Effect of long-term selection for increased leanness on meat and eating quality traits in Duroc swine1

Abstract

A study was conducted to evaluate differences in meat and eating quality traits between purebred Duroc pigs sired by boars currently available and pigs sired by boars from the mid 1980s. Two lines were developed by randomly allocating littermate and half-sib pairs of females to matings by current time period (CTP) or old time period (OTP) boars. Matings by CTP boars were made using fresh semen, and matings by OTP boars were via frozen semen. All available barrows and randomly selected gilts were sent to a commercial abattoir and used for meat and eating quality evaluation. A total of 178 pigs from 23 CTP sires and 99 pigs from 15 OTP sires, across 2 replications and at a mean live weight of 109 kg, were slaughtered and analyzed. Chemical intramuscular fat percentage was determined by lab analysis of a slice from the LM at the 10th rib. Additional meat and eating quality traits measured on the LM were Minolta reflectance and Hunter L color (24 h); pH (24 h and 7 d); water-holding capacity; subjective visual scores for color, marbling, and firmness (48 h); Instron tenderness; cooking loss; and trained sensory panel evaluations (7 d). Time period differences were assessed by use of a mixed model that included fixed effects of sire time period, replication, sex, contemporary group, and the interaction of sex x time period. The random effect of dam and the random effect of sire nested within time period were also included. Loins from pigs sired by OTP boars had greater intramuscular fat (3.48 vs. 3.09%) and visual marbling scores (3.54 vs. 3.07), required less Instron force (5.31 vs. 5.98 kg) to compress, and had darker visual color scores (4.09 vs. 3.87) compared with loins from pigs sired by CTP boars (P < 0.05). No differences were observed between time periods for Minolta reflectance, Hunter L (24 h), water-holding capacity, pH (24 h and 7 d), or subjective firmness scores. Trained sensory evaluations revealed more pork flavor and less off-flavor (P < 0.05) for OTP-sired pigs; however, no differences in tenderness score, juiciness score, chewiness score, or cooking loss were found between lines. Long-term selection response in carcass composition has been at the expense of meat and eating quality traits.

The inclusion of Duroc breed in maternal line affects pork quality and fatty acid profile

“…have also occurred (Sosnicki, Pommier, Klont, Newman, & Plastow, 2003). Therefore, quantifying the effect that long-term intensive selection for increased carcass leanness has had on meat quality characteristics, some researchers (Schwab, Baas, Stalder, & Mabry, 2006) have recommended that selection practices should emphasise on pork quality (in addition to lean percentage) in commercial breeding programmes. For this reason, maintaining acceptable meat quality in the pork industry is becoming a relevant issue.…”

The Longissimus and Semimembranosus Muscles Display Marked Differences in Their Gene Expression Profiles in Pig

“…Breeding programs aiming at improving pig production efficiency through increased growth rate and lean meat content and decreased fatness have also affected some meat quality traits playing an important role in consumer acceptance of pork like water holding capacity, color, intramuscular fat (IMF) content and tenderness [1]. Meat quality is a complex trait which depends on the interactive effects of pig genotype, environmental conditions, pre-slaughter handling and slaughtering procedure [2].…”

Predictive markers in calpastatin for tenderness in commercial pig populations1,2

“…Unfortunately, recent intense selection for increased lean growth has resulted in reduced meat quality and issues with consumer acceptance (Schwab et al, 2006). Although pork quality is not directly an economically important trait, demand is ultimately determined by consumer preference, and selection for pork quality would increase consumer acceptance and benefit the pork industry.…”