Commercial diets for the bullfrog (Rana catesbieana) showed pathology at 16% protein and good
health and growth at 23% protein (Coppo and Mussart, 2005). Martínez et al. (2004) showed that
Rana perezi juveniles showed the best growth and health when fed trout fodder with a composition of
46% protein, 22% lipids, and 13.5% carbohydrates. 45% protein was found the optimum for R.
catesbieana tadpoles (Carmona-Osalde et al., 1996). There is probably only a negligible amount of
calorific value in carbohydrates from amphibian diets. Amphibians fed diets with excessive fibre have
developed intestinal blockage, but the effects of the amounts of digestible carbohydrate is unknown
(McWilliams, 2008).