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Biomedical subjects

W G Pond

Publications and source records attributed to W G Pond.

At least 37 records · Page 2Linked to original sources
PubMed1995

Both maternal over- and undernutrition during gestation increase the adiposity of young adult progeny in rats.

We examined the influence of maternal diet during gestation on the growth and body composition of the progeny. On day 1 of gestation, rat dams were assigned to one of four feeding regimens: free access to standard rodent chow throughout gestation (AL); 20 g feed/day (prebreeding intake) throughout gestation (PB); 10 g feed/day from day 1 to day 14, then ad libitum from day 15 to parturition (RAL); 10 g feed/day from day 1 to 14, then 20 g/day to parturition (RPB). Progeny were fed ad libitum on standard chow diet from 3 to 12 weeks of age; food intake and weight gain were measured over this time. Body composition was measured at 12 weeks. The PB regimen restricted maternal food intake during the third trimester only; the RAL regimen restricted intake by 50% for two trimesters and produced hyperphagia in the third; the RPB regimen restricted intake by 50% for two trimesters, then intake (per unit body weight) was similar to that of AL dams during the third trimester. Litter size and progeny birth, weaning, and 12-week body weights were similar among the four groups. At 12 weeks of age, PB progeny had the highest body fat (per kg fat-free mass), despite similar feed intake during the 9-week postweaning period. The increased fat was proportionally distributed among intra-abdominal and subcutaneous depots. Progeny of RAL, AL, and RPB dams had similar amounts of body fat, but in RAL progeny more fat was present in intra-abdominal depots. The weights of fat-free mass, gastrointestinal tract and hindlimb skeletal muscles were unaffected by maternal diet. Restriction of maternal feed intake during the third week of gestation had subtle effects on the body composition of young adult progeny that could not be explained on the basis of differences in postweaning voluntary feed intake.

Abdomen↗
PubMed1995

Administration of porcine somatotropin by daily injection: growth and endocrine responses in genetically lean and obese barrows and gilts.

Influences of genotype and sex on responses to porcine somatotropin (pST) administered by daily injection were examined in genetically lean and obese gilts and barrows. Pigs (59 +/- 1.4 kg BW, eight per pST dose x line x sex) were injected daily with pST at doses of 0, 2, and 4 mg/d for 6 wk. Administration of pST induced dose-dependent decreases in feed intake and rate of backfat deposition, whereas rate and efficiency of gain were increased in a quadratic manner indicating that 4 mg of pST/d approached the optimal dose. These live measures of growth were also influenced (P < .05) by sex and line. Line, sex, and pST dose effects (P < .05) were noted for most offal components and carcass components. Quantity of lean and bone in the ham was increased (P < .01) and that of fat decreased (P < .01) with dose of pST. Throughout the trial pST induced increases (P < .05) in serum concentrations of IGF-I, IGF-II, insulin, and glucose and decreases in urea nitrogen. Concentrations of pST 24 h after injection were lower (P < .05) in pST-injected pigs than in buffer-injected pigs, indicating negative feedback on endogenous pST secretion. The pST-induced increases (P < .05) in insulin, IGF-I, and IGF-II and the decrease in urea nitrogen were evident at 24 h after the initial injection. Although pST administration improved the growth performance and composition of lean and obese barrows and gilts, the influences of line and sex were not expunged by administration of pST.

Animals↗
PubMed1995

Response to dietary fat and cholesterol in young adult boars genetically selected for high or low plasma cholesterol.

Twenty-eight young adult boars (age 7 to 8 mo) genetically selected for four generations for high (HG) or low (LG) plasma cholesterol were studied to assess dietary and genetic effects and their interactions on cholesterol metabolism. Boars within a genetic group were paired according to their plasma cholesterol concentration at 8 wk of age and were fed for 15 wk (2.7 kg/d) one of two diets (16.5% fat and 1,156 mg of cholesterol/kg diet, HD; or 3.1% fat and 0 cholesterol diet, LD) in a 2 x 2 factorial arrangement. Plasma total cholesterol (P < .01) and HDL-cholesterol (P < .01) concentrations were higher in boars fed HS (P < .01) and in HG boars (P < .01). There was a trend toward a diet x genotype interaction for plasma HDL-cholesterol (P < .06). Plasma insulin concentration tended to be lower in boars fed HD (P < .09) or HG boars (P < .10). There was a diet x genotype interaction for plasma glucagon (P < .04) concentration and a trend toward an interaction for insulin (P < .07). After 15 wk, all boars were killed by electrocution and exsanguination and measurements were taken. Backfat thickness was greater (P < .01) and carcass length (P < .01) and weights of the four lean cuts (P < .02) were lower in LG than in HG boars. No microscopic atherosclerotic plaques were observed in aorta or coronary arteries. Cholesterol concentration in subcutaneous fat was lower (P < .04) in LG boars, suggesting that cholesterol content of depot fat can be reduced by genetic selection in swine.

