A comprehensive characterisation of the fibre composition and properties of a limb (flexor digitorum superficialis, membri thoraci) and a trunk (psoas major) muscle in cattle

Effects of quality grade and intramuscular location on beef semitendinosus muscle fiber characteristics, NADH content, and color stability

The objective of this study was to determine the impact of quality grade and steak location on color stability of semitendinosus (ST) steaks during a 9-d refrigerated study. Twenty-one ST muscles (12 Choice and 9 Select) were purchased from a commercial beef packing plant and fabricated into twelve 2.54-cm thick steaks per muscle. Steaks 1, 6, and 12 were designated for immunohistochemistry while remaining steak locations of proximal (steaks 2 to 4), middle (5 to 8), and distal (9 to 11) were randomly assigned to 0, 4, or 9 d of simulated retail display. Surface color attributes of day-9 steaks were recorded daily by a visual color panel and spectrophotometer. On days 0, 4, and 9 of display, steaks were analyzed for metmyoglobin reducing ability (MRA) and oxygen consumption (OC). Grade × day of display (DOD) interactions were detected for L*, a*, surface oxymyoglobin (OMb) and metmyoglobin (MMb) percentages, and visual panel surface redness and discoloration scores (P ≤ 0.02); however, no Grade × DOD interactions were observed for MRA or OC (P > 0.17). There were location main effect (LOC) × DOD interactions for L*, a*, surface MMb, visual panel surface redness and discoloration, and MRA (P ≤ 0.02). Distal steaks had lower L* values compared with the other locations (P < 0.01), which coincided with steaks being rated visually darker red (P < 0.01). Proximal steaks had greater a* values and had less surface discoloration than middle steaks (P < 0.05), which had an increased percentage of surface MMb (P ≤ 0.04). Distal and proximal steaks had increased MRA compared with middle steaks on days 0 and 4 (P < 0.05), and distal steaks had greater OC than the other locations throughout display (P < 0.01). There were fewer type I fibers at the proximal end with a greater percentage located at the middle and distal ends, and an increased percentage of type IIX fibers at the middle and proximal locations (P ≤ 0.01). Less type IIA fibers were detected at the middle LOC compared with the other two locations (P < 0.10). Larger type I, IIA, and IIX fibers were located at the proximal and middle locations compared with the distal LOC (P < 0.01). ST color and color-stability characteristics were influenced by DOD and LOC, which may partially be explained by differences in fiber types among locations.

Muscle Fiber Typing in Bovine and Porcine Skeletal Muscles Using Immunofluorescence with Monoclonal Antibodies Specific to Myosin Heavy Chain Isoforms

The aim of this study was to optimize staining procedures for muscle fiber typing efficiently and rapidly in bovine and porcine skeletal muscles, such as longissimus thoracis, psoas major, semimembranosus, and semitendinosus muscles. The commercially available monoclonal anti-myosin heavy chain (MHC) antibodies and fluorescent dye-conjugated secondary antibodies were applied to immunofluorescence histology. Two different procedures, such as cocktail and serial staining, were adopted to immunofluo-rescence analysis. In bovine muscles, three pure types (I, IIA, and IIX) and one hybrid type, IIA+IIX, were identified by the cocktail procedure with a combination of BA-F8, SC-71, BF-35, and 6H1 anti-MHC antibodies. Porcine muscle fibers were typed into four pure types (I, IIA, IIX, and IIB) and two hybrid types (IIA+IIX and IIX+IIB) by a serial procedure with a combination of BA-F8, SC-71, BF-35, and BF-F3. Unlike for bovine muscle, the cocktail procedure was not recommended in porcine muscle fiber typing because of the abnormal reactivity of SC-71 antibody under cocktail procedure. Within the four antibodies, combinations of two or more anti-MHC antibodies allowed us to distinguish pure fiber types or all fiber types including hybrid types. Application of other secondary antibodies conjugated with different fluorescent dyes allowed us to get improved image resolution that clearly distinguished hybrid fibers. Muscle fiber characteristics differed depending on species and muscle types.

