Muscle Tissue Weight Research Articles

The effect of intramuscular injection of dinoprost or gonadotropin-releasing hormone in dairy cows on beef quality1

Intramuscular injections of drugs and vaccines cause tissue damage and subsequent effects on tenderness and consumer acceptability of beef. In the 2007 National Market Cow and Bull Beef Quality Audit, 100% of plants reported fabricating subprimal cuts such as rib eyes and tenderloins from cow and bull carcasses. Dairy beef quality should therefore be a consideration when injections are given to dairy animals. The discussion about injection site reactions and tenderness has focused on vaccines and antimicrobial drugs with little concern for the effects of reproductive hormones. The objective of this study was to quantify antemortem the effects of semimembranosis/semitendinosis muscle injection of dinoprost and GnRH in lactating dairy cows by estimating the weight of tissue damaged and comparing that with a drug known to cause extensive tissue damage, flunixin meglumine. Tissue damage was estimated from previously reported equations for grams of muscle tissue damage based on area under the curve of serum concentrations of the muscle enzyme creatine kinase over time. Dinoprost and flunixin injection both caused a significantly increased estimate of muscle tissue damaged compared with needle only (P = 0.0351 and 0.0355, respectively). Dinoprost and flunixin caused a marginally significant increased muscle tissue damage compared with GnRH (P = 0.1394 and 0.1475, respectively). No statistically significant difference was found between the estimated weight of muscle tissue damaged by flunixin compared with dinoprost (P = 1.0000), or by saline compared with GnRH (P = 0.7736) or needle only (P = 0.4902). The assumption that reproductive hormones are less damaging than vaccines and antimicrobial drugs should be examined more closely, including postmortem evaluation of injection site lesions and effects on tenderness.

Virtual dissection of lamb carcasses using computer tomography (CT) and its correlation to manual dissection

Hundred and nineteen lambs from a single abattoir in Norway were scanned using computer tomography (CT) at different equidistances (40, 80, 160 and 320 mm) to perform a virtual dissection of the carcasses, separating muscle, fat and bone tissue. The population of sheep used covered the commercial range of breeds and body composition in Norway and the full range of fat and conformation scores. After CT scanning, the carcasses were manually dissected by trained butchers. The volume and weight of all carcasses were estimated using Cavalieri estimation of the different equidistances of CT slices. The precision and reliability of virtual dissection were estimated from repeated measurements using splitting of carcasses into two halves. The results showed that virtual dissection (r > 0.95) was more precise and reliable than manual dissection (r > 0.80), both for carcass tissue weights and proportions. The correlation between virtual and commercial dissection was high for carcass weight and muscle tissue weight, however, lower for fat and bone tissues. The precision and reliability of virtual dissection, and the correlation between virtual and manual dissection were highest using low equidistance CT scanning (40 mm). There were some biases between virtual and manual dissection, especially for bone tissue. The source of bias can be explained by inaccurate manual dissection performed by the butchers and underestimation of bone using Cavalieri estimation.

Differences in the condition of Norway lobsters (Nephrops norvegicus (L.)) from trawled and creeled fishing areas

The condition of trawled and creeled Norway lobsters, Nephrops norvegicus, was compared in individuals caught along the Swedish west coast. Female and male N. norvegicus were collected from trawled and creeled areas in the spring and autumn. Their nutritional state was determined by analysing individuals for haemocyanin concentration, the dry weight/wet weight relationship in muscle and hepatopancreas and the percentage dry weight of muscle and hepatopancreas of total animal dry weight. All parameters were measured on an individual basis and checked for size dependence. Creeled individuals were generally found to be in better condition than individuals from trawled areas, and animal condition increased from spring to autumn. Autumn males from creeled sites were overall in the best condition, having the highest mean haemocyanin concentration, muscle and hepatopancreas dry weight/wet weight relationship and percentage dry weight of muscle tissue. Claw symmetry (paired cutters) was suggested as an indicator of limb loss, with the highest occurrence found in females from trawled sites. Crusher absence had no effect on the animal's individual percentage dry weight of muscle, although the mean was lower in trawled females than in other groups. Resource limitation and physical stress are discussed as possible underlying factors affecting the observed differences.