Adipose Tissue↗
PubMed1994

Protein restriction in early pregnancy alters fetal and placental growth and allantoic fluid proteins in swine.

This study was designed to determine the impact of protein malnutrition during early pregnancy on fetal and placental growth and on the protein synthesis capacity of placental and endometrial tissues. Twelve crossbred sows received 1.8 kg/d of a control (13% protein) or protein-restricted (0.5% protein) diet from the day of breeding to Day 63 of pregnancy, when dissections were performed on each conceptus unit. The de novo protein synthetic rate of placental and endometrial explants was measured using (35)S-methionine. These proteins and the proteins from amniotic and allantoic fluids were separated by polyacrylamide gel electrophoresis. Placental weight was significantly reduced in the sows fed the restricted diet, with a tendency for decreased fetal weight as well. No differences were found due to dietary treatment in de novo protein synthesis or in the electrophoretic patterns of secreted proteins of the placenta or endometrium. The apparent quantity of 3 proteins in the allantoic fluid of the restricted diet fetuses decreased, while 1 protein increased in comparison with that of the control fetuses. These data suggest that protein malnutrition in early pregnancy decreases placental growth, thereby decreasing both fetal growth and the opportunity for compensatory growth upon nutritional rehabilitation.

Journal Article↗
PubMed1994

An improved HPLC method to purify erythrocyte cholesterol for estimation of in vivo cholesterol synthesis using the deuterium method.

We report on an improved HPLC method to purify erythrocyte cholesterol for use in measuring in vivo cholesterol synthesis from 2H2O. The new procedure uses a smaller compression cartridge column at a flow rate of 3 mL/min. The new method reduces by almost tenfold the amount of solvent required to maintain the analytical purity of the isolated cholesterol.

Animals↗
PubMed1994

Accuracy of dual-energy x-ray absorptiometry for body-composition measurements in children.

The accuracy of body-composition measurements by dual-energy x-ray absorptiometry (DXA) was assessed by comparison with total carcass chemical analysis in 16 pigs with a weight range of 5-35 kg. Two software versions for body-composition analyses with the DXA instrument were evaluated. Although both software versions accurately predicted body weight, there were significant differences in the partitioning between bone mineral content (BMC), nonbone lean tissue, and body-fat compartments. All estimates of body composition were highly correlated (r2 > or = 0.98) with the results of the direct chemical reference method. SEEs were 226-271 g for body weight, 387-429 g for fat, 3.5-4.3 kg for fat-free mass, and 35.4-36.5 g for BMC. For bone, both software versions produced BMC values that were approximately 25% below the total carcass ash content. For the absolute mass of body fat, one DXA analysis provided underestimates that averaged 19.5% below the reference chemical method, whereas the alternate software version resulted in over-estimates, averaging 15.5%. Conversely, the average fat-free compartment was initially overestimated by 968 g, then underestimated by 892 g. The impact of these differences in the body-composition analyses by DXA were examined in a group of 18 young boys 4-12 y of age.

Absorptiometry, Photon↗
PubMed1994

Dietary cholesterol supplementation improves growth and behavioral response of pigs selected for genetically high and low serum cholesterol.

