Age-related changes and nutritional regulation of myosin heavy-chain composition in longissimus dorsi of commercial pigs

Abstract

The objective of this study is to investigate the age-related changes of and the effects of dietary conjugated linoleic acid (CLA) on muscle-fibre types in commercial pigs. We divided 25 crossbred male pigs into five age groups (7, 30, 60, 100 and 180 days) and 30 finishing pigs into two dietary groups (one fed a CLA-enriched diet and the other fed a control diet for 30 days). We analysed the composition (%) of myosin heavy-chain (MyHC) mRNA according to the absolute copies of each MyHC (I, IIa, IIb and IIx) mRNA, and the activities of succinate dehydrogenase (SDH) and malate dehydrogenase (MDH) in the longissimus muscle. From days 7 to 180, the MyHC I mRNA abundance and SDH and MDH activities presented a decreasing trend, the MyHC IIb mRNA abundance presented a steady trend and the MyHC IIa and IIx mRNA abundances presented an increasing trend. On day 30, MyHC I and IIb mRNA abundances were at their lowest (P , 0.05), and the MyHC IIa and IIx mRNA abundances were at their highest (P , 0.05). In the CLA group, the MyHC I mRNA abundance and the activities of SDH and MDH were improved in the longissimus muscle, whereas pressure loss, drip loss and average back fat depth significantly decreased (P , 0.01) and shear force significantly increased (P , 0.01). Loin eye area, feed conversion rate and meat colour showed some tendency to be improved. These results indicated that more oxidative fibres might convert to glycolytic fibres with increasing age or weight, and that the early developmental stage might be a key stage for this conversion. During the finishing stage, the proportion of oxidative fibres might be increased by dietary CLA supplementation, which may contribute to the water-holding capacity of meat. The results would provide an important basis for the application of muscle-fibre types in the improvement of pork quality.

Effect of maternal or post‐weaning methyl donor supplementation on growth performance, carcass traits, and meat quality of pig offspring

“…It is therefore possible that the increase in muscle fiber size and the percentage of type II fibers in the LD muscle of pigs directly contribute to skeletal muscle growth and performance at day 180. It was also reported that oxidative fibers (MyHC‐I, MyHC‐IIa) are converted to glycolytic fibers (MyHC‐IIx, MyHC‐IIb) with age in skeletal muscles, and that the early developmental stage might be a key stage for their conversion . Maternal MET supplementation during gestation and lactation may affect muscle fiber conservation in early development.…”

Transfer of β-hydroxy-β-methylbutyrate from sows to their offspring and its impact on muscle fiber type transformation and performance in pigs

“…In addition, research has suggested that MyHC-IIb is the determining fiber contributing to the differentiation of large and small muscle area in the pig, and high muscularity is positively correlated with a high abundance of MyHC-IIb transcript [31], and more oxidative fibers might convert to glycolytic fibers with increasing age or weight, and that the early developmental stage might be a key stage for this conversion [32]. In this experiment, we found that maternal HMB treatment during lactation greatly increased MyHC-IIb mRNA and fast-MyHC protein levels in LD of the offspring at weaning and finishing stages (Figs.…”

Effects of dietary supplementation with carnosine on growth performance, meat quality, antioxidant capacity and muscle fiber characteristics in broiler chickens

“…Nowadays, nutritional strategy has been identified as an effective means to improve meat quality. Dietary supplementation with α ‐lipoic acid and sodium butyrate in poultry can enhance antioxidant capacity, while conjugated linoleic acid supplementation in pigs can increase the ratio of type I fiber …”

“…Dietary supplementation with -lipoic acid and sodium butyrate in poultry can enhance antioxidant capacity, 6,7 while conjugated linoleic acid supplementation in pigs can increase the ratio of type I fiber. 8 Carnosine, a natural dipeptide composed of L-histidine and -alanine, was first found in beef extract 9 and exists in nearly all body organs, though mainly in the skeletal muscle. 10 Carnosine can be synthesized from L-histidine and -alanine under the action of carnosine synthase.…”