Near-infrared spectrometry : a rapid analytical tool for n-3 polyunsaturated fatty acid measurement on backfat of pig carcass A survey carried out by IFIP among slaughterhouses that are or are not engaged in strategies for improvingthe lipid profile of pork demonstrates the need for a tool for rapid and early determination of the fatty acid profile of a carcass. This work aims to develop models to predict the fatty acid composition, including n-3 polyunsaturated fatty acid (n-3 PUFA) from a near infrared spectroscopy (NIRS) measurement directly on the slaughter line. The infrared measurements were performed on 282 pigs, 50% coming from the Bleu-Blanc-Coeur label (that guarantees higher levels of n-3 PUFA). They were performed on the slaughter line on hot carcass and on the backfat, using a near infrared spectrometer (LabSpec 5000, ASD). The samples were collected and their fatty acid compositions were obtained using gas chromatography. The regression method employed was partial least squares (PLS). The results show that the spectral range 800-1830 nm provides the best predictions. The models developed for C18:3n-3, n-3 PUFA and total PUFA gave the best results (R²= 0.87, 0.86 and 0.86, respectively) with an associated uncertainty of 1.2, 1.5 and 2.8 points and average values of 2.4; 3.2; and 16.2, respectively. For all other fatty acids, the determination coefficients (R²) were lower than 0.75. The results show that it is possible to use NIRS to determine on the slaughter line the n-3 PUFA content of pigs and enable them to be sorted according to quality criteria of fat.