Böswald LF et al. (2024), Investigations on Xenopus laevis body compositi...

XB-ART-60722

Sci Rep 2024 Apr 25;141:9517. doi: 10.1038/s41598-024-59848-0.

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

Böswald LF , Matzek D , von La Roche D , Stahr B , Bawidamann P , Popper B .

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.

PubMed ID: 38664518
PMC ID: PMC11045782
Article link: Sci Rep

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References [+] :

Anzeraey, The effect of food properties on grasping and manipulation in the aquatic frog Xenopus laevis. 2017, Pubmed, Xenbase

	Figure 1. (A) Exponential relationship between body length (cm) and body weight (g) and (B) a linear relationship between the log-transformed parameters.
	Figure 2. Body weight and BCS measures of cohort I and II. (A) Body weight of the frogs in cohort I in trial 2 at baseline and after feeding the respective diets (A-C). (B) Body condition score (BCS) of cohort I at the end of the feeding trials. (C) Body weight of the frogs in cohort II in trial 2 at baseline and after feeding the respective diets (A-C). (D) Body condition score (BCS) of cohort II at the end of the feeding trials.
	Figure 3. Heat maps of cohort I and II before and after feeding. Video monitoring was performed relative to the meals (Sinking and Floating (Diet A), Floating (Diet B), Sinking (Diet C)) as follows: t0 = -5 min to 0 min; t1 = 0 to + 10 min; t2 = + 10 to + 20 min; t3 = + 20 to + 25 min for cohort I (A–C) and II (D–F). Cohort I/II consisted of 10 animals per tank. The frequency of movement (active vs. inactive) is given as grey values.
	Figure 4. Fanning behavior of cohort I and II (trial 2) at different time points. Video datasets were analyzed at t1 = 0 to + 10 min; t2 = + 10 to + 20 min; t3 = + 20 to + 25 min to quantify the animals fanning events. Cohort I/II consisted of 20 animals per tank. The bars represent means, whiskers the standard error of the mean (SEM) ** is p < 0.01.