Genetic parameter estimates of meat quality traits in Duroc pigs selected for average daily gain, longissimus muscle area, backfat thickness, and intramuscular fat content

Abstract

Using a multitrait animal model BLUP, selection was conducted over seven generations for growth rate (ADG), real-time ultrasound LM area (LMA), backfat thickness (BF), and intramuscular fat content (IMF) to develop a new line of purebred Duroc pigs with enhanced meat production and meat quality. This selection experiment examined 543 slaughtered pigs (394 barrows and 153 gilts) from the first to the seventh generation for meat quality traits. Further, electric impedance and collagen content of loin meat were measured from the fourth to sixth generation. The present study was intended to estimate genetic parameters of the correlated traits of tenderness (TEND), meat color (pork color standard: PCS; lightness = L*), drip loss (DL), cooking loss (CL), pH (PH), electric impedance (IMP), and collagen (COL) of the LM, and the genetic trends of these traits. Respective heritability estimates for IMF, TEND, DL, CL, PCS, L*, PH, IMP, and COL were 0.39, 0.45, 0.14, 0.09, 0.18, 0.16, 0.07, 0.22, and 0.23. Genetic correlations of IMF with ADG and BF were low and positive, but low and negative with LMA. Tenderness was correlated negatively with ADG (-0.44) and BF (-0.59), but positively correlated with LMA (0.32). The genetic correlation between LMA and DL was positive and high (0.64). The genetic correlations of TEND with IMF and COL were low (-0.09 and 0.26, respectively), but a moderate genetic correlation (0.43) between COL and IMF was estimated, suggesting related increases of IMF and connective tissue. Genetic correlations among meat quality traits suggested that when IMF increases, the water holding capacity improves. Genetic trends of meat quality traits showed increased IMF and lighter meat color.

Genetic parameters of meat quality traits in two pig breeds measured by rapid methods

“…The heritabilities estimated for IMF were in good agreement with previously reported estimates published by Hovenier et al (1992), de Vries et al (1994 and Suzuki et al (2005), who used chemical analyses, and Hermesch et al (2000a) and Kadarmideen et al (2004), who used NIR for the IMF measurements, as in this study. In addition, heritabilities estimated for marbling were lower in two studies using marbling as a method for measuring IMF (Sonesson et al, 1998;van Wijk et al, 2005).…”

“…The Duroc estimate was similar to the highest values reported in earlier studies (Hermesch et al, 2000a;Suzuki et al, 2005;van Wijk et al, 2005), while the Landrace estimate was much higher. Common to the study reporting the highest heritability (Hermesch et al, 2000a) and our study was a fixed effect for all the animals tested at the same time, which had a large effect on the heritability estimate in our study (in spite of good routines for calibration).…”

“…A negative genetic correlation between lightness and IMF was reported by Hovenier et al (1992), and positive genetic correlations were reported by Hermesch et al (2000b) and Suzuki et al (2005). Suzuki et al (2005) studied a Duroc population with a high level of IMF (4.25%), and found that meat with higher IMF was lighter in colour. Muscles with high levels of IMF are usually more oxidative than muscles with low levels, since oxidative muscles use more fat in metabolism (Essé n- Gustavsson and FjelknerModig, 1985).…”

“…Our results are in agreement with heritability estimates for drip loss published by Hovenier et al (1992), who used a filter paper method, and also with those of de Vries et al (1994) and Hermesch et al (2000a), who both used a bag method. Lower heritability estimates were found by Suzuki et al (2005), who used loin chops hanging from a wire in specimen cases, and by van Wijk et al (2005), who used a method similar to the EZ-DripLoss method. All methods for the determination of drip loss are relatively sensitive to variations in operator and procedure.…”

Genomic selection in a pig population including information from slaughtered full sibs of boars within a sib-testing program

“…Repetitions and heritability For each method, the whole simulation process (editing of data, variance components, marker effect estimation and calculation of BVs) was repeated twice considering the following two different types of traits: (1) traits with intermediate heritability (0.40) -for example, carcass traits or average daily gain; (2) traits with low heritability (0.10) -for example, for several meat quality parameters such as the average values for pH or cooking losses (Suzuki et al, 2005). Samorè, Buttazzoni, Gallo, Russo and Fontanesi…”