Growth and body composition in captive Testudo graeca terrestris fed with a high-energy diet

Abstract

Wild populations of Testudo graeca may face extinction due to large demand in the pet trade and habitat loss. Establishment of reproduction farms could alleviate the danger from collection of wild tortoises; management of such farms requires nutritional guidance. Our initial trials resulted in tortoises with soft shell syndrome and gout, due to improper nutrition. These problems were solved by using a high energy, amino acid-balanced diet for hatchlings and young tortoises. This diet also increased growth compared to wild tortoises. We determined changes in body composition with size in order to be able to formulate specific diets according to the nutritional needs of each stage of growth. Water content was about 70% in newly hatched tortoises, increased slightly till they doubled their mass, and thereafter declined gradually, stabilizing at about 60% at a body mass of 170 g. Ash content was 5% at hatching, increased gradually to 15% at 170 g, and remained stable thereafter. Lipid content was about 7% at hatching, due to the residual yolk, declined to a minimum of 2.8% at 94 g, and resumed the level of 7% from 170 g. Sulfur-amino acid levels (methionine and cysteine) were lower than those found in homeotherms; a negative correlation between sulfur and protein contents suggested a substantial sulfur compartment outside of amino acids.