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Functional anatomy and intestinal morphometry of bullfrog tadpoles subjected to a dietary regime with commercial feeds

Anatomia funcional e morfometria do intestino de girinos de rã-touro submetidos a regime alimentar com rações comerciais

ABSTRACT

One of the main hindrances to frog farming is the lack of knowledge of the nutritional requirements of tadpoles that allow nutritionists to formulate the ideal diet for this phase, reducing operational costs and providing homogeneity to the shoal. This study aimed at evaluating the anatomy of the digestive tract and morphometry of the midgut and hindgut of bullfrog (Lithobates catesbeianus) tadpoles to provide subsidies for nutritionists to make adjustments in the balancing of suitable diets for this species. The population of tadpoles that received the dietary regimen named DR3, which consisted of a fortnight increase of the dietary protein levels (from 32 to 45% of CP) for 60 days, showed the best results regarding weight gain, survival rate, and homogeneity in the passage of the larval stages as compared with the other dietary regimens tested. Additionally, the morphometry of the intestines of the animals subjected to DR3 showed a greater length (419.2 mm) and higher caliber of the midgut portion where most of the nutrient absorption takes place. It can thus be inferred that this fact is related to the height of the absorptive intestinal folds resulting from the supply of a diet with better quality, confirmed by the weight of the juveniles.

Index terms:
Amphibians; feed and feeding; frog nutrition; nutritional requirement; protein

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