Long-term changes in performance and meat quality of Danish Landrace pigs: a study on a current compared with an unimproved genotype

Abstract

An experiment was conducted in 1995 in order to examine muscle growth, muscle histochemical properties, muscle metabolism and meat quality of two types of Danish Landrace pigs representing the growth potential of years 1976 and 1995, respectively. Danish Landrace pigs representing 1976 (slow-growing, SG) originated from a breeding station where the population was maintained without being selected for production traits such as daily gain, food conversion ratio and meat content. Pigs representing Danish Landrace of 1995 (fast-growing, FG) were bought from certified Danish pig breeders. The pigs were simultaneously tested for performance from 40 to 95 kg live weight. The daily gain, food conversion ratio and meat content of the carcass were improved proportionately by 0·43, 0·24 and 0·03 in FG pigs compared with SG pigs. In m. longissimus dorsi (LD), the cross-sectional area of muscle fibres was smaller in FG pigs compared with SG pigs indicating increased muscle fibre number. Data further suggest increased satellite cell proliferation in muscles of FG pigs. Serum from FG pigs stimulated the proliferation of C2C12 muscle cells to a greater extent than serum from SG pigs, although the serum level of insulin-like growth factor 1 did not differ between pig types. The effect of serum on protein turn-over of C2C12 myotubes did not depend on pig type. The glycogen concentration in the LD did not differ significantly between pig types, while the activity of citrate synthase, 3-OH-acyl-CoA-dehydrogenase, and lactate dehydrogenase were higher in the LD of SG pigs compared with FG pigs. Pork chop colour of FG pigs was proportionately 0·09 lighter (L⋆) and 0·13 less red (a⋆) than pork chops of SG pigs. The total muscle pigment concentration in the LD, m. biceps femoris and m. vastus intermedius was proportionately reduced by 0·17, 0·19 and 0·11, respectively, in FG pigs compared with SG pigs. In the LD, the concentration of myoglobin was proportionately reduced by 0·17 in FG pigs. The chemical composition of the LD differed between pig types such that the water content was higher and protein content lower in LD from FG pigs compared with SG pigs. The pH of the LD measured 45 min and 24 h post mortem, drip loss and thawing loss were similar for both pig types. Meat tenderness of conditioned pork chops of FG pigs was slightly reduced in accordance with a decreased intensity of the 31 kDa peptide band and increased cooking loss. The present study suggests that increased muscle fibre number and rate of muscle DNA deposition (satellite cell proliferation) have contributed to the increased muscle growth as a result of selection for performance in pigs under Danish conditions. However, the increase in growth performance was accompanied by deterioration in muscle colour and slightly reduced tenderness.

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).…”

Reactive oxygen species are important mediators of taurine release from skeletal muscle cells

“…The myoblast cell line (C2C12), originally derived from the thigh muscle of the mouse (Ref. 44; American Type Culture Collection, Manassas, VA), was prepared, grown, and differentiated for experiments as described previously (34).…”

Compensatory growth feeding strategy does not overcome negative effects on growth and carcass composition of low birth weight pigs

“…DNA and RNA concentration in the LM and STM dark Muscle samples of the LM and STM dark collected within 30 min after exsanguination were assayed for DNA and RNA concentration as described by Oksbjerg et al (2000). The DNA content was measured fluorometrically by a picogreen dsDNA quantitation reagent kit (Quant-iT™ PicoGreen ® dsDNA Assay Kit, P7589, Life Technologies Europe B.V., Zug, Switzerland).…”