New findings in the searching of an optimal diet for the axolotl Ambystoma mexicanum: protein levels.

Objective: To determine the protein nutritional requirements in juvenile axolotls, for this purpose, four isocaloric diets (8 % lipids) with 30, 35, 30 and 45 % protein were prepared. Design/methodology/approach: Six axolotls were used per test, during a period of 81 days. The diets were prepared using fishmeal as a protein source and fish oil as a lipid source. The feed was supplied every 48 hours with 4% of the weight of the biomass of organisms per experimental reservoir. Four biometries were performed throughout the experiment and growth parameters were determined: height, weight gained per day, specific growth rate, survival, Fulton's K, and protein efficiency rate. The digestibility of each of the diets was also determined. Results: There were significant differences (p> 0.05) in the growth and survival of the axolotls, the diet with 45% protein showed the best growth results. Limitations/Implications: No more protein levels could be tested, due to the number of organisms available for bioassays. Findings/conclusions: Diets for A. mexicanum containing 45% protein level promote good development and survival. This allows for improved cultivation and management plans for the species. [ABSTRACT FROM AUTHOR]