Lipids performance of biopsies from the subcutaneous back tissue of Iberian pig along montanera fattening period

Iberian pigs fattened at montanera (free-range fattening phase, with diet based on grass and Quercus acorns) products are the most recognized from dehesa, because their high contents in unsaturated fatty acids. Spanish regulation establishes an official method to separate commercial categories depending of fattening period feed. Fatty acid profile evolution during fattening period helps stockmen to organize grazing and to decide slaughter date. In this study 120 pure breed Iberian pigs have been studied using the "Spring loaded biopsy" method for in vivo biopsy; obtaining 1.45 ± 0.28 g of tissue at the beginning of montanera (1 st day) and 1.26 ± 0.68 g one month later. Fat was extracted by microwave to obtain 0.83 ± 0.17 g and 0.73 ± 0.23 g from the first and second biopsy respectively. A regression model has been obtained to predict the amount of extracted fat knowing biopsies weigh (EF=-0.218+0.767*BW first biopsy and EF=0.046+533*BW in the second). The amounts of fat obtained are enough for individual fatty profile analysis following the official methods of analysis.