Feeding level in the period previous to the late fattening phase influences fat composition at slaughter in free-ranged Iberian pigs

A group of 11 pigs was fed with 70 g feed per kg of metabolic weight ( H pigs) and another group of 11 pigs was fed with 50 g feed per kg of metabolic weight ( L pigs). In both experimental groups ( H and L pigs), it was observed that the higher initial proportion of C16: 0, C18: 0 and C18: 2 (n-6) in backfat at the beginning of the free-range feeding period, the greater decrease rate of these fatty acid proportions regarding weight gain during the free-range fattening period took place. On the other hand, the greater initial proportion of C18: 1 (n-9), the smaller increase rate in the concentration of this fatty acid was observed. The intramuscular neutral lipids from L pigs had higher C18: 3 (n-3) and lower proportions of monounsaturated fatty acids (MUFA) than those from H pigs, while intramuscular polar lipids from L pigs had significantly higher proportions of C18: 0, PUFA, C18: 3 (n-3) and (n-3) and significantly lower MUFA and C18: 1 ( n-9) proportions than those from H pigs. The alpha-tocopherol concentration found in Longissimus dorsi from L pigs was significantly higher (p<0.012) than those from H pigs.