AN EVALUATION OF ULTRASOUND AND NUCLEAR-MAGNETIC-RESONANCE SPECTROSCOPY TO MEASURE IN-VIVO INTRAMUSCULAR FAT-CONTENT OF LONGISSIMUS MUSCLE OF PIGS

Intramuscular fat content (IMF) of longissimus muscle of pigs growing from approximately 20 to 100 kg was measured in vivo using biopsies af ter complete or localized anaesthesia, ultrasound and H-1 nuclear magn etic resonance (NMR) technology. Three lines of pigs, with 60 animals each, were available. Biopsies were taken from the same pigs at 20, 60 , and 100 kg, and fat was extracted for gravimetric determination. At 20 kg, ultrasound images mere collected, and in vivo H-1 NMR spectrosc opy was applied. A-mode ultrasound measurements were collected at 60 a nd 100 kg. The overall mean value of IMF was 1.60 +/- .56% at 20 kg, 1 .53 +/- .50% at 60 kg, and 1.71 +/- .60% at 100 kg. Interactions betwe en lines and body weight were observed. No statistically significant d ifferences were found between methods at 20 kg. No significant correla tions were found between the A-mode ultrasound measurements and the me an values of the gravimetric measurements. No visible pain or infectio ns were observed in relation to the collection of a single biopsy. The ultrasound method in combination with image analysis is advantageous fi om the labor point of view and will also improve welfare of pigs in case of repeated sampling. However, further research is necessary to make the technology sufficiently reliable. A correlation between IMF a nd backfat thickness was not found.