Genetics of Pig Meat Quality: A Review

Abstract

This paper is a review of current knowledge about genetic effects on technological and eating qualities of pork. These effects have been recognized as primordial sources of variation of meat quality in the porcine species. Nevertheless, some significant advances have recently been obtained in this area. This literature survey reveals that: The halothane sensitivity gene (HALn) explains to a large extent the overall genetic variation in technological quality and eating quality of pork. Evidence is accumulating that the halothane sensitivity gene is not completely recessive regarding its effects on quality traits. Producing slaughter pigs heterozygous at the HAL locus may result in deficiencies in meat quality, probably depending on slaughter conditions and perhaps also on slaughter weight. Breed differences in technological and sensory qualities of pork partly result from the large breed variation in incidence of halothane sensitivity, but other factors are implied, particularly ultimate pH and intramuscular fat content of meat. The major dominant gene RN‐is probably at the origin of the previously described “Hampshire effect” on meat quality. Heritability of most traits referring to the technological quality of meat is low to moderate (0.15 to 0.30), whereas heritability of intramuscular fat content is high (0.40 to 0.50). A genetic antagonism exists between technological quality of pork and growth or body composition traits. The halothane sensitivity gene is the major factor responsible for the “meat quantity — meat quality” genetic antagonism.

Comparison between the three porcine RN genotypes for growth, carcass composition and meat quality traits

“…On the whole, preceding hypotheses [7,22,23,30,33] concerning the implication of the RN gene in the occurrence of the "Hampshire effect" are fully supported by these new observations. On the other hand, the present comparison including homozygous carrier animals allows confirmation of the complete dominance of the RN − allele for most physico-chemical characteristics of meat, e.g.…”

Comparison of PRKAG3 and RYR1 gene effect on carcass traits and meat quality in Slovenian commercial pigs

“…The recessive "n" allele at RYR1 gene influences the rate of pH fall by favouring the calcium release in muscle cells (Gueblez et al, 1995;De Smet et al, 1996;Larzul et al, 1997;Monin et al, 1999;Fisher et al, 2000). On the other hand, dominant allele RN -induces high glycogen levels in αW muscle fibres (Marinova et al, 1992;Čandek-Potokar et al, 1999) and consequently low ultimate pH (Le Roy et al, 1990;Sellier and Monin, 1994;Le Roy et al, 2000). In many breeding schemes these causative mutations were preserved due to their beneficial impact on leanness (Pommier et al, 1992;Leach et al, 1996;Hamilton et al, 2000;Le Roy et al, 2000).…”

A genome-wide analysis of the ultimate pH in swine

“…Glycolysis is a very important factor in PM contribution to meat quality characteristics. Even though criteria for PM pH level are not clear, several studies have proposed that the threshold of pH 24 to differentiate PSE (pale, soft, and exudative) meat from normal meat is less than 5.5 (Sellier and Monin, 1994;Forrest, 1998);5.7 (van Laack et al, 2001); 5.69 (Kusec et al, 2005); and 5.8 (Sellier and Monin, 1994). However, studies have also reported that PM metabolism of glycogen can vary depending on environmental factors, such as elevated metabolism at slaughter (Rosenvold and Andersen, 2003), and PM meat chilling (Tomovic et al, 2008).…”

“…Although studies have not characterized how many genes, or what kinds of genes may be responsible for changes in PM pH, utilization of genetic markers in pig populations are ideal tools for animal production systems, in terms of pH levels (Sellier and Monin, 1994).…”