Animal-intrinsic variation in the partitioning of body protein and lipid in growing pigs

Abstract

AbstractBody composition in the pig, and its variation, is mostly referred to in terms of body protein and lipid content of the whole body. This study was made to check for animal-intrinsic variation in the partitioning of body protein into protein pools and of body lipid into lipid depots. Results from serial slaughter trials on 316 Danish Landrace and 76 Danish Yorkshire pigs were used to estimate additive genetic and litter-associated variance components for several traits. These traits were total body protein and lipid mass (TOTPROT and TOTLIPD), the proportions of total body protein that are present in the muscles (PROTMUS) or in the (sub-)cutaneous tissue plus bones (connective tissue protein, PROTCON), and the proportions of total body lipid that are present in the (sub-)cutaneous tissue (LIPDSUB), in the muscles (inter- and intramuscular fat, LIPDMUS), or in the bones (LIPDBON). TOTPROT and TOTLIPD were adjusted by regression for body weight; PROTMUS and PROTCON were adjusted for PROTCON, and LIPDSUB, LIPDMUS and LIPDBON were adjusted for TOTLIPD. The pooled estimates (± s.e.) of the degree of genetic determination (the sum of the additive genetic and litter-associated variance components, which approximates the repeatability) of these traits were 0·48 ± 0·19 for TOTPROT, 0·56 ± 0·20 for TOTLIPD, 0·56 ± 0·12 for PROTMUS, 0·57 ± 0·15 for PROTCON, 0·32 ± 0·10 for LIPDMUS, 0·33 ± 0·12 for LIPDSUB, and 0·22 ± 0·10 for LIPDBON. It is concluded that there is animal-intrinsic variation in partitioning of body protein and lipid.