Biomedical subjects

P J Bechtel

Publications and source records attributed to P J Bechtel.

At least 19 recordsLinked to original sources

PubMed1992

Effects of diet containing extruded full-fat soybeans or butter on the growth, composition, and sensory characteristics of pork.

Ninety-six crossbred barrows were randomly allotted to five replications of four treatments to determine the effects of diets containing 20% extruded full-fat soybeans (FFS) or 4% butter (B) on the growth, composition, and sensory characteristics of finishing pigs. Pigs were housed five per pen, except for one replication that had four pigs per pen, in environmentally regulated barns. Pigs were given ad libitum access to a corn-soybean meal diet for 11 wk (control); a corn-extruded soybeans and soft wheat midds diet for 11 wk (FFS-11); a corn-soybean meal diet for 6 wk, changed to a corn-extruded soybeans and soft wheat midds diet for 5 wk (FFS-5); or a corn-soybean meal diet for 6 wk, changed to a corn-soybean meal, soft wheat midds, and 4% butter diet for 5 wk (B). Feed intake and weight gain were measured once every 2 wk. Pigs were slaughtered and carcass data were collected. Sensory characteristics (tenderness, juiciness, pork flavor intensity, off-flavor intensity, and overall acceptability), shear force, moisture, and fat content were determined for the longissimus muscle. Sensory characteristics (pork flavor, off-flavor, rubbery, cohesiveness, and juiciness) and 2- thiobarbituric acid values were determined for ground pork (30% fat) after 1, 4, and 7 d for control, FFS-11, and B treatments. No differences (P > .05) in ADG were observed between diets. Feed efficiency of the FFS-11 group was better (P < .05) than that of the control or B groups. No consistent differences were observed for carcass, sensory, or shear-force characteristics of the longissimus muscle or ground pork.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗

PubMed1992

Effect of feeding finishing pigs extruded full-fat soybeans on performance and pork quality.

This experiment was designed to test whether changing the type and amount of added dietary fat would affect performance or meat quality. Dietary fat was added as tallow or extruded full-fat soybeans (FFS). Isoenergetic diets containing 10% FFS, 20% FFS, or 4% tallow were fed for 3 or 6 wk before slaughther. A conventional corn-soybean meal diet served as a no-added-fat control. Each of the seven dietary groups contained 20 pigs, equally distributed among four pens, with barrows and gilts segregated. Significance of treatment, sex, and interaction effects were evaluated for 34 meat quality, composition, and sensory evaluation traits. Treatment x sex interactions were not detected (P greater than .05). Treatment main effects were detected for percentage of fat and water in the bacon and for lipid oxidation in bacon and the longissimus muscle. The 6 df for treatment were partitioned into six contrasts to test for the trends within and between diets. A trend toward reduced fat and increased moisture in bacon was detected in the 10% FFS diet over time (P less than .05). In general, lipid oxidation of bacon and longissimus muscle increased with level of FFS in the diet, length of time on the diet, and storage time of the meat. Although statistically significant, the magnitude of these effects was small and did not affect the sensory characteristics of longissimus muscle samples. It was concluded that short-term feeding of FFS before slaughter did not adversely affect animal growth or meat quality.

Adipose Tissue↗

PubMed1992

Characterization of lipid in loin and bacon from finishing pigs fed full-fat soybeans or tallow.

This experiment tested whether the lipid composition of pork could be altered by changes in dietary lipid, that what effects these changes would have on production and meat characteristics. Pigs were fed diets containing 10 or 20%+ extruded full-fat soybeans (FFS) or 4% tallow for a 3- or 6-wk finishing period, with a corn-soybean meal diet fed as a control. Seventy barrows and 70 gilts were allotted into seven treatment groups with four pens per group. Analysis was on 28 experimental units, which were composite samples from pens. The significance of treatment, sex, and treatment x sex interaction F-statistics was evaluated on chloroform-methanol extractable total lipid, triacylglycerol, phospholipids, cholesterol, individually fatty acids (FA), and the major classes of FA obtained from longissimus muscle and bacon. Treatment effects (P less than .05) were detected for cholesterol content of longissimus and for total lipid and phospholipid content of bacon. Treatment effects (P less than .01) were detected for monoenoic, dienoic, and polyenoic (P) FA in both tissues, and for saturated (S) FA in bacon (P less than .05). Treatment effects (P less than .001) were detected in both tissues for the P:S ratio. The P:S ratio increased 54% for longissimus and 100% for bacon in the pigs fed FFS for 6 wk compared with pigs consuming a corn-soybean meal diet.

