Adipose tissue growth and cellularity: changes in bovine adipocyte size and number.

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.

Neural catecholamine deficiencies in the porcine stress syndrome.

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.

Structural and palatability relationships in frozen ground beef patties as a function of freezing treatments and product formulation.

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.

Examination of a lognormal distribution equation for describing distributions of diameters of bovine adipocytes.

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.

Blood lactate kinetics in normal and stress-susceptible pigs.

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.

Fatty acid synthesis from lactate in growing cattle.

Rates of fatty acid synthesis from lactate and acetate and activities of selected lipogenic and NADPH-generating enzymes were determined in subcutaneous, intermuscular and intramuscular adipose tissues of cattle that were 11-19 months of age. Fatty acid synthesis from lactate and acetate increased from 11 to 13 months of age in subcutaneous and intermuscular adipose tissues; synthesis from lactate increased until 17 months of age. In intramuscular adipose tissue, synthesis from lactate also increased until 17 months of age while that from acetate continually increased.

Urinary and caudate nuclei catecholamine levels in stress-susceptible and normal swine.

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.

Influence of caffeine on blood creatine phosphokinase levels in swine.

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.

Conversion of alanine, aspartate and lactate to glucose and CO2 in liver from stress-susceptible and stress-resistant pigs.

Rates of conversion of lactate, alanine and aspartate to glucose and oxidation of each to CO2 were determined in incubated liver slices from nine stress-susceptible (SS) and seven stress-resistant (SR) Yorkshire pigs ranging in body weight from 24 to 54 kg. Pigs were screened for stress susceptibility by exposure to halothane at 7 weeks of age. Stress was minimized before slaughter, and liver samples were obtained immediately after death.

Gluconeogenesis from lactate in liver of stress-susceptible and stress-resistant pigs.

In vitro rates of lactate conversion to glucose and oxidation to CO2 were determined in livers of stress-susceptible (SS) and stress-resistant (SR) pigs because we hypothesized that livers of SS pigs had a lower capacity than livers of SR pigs to remove lactate from blood. Stress-susceptibility was determined by reaction to halothane at 7 weeks of age. At approximately 9 weeks of age, pigs were assigned to one of three experimental diets.

Glucocorticoid induced stress susceptibility in swine: adrenocortical pathology.

The studies reported here were undertaken to better characterize the role of the adrenal cortex in the increased susceptibility to stress observed in porcine stress syndrome. Since adrenal hypofunction was suggested during early studies as a factor in events leading to porcine stress syndrome it was decided to produce such a state by the exogenous administration of the glucocorticoids prednisolone and fluoroprednisolone.A total of 34 pigs (weighing 90 to 100 kg) received a series of graded doses (given intramuscularly) of one or the other of the foregoing compounds and were necropsied 48, 72, and 120 hours after the last treatment.