Mixing it up: the biological significance of hybrid skeletal muscle fibers

Skeletal muscle fibers are classified according to the myosin heavy chain (MHC) isoforms and other myofibrillar proteins expressed within these cells. In addition to 'pure' fibers expressing single MHC isoforms, many fibers are 'hybrids' that co-express two or more different isoforms of MHC or other myofibrillar proteins. Although hybrid fibers have been recognized by muscle biologists for more than three decades, uncertainty persists about their prevalence in normal muscles, their role in fiber-type transitions, and what they might tell us about fiber-type regulation at the cellular and molecular levels. This Review summarizes current knowledge on the relative abundance of hybrid fibers in a variety of muscles from different species. Data from more than 150 muscles from 39 species demonstrate that hybrid fibers are common, frequently representing 25% or more of the fibers in normal muscles. Hybrid fibers appear to have two main roles: (1) they function as intermediates during the fiber-type transitions associated with skeletal muscle development, adaptation to exercise and aging; and (2) they provide a functional continuum of fiber phenotypes, as they possess physiological properties that are intermediate to those of pure fiber types. One aspect of hybrid fibers that is not widely recognized is that fiber-type asymmetries - such as dramatic differences in the MHC composition along the length of single fibers - appear to be a common aspect of many fibers. The final section of this Review examines the possible role of differential activities of nuclei in different myonuclear domains in establishing fiber-type asymmetries.

Evaluation of muscle tissue and liver glycogen of cattle submitted to transport over long distances and subjected to emergency slaughter

ABSTRACT The study evaluated the effect of transportation over long distances on cattle muscle tissue of submitted to emergency slaughter in slaughterhouses in northern Tocantins, Brazil. The evaluations consisted in pH, muscle and liver glycogen, muscle histopathology and creatine kinase (CK), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity. Animals were placed into two groups: Experimental Group (EG), consisting of 19 bovines intended for immediate emergency slaughter, and Control Group (CG), composed of 24 bovines slaughtered in accordance with the normal flow. CK and ALT levels were high in EG. AST did not differ between groups. EG showed higher muscle pH and mean of degenerate fibers, mainly on the intercostal. However, muscle and liver glycogen did not differ between groups. In conclusion, cattle transported over long distances and subjected to immediate emergency slaughter showed markedly stress condition, with changes in biochemical parameters in the muscle tissue, determined by cellular degeneration.

Effect of Sex and Muscle on the Fiber-Type Composition and Cross-Sectional Area of Springbok (Antidorcas marsupialis) Muscle

This study aimed to compare the fiber-type composition and fiber cross-sectional area (CSA) of male and female springbok (Antidorcas marsupialis) Longissimus thoracis et lumborum (LTL) and Biceps femoris (BF) muscles. Frozen samples from 4 male and 3 female springbok were fiber-typed immunohistochemically using the primary antibodies A4.74, BA-D5 and BF-35. The CSA of the fibers was determined using the software Image J. Type IIX fibers accounted for 64 to 77% of the fibers in all samples, with type IIA (12.7 to 19.1%), type IIAX (6.4 to 9.3%) and type I (2.4 to 8.5%) making smaller (P < 0.001) contributions. Female springboks’ muscles contained more type IIX fibers than males’ (P = 0.004) and the BF contained more type I fibers and fewer type IIA and IIAX fibers than the LTL (P < 0.001). CSA values did not differ between sexes or muscles; however, they increased with apparent fiber glycolytic capacity (I < IIA < IIAX < IIX; P < 0.001). The glycolytic nature suggested by the fiber-type composition of springbok muscle found in this study is in contrast with previous reports on the physicochemical nature of springbok meat. This casts doubt on the application of standard associations between fiber-type and meat quality to this species. However, it may provide some explanation for the low shear force values found for springbok meat in previous studies.

Effect of Sex and Muscle on the Fiber-Type Composition and Cross-Sectional Area of Springbok (Antidorcas marsupialis) Muscle

This study aimed to compare the fiber-type composition and fiber cross-sectional area (CSA) of male and female springbok (Antidorcas marsupialis) Longissimus thoracis et lumborum (LTL) and Biceps femoris (BF) muscles. Frozen samples from 4 male and 3 female springbok were fiber-typed immunohistochemically using the primary antibodies A4.74, BA-D5 and BF-35. The CSA of the fibers was determined using the software Image J. Type IIX fibers accounted for 64 to 77% of the fibers in all samples, with type IIA (12.7 to 19.1%), type IIAX (6.4 to 9.3%) and type I (2.4 to 8.5%) making smaller (P < 0.001) contributions. Female springboks’ muscles contained more type IIX fibers than males’ (P = 0.004) and the BF contained more type I fibers and fewer type IIA and IIAX fibers than the LTL (P < 0.001). CSA values did not differ between sexes or muscles; however, they increased with apparent fiber glycolytic capacity (I < IIA < IIAX < IIX; P < 0.001). The glycolytic nature suggested by the fiber-type composition of springbok muscle found in this study is in contrast with previous reports on the physicochemical nature of springbok meat. This casts doubt on the application of standard associations between fiber-type and meat quality to this species. However, it may provide some explanation for the low shear force values found for springbok meat in previous studies.

