Dosage haut débit des lipides intramusculaires de la viande de porc par imagerie par résonance magnétique
Résumé
In all animal species, the amount of fat and its distribution within body compartments determine both the productive efficiency and quality of meat, including sensory acceptability and potential benefits for human nutrition. Among the characteristics of the pig muscle that predict these qualities, the level of intramuscular fat (IMF) is the most commonly used because of its high heritability and its strong mean genetic correlation with overall acceptability of the meat. For example, the specifications for fresh meat under the French “Label Rouge” set the desirable level of IMF at 3% in the loin. The determination of intramuscular fat is based on meticulous and time-consuming standard chemical extraction methods. In this work, we validated a reliable and accurate magnetic resonance imaging (MRI) method to determine IMF content and distribution in intact pig muscle samples using very limited sample preparation and image analysis by comparison with a standard chemical extraction method and two physical methods, the near infrared transmittance and a self-calibrated nuclear magnetic resonance NMR relaxometry. IMF values obtained through MRI matched well with those obtained by the NMR technique with a standard error of calibration of 0.18% and by the Soxhlet extraction technique and the NIT technique, with an identical standard error of calibration of 0.25%. This high throughput MRI method is able to scan 24 samples simultaneously and to determine the IMF content of more than 500 samples per day.