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1.
J Anim Sci ; 51(1): 74-7, 1980 Jul.
Article in English | MEDLINE | ID: mdl-7410279

ABSTRACT

Eight stress-susceptible and eight normal pigs were used in the first portion of the study. Urine samples were collected for 24 hr over 4 consecutive days while the pigs were kept in metabolism cages. Each 24-hr sample was assayed for epinephrine, norepinephrine and dopamine. Urinary levels of dopamine were lower (P < .01) in the stress-susceptible pigs. No significant differences in urinary epinephrine or norepinephrine were observed. The second portion of the study evaluated the catecholamines in the caudate nucleus of the brain. Six stress-susceptible and six control pigs were examined. Immediately after exsanguination, caudate nuclei were excised and frozen in liquid nitrogen. The caudate nuclei were assayed for catecholamines within 2 to 3 days of freezing. Caudate nuclei dopamine levels were lower (P < .01) in stress-susceptible pigs (5,961 ng/g) than in control pigs (10,878 ng/g). No significant differences in norepinephrine levels of the caudate nuclei were observed between the two groups.


Subject(s)
Catecholamines/analysis , Caudate Nucleus/analysis , Stress, Physiological/veterinary , Swine Diseases/metabolism , Swine/metabolism , Animals , Creatine Kinase/blood , Dopamine/urine , Epinephrine/urine , Malignant Hyperthermia/blood , Malignant Hyperthermia/metabolism , Malignant Hyperthermia/urine , Malignant Hyperthermia/veterinary , Norepinephrine/urine , Stress, Physiological/blood , Stress, Physiological/metabolism , Stress, Physiological/urine , Swine/blood , Swine/urine
2.
J Anim Sci ; 50(3): 442-51, 1980 Mar.
Article in English | MEDLINE | ID: mdl-7364680

ABSTRACT

Eight stress-susceptible and eight normal pigs weighing 35 to 50 kg were studied to determine if caffeine administration would trigger the stress syndrome and affect blood CPK levels. The pigs were littermates of Yorkshire descent. One gram of caffeine (dissolved in 10 ml of saline-sodium benzoate solution) was infused into the pigs through a jugular catheter at a rate of 1.0 ml/min. Blood samples were collected through the catheter before caffeine administration and at specific intervals up to 8 hr after the caffeine administration for the determination of blood creatine phosphokinase levels. The pigs were sacrificed approximately 48 hr after caffeine administration, and M. longissimus pH and reflectance values were obtained 45 min and 24 hr postmortem. Caffeine administration stimulated the development of the signs associated with the porcine stress syndrome in seven of the eight pigs genetically classified as stress-susceptible, and only one control pig exhibited an early sign of the stress syndrome, muscle tremors. Blood CPK levels did not differ significantly between the normal and stress-susceptible groups until visual signs of the stress syndrome were no longer observed (approximately 45 min after caffeine administration). Stress-susceptible pigs had significantly higher blood CPK levels than controls 45 min after the initial caffeine administration. Physical stress received by the pigs during transport and the stress from being held in a new environment resulted in a greater elevation of blood CPK than did the stress administered through the caffeine infusion.


Subject(s)
Caffeine/pharmacology , Creatine Kinase/blood , Swine/blood , Animals , Muscle Contraction/drug effects
3.
J Anim Sci ; 53(4): 1000-5, 1981 Oct.
Article in English | MEDLINE | ID: mdl-7319957

ABSTRACT

In vitro rates of lactate metabolism were determined in stress-susceptible (SS) and stress-resistant (SR) pigs. Three SR and three SS pigs were given 20 muCi of [U-14C] L-lactate by a single injection method and resting blood lactate kinetics were measured. Seventeen blood samples were taken during the 60 min after injection. Lactate was separated from the deproteinized plasma by silicic acid column chromatography, and specific radioactivity was determined. Kinetic characteristics were calculated from plots of specific activity versus time. Pigs met steady-state requirements during the sampling period. There were no differences in kinetic characteristics of resting SS and SR pigs. Later, a second isotope injection was given after 5 min of electrical stress. Lactate pool sizes increased similarly in both types of pigs after stress; however, SS pigs had greater plasma lactate concentrations after stress. It is concluded that SS and SR pigs respond differently to stress but have similar capacities to metabolize lactate while resting.