Feeding microalgae meal (All-G Rich; CCAP 4087/2) to beef heifers. I: Effects on longissimus lumborum steak color and palatibility

The objective of this study was to examine effects of 4 levels of microalgae meal (All-G Rich, CCAP 4087/2; Alltech Inc., Nicholasville, KY) supplementation to the diet of finishing heifers on longissimus lumborum (LL) steak PUFA content, beef palatability, and color stability. Crossbred heifers ( = 288; 452 ± 23 kg initial BW) were allocated to pens (36 pens and 8 heifers/pen), stratified by initial pen BW (3,612 ± 177 kg), and randomly assigned within strata to 1 of 4 treatments: 0, 50, 100, and 150 g·heifer·d of microalgae meal. After 89 d of feeding, cattle were harvested and LL were collected for determination of fatty acid composition and Warner-Bratzler shear force (WBSF), trained sensory panel evaluation, and 7-d retail color stability and lipid oxidation analyses. Feeding microalgae meal to heifers increased (quadratic, < 0.01) the content of 22:6-3 and increased (linear, < 0.01) the content of 20:5-3. Feeding increasing levels of microalgae meal did not impact total SFA or MUFA ( > 0.25) but tended ( = 0.10) to increase total PUFA in a quadratic manner ( = 0.03). Total omega-6 PUFA decreased (linear, = 0.01) and total omega-3 PUFA increased (quadratic, < 0.01) as microalgae meal level increased in the diet, which caused a decrease (quadratic, < 0.01) in the omega-6:omega-3 fatty acid ratio. Feeding microalgae meal did not affect WBSF values or sensory panel evaluation of tenderness, juiciness, or beef flavor scores ( > 0.16); however, off-flavor intensity increased with increasing concentration of microalgae meal in the diet (quadratic, < 0.01). From d 5 through 7 of retail display, steaks from heifers fed microalgae meal had a reduced a* value and oxymyoglobin surface percentage, with simultaneous increased surface metmyoglobin formation (quadratic, < 0.01). Lipid oxidation analysis indicated that at d 0 and 7 of display, as the concentration of microalgae meal increased in the diet, the level of oxidation increased (quadratic, < 0.01). Muscle fiber type percentage or size was not influenced by the inclusion of microalgae meal in diets ( > 0.19); therefore, the negative effects of microalgae on color stability were not due to fiber metabolism differences. Feeding microalgae meal to finishing heifers improves PUFA content of beef within the LL, but there are adverse effects on flavor and color stability.

Effects of the Programmed Nutrition Beef Program on meat quality characteristics

The objective of this study was to examine the effects of alternative finishing strategies on beef steak color and cooked meat characteristics. Beef steers (n = 64 pens; 8 steers/pen) were allocated to a randomized complete block design with a 2 × 2 factorial treatment arrangement and initial body weight serving as the blocking factor. Factor 1 consisted of dietary treatment with cattle either being fed a conventional feedlot diet (CON) or a diet that included Programmed Nutrition Beef Program supplements. Cattle in the Programmed Nutrition (PN) treatments were fed in two-stages: 1) the basal diet with Programmed Nutrition Beef Receiver from d 1 to 20 and the basal diet with Programmed Nutrition Beef Finisher from d 21 to harvest. Factor 2 consisted of the inclusion (EGP+) or absence (EGP-) of an exogenous growth promoting program. Steers in the EGP+ treatments were implanted initially with Component E-S, reimplanted with Component TE-IS, and fed 400 mg · d(-1) · steer(-1) of ractopamine hydrochloride for the final 28 d before harvest. Steers were harvested on d 175 of feeding and 1 strip loin was removed from 2 carcasses selected at random from each pen for transport to Kansas State University. After 14 d of aging, loins were fabricated into 2.54-cm thick steaks for objective and trained sensory panel measurement of cooked meat characteristics and objective color measurements during 7 d retail display. There were no interactions (P > 0.10) between feeding strategy and exogenous growth promotants for all objective measures of color and cooked meat characteristics. Throughout the display period, PN steaks were darker (P = 0.02) than CON steaks, but surface percentages of oxymyoglobin and metmyoglobin and metmyoglobin reducing ability were unaffected by feeding strategy (P > 0.10). Loins and steaks from PN cattle possessed decreased moisture loss during aging and cooking (P < 0.01). Trained sensory panel evaluation of cooked meat revealed a dietary program × growth promotant interaction for myofibrillar tenderness, connective tissue amount, and overall tenderness (P = 0.01). Compared to the CON/EGP- and PN/EGP- treatments, steaks from the CON/EGP+ and PN/EGP+ treatments were evaluated by panelists as being less myofibrillar and overall tender (P < 0.05). The alternative feeding strategies presented in this study can favorably impact water-holding capacity without negatively compromising retail display discoloration.

