Starch ou fat intake on digestibility, energetic metabolism and health of tortoises (Chelonoidis carbonaria)

Abstract

Tortoises are reptiles that in captivity exhibit metabolic disorders, such as Obesity and Hepatic Lipidosis, due to be fed with unbalanced and high energy diets. The present study aims to evaluate the intake, nutrient digestibility, gastrointestinal transit time, fermentation products formation, serum parameters of fat metabolism, histopathological aspects of the liver tissue and the energy metabolism of adult tortoises fed with extruded diets high in starch, high in fiber or high in fat. Fourth-two adult clinically healthy tortoises will be used, distributed in three extruded foods (high fiber, high starch, and high fat), totaling 14 repetitions (tortoises) per treatment. The experimental period will last 12 months, and will include: blood collection for hematological, biochemical and fat metabolism analysis at day 1 (baseline), days 182 to 183 and days 360 to 361 (final); liver biopsy for histopathological evaluation in six tortoises per food at baseline (days 2 and 3) and at the end of the study (days 362-365); determination of experimental food preferences, gastrointestinal transit time, digestibility, and fecal concentration of volatile fatty acids, lactate, ammonia and pH (day 60 to 160); determination of basal energy expenditure and heat increment on respirometric chambers (days 240 to 300); daily energy expenditure, body water composition and body water flow by the double labeled water method (days 300 to 340). The data will be submitted to analysis of variance and the means compared by the Tukey test (P <0.05). (AU)