Selection for reduced muscle glycolytic potential in Large White pigs I. Direct responses

Abstract

A six-generation selection experiment comprising a selected (S) and a control (C) line has been conducted with the objective of decreasing muscle glycolytic potential in purebred French Large White pigs. Both lines consisted of six to eight sires and about 40 dams per generation, and each dam produced two litters. The selection criterion in the line S was the in vivo glycolytic potential (IVGP) of the Longissimus (ld) muscle, measured on a shot-biopsy sample removed at 75 kg live weight on boars and gilts from first-parity litters. In addition, the post mortem glycolytic potential (PMGP) of ld, semime!n6ranosus (sm) and semispinalis capitis (sc) muscles was recorded on pigs from second-parity litters slaughtered at 100 kg live weight. Throughout the experiment, 2 981 and 454 animals were recorded for IVGP and PMGP, respectively. A consistent decrease in IVGP and, to a lesser extent, in PMGP was obtained in the line S compared with the line C. Estimates of genetic changes per generation were -0.18, -0.11, -0.07 and -0.09 SD units of the trait for IVGP and PMGP of ld, sm and sc muscles, respectively. The REML heritability estimates were 0.25 ! 0.02, 0.15 f 0.06, 0.14 ± 0.06 and 0.17 ! 0.05 for the above four traits, respectively. The REML estimate of genetic correlation of IVGP with PMGP ld (0.87 f 0.15) was somewhat higher than those of IVGP with PMGP of sm and sc (0.56 iL 0.14 and 0.68 t 0.13, respectively). It is concluded that downward selection on muscle glycolytic potential may be effective in pigs. © Inra/Elsevier, Paris pig / muscle glycolytic potential / selection experiment / genetic parameters

Glycolytic Potential in Semimembranosus Muscle of Italian Large White Pigs

“…Correlations between GP and EBVs for daily gain and feed : gain ratio were weak and not significant, confirming previous results obtained in a French Large White population free from the RN ‐ allele (Le Roy et al. 1998).…”

Effects of Live Animal Sampling Procedures and Sample Storage on the Glycolytic Potential of Porcine Longissimus Muscle Samples

“…However, Femandez et al (1992) reported that lactate content in longissimus biopsy samples taken from the live animal was low, indicating that glycogenolysis occurred to a limited extent prior to sampling and during storage. Although a number of studies have measured glycolytic potential in muscle samples obtained from the live animal (Fernandez et al 1992;Estrade et al 1993;LeRoy et al 1998;Larzul el al. 1999), there is limited information on the impact of animal handling procedures before and during sampling and of the effect of sample preparation and storage prior to assay on GP values.…”