Adipose Tissue↗

PubMed1991

Molecular dynamics of water in foods and related model systems: multinuclear spin relaxation studies and comparison with theoretical calculations.

A review of recent studies of molecular dynamics of water in foods and model systems is presented, and the theoretical results are compared with experimental data obtained by several techniques. Both theoretical and experimental approaches are discussed for electrolytes, carbohydrates, and food proteins in solution. Theoretical results from Monte Carlo simulations are compared with experimental NMR relaxation data for quadrupolar nuclei such as those of deuterium and oxygen-17. Hydration studies of wheat, soybean, corn, and myofibrillar proteins by multinuclear spin relaxation techniques are discussed, and several new approaches to the analysis of the experimental data are considered. Correlation times of water motions in hydrated food systems are determined from NMR and dielectric relaxation data. The values of the correlation times for dilute solutions of electrolytes and carbohydrates estimated by NMR are in good agreement with those calculated from dielectric relaxation data, but seem to differ significantly from those proposed from Monte Carlo simulations. Several new and important results concerning the hydration of potato and cereal starches are presented, showing the very different hydration behaviors of these two major groups of starches. The combination of molecular dynamics computations with NMR relaxation techniques will hopefully stimulate novel technological developments in food engineering based on such fundamental studies.

Carbohydrates↗

PubMed1991

Varying amounts of stretch stimulus regulate stretch-induced muscle hypertrophy in the chicken.

1. The effects of different amounts of passive stretch per day and number of days of stretch on muscle hypertrophy in the chicken patagialis (PAT) muscle were determined. 2. Stretch for 24 hr per day (h/d) resulted in a more rapid hypertrophy both on a wet and dry tissue basis (P less than 0.001) than stretch for 4 h/d. 3. Stretch increased PAT weight 43% and 25% in 24 h/d and 4 h/d treatments, respectively, after 10 days of stretch, but by day 25 of stretch there was no difference between treatments. 4. In a second experiment, the PAT muscle was hypertrophied and then the effects of intermittent stretch (4 h/d) on regression of hypertrophy (muscle atrophy) were investigated. 5. Intermittent stretch (4 h/d) for 5 and 10 d significantly (P less than 0.001) inhibited regression of hypertrophied muscle. 6. The results of the present study indicate that stretch-induced hypertrophy can be modulated by varying the amount of stretch applied per day. 7. Intermittent stretch can be used to inhibit the regression which occurs when a continuous stretch stimulus is removed. 8. Intermittent stretch is a useful model for investigating mechanisms of muscle hypertrophy and inhibition of muscle atrophy.

Animals↗

PubMed1991

Expression of embryonic myosin heavy chain mRNA in stretched adult chicken skeletal muscle.

Chronic stretch of the chicken fast-twitch patagialis muscle increases the rate of growth and percentage of fast-twitch oxidative fibers. We have analyzed the effects of stretch on the expression of two previously identified "embryonic" myosin heavy chain (MHC) mRNAs (p251 and p110). Both MHC mRNAs were expressed in the patagialis at their highest levels in the embryo and 1 wk after hatching. During posthatch development (7-52 wk), the p110 mRNA was expressed in only trace quantities while the p251 mRNA was not detectable. After 2 wk of stretch of the patagialis in 7- or 38-wk-old birds, the p110 mRNA was increased to levels similar to that found in patagialis of newly hatched chicks, whereas expression of the p251 transcript was not affected. The existence of two other MHC mRNAs homologous to the p110 mRNA was suggested by the S1 mapping analysis, one of which was expressed at dramatically reduced levels in the stretched patagialis. It is concluded that stretch can cause selective alterations in the expression of developmentally regulated MHC isoforms in chicken fast-twitch muscle.