In ovo leptin administration accelerates post-hatch muscle growth and changes myofibre characteristics, gene expression and enzymes activity in broiler chickens

To evaluate the effect of maternal leptin on muscle growth, we injected 0 μg (control, CON), 0.5 μg (low leptin dose, LL) or 5.0 μg (high leptin dose, HL) of recombinant murine leptin dissolved in 100 μl of PBS into the albumen of broiler eggs prior to incubation. The newly hatched chicks were all raised under the same conditions until 21 days of age (D21), when body weight was measured and samples of gastrocnemius muscle were collected and weighed. Myosin ATPase staining was applied to identify myofibre types and measure the cross-sectional area (CSA) of myofibres. Real-time PCR was performed to quantify leptin receptor (LEPR), insulin-like growth factor 1 (IGF-1), IGF-1 receptor (IGF-1R), growth hormone receptor (GHR) and myostatin (MSTN) mRNA expression in the gastrocnemius muscle. The activity of calpains (CAPNs) in the gastrocnemius muscle was measured using a quantitative fluorescence detection kit. Male chickens treated with both high and low doses of leptin had significantly higher (p < 0.05) body weight on D21. The high leptin significantly increased the CSA (p < 0.05) of gastrocnemius muscle in male chickens, which coincided with a 93% increase (p < 0.05) in IGF-1 mRNA expression. Likewise, the LL dose increased the weight of gastrocnemius muscle in male chickens (p < 0.05), which was accompanied by a 41% down-regulation (p < 0.05) of MSTN mRNA expression and a decreased activity of CAPNs. However, all these changes were not observed in female chickens. The proportion of myofibre types did not altered. No significant change was detected for LEPR and GHR mRNA expression. These results indicate that in ovo leptin treatment affects skeletal muscle growth in chickens in a dose-dependent and sex-specific manner. The altered expression of IGF-1, MSTN mRNA and activity of CAPNs in skeletal muscle may be responsible for such effects.

Adaptive functional specialisation of architectural design and fibre type characteristics in agonist shoulder flexor muscles of the llama, Lama glama

Like other camelids, llamas (Lama glama) have the natural ability to pace (moving ipsilateral limbs in near synchronicity). But unlike the Old World camelids (bactrian and dromedary camels), they are well adapted for pacing at slower or moderate speeds in high-altitude habitats, having been described as good climbers and used as pack animals for centuries. In order to gain insight into skeletal muscle design and to ascertain its relationship with the llama's characteristic locomotor behaviour, this study examined the correspondence between architecture and fibre types in two agonist muscles involved in shoulder flexion (M. teres major - TM and M. deltoideus, pars scapularis - DS and pars acromialis - DA). Architectural properties were found to be correlated with fibre-type characteristics both in DS (long fibres, low pinnation angle, fast-glycolytic fibre phenotype with abundant IIB fibres, small fibre size, reduced number of capillaries per fibre and low oxidative capacity) and in DA (short fibres, high pinnation angle, slow-oxidative fibre phenotype with numerous type I fibres, very sparse IIB fibres, and larger fibre size, abundant capillaries and high oxidative capacity). This correlation suggests a clear division of labour within the M. deltoideus of the llama, DS being involved in rapid flexion of the shoulder joint during the swing phase of the gait, and DA in joint stabilisation during the stance phase. However, the architectural design of the TM muscle (longer fibres and lower fibre pinnation angle) was not strictly matched with its fibre-type characteristics (very similar to those of the postural DA muscle). This unusual design suggests a dual function of the TM muscle both in active flexion of the shoulder and in passive support of the limb during the stance phase, pulling the forelimb to the trunk. This functional specialisation seems to be well suited to a quadruped species that needs to increase ipsilateral stability of the limb during the support phase of the pacing gait. Compared with other species, llama skeletal muscles are well suited for greater force generation combined with higher fatigue resistance during exercise. These characteristics are interpreted as being of high adaptive value, given the llama's habitat and its use as a pack animal.

