The relationship of oxidative and glycolytic capacity of longissimus dorsi muscle to meat quality when different pig breeds and crossbreeds are compared

Abstract

The oxidative and glycolytic capacities as well as the calcium release and uptake of sarcoplasmic reticulum and mitochondria of longissimus dorsi (LD) from seven pig breeds or crosses, i.e. Landrace, Yorkshire, Hampshire, Hampshire x (Yorkshire x Landrace), Duroc x (Yorkshire x Landrace), Landrace x (Yorkshire x Landrace), and Yorkshire x (Yorkshire x Landrace), were studied. These muscle properties were compared to meat quality. No studies concerning oxidative capacity or calcium metabolism of Finnish Landrace and Yorkshire pigs have been published before. To determine the oxidative capacity of the LD muscle, the activities of citrate synthase and 3-hydroxyacyl-CoA-dehydrogenase as well as the mitochondrial volume density were measured. To elucidate the glycolytic capacity of the LD muscle, lactate, glycogen, the glycolytic potential as well as activity of glycogen phosphorylase and lactate dehydrogenase (LDH) were measured. Also the content of LDH isoenzymes were determined. The muscle quality of Landrace and Yorkshire was similar. The LDH activity was lower in the Hampshire cross LD and higher in the Duroc cross LD than in either Landrace or Yorkshire. There were no other differences between breeds. Lower lactate and higher glycogen levels were noted in the Hampshire cross LD as compared to the Duroc cross LD. In Duroc cross and Hampshire muscle, the proportion of LDH-1 was higher and LDH-5 lower than in most other breeds. Higher glycolytic potential, but lower ultimate pH and LDH activity were noted in the Hampshire breed. In Hampshire and its cross, the ultimate pH was lower than in other breeds or crosses. The activities of 3-hydroxyacyl-CoA-dehydrogenase and citrate synthase were higher in Hampshire than in the other breeds. Calcium uptake of sarcoplasmic reticulum and mitochondria as well as mitochondrial calcium release were lower in crosses than in purebred pigs. The redder the meat color (measured instrumentally), the higher the oxidative capacity and the glycolytic potential was. There was no correlation between the glycolytic potential and the sensory quality of meat. The LD of Hampshire was the most oxidative. High muscle oxidative capacity seemed to improve meat flavor and juiciness. This study concerned only the pig LD, so the results can not be generalised to the whole pig. The muscle properties of Hampshire and Duroc crosses were quite similar to those of Landrace and Yorkshire in most of properties studied, but not in the LDH isoenzyme distribution. There was a great interindividual heterogeneity, in properties studied, in every breed and cross.