The Journal of Nutrition Vol. 127 No. 8 August 1997, pp. 1501-1507
Copyright ©1997 by the American Society for Nutritional Sciences

Dietary Fiber Influences Nutrient Utilization, Growth and Dry Matter Intake of Green Iguanas (Iguana iguana)

Manuscript received 21 January 1997. Initial reviews completed 12 February 1997. Revision accepted 15 April 1997.

David J. Baer^{*, , ,} , Olav T. Oftedal^*, William V. Rumpler, and Duane E. Ullrey

^* National Zoological Park, Department of Zoological Research, Washington, DC 20008;  USDA, ARS, BARC-East, Beltsville Human Nutrition Research Center, Diet and Human Performance Laboratory, Beltsville, MD 20705; and  Department of Animal Science, Comparative Nutrition Group, Michigan State University, East Lansing, MI 48824

Herbivory is an uncommon feeding strategy in lizards. Appropriate diet formulations for captive lizards should be based on performance measures, yet few data are available on the effect of plant fiber on food intake, nutrient utilization and growth of captive herbivorous lizards. This study was conducted to determine the effect of three levels of dietary fiber on dry matter intake, nutrient and energy metabolizability and growth rate of the green iguana (Iguana iguana). Twenty-one captive iguanas were fed nutritionally complete diets containing three levels of dietary fiber: 19, 24, and 27% neutral detergent fiber. The iguanas were fed each diet for at least 12 wk, and total excreta were collected for 11.3 ± 4.0 d (means ± SEM, range of 7 to 25 d). Diets and excreta were analyzed for dry matter, organic matter, gross energy, neutral detergent fiber, acid detergent fiber, and acid detergent lignin. The study was designed as a Latin square crossover. Across all diets, dry matter intake was proportional to body mass^1.0 (BM). Growth rate was greater (P < 0.05) when iguanas were fed the low and medium fiber diets (2.2 and 2.4 g/d, respectively) than when fed the high fiber diet (1.4 g/d). However, mean daily dry matter intake of the three diets [7.2 g/(d·kg BM)] was not different. In general, digestibility of fiber fractions and the metabolizability of dietary energy decreased (P < 0.05) as the level of dietary fiber increased. These data suggest that a diet containing less than 27% neutral detergent fiber should be fed if rapid growth is to be sustained during intensive captive production of green iguanas.