weeks with the Tubifex tubifex slimeworm inoculated with 1 X 107 CFU/g with the probiotic PROBION-Forte© (Bacillus subtilis, Bacillus coagulans and Clostridium butyricum). To verify the effect of the probiotic on the organisms, survival, growth (height and weight) as well as their degree of well-being were determined. The results reveal that the specimens fed the enriched diet present a survival of 100% compared to those fed the unenriched diet was 75%. On the other hand, the growth showed significant differences between the two treatments (p