Solubility of Cod Muscle Myofibrillar Proteins at Alkaline pH

The solubility characteristics of proteins are of interest because of their relation to many functional properties. The solubility of the proteins of washed cod muscle mince increased dramatically between pH 8.9 and 9.2 at an ionic strength of 10 mM, whereas a high but constant solubility was observed at 430 mM sodium chloride over the pH range from 7 to 9.5. At pH 9.2, the proteins of the washed cod muscle were greater than 60% soluble at a sodium chloride concentration of 6.6 mM but were salted out at slightly higher concentrations. Above about 100 mM to about 900 mM salt, the proteins were salted in, and greater than 90% solubility was achieved. Maximal extractability was observed with a ratio of 36 volumes of extracting solution to 1 weight of minced muscle at pH 9.2. At pH 8.5, the extractability of the protein increased from 11% to 24% over a range in extraction volumes of 12:1 to 144:1 of volume of extracting solution to muscle tissue weight.

Growth and Muscle Protein Synthesisin vitroof Saithe (Pollachius virens) and Rainbow trout (Salmo gairdneri) in Response to Protein-Energy Intake

Abstract Saithe (Pollachius virens) and rainbow trout (Salmo gairdneri) were fed diets containing increasing levels from 12 to 60% of protein energy relative to metabolizable energy for 8 and 3 weeks, respectively. Ribosomes were isolated from skeletal muscle tissue and the rate of protein synthesis in vitro determined. Ribosomal capacity for protein synthesis per g wet weight of muscle tissue was significantly correlated (p<0.01) with specific growth rates measured as percent weight gain per day, in both saithe (r=0.8812, n=56) and rainbow trout (r=0.5722, n=49). Optimal weight gain was reached for saithe at a dietary protein energy level of 40% and for rainbow trout at a 30% level. A dietary ratio of protein energy relative to metabolizable energy of 40–45% was required for optimal protein synthesis in both species.

Urea tolerance and osmoregulation in Bufo viridis and Rana ridibunda.

1. The tolerance and adaptation to urea solutions by terrestrial green toads (Bufo viridis) and semi-aquatic frogs (Rana Ridibunda) were studied. 2. the green toad showed tolerance to urea solution of 800 mM and the frogs showed tolerance only to about 400 mM urea solution. 3. The plasma concentrations of both species was hyperosmotic to the external medium in all the different urea solutions. 4. Blood osmolality, urea, Na+ and Cl- concentrations of B. viridis were always higher than in R. ridibunda. 5. The urea concentration in muscle of R. ridibunda was higher than the urea concentration in muscle of B. viridis. 6. The muscle tissue weight loss of B. viridis was significantly lower than R. ridibunda.

Androgenic Regulation of Estrogenic Action on Accessory Sex Organ Smooth Muscle

AbstractOur previous research has shown that 4 weeks of daily estrogen treatment, started on the day of castration, resulted in significant growth of the guinea pig seminal vesicle smooth muscle, yet little or no estrogenic effect on muscle tissue weight or DNA content was observed when the treatment was initiated after a 1-month period of castration induced regression. With the hypothesis that castration induced reductions in estrogenic sensitivity were due to alterations in the intracellular fate of estradiol in the muscle, we determined, following the intravenous injection of 3H-estradiol to normal, 24-hour castrates and 1-month castrates, the whole muscle tissue accumulation and subcellular distribution of 3H-estradiol. In the same 3 experimental groups, we also determined, using in vitro exchange assays with 3H-estradiol, the number of estrogen binding sites in both the cytosol and salt (1.2m KCl) soluble fraction of the crude nuclear-myofibrillar pellet. It was found that the loss of estrogenic sensitivity in the 1-month castrate was not due to a reduction in either whole tissue accumulation, subcellular distribution, cytosol binding or salt-soluble nuclear binding of 3H-estradiol.Restoration of estrogenic responses in muscle DNA content and wet weight was achieved by priming 1-month castrates with 5 daily injections of dihydrotestosterone immediately prior to the onset of estrogen treatment. Shorter periods of androgen priming (e.g., 1, 2 or 3 days) slightly enhanced, but did not completely restore, estrogenic responses in muscle wet weight and DNA content. For estrogen sensitive parameters of muscle growth, such as collagen and RNA content, which were not altered in their response to the estrogen treatment by a 1-month period of castration-induced regression, androgen priming prior to estrogen treatment had no effect.Therefore, testicular androgens regulate selected facets of estrogenic sensitivity in guinea pig seminal vesicle smooth muscle; changes in the muscle cytosol or salt-soluble nuclear myofibrillar estrophiles do not appear to be responsible for the changes in estrogenic sensitivity.