We hypothesized that, in pigs selected for low (L) or high (H) serum cholesterol for four generations, neonatal endogenous cholesterol synthesis would be sufficient to meet requirements for brain and body growth. In Experiment 1, eight 16-wk-old L pigs received a diet with or without 200 mg cholesterol/100 g diet for 35 d. Supplemented pigs grew approximately 25% faster and had a significantly greater concentration of free cholesterol in the cerebrum. In Experiment 2, 16 H and 16 L newborn pigs were fed a milk replacer with or without 200 mg cholesterol/100 g diet for 28 d. Pigs fed cholesterol had greater average daily gain (P < or = 0.09), significantly reduced liver 3-hydroxy-3-methylglutaryl-coenzyme A reductase activity, and significantly increased cerebral cholesterol content than pigs not fed cholesterol. One of three indices of exploratory behavior was significantly greater in the L pigs that received cholesterol compared with L pigs that did not receive cholesterol. These data suggest that these neonatal pigs are unable to produce sufficient cholesterol to meet requirements for normal growth and brain development and are dependent on dietary cholesterol in milk.

Animal Feed↗
PubMed1994

Dietary cholesterol inhibits whole-body but not cerebrum cholesterol synthesis in young pigs.

We studied the effect of dietary cholesterol on tissue cholesterol synthesis in 10 genetically lean pigs using the 2H2O incorporation method. Five pigs were fed a diet containing 0% cholesterol (controls) and five were fed a diet containing 0.5% cholesterol (cholesterol-fed) from d 1 to d 54 of age. From d 30 to d 54, they received 2H2O and cholesterol synthesis was determined by measuring deuterium enrichment in erythrocyte cholesterol. All pigs were killed on d 54 and liver, ileum, jejunum, kidney, adipose tissue, muscle, and cerebrum were collected for measurement of free and esterified cholesterol and of the deuterium content of tissue free cholesterol. In vivo cholesterol synthesis was inhibited by dietary cholesterol as reflected by a decrease in fractional synthesis rate from 16.8 +/- 1.7%/d in controls to 2.3 +/- 1.1%/d in cholesterol-fed pigs. Cholesterol feeding raised cholesterol ester concentration in plasma, liver, and other tissues. Deuterium enrichment of free cholesterol in tissues, such as liver, was reduced from 11.98 +/- 2.82 milli atom percent excess in controls to 1.83 +/- 1.14 in cholesterol-fed pigs. Greater cholesterol intake did not inhibit cholesterol synthesis in the cerebrum. Deuterium enrichment levels of cholesterol in plasma and liver were similar to those in other tissues except for brain, suggesting an equilibration of cholesterol between the liver and most extrahepatic tissues. The control of cholesterol synthesis in brain appears to be independent of that in liver and other tissues of the body.

Animals↗
PubMed1994

Concentrations of inorganic elements in milk of sows selected for high and low serum cholesterol.

Comprehensive information on the composition of the whole spectrum of essential inorganic elements in sow milk is very limited. The objectives of this study were to measure concentrations of major and trace mineral elements in milk of third-generation sows selected for high (H) or low (L) serum cholesterol concentrations at 8 wk of age and to determine correlations between concentrations of milk cholesterol and major and trace mineral elements in sow milk. Twenty-one H and 21 L and 8 contemporary unselected control (U) Chester White x Landrace x Large White x Yorkshire crossbred sows were milked on d 20 or 21 of their first lactation. A standard corn and soybean meal-based diet was fed to all sows during pregnancy and lactation. There were no differences among the sow groups in milk concentrations of Ca, K, Mg, Na, and P, indicating that the genetic selection for serum cholesterol did not affect major mineral contents of the milk. Concentration of S in milk of the H sows was significantly (P < .05) higher than that of the U sows. Effects of genetic group were significant for concentrations of B, Al, Cu, and Mn in the milk, but not for Mo and Zn concentrations. Milk cholesterol concentration was negatively correlated with milk Al (P < .05), B (P < .01), and Mn (P < .05) for pooled data; there was no relationship between milk cholesterol concentration and that of other mineral elements.

Analysis of Variance↗
PubMed1993

Protein restriction during pregnancy affects postnatal growth in swine progeny.