Aging↗

PubMed1991

The effect of ractopamine hydrochloride on the carcass cutting yields of finishing swine.

This study was designed to evaluate growth performance, carcass cutting yield, and processing characteristics of boneless hams and bellies from finishing pigs fed diets containing 0, 5, 10, or 20 ppm of the phenethanolamine ractopamine hydrochloride (RAC). Sixty pigs were blocked by starting weight and randomly assigned to pens (four pigs/pen) within each of three blocks. Treatments were then randomly assigned to the pens to total six pens of the 0-ppm level and three pens each at the 5-, 10-, and 20-ppm RAC levels. Weight gain and feed consumption were monitored and animals were slaughtered by weight block after approximately 48 d on trial. Slaughter weight, ADG, and feed/gain were improved (P less than .05) for RAC treatments. Dressing percentage was higher and increased linearly (P less than .05) for RAC treatments. Carcass weight, length, leaf fat weight, backfat thickness, loin eye area, and color, marbling, and firmness of the longissimus were evaluated. The RAC-treated carcasses were heavier (P less than .05) and loin eye area increased linearly (P less than .05). One side of each carcass was fabricated using National Association of Meat Purveyors specifications. Trimmed hams and loins from the RAC treatments were heavier (P less than .05) than those from control animals. No differences (P greater than .05) in carcass cutting yield (percentage of trimmed primal cuts) were observed between treatments. However, trimmed hams and loins from the 20-ppm RAC treatment represented a greater (P less than .05) percentage of carcass weight than did those from control animals. Ractopamine did not affect raw belly or bacon characteristics (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗

PubMed1990

Multinuclear spin relaxation and high-resolution nuclear magnetic resonance studies of food proteins, agriculturally important materials and related systems.

An overview of the applications of Nuclear Magnetic Resonance (NMR) techniques in Agriculture and Food Chemistry, covering high-resolution, solid-state, pulsed gradient and two-dimensional techniques is presented. The systems investigated by such techniques range from purified proteins to mixtures, starch granules and wheat grains. Both hydration and structural/composition approaches that employ NMR techniques are discussed from the point of view of applications rather than technique development. Hydration models derived from multinuclear studies are discussed for food proteins and enzymes. The role of protein-protein interactions in the analysis of the NMR results on hydration is also discussed. Amongst the food proteins considered are: wheat gliadins, glutenins, corn zeins, soy glycinins and conglycinins, as well as muscle proteins. Several new applications and new directions of development of NMR in Agriculture and Food Chemistry are suggested, and potential practical applications are pointed out.

Agriculture↗

PubMed1990

Effects of food restriction on stretch induced muscle hypertrophy in chickens of various ages.

1. The patagialis muscle of three groups of different aged chickens was subjected to passive stretch by placing an inflexible sleeve over the left wing, and the right wing served as the control. 2. Food was removed from the animals 2 days prior to applying passive stretch. After 6 days of passive stretch on young 7-week-old animals, the stretched muscle was 200% larger than the control. 3. During the restriction, control muscle lost 69% of its weight and the stretched muscle maintained its original weight. 4. Changes in muscle DNA and hydroxyproline content were similar to changes in muscle weight but hydroxyproline content lagged changes in muscle weight. 5. Restricted 10-month-old chickens responded to passive stretch with an absolute increase in muscle mass which was accompanied by increases in protein, DNA and hydroxyproline content. 6. Muscle from the 28-month-old chickens did not respond to either 11 days of restriction or passive stretch. 7. The results of the present study indicate that as the chicken grows older, the ability of the muscle to respond to stimuli, stretch and/or starvation, is reduced.

Aging↗

PubMed1990

Dibutyryl cAMP-induced increases in triacylglycerol lipase activity in developing L8 myotube cultures.

