C.J. López Bote

Prediction of body composition of Iberian pigs by means bioelectrical impedance

Twelve barrow Iberian pigs with an average weight at slaughter of 109.2kg were used to evaluate bioelectrical impedance procedures to predict the body composition of live pigs. Twelve hours before slaughter pigs were weighed, and a four-terminal body composition analyser (Model BIA-101, RJL Systems, Detroit, MI) was utilized to determine resistance (R(s) in Ω) and reactance (X(c) in Ω). The length values (L in cm) were measured between detector electrodes with a flexible steel tape. Twenty four hours after slaughter the left side of each carcass was separated using a scalpel into fat, lean, bone and skin. Multiple regression equations for estimating lean, fat, bone and skin amounts and lean, fat, bone and skin proportions with respect to slaughter weight were calculated. The live weight (LW) and L independent variables predicted 85.3% and 64.3% of the variability of the lean amount and lean proportion, respectively. The LW, X(c) and L variables accounted for 96% and 91.6% of the variation in fat quantity and fat proportion, respectively. The LW and R(s) accounted for 58.9% of the variation in bone amount, and the same variables predict 79.1% of the variability of bone percentage. The R(s) and L variables explained 68% of the variability of skin quantity and LW, R(s) and X(c) predicted 83.1% of the variation of skin proportion. Results from this experiment indicate that bioelectrical impedance may be of interest for body composition prediction of live Iberian pigs.

Carcass traits and fatty acid composition of subcutaneous, intramuscular and liver fat from Iberian pigs fed in confinement only with acorns or a formulated diet.

Twenty castrated male Iberian pigs were divided into two groups of 10 pigs each according to the experimental diet received daily during the fattening period in confinement (acorn fed ad libitum or 4 kg of a formulated diet rich in C18:1 n—9). Dietary effects on performance, carcass characteristics and backfat, intramuscular, and liver fatty acid composition were assessed. Pigs fed only with acorns ate less, leading to a lower growth performance and carcass quality than pigs fed the formulated diet. Pigs fed acorns had lower C16:0 proportions in outer, inner, and subinner subcutaneous backfat layers. The C18:1 n—9 proportions in the inner and subinner subcutaneous backfat layers were higher in pigs fed acorns than in those fed the formulated diet. Pigs fed acorns had higher C18:2 n—6 proportion than those fed the formulated diet in outer subcutaneous backfat layer. The diet did not affect outer, inner, and subinner subcutaneous backfat melting points. Except a higher C18:0 in intramuscular fat polar lipids and higher C16:1 n—9 in the liver polar lipid fraction in pigs fed acorns, the diet had no significant effect on intramuscular and liver fatty acid composition.

FATTY ACID COMPOSITION OF DIFFERENT ADIPOSE TISSUES IN HEAVY PIGS

Forty-seven castrated male Duroc x (Landrace x Large White) pigs were used to determine fatty acids compositions from different adipose tissues. The outer subcutaneous backfat layer had a lower proportion of saturated and higher monounsaturated and polyunsaturated fatty acids than the inner layer. Liver fat had the highest proportion of polyunsaturated fatty acids. Intramuscular fat followed by subcutaneous backfat had the highest monounsaturation indexes. Moreover, omental and hepatic fat had the highest amount of n-3 fatty acids. In conclusion, the fatty acid profile was depended on fat location, with intramuscular and outer backfat the most beneficial from the point of view of nutrition and health.