# Investigations on Xenopus laevis body composition and feeding behavior in a laboratory setting

## TL;DR

This study explores the body composition and feeding behavior of African clawed frogs in a lab to improve their care and feeding practices.

## Contribution

The study introduces a digital tracking system to analyze feeding behavior and provides insights into adjusting feeding regimens for animal welfare.

## Key findings

- No significant differences in allometric data or nutrient contents were found between diet groups.
- Body fat content increased with body weight, indicating energy reserves.
- Feeding activity peaked within 20 minutes after a meal, influenced by diet type.

## Abstract

The African clawed frog, Xenopus laevis, has been used as a laboratory animal for decades in many research areas. However, there is a lack of knowledge about the nutritional physiology of this amphibian species and the feeding regimen is not standardized. The aim of the present study was to get more insights into the nutrient metabolism and feeding behavior of the frogs. In Trial 1, adult female X. laevis were fed either a Xenopus diet or a fish feed. After 4 weeks, they were euthanized, weighed, measured for morphometrics and dissected for organ weights and whole-body nutrient analysis. There were no significant differences between the diet groups regarding the allometric data and nutrient contents. The ovary was the major determinant of body weight. Body fat content increased with body weight as indicator of energy reserves. In Trial 2, 40 adult female frogs were monitored with a specifically developed digital tracking system to generate heat-maps of their activity before and up to 25 min after a meal. Three diets (floating, sinking, floating & sinking) were used. The main feed intake activity was fanning the feed into the mouth, peaking until 20 min after the meal. The different swimming characteristics of the diets thereby influenced the activity of the animals. Our dataset helps to adjust the feeding needs to the physical composition and also to meet the natural behavioral patterns of feed intake as a prerequisite of animal wellbeing and animal welfare in a laboratory setting.