Muscle histochemical and biochemical properties in relation to meat quality during selection for increased lean tissue growth rate in pigs1

Abstract

The relationship between the histochemical and biochemical properties of muscle and the quality of meat during selection to improving the lean tissue growth rate was studied. Pigs (n = 82) from Generations 2 and 4 were randomly sampled in a selection experiment in which the genotype x protein interaction was studied. Comparisons were made of longissimus muscle (LM) and quadriceps femoris (QF) from Generations 2 and 4, and biceps femoris (BF) in the fourth generation from pigs fed a low- or high-protein diet. A higher total growth rate, lean tissue growth rate, and lean percentage were found in pigs fed the high-protein diet than in pigs fed the low-protein diet. Pigs fed the high-protein diet had a higher glycolytic capacity in all muscles than pigs fed the low-protein diet. When the meat quality traits were compared, pigs fed the high-protein diet had a lower intramuscular fat content, higher shear force value, higher protein extractability, lower light reflectance, and somewhat higher water-holding capacity. With selection, pigs became fatter on both diets. In Generation 4, glycolytic and oxidative capacity was somewhat higher in muscle tissue than in Generation 2. Muscle metabolic profile and meat quality traits differed among muscles (LM, BF, QF) but no pronounced differences were found between generations. No marked changes were observed in Type I, IIA, or IIB fibers, either between diets or between generations. The Type IIC fibers could only be identified in Generation 4.

The Asp298Asn missense mutation in the porcine melanocortin-4 receptor (MC4R) gene can be used to affect growth and carcass traits without an effect on meat quality

“…Divergent selection for lean growth rate or efficiency of feed conversion can result in similar responses in carcass composition, but can have different effects on meat quality traits (Cameron et al, 1999). In contrast to ours, the increased ADG was not accompanied by changes in LMP in the studies of Karlsson et al (1993) and Oksbjerg et al (2000). In our study, higher ADG was associated with lower LMP, mainly due to a higher fat thickness.…”

“…For instance, numerous studies have reported the positive effect of the halothane genotype on carcass lean content and conformation; however, this positive effect was often accompanied by a negative effect on meat quality traits (De Smet et al, 1995 andLeach et al, 1996). Also in other studies aiming at increasing lean tissue growth by selection or by feeding strategies, a decrease in meat quality was noticed (Karlsson et al, 1993;Oksbjerg et al, 2000). On the other hand, the IGF-2 mutation shows that selection for increased LMP does not have to have unfavourable effects on meat quality (Van den Maagdenberg et al, 2005 and unpublished results).…”

The effect of genotype on muscle fibre characteristics of m. longissimus lumborum of fatteners

“…Differences in fibre types composition observed in present study between three different crossbreeds of fatteners appear similar to those reported earlier by Karlsson et al (1993) and Larzul et al (1997), in which authors have demonstrated that muscle fibre composition and size is specific for different pig breeds or lines. Ruusunen and Puolanne (1997) found that Pig muscles with many oxidative fibres tolerate stressful conditions better during transport, resulting in a slower fell in pH after slaughter.…”

“…According to Essen-Gustavsson and Fjelkner-Modig (1985) muscle oxidative capacity affects meat quality by improving the sensory properties of meat. Moreover, evidence from the literature (Karlsson et al, 1993;Koch et al, 1995) indicates that muscle characteristics and particularly fibre type frequency may be an important source of variation in eating quality. However, the influence of fibre type on meat tenderness is not fully understood.…”

“…Histological and histochemical investigations on pig muscles have revealed relationships between fibre traits and meat quality, such as pH, water-holding capacity, colour and meat tenderness (Essen-Gustavsson and Fjelkner-Modig, 1985;Karlsson et al, 1993;Koch et al, 1995;Ryu and Kim, 2005;Lefaucheur 2006).…”