Triacylglycerol (TG) lipase activity, with an alkaline pH optimum, has been identified in the cellular fraction of L8 myotube cultures. This TG lipase activity was stimulated by serum and inhibited by NaCl and protamine sulfate. These characteristics have been classically described for lipoprotein lipase. It was possible to increase the activity of this TG lipase three- to five-fold by incubating the cells with dibutyryl cAMP. Maximal enzyme activity was observed 16 h following the addition of 10-100 microM dibutyryl cAMP to the cultured cells. Enzyme activity returned to control levels 24 h after removal of the nucleotide from the culture medium. Serum-sensitive alkaline TG lipase activity was also identified in five other myotube preparations of cultured muscle cells. The highest levels of activity were found in rat skeletal muscle primary, H9, and L6 cell types. The finding that dibutyryl cAMP is an effective inducer of alkaline TG lipase activity provides us with a valuable model to investigate mechanisms regulating synthesis, compartmentalization, and transport of lipoprotein lipase in muscle.

Animals↗

PubMed1990

Activation of insulin-like growth factor gene expression during work-induced skeletal muscle growth.

We have investigated the hypothesis that there is local regulation of insulin-like growth factor (IGF) gene expression during skeletal muscle growth. Compensatory hypertrophy was induced in the soleus, a predominantly slow-twitch muscle, and plantaris, a fast-twitch muscle, in 11- to 12-wk-old female Wistar rats by unilateral cutting of the distal gastrocnemius tendon. Animals were killed 2, 4, or 8 days later, and muscles of the nonoperated leg served as controls. Muscle weight increased throughout the experimental period, reaching 127% (soleus) or 122% (plantaris) of control values by day 8. In both growing muscles, IGF-I mRNA, quantitated by a solution-hybridization nuclease-protection assay, rose by nearly threefold on day 2 and remained elevated throughout the experimental period. IGF-II mRNA levels also increased over controls. A more dramatic response was seen in hypophysectomized rats, where IGF-I mRNA levels rose by 8- to 13-fold, IGF-II values by 3- to 7-fold, and muscle mass increased on day 8 to 149% (soleus) or 133% (plantaris) of the control contralateral limb. These results indicate that signals propagated during muscle hypertrophy enhance the expression of both IGF genes, that modulation of IGF-I mRNA levels can occur in the absence of growth hormone, and that locally produced IGF-I and IGF-II may play a role in skeletal muscle growth.

Animals↗

PubMed1990

Renal expression of IGF I in hypersomatotropic states.

We examined insulin-like growth factor I (IGF I) gene expression in kidney in two models of hypersomatotropism, rats implanted with GH3 pituitary tumors, and rats administered exogenous growth hormone (GH). Both GH3 tumor-bearing rats and rats administered GH gained weight more rapidly than control animals, and had kidneys that were larger than those of controls. Tumor-bearing rats had increased levels of circulating IGF I. Glomeruli from tumor-implanted rats were sclerotic. Immunostainable IGF I was increased in medullary collecting ducts from tumor-bearing and GH-injected rats compared with kidneys from control animals. Levels of IGF I mRNA in kidneys of rats implanted with GH3 tumors and GH-injected rats were elevated compared with levels in kidneys from controls. Our findings demonstrate enhanced renal IGF I gene expression in hypersomatotropism. Stimulation of renal IGF I synthesis by GH could be causative of changes in renal function and renal size that occur in states of GH excess such as acromegaly.

Animals↗

PubMed1990

Changes in the metabolic profile of equine muscle from birth through 1 yr of age.

