In VivoDetermination of Body Composition in Zebrafish (Danio rerio) by Quantitative Magnetic Resonance

Abstract

Zebrafish (Danio rerio) as a model research organism continues to expand its relevance and role in multiple research disciplines, with recent work directed toward models of metabolism, nutrition, and energetics. Multiple technologies exist to assess body composition in animal research models at various levels of detail (tissues/ organs, body regions, and whole organism). The development and/or validation of body composition assessment tools can open new areas of research questions for a given organism. Using fish from a comparative nutrition study, quantitative magnetic resonance (QMR) assessment of whole body fat and fat-free mass (FFM) in live fish was performed. QMR measures from two cohorts (n = 26 and n = 27) were compared with chemical carcass analysis (CCA) of FM and FFM. QMR was significantly correlated with chemical carcass values (fat, p < 0.001; lean, p = 0.002), although QMR significantly overestimated fat mass (FM) (0.011 g; p < 0.0001) and underestimated FFM (-0.024 g; p < 0.0001) relative to CCA. In a separate cross-validation group of fish, prediction equations corrected carcass values for FM ( p = 0.121) and FFM ( p = 0.753). These results support the utilization of QMR-a nonlethal nondestructive method-for cross-sectional or longitudinal body composition assessment outcomes in zebrafish.

Validation of Body Condition Indices and Quantitative Magnetic Resonance in Estimating Body Composition in a Small Lizard

“…QMR overcomes all these issues, as live, conscious individuals are simply placed in the QMR machine for a very brief scan (∼2.5 min). Moreover, QMR is highly accurate and precise in quantifying lean, fat, and water mass in small mammals (Johnson et al., ; Jones et al., ; McGuire and Guglielmo, ), birds (Guglielmo et al., ), and small fish (Fowler et al., ), and we see similar accuracy reported here in a small lizard. Indeed, slopes of the relationship between values from CCA with values from QMR scans were nearly 1 for each body component.…”

“…Quantitative magnetic resonance (QMR) was developed for quantifying body fat and lean mass in small mammals used primarily in medical research, and in studies of nutrition and obesity (Taicher et al., ; Johnson et al., ; Schwartz et al., ). Validation studies of this method in rodents, bats, birds, and fish demonstrate that it is accurate and precise (Johnson et al., ; McGuire and Guglielmo, ; Guglielmo et al., ; Fowler et al., ). QMR is based on the principles of nuclear magnetic resonance, which uses radio waves to manipulate how nuclei of atoms spin in order to identify the molecules being tested (Taicher et al., ).…”

Dietary methionine restriction: Effects on glucose tolerance, lipid content and micro-RNA composition in the muscle of rainbow trout

“…At time of analysis total viscera was weighed for calculation of viscerosomatic indices (VSI) as well as individual liver for calculation of hepatosomatic indices (HSI). Individual liver and muscle samples were analyzed for total lipids using an adaptation of the protocol described by Fowler et al (Fowler et al, 2016). Briefly, livers were freeze dried for 48h until attainment of stable weight before being minced and weighed for triplicate samples (~150mg) placed into individual 40ml glass vials.…”

Influence of Commercial and Laboratory Diets on Growth, Body Composition, and Reproduction in the ZebrafishDanio rerio

“…Total lipid content was determined gravimetrically with a protocol of the Folch lipid extraction procedure 38 optimized for zebrafish. A detailed description of this protocol can be found in a previous publication by Fowler et al 39 Females analyzed for total lipid content were ovariectomized before storage at -80°C. Weights for total lipid content and female gonads were recorded to 0.0001 g.…”