Skeletal muscle specific genes networks in cattle

While physiological differences across skeletal muscles have been described, the differential gene expression underlying them and the discovery of how they interact to perform specific biological processes are largely to be elucidated. The purpose of the present study was, firstly, to profile by cDNA microarrays the differential gene expression between two skeletal muscle types, Psoas major (PM) and Flexor digitorum (FD), in beef cattle and then to interpret the results in the context of a bovine gene coexpression network, detecting possible changes in connectivity across the skeletal muscle system. Eighty four genes were differentially expressed (DE) between muscles. Approximately 54% encoded metabolic enzymes and structural-contractile proteins. DE genes were involved in similar processes and functions, but the proportion of genes in each category varied within each muscle. A correlation matrix was obtained for 61 out of the 84 DE genes from a gene coexpression network. Different groups of coexpression were observed, the largest one having 28 metabolic and contractile genes, up-regulated in PM, and mainly encoding fast-glycolytic fibre structural components and glycolytic enzymes. In FD, genes related to cell support seemed to constitute its identity feature and did not positively correlate to the rest of DE genes in FD. Moreover, changes in connectivity for some DE genes were observed in the different gene ontologies. Our results confirm the existence of a muscle dependent transcription and coexpression pattern and suggest the necessity of integrating different muscle types to perform comprehensive networks for the transcriptional landscape of bovine skeletal muscle.

Specific fibre composition and metabolism of the rectus abdominis muscle of bovine Charolais cattle

BACKGROUND

An important variability of contractile and metabolic properties between muscles has been highlighted. In the literature, the majority of studies on beef sensorial quality concerns M. longissimus thoracis. M. rectus abdominis (RA) is easy to sample without huge carcass depreciation and may appear as an alternative to M. longissimus thoracis for fast and routine physicochemical analysis. It was considered interesting to assess the muscle fibres of M. rectus abdominis in comparison with M. longissimus thoracis (LT) and M. triceps brachii (TB) on the basis of metabolic and contractile properties, area and myosin heavy chain isoforms (MyHC) proportions. Immuno-histochemical, histochemical, histological and enzymological techniques were used. This research concerned two populations of Charolais cattle: RA was compared to TB in a population of 19 steers while RA was compared to LT in a population of 153 heifers.

RESULTS

RA muscle had higher mean fibre areas (3350 microm(2) vs 2142 to 2639 microm(2)) than the two other muscles. In RA muscle, the slow-oxidative fibres were the largest (3957 microm(2)) and the fast-glycolytic the smallest (2868 microm(2)). The reverse was observed in TB muscle (1725 and 2436 microm(2) respectively). In RA muscle, the distinction between fast-oxidative-glycolytic and fast-glycolytic fibres appeared difficult or impossible to establish, unlike in the other muscles. Consequently the classification based on ATPase and SDH activities seemed inappropriate, since the FOG fibres presented rather low SDH activity in this muscle in comparison to the other muscles of the carcass. RA muscle had a higher proportion of I fibres than TB and LT muscles, balanced by a lower proportion either of IIX fibres (in comparison to TB muscle) or of IIA fibres (in comparison to LT muscle). However, both oxidative and glycolytic enzyme activities were lower in RA than in TB muscle, although the LDH/ICDH ratio was higher in RA muscle (522 vs 340). Oxidative enzyme activities were higher in RA than in LT muscle, whereas glycolytic enzyme activity was lower. In RA muscle, contractile and metabolic properties appeared to be less well-correlated than in the two other muscles.

CONCLUSIONS

RA muscle has some particularities in comparison to the LT and TB muscles, especially concerning the unusual large cross-section surface of SO fibres and the very low oxidative activity of intermediate IIA fibres.