The purpose of this study was to investigate metabolic changes in equine muscle from birth to 1 yr of age. Duplicate biopsies from the middle portion of the gluteus medius were obtained from a depth of 2 cm beneath the superficial fascia at 1 day, 7 days, 1 mo, 3 mo, 6 mo, and 1 yr of age in 11 quarter horses and at 1 day, 3 mo, 6 mo, and 1 yr of age in 5 Standardbreds. Muscle enzyme activities determined were citrate synthase, 3-hydroxyacyl-CoA dehydrogenase, phosphorylase, and lactate dehydrogenase. Percent fast-twitch, fast-twitch high oxidative, and slow-twitch oxidative fiber types were determined using succinate dehydrogenase and myosin adenosinetriphosphatase (pH 9.4) histochemical stains. Histochemically determined muscle fiber-type percents did not change dramatically with increasing age. However, lactate dehydrogenase activity increased threefold in quarter horses and twofold in Standardbreds, and phosphorylase activity increased sixfold in quarter horses and sevenfold in Standardbreds from 1 day to 6 mo of age. Citrate synthase and 3-hydroxyacyl-CoA dehydrogenase activities decreased during the first 3 mo of age in quarter horses.

3-Hydroxyacyl CoA Dehydrogenases↗

PubMed1990

Effect of prenatal testosterone treatment on nitrogen utilization and endocrine status of ewe lambs.

Thirty-eight pregnant Suffolk ewes were assigned randomly to a control group or implanted with approximately 2 g of testosterone propionate (TP) when they were between d 40 and 60 of gestation. Implants were removed 3 wk prior to lambing. Five ewe lambs born to implanted ewes and ten ewe lambs born to nonimplanted ewes were utilized in this experiment. Ram lambs were not used in this trial. No differences (P greater than .10) were observed for fecal, urinary and total N excretion and amount of N absorbed. Nitrogen retained (percentage of N intake and g/d) was higher (P less than .05) in prenatally androgenized ewe lambs than in control ewe lambs. Plasma insulin concentrations averaged 99% higher (P less than .05) in prenatally androgenized ewe lambs. Plasma insulin-like growth factor I (IGF-I) concentrations averaged 29% higher (P less than .06) in ewe lambs treated prenatally with testosterone. Nonesterified fatty acid (NEFA) concentrations averaged 41% higher (P less than .05) in prenatally androgenized ewe lambs. Significant (P less than .05) treatment x time effects were observed in plasma thyroxine, glucose and urea N concentrations of prenatally androgenized vs control ewe lambs. These significant modifications in the plasma metabolite and endocrine status could be an important element of the physiological mechanism(s) by which prenatal androgenization improves growth performance and leanness of ewe lambs.

Animals↗

PubMed1990

Dose response in growth of pigs injected daily with porcine somatotropin from 57 to 103 kilograms.

Exogenous administration of porcine somatotropin (PST) has been shown to promote growth in the pig; however, dose-response relationships and interactions with PST source and sex for animals taken to market weight have not been established clearly. The present study was conducted to determine the relationship between dosage of pituitary-derived and recombinantly manufactured PST (pPST and rPST) and growth (ADG), structural soundness, gain-to-feed ratio (G/F) and average daily feed intake (ADF). Crossbred barrows (n = 113) and gilts (n = 97) were injected with either saline, 1.5, 3.0, 6.0 or 9.0 mg/d of pPST or rPST from 57 +/- .3 to 103.5 +/- .7 kg live weight. Pigs were housed five per pen and had ad libitum access to an 18% crude protein diet for the duration of the experiment. Response curves for pPST and rPST did not differ (P greater than .20) for ADG, soundness score or ADF. Although regression coefficients for response of G/F to pPST and rPST differed (P = .05), pairwise comparisons of treatment means did not (P greater than .10). Response curves for barrows and gilts did not differ for ADG or soundness (P greater than .05). Averaged over PST source and sex, quadratic dose-responses were detected for ADG, G/F and ADF (P less than .01), but PST had no effect on soundness (P greater than .25). Exponential regression models best described the dose-response relationships, and 6.0 mg.pig-1.d-1 was predicted to result in 95% of maximal achievable response for days to 103.5 kg and G/F. At this dose, pigs were predicted to grow .15 kg/d (20%) faster during the treatment period, reach slaughter weight 11.6 d earlier, consume .56 kg/d (19%) less feed, and have a G/F .095 (36%) greater than controls.

Animals↗

PubMed1988

Changes in the metabolic profile of the equine gluteus medius as a function of sampling depth.

