Effects of Pig Dietary n-6/n-3 Polyunsaturated Fatty Acids Ratio and Gender on Carcass Traits, Fatty Acid Profiles, Nutritional Indices of Lipid Depots and Oxidative Stability of Meat in Medium-Heavy Pigs.

The effects of different dietary n-6/n-3 polyunsaturated fatty acids (PUFA) ratios and gender on key carcass traits, as well as the nutritional and technological quality of lipids in medium-heavy pig tissues have been poorly studied. To investigate the subject, 24 Large White, barrows and gilts, evenly divided into two groups of 12, were fed from 80 kg of live-weight (LW) until slaughter at 150 kg LW, either a high (9.7:1) (HPR) or low (1.4:1) (LPR) dietary n-6/n-3 PUFA ratio. On individual samples of longissimus thoracis muscle (LTM), subcutaneous (SF) and perirenal (PF) adipose tissues (ATs), the fatty acid (FA) composition was determined by gas chromatography, and lipid nutritional indices (LNIs) were calculated. The oxidative stability of meat was evaluated by determining the malondialdehyde content on raw and cooked (24 h postmortem) and refrigerated (8 days postmortem) LTM samples. The carcass traits did not vary between genders and diets. The LPR group showed a higher n-3 PUFA level and a lower n-6/n-3 PUFA ratio in all the tissues examined and better LNI, especially in the ATs. Diet did not affect the oxidative stability of meat. Gender did not influence the n-6/n-3 PUFA ratio, while barrows showed improvements in some LNI in ATs. Reducing the n-6/n-3 ratio in the diet of growing-finishing medium-heavy pigs improved the FA profile in all tissues and most LNI in ATs without impairing the oxidative stability of meat.

Calculating the iodine value for Italian heavy pig subcutaneous adipose tissue from fatty acid methyl ester profiles.

In this work, different equations were compared as for their effectiveness in predicting the iodine value (IV), based on fatty acid (FA) composition of subcutaneous adipose tissue of Italian heavy pigs. In particular, six equations were tested: AOCS (1); modified AOCS (2), including all unsaturated FA (UFA); regression models obtained using the stepwise regression procedure as variable selection method, calculated considering only UFA (3) or all the FA (4); regression models obtained using the backward elimination procedure, calculated considering only UFA (5) or all the FA (6). The comparison of the equations performance, estimated using an external test set, showed that the use of regression models led to significant enhancements of prediction accuracy with respect to the AOCS equations. Using both equations 4 and 6, the average paired differences between experimental and predicted IV values were not statistically significant. Therefore, it is possible to use these equations for IV estimation of the subcutaneous adipose tissue of Italian heavy pigs.