LIVE ANIMAL ULTRASONIC MEASUREMENTS OF SUBCUTANEOUS FAT THICKNESS AS PREDICTORS OF BEEF CARCASS COMPOSITION

Data on the total dissectible muscle and fat tissue from primal cuts of the left hindquarters of 356 crossbred steers and heifers, and from the entire left side of 98 Shorthorn steer carcasses were used to evaluate the usefulness of subcutaneous fat depth measurements between the 11th and 12th ribs for predicting carcass composition. Analyses revealed that the use of multiple fat depth measurements from different sites on one or both sides conferred no advantage over the use of the best single measurement. The major sources of variation in total weight of muscle and fat tissue from the crossbreds were breeding group, sex and weight. The residual variances remaining after adjustment for these sources of variation were significantly reduced (P &lt; 0.05) by inclusion of a single fat measurement with reductions of 12.5% (muscle) and 22.0% (fat) provided by the carcass fat measurement and 7.1% (muscle) and 13.1% (fat) for the Krautkramer measurement. For the Shorthorn steers, line and weight were the major sources of variation and larger reductions in the residual variances (16.3% for muscle and 24.6% for fat) were obtained by inclusion of carcass fat in the model. The ultrasonic fat measurements were less effective than carcass fat and the Scanogram gave larger reductions in residual variance than the Krautkramer (e.g., 8.1 vs. 3.9% for weight of muscle tissue). The results of this study suggest that live animal ultrasonic measurements of subcutaneous rib fat depth can be used to achieve modest improvement in predictors of beef carcass composition.

Mechanism of reinnervation of skeletal muscles injured by botulinus toxin

The course of reinnervation of a skeletal muscle, whose own myoneural apparatus has been damaged by botulinus toxin, by an implanted nerve was investigated in experiments on rats in order to determine the essential conditions for regeneration of nerve fibers in an area of paralysis due to botulism. Injection of a sublethal dose of the toxin into the limb was shown to hasten synaptogenesis of the implanted nerve. As a result, restoration of the normal weight of muscle tissue and the level of polarization of its fibers was promoted.

Simultaneous measurement of the calf blood flow by strain-gauge plethysmography and the calf muscle blood flow measured by 133Xenon clearance.

133Xenon clearance technique as a measure of the blood flow per unit weight of muscle tissue has been compared to venous occlusion plethysmography in the calf of normal subjects. The comparison was made during reactive hyperemia and in the post-exercise period. In the first mentioned experiments, no agreement between the results by the two methods was obtained.In the experiments in the post-exercise period a highly significant correlation between the two methods was found in each experiment. The mean value of the muscle blood flow, calculated from 133Xenon clearance from six experiments, averages 113 per cent of the flow, measured simultaneously by plethysmography. The standard deviation in the 6 experiments was calculated to ± 63 per cent. The major part of this deviation is ascribed to the difficulty of such a comparison.

Response Heterogeneity in Adductor Muscle Efferents of the Surf Clam*

ABSTRACT Neuromuscular control in the Mollusca presents numerous interesting problems to the comparative physiologist. Among these are the extent of polyneural and multi-terminal innervation, the possibility of peripheral inhibition, and the anatomical basis for wholly peripheral reflex activities. Perhaps in no area are the problems more intriguing—and the experimental results more equivocal—than with regard to the physiology of lamellibranch tonic smooth muscle. These muscles are unique, not only for the fact that they are able to exert the largest known force for weight of muscle tissue, but also for their well-known ability to remain in the contracted state for prolonged periods of time with very little expenditure of metabolic energy (for a review, see Hoyle, 1964). While these muscles can also contract in a phasic manner, relaxing quickly after a brief twitch-like response, in some cases there is no histological differentiation to complement the functional dichotomy. It is therefore logical to inquire whether the different states of activity may have their bases in different types of excitatory synapses made with the muscle fibres by specific ‘tonic’ and ‘phasic’ motoneurons. Another suggestion (Takahashi, 1960) is that phasic responses occur following simultaneous activity in excitatory and inhibitory nerve fibres, the latter drastically limiting the duration of the contracted state of the muscle.