Flatbed Scanning as a Novel Approach for Examining Lipid Distribution in Fish: Comparison with MRI and Traditional Chemical Methods

Depending upon species, the concentration and distribution of lipid in fish flesh impacts both processing requirements and eating quality. Dispersal of lipid within fish muscle may be manipulated by diet, feeding strategy, and through selective breeding. Several methods are currently used to examine lipid deposition in fish, but these are either arduous, costly, or reliant upon noxious chemicals. The need exists for a rapid, inexpensive, and safe method for examining lipid distribution in fish flesh. A technique that satisfies the preceding criteria was developed. Fish cutlets were stained with oil red O, scanned, and the images saved in 600 dpi *.tiff format. Oil red O was employed to differentiate muscle tissue from lipid. Cutlets were examined using computer-assisted image analysis and lipid presence in each cutlet recorded in percent terms. The results were compared to data generated from the same cutlets using Magnetic Resonance Imaging to separate muscle from lipid. No differences were detected between methods with regards to lipid distribution, which followed an anterior to posterior decline in the body. Lipid dispersal did not differ with gender. Estimates of total lipid in scanned images were identical to those recorded using chemical analysis.