Compositional and enzymatic characteristics of the Longissimus Dorsi muscle from large white, halothane-positive and halothane-negative pietrain, and hampshire pigs

The rs196952262 Polymorphism of the AGPAT5 Gene is Associated with Meat Quality in Berkshire Pigs

High-quality meat is of great economic importance to the pig industry. The 1-acylglycerol-3-phosphate-O-acyltransferase 5 (AGPAT5) enzyme converts lysophosphatidic acid to phosphatidic acid in the mitochondrial membrane. In this study, we found that the porcine AGPAT5 gene was highly expressed in muscle tissue, influencing meat characteristics, and we also identified a non-synonymous single-nucleotide polymorphism (nsSNP) (rs196952262, c.673 A>G) in the gene, associated with a change of isoleucine 225 to valine. The presence of this nsSNP was significantly associated with meat color (lightness), lower cooking loss, and lower carcass temperatures 1, 4, and 12 h after slaughter (items T1, T4, and T12 on the recognized quality scale, respectively), and tended to increase backfat thickness and the water-holding capacity. These results suggest that nsSNP (c.673A>G) of the AGPAT5 gene is a potential genetic marker of high meat quality in pigs.

Effects of age and/or weight at slaughter on longissimus dorsi muscle: Biochemical traits and sensory quality in pigs

The effect of increasing either age alone through feed restriction, or both age and weight at slaughter, on the quality of the longissimus dorsi muscle (LM) was investigated. Starting at 83 days of age and 32 kg, 80 pigs were allotted within litter to four experimental groups. All pigs were free of RYR1 mutated gene. Pigs were fed either ad libitum (A100, A130) or restricted 30% (R100, R130) and slaughtered at either 100 kg (A 100, R100) or 130 kg (A130, R130) body weight. Restricting feed intake in order to increase age at the same weight resulted in slower growth, better feed efficiency and increased leanness, whereas increasing age and weight simultaneously elicited slower growth, reduced feed efficiency and fatter carcasses. Intramuscular fat (IMF) and muscle collagen concentration were reduced by restricted feeding. Increase in both age and weight of pigs resulted in lower water, and higher protein and IMF concentrations. Although pigs were free of RYR1 gene, the PSE condition (defined as pH1 ≤ 5.9) developed in 25 carcasses, with a higher incidence in restricted pigs. PSE animals were excluded from the subsequent analysis of meat quality data. Feed restriction resulted in higher drip loss and lower a(∗) and c(∗) (saturation index) values. Longer myofibril fragments in muscle of restricted pigs on day 1 post mortem are indicative of slower maturation, while longer fragments on day 4 in heavier pigs, suggest that the extent of post mortem tenderisation could be negatively affected by the elevation of slaughter weight. Feed restriction had no significant effect on meat sensory quality, whereas increase in both age and weight resulted in lower tenderness, chewiness and mouth coating scores. Our results indicate that increasing age at a given body weight, via feed restriction, reduced IMF and collagen concentrations, and the rate of post mortem proteolysis, however, this had no significant impact on pork quality assessed after 4 days of ageing. On the other hand, increasing both age and weight at slaughter could alter pork texture, in spite of elevated IMF concentration.

Influence of breed and muscle metabolic type on muscle glycolytic potential and meat pH in pigs

Glycolytic potential and activities of myofibrillar ATPase, lactate dehydrogenase, citrate synthase, glycogen synthetases and glycogen phosphorylases were measured in five muscles from five Large White, eight Pietrain, seven Belgian Landrace and eight Penshire pigs (Penshire is a composite line including 50% Hampshire, 35% Duroc and 15% Large White blood). Additionally, ultimate pH was measured on the loin and four ham muscles. Muscles could be classified as follows on the basis of enzyme activities: Longissimus dorsi and Semimembranosus as 'fast white', Rectus abdominis as 'intermediate'. Trapezius and Masseter as 'slow red'. Small breed differences were observed in enzyme activities except for citrate synthase activity and degree of activation of glycogen phosphorylase in the 'fast white' muscles. Large Whites, Pietrains and Belgian Landraces did not differ in glycolytic potential whatever the muscle involved. Compared with these three breeds, Penshires had much higher glycolytic potential values in the 'fast white' muscles (+51 to 75%) and in the 'intermediate' muscle (+29 to 56%). However, in the 'slow red' muscles, there was almost no difference in this trait between the four breeds. The Penshire pigs showed lower ultimate pH than the pigs from the other breeds in three of the four ham muscles studied. It is concluded that muscle metabolic type must be considered when assessing breed variation in glycolytic potential, and that the high muscle glycolytic potential characterizing the Hampshire could be inherited as a dominant trait in Hampshire crosses.

Carcass and meat quality traits of four different pig crosses

The study compared properties of Finnish Landrace×Yorkshire crossbred sows mated with Finnish Landrace (FL), Norwegian Landrace (NL), Norwegian Duroc×Norwegian Landrace (NDL), or Swedish Hampshire (SH) boars. The focus was to study the cross-sectional area of loin, cross-sectional area and number of muscle fibres, loin colour and pH value as well as the ratio of water to protein in the loin. The four studied crosses were quite similar having only small differences in carcass and meat quality. The carcass lean content was the lowest in NDL. The loins of FL and NL were longer than the loins of NDL and of SH. The cross-sectional area of loin was the largest in SH. The loin of FL was lighter in colour and the loin of SH was redder than the loins of the other crosses studied. The protein content was lower and the ratio of water to protein higher in loin of SH than in the other crosses.

Enzyme activities of glycogen metabolism and mitochondrial characteristics in muscles of RN- carrier pigs (Sus scrofa domesticus)

High glycogen content and abnormal mitochondria have been seen in muscles from RN- carrier pigs in a previous work. Glycogen synthase, branching enzyme, phosphorylase and debranching enzyme activities, and mitochondrial characteristics were studied in normal and RN- carrier pigs. Branching enzyme activity was higher (P < 0.01) and glycogen synthase activity tended to be higher in longissimus dorsi muscle from RN- carrier pigs compared to normal pigs. There were no differences in the activities of either phosphorylase and debranching enzyme between both types of pigs. Citrate synthase activity and mitochondrial respiration were slightly higher in muscle from RN- pigs compared to normal pigs. Glycogen content in muscle from RN- pigs could result from the imbalance between anabolic and catabolic enzyme activities of glycogen metabolism. The higher specific activity in mitochondria of RN- pigs muscle might be the compensatory effect of an abnormal glycolytic metabolism.