Subject(s)
Lactates/blood , Stress, Physiological/veterinary , Swine Diseases/blood , Swine/blood , Animals , Carbon Radioisotopes , Chromatography , Electric Stimulation , Kinetics , Stress, Physiological/blood
4.
J Anim Sci ; 53(5): 1236-45, 1981 Nov.
Article in English | MEDLINE | ID: mdl-7319968

ABSTRACT

Samples of subcutaneous, intermuscular and mesenteric adipose tissues from beef steers were fixed with osmium tetroxide, and freed adipocytes were counted with an automatic particle counter to determine whether a lognormal distribution function would describe adipocyte size distributions more accurately than a normal distribution function. Modes and medians of size distributions generally were larger than means for adipocyte size distributions modeled with a lognormal distribution function. Normalized third and fourth moments of predicted lognormal distributions often were close to 0 and 3, respectively, which are expected values for a normally distributed population. Considerable variation was observed in the skewness of adipocyte size distributions. Both normal and lognormal models for adipocyte size distribution yielded similar means. The lognormal model yielded a greater standard deviation than the normal model for adipocyte size distributions. Smaller chi-square values were found for size distributions modeled with a lognormal than with a normal distribution function. Results suggest that a lognormal distribution function more accurately models the size distributions of bovine adipocytes.


Subject(s)
Adipose Tissue/cytology , Cattle/anatomy & histology , Animals , Cell Count , Male
5.
J Anim Sci ; 60(4): 970-6, 1985 Apr.
Article in English | MEDLINE | ID: mdl-3988658

ABSTRACT

Forty crossbred steers of similar birth date and fed the same growing-finishing diet were used to study adipocyte changes in six fat depots during growth from 11 to 19 mo of age. Steers were slaughtered at 2-mo intervals. Adipose tissue samples were obtained from kidney, mesenteric and brisket fat and subcutaneous, intermuscular and intramuscular fat from the 10th to 12th rib section. The osmium tetroxide fixation technique was used for determination of cell size and number. Except for three brisket fat samples, distributions of adipocyte diameters from six different fat depots were monophasic during the age range considered in this study. At 17 mo of age, the mean adipocyte diameter, in decreasing order, was: kidney fat greater than mesenteric greater than subcutaneous greater than intermuscular greater than intramuscular greater than brisket fat. Fat deposition during growth to 19 mo of age occurred mainly by hypertrophy of adipocytes. An apparent cell hyperplasia occurred in the intramuscular fat depot from 11 to 15 mo and in the brisket fat depot after 15 mo of age. Based on cellularity characteristics, evidence exists to classify intramuscular and brisket fat depots as late-developing ones. Cell number/gram of intramuscular adipose tissue was a better predictor of marbling score than was fat cell diameter.


Subject(s)
Adipose Tissue/cytology , Cattle/growth & development , Animals , Body Composition , Cattle/anatomy & histology , Cell Count/veterinary , Lipids/analysis , Male , Muscles/analysis
6.
Am J Vet Res ; 44(3): 368-71, 1983 Mar.
Article in English | MEDLINE | ID: mdl-6838032

ABSTRACT

A study was conducted to compare catecholamine concentrations in nervous tissues of stress-susceptible (SS) and stress-resistant (SR) pigs that were physically stressed. Ten pigs were included in each group on the basis of results of halothane screening tests, blood typing analysis, and examination for serum creatine kinase (CK) activities at 6 weeks of age. The nervous tissues analyzed included the substantia nigra (SN) and the caudate nucleus (CN) which were taken from pigs as soon as possible after death and frozen in liquid nitrogen. Tissues were radioenzymatically assayed for dopamine, norepinephrine, and epinephrine concentrations. The SS pigs exhibited significantly greater (P less than 0.001) CK activity concentrations than did those SR pigs before and after physical stress. Concentrations of dopamine, norepinephrine, and epinephrine in the CN of SS pigs were significantly lower (P less than 0.05) than those in the CN of SR pigs. Similarly, the SN of SS pigs had lower dopamine, norepinephrine, and epinephrine concentrations than did the SN of SR pigs. The catecholamine deficiencies observed in the porcine stress syndrome seem to have similarities with certain human extrapyramidal diseases.


Subject(s)
Catecholamines/analysis , Caudate Nucleus/analysis , Stress, Physiological/veterinary , Substantia Nigra/analysis , Swine Diseases/metabolism , Animals , Creatine Kinase/blood , Disease Susceptibility/veterinary , Dopamine/analysis , Epinephrine/analysis , Norepinephrine/analysis , Stress, Physiological/metabolism , Swine
7.
Meat Sci ; 8(2): 135-46, 1983 Feb.
Article in English | MEDLINE | ID: mdl-22055450

ABSTRACT

Four freezing rates for ground beef patties were evaluated for product quality effects and microstructural changes. These rates were further evaluated for different pattie formulations involving post-rigor and pre-rigor meat. Both light microscopy (LM) and scanning electron microscopy (SEM) were utilised for microstructural comparisons. Fast freezing rates had a positive effect on pattie quality, resulting in increased juiciness, tenderness and overall acceptability. Photomicrographs showed increased ice cavity size with decreased freezing rates, which probably contributed to increased cooking shrink and tenderness changes observed. Pre-rigor patties compared very favourably with conventional post-rigor beef patties and showed no obvious structural differences.

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