Protein deficiency during pregnancy affects fetal development. The critical period, when the fetus is most susceptible to maternal protein deficiency and its effect on neonatal growth, is unknown. Therefore, we studied the effect of a protein-restricted diet during early and late pregnancy and throughout pregnancy on growth of pigs from birth to market weight. Sows were fed a control (13% protein) or protein-restricted (0.5% protein) diet throughout pregnancy or protein-restricted diet from d 1 to 44, then control diet to term or control diet from d 1 to 81, then the protein-restricted diet to term. In Experiment 1, birth weights were measured, and 12 pigs/diet group were weaned at 4 wk and raised to market weight. Feeding the protein-restricted diet throughout pregnancy reduced birth and slaughter weights, whereas the control followed by protein-restricted and protein-restricted followed by control diets reduced only birth weight relative to controls. Indices of carcass lean were reduced in the protein-restricted piglets, with carcass fat not affected. In Experiment 2, control and control-protein-restricted litters were reduced to six piglets and 3/litter cross-fostered to a sow of the other treatment group. After weaning at 4 wk, 4 piglets/group were individually fed to 8 wk. The control and control followed by protein-restricted diet fed piglets had similar weights at birth, but piglets raised by a control-protein-restricted sow tended to weight less at weaning than their littermates raised by a control sow. After weaning, these piglets had greater feed intakes relative to other groups and there were no weight differences by 8 wk.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Reproductive, endocrine, and organ weight differences of swine selected for high or low serum cholesterol.

Three generations of selection for 56-d blood cholesterol concentrations were used to establish low and high cholesterol lines of pigs in which cholesterol concentrations differed by 39% in the last generation. Litter size (number of fully formed pigs born per litter) diverged with each successive generation of selection and, at the third generation, litter size differed between the low and high line by two pigs (high line = 8.5 +/- .6; low line = 10.5 +/- .5; P < .05). A random selection of offspring (gilts, n = 109; boars, n = 46; barrows, n = 94) from the third generation and a control line maintained throughout the experiment were monitored for hormonal and anatomical relationships that might provide insight into the mechanisms that altered fecundity. Ovulation rate (number of corpora lutea) as determined on d 60 of pregnancy was increased in the low (n = 29) compared with the high cholesterol line (n = 38; 11.8 +/- .3 vs 9.8 +/- .3, respectively; P < .05), and litter size continued to be increased in the low cholesterol line (P < .05). No differences were noted between lines in kidney, ovarian, or total corpora lutea weight. Empty uterine weight and adrenal weight were increased in the high cholesterol line (P < .05) in randomly selected offspring of the third generation, and liver weight increased in the low line (P < .05). Associated with increased concentrations of cholesterol were increased serum concentrations of progesterone (gilts) and testosterone (boars) in the high cholesterol line (P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Glands↗
PubMed1993

A semiautomatic device for feeding liquid milk-replacer diets to infant pigs.

We describe the design and use of a device that enables the semiautomatic feeding of various quantities of liquid, milk-replacer diet. The apparatus consists of a programmable fraction collector (with attachments for preparative work) driven by a high-flow peristaltic pump. To reduce bacterial growth and lipid oxidation of the liquid diet, we kept the milk-replacer in an ice bath and bubbled a slow stream of nitrogen through it at all times. The liquid diet was kept in suspension by continuous recirculation and agitation. The device can be used to dispense prespecified amounts of either the same volume of feed, or a different volume to each of two groups of animals at regular intervals over 24 h; alternatively, by using the time-windows feature of the fraction collector, up to 11 different volumes can be dispensed to 11 animals. We present results of a preliminary trial in which we used the equipment to feed 11 pigs, weaned at 1 d of age, for 11 d. Daily maintenance and programming of two systems, including diet preparation and pig weight measurements, were accomplished in approximately 90 min. The feeder is simple to program and enables the feed intake of the pigs to be adjusted accurately for individual BW on a daily basis. The pigs had no diarrhea and grew well on the rations allocated to them.

Animal Feed↗
PubMed1993

Effect of dietary fat and cholesterol level on tissue cholesterol concentrations of growing pigs selected for high or low serum cholesterol.

Thirty-six female pigs selected for three generations for high or low serum cholesterol were chosen to evaluate the effects of a high-fat, high-cholesterol diet and a low-fat, low-cholesterol diet provided on an ad libitum basis for 92 d beginning at 12 wk of age on the cholesterol content and percentage of fat in muscle and organ tissues. The pigs were four-way crosses (Chester White x Landrace x Large White x Yorkshire). Samples of cerebrum, heart, ileum, kidney, liver, longissimus muscle, semitendinosus muscle, and subcutaneous fat were collected from each animal for determination of cholesterol concentration. The liver was the only tissue that had a significant difference in cholesterol content and in fat percentage between the genetic groups (high serum cholesterol and low serum cholesterol) and between the two diets (high-fat, high-cholesterol diet and