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

Abstract

A promising tool to improve daily gain in pigs is the missense mutation (Asp298Asn) in the melanocortin-4 receptor (MC4R) gene, especially in the Belgian pig industry where the slow-growing Pié train breed is very frequently used as the sire breed. The MC4R is expressed in the appetite-regulating region of the brain where it regulates feed intake and energy balance. The mutation has been associated with differences in fatness, daily gain and feed intake. However, less information on the correlated effects on meat quality is available. In order to evaluate the influence of the MC4R mutation on carcass and meat quality parameters, a total of 1155 pigs of a four-way cross were slaughtered at an average live weight of 109 kg, and data about daily live-weight gain, carcass and meat quality were collected. Allelic frequencies were 0.69 for the G-allele (298Asp variant or well-conserved variant) and 0.31 for the A-allele (298Asn variant or the mutated variant). Barrows and gilts were almost equally distributed in this population with, respectively, 49.9% and 50.1%. Moreover, independent of this mutation, the relationship between average daily gain (ADG) and carcass on the one hand and meat quality traits on the other hand was evaluated in this population. A significant positive influence of the MC4R mutation on ADG (P , 0.001) was found, accompanied by a higher fat thickness (P , 0.05) and a lower carcass lean meat content (P , 0.01), whereas muscle thickness and carcass conformation traits were not affected. The effects on meat quality traits were not significant, except for a lower shear force (P 5 0.054) and a higher intramuscular fat content (P 5 0.052) in AA animals. In the longissimus, pH and pork quality meter (PQM) values were not influenced, and effects on drip loss and colour were not apparent. Residual correlation coefficients between ADG and carcass lean meat content on the one hand and meat quality traits on the other hand were generally very low (| r|.0.1). Higher ADG, higher carcass fat thickness and lower carcass lean meat content were correlated with slightly lower shear force values (| r| , 0.1, P , 0.05). In conclusion, in the studied population, the Asp298Asn mutation in the MC4R gene was associated with improved daily gain, higher carcass fatness and almost no effect on meat quality traits.

Effect of missense mutation Asp298Asn in MC4R on growth and fatness traits in commercial pig crosses in the Czech Republic

“…Although this study did not detect a significant influence on any traits of fatness, in agreement with Park et al (2002), Meidtner et al (2006) and Van den Maagdenberg et al (2007) it can be assumed that the A allele corresponds with increased fatness. This assumption was demonstrated by several studies which indicated a significant influence of A allele on backfat thickness (Kim et al, 2000b;Hernández-Sánches et al, 2003;Houston et al, 2004;Fan et al, 2009).…”

“…Several authors have reported a similar association of the Asp298Asn polymorphism of the MC4R gene with fatness and growth traits in pigs with different backgrounds (Kim et al, 2000b;Houston et al, 2004;Jokubka, 2006;Óvilo et al, 2006;Van den Maagdenberg et al, 2007;Fan et al, 2009). The authors also noted that the mutation c.746G>A of the MC4R gene is considered useful for markerassisted selection.…”

“…G allele correlated with higher values of IMF in Polish Landrace. Van den Maagdenberg et al (2007) reported that the GG genotype had a lower IMF content compared with the AA genotype in 1155 pigs (P < 0.05). These findings were confirmed by our study (Table 3).…”

“…The association of the c.746G>A missense mutation with fatness and growth rate has been confirmed in several populations of pigs with different genetic backgrounds (Kim et al, 2000b;Houston et al, 2004;Jokubka et al, 2006;Óvilo et al, 2006;Van den Maagdenberg et al, 2007;Fan et al, 2009). …”

SNPs detected in the yak MC4R gene and their association with growth traits

“…Moreover, significant associations were found between MC4R genotypes and backfat, growth rates and feed intake in some breeds or lines of livestock animals. A functional mutation (Asp298Asn) was associated with daily food intake, growth and fat deposition traits in some commercial pig lines (Hernandez-Sanchez et al, 2003;Houston et al, 2004;Van den Maagdenberg et al, 2007). Variants (−293C > G and −129A > G) in the 5′-untranslated region of the bovine MC4R gene were associated with two growth traits in Nanyang cattle breed (Zhang et al, 2009).…”