1. Cross sections from the middle of the gluteus medius were removed from 10 adult horses and used to evaluate changes in histochemically determined muscle fiber type and biochemically determined metabolic enzyme activities as a function of sample depth. 2. Muscle fiber types determined using histochemical methods for myosin ATPase (pH 9.4) and succinic dehydrogenase (SDH) activity indicated percent fast-twitch glycolytic (FG) muscle fibers decreased and slow-twitch oxidative (SO) fibers increased as a function of increasing sampling depth. 3. Percent histochemically determined fast-twitch oxidative glycolytic (FOG) fibers decreased slightly only in the deepest region of the gluteus medius. 4. Citrate synthase (CS) enzymatic activity, used as a marker for mitochondrial oxidative potential, increased 2.5-fold in activity per g of muscle protein from 1 to 8 cm sampling depth. 5. 3-hydroxyacyl-CoA dehydrogenase (HAD) enzymatic activity, used as a marker for lipid oxidation potential, increased 3-fold in activity per g of muscle protein when the depth increased from 1 to 8 cm. 6. Phosphorylase (PS) enzymatic activity, used as a marker for potential glycogen utilization, decreased 50% in activity per g of muscle protein when going from 1 to 8 cm. 7. Lactate dehydrogenase (LDH) enzymatic activity, used as a marker for anaerobic glycolytic potential, decreased about 50% in activity as the sampling depth increased from 1 to 8 cm. 8. In summary, the superficial portion of the equine gluteus medius was found to be more glycolytic and less aerobic in its metabolic profile than deeper regions. The muscle became progressively more aerobic and less glycolytic with increasing sampling depth.

Animals↗

PubMed1988

Focal expression of insulin-like growth factor I in rat kidney collecting duct.

To address the question of insulin-like growth factor (IGF) I localization and synthesis in kidney, we used two complementary experimental approaches: immunohistochemistry of fixed paraffin-embedded rat kidney sections; and measurement of IGF I mRNA in isolated components of the rat nephron, using a highly sensitive and specific solution hybridization assay. Immunostainable IGF I was localized exclusively to principal cells of cortical and medullary collecting ducts. Administration of growth hormone to hypophysectomized rats for 8 d resulted in enhanced immunohistochemical staining of IGF I within collecting ducts, but no detectable IGF I in other portions of the nephron. The abundance of IGF I mRNA was 7-12-fold higher in isolated papillary collecting ducts than in proximal tubules or glomeruli, and was enriched 10-fold compared with whole kidney. Our data demonstrate colocalization of IGF I and IGF I mRNA in the collecting duct, consistent with focal expression of the IGF I gene at this site.

Animals↗

PubMed1988

Induction of mRNA for IGF-I and -II during growth hormone-stimulated muscle hypertrophy.

The expression of insulin-like growth factor (IGF) genes during skeletal and cardiac muscle hypertrophy was examined using skeletal and cardiac muscle hypertrophy was examined using adult 5-mo-old female Wistar-Furth rats implanted with growth hormone-secreting GH3 cells. Control and treated animals were killed at 40, 60, and 80 days after initiation of the experiment. From the time of injection to day 80, body, heart, skeletal muscle, and liver weights increased 112, 93, 55, and 314%, respectively. RNA was extracted and steady-state levels of IGF-I and IGF-II mRNAs were quantitated using a solution-hybridization nuclease-protection assay. Low levels of mRNA for both growth factors were detected in control tissues. By day 80 IGF-I mRNA had increased eightfold and IGF-II mRNA sixfold in skeletal muscle from treated rats. In cardiac muscle the levels of mRNA for both growth factors rose three- to fourfold. Although growth hormone induced an increase in hepatic IGF-I mRNA, IGF-II mRNA remained nearly undetectable. This study shows that during growth hormone-stimulated muscle growth mRNAs for both IGF-I and IGF-II accumulate, supporting other observations implicating the IGFs as paracrine or autocrine factors involved in skeletal muscle growth.

Animals↗