Feasibility, accuracy and safety of a percutaneous fine-needle biopsy technique to obtain qualitative muscle samples of the lumbar multifidus and erector spinae muscle in persons with low back pain.

The lumbar muscular system, in particular the lumbar multifidus muscle (LM) and the erector spinae muscle (ES), plays an important role in stabilizing and mobilizing the lumbar spine. Based on the topography, the lumbar paraspinal muscles can be classified into local and global muscles. LM is part of the local system, whereas ES is part of the global system. Therefore, it is interesting to investigate the muscle fibre type composition in both muscles. There is accumulating evidence that nonspecific chronic low back pain is associated with lumbar muscle dysfunction. To further elucidate this lumbar paraspinal muscle dysfunction, it is important to understand the structural characteristics of individual muscle fibres of LM and ES. Muscle fibre type composition can be investigated in muscle tissue samples. So far, muscle samples are taken by using invasive procedures that are not well tolerated. The aim of this article was to evaluate the feasibility, accuracy and safety of a percutaneous fine-needle biopsy technique to obtain muscle samples from LM and ES in persons with nonspecific chronic low back pain and to evaluate the feasibility of performing immunofluorescence analysis of myosin heavy chain isoform expression to investigate muscle fibre type composition. Preliminary investigations in cadavers were performed to determine the optimal vertebral level and puncture site to obtain muscle samples of LM and ES through a single skin puncture. In 15 persons with nonspecific chronic low back pain, muscle samples of LM and ES were taken under local anaesthesia with the percutaneous fine-needle biopsy technique, preceded by determination of the puncture site with ultrasonography. Muscle fibre type composition was investigated using immunofluorescence analysis of myosin heavy chain expression. The subjects reported little or no pain and were willing to repeat the procedure. The obtained muscle tissue contained transverse-sectioned muscle fibres in which muscle fibre contractile characteristics of the paraspinal muscles could be evaluated with immunofluorescence analysis of the myosin heavy chains. We can conclude that percutaneous microbiopsy appears to be feasible and accurate, and safe to use to obtain muscle tissue from the paraspinal muscles. The use of ultrasonography to determine the puncture site is necessary to ensure biopsy of the correct muscles and to ensure the safety of the procedure.

Restricted maternal nutrition and supplementation of propylene glycol, monensin sodium and rumen-protected choline chloride during late pregnancy does not affect muscle fibre characteristics of offspring.

BACKGROUND: Grazing in arid and semi-arid regions faces pregnant ewes with feed restrictions and hence affects the offspring muscle fibre characteristics. Using feed additives that enhance nutrient availability during foetal muscle development is expected to alter offspring skeletal muscle characteristics. OBJECTIVES: This study evaluated the effect of maternal restricted nutrition and supplementation of propylene glycol, monensin sodium and rumen-protected choline chloride on lamb's muscle fibre characteristics. METHODS: Forty-eight Ghezel ewes were randomly allocated to one of six diets (N = 8) during the last 6 weeks of gestation: ad libitum feed intake (AL); restricted feeding (RF); restricted feeding containing propylene glycol (PG); restricted feeding containing propylene glycol and monensin sodium (MS); restricted feeding containing propylene glycol and rumen-protected choline chloride (RPC); restricted feeding containing propylene glycol, monensin sodium and rumen-protected choline chloride (PMC). The muscle samples were obtained from the semitendinosus muscle of 2-week-old male lambs (n = 5/treatment) via biopsy and were stained and classified as fibre types I, IIA and IIB. RESULTS: Pre-parturient maternal feed restriction and administration of propylene glycol, monensin sodium and rumen-protected choline chloride had no significant effect on fibre-type composition, fibre density of muscle, muscle cross-sectional area and volume density of fibres (p > 0.05). CONCLUSIONS: Either maternal dietary restriction or supplementation of nutrient flux-involved additives during late pregnancy did not alter muscle fibre development and had no short-term effects on muscle properties of the resulting offspring as myogenesis occurs in early and mid-gestation, not late gestation. Therefore, maternal nutrition may not be a problematic issue in sheep production in arid and semi-arid areas.

Genetic correlation between biopsied and post-mortem muscle fibre characteristics and meat quality traits in swine.

Muscle fibre characteristics (MFCs) are related to lean meat production and meat quality. We newly estimated the heritability and genetic correlation of MFCs and meat quality in biopsied and post-mortem meat samples of 595 Jeju black pigs (JBPs). The cross-sectional area (CSA) (Type I: 0.76 and Type IIA: 0.89), % MF area (MFA) (Type I: 0.82), and % MF number (MFN) between the biopsied and post-mortem samples had high absolute genetic correlation coefficients. Moreover, the genetic correlation between the biopsied samples and drip loss (MFN of Type I: -0.77), lightness (CSA of Type I: 0.56), colour score (MFA of Type IIB: -0.79), and marbling score (CSA of Type IIB: 0.84 and MFA of Type IIA: -0.42) were moderate to high. Therefore, the MFCs of biopsied pre-mortem samples could predict the post-mortem MFCs and quality of the meat. Consequently, the biopsy method could be useful for the estimation of MFCs and meat quality in live JBPs.

Effect of Animal Age at Slaughter on the Muscle Fibres of Longissimus thoracis and Meat Quality of Fresh Loin from Iberian × Duroc Crossbred Pig under Two Production Systems.

Two production systems and several ages at slaughter were used: 12, 14 and 16 months for outdoor rearing (with the final finishing phase in the Montanera system, in which fed was based on natural resources, mainly acorns and grass) and 8, 10 and 12 months for animals reared indoors (intensive system: with feed based on commercial fodder) to evaluate their effect on the muscle fibre population and size of the Longissimus thoracis, (LT) muscle, as well as fresh loin quality traits. Animals that were older at slaughter revealed increased fibre sizes of the LT muscles in the pigs reared in the Montanera system. The LT muscles of the animals reared in intensive systems had a lower percentage of type I fibres and higher size of type IIB than those reared in the Montanera system. The approximate composition and instrumental colour of Montanera fresh loins were affected by the animal slaughter age. In the case of the intensive system, the effect of animal slaughter age had an impact on the approximate composition, instrumental colour, water loss and textural properties. Therefore, different ages at slaughter of Iberian pigs showed variations in some quality parameters in the fresh loins in both the Montanera and Intensive systems, thus proving to be a factor of variability and homogeneity of the Iberian products. The meat from Iberian pigs reared in an intensive system and slaughtered at a younger age proved to be more tender. The production system affected all the above quality traits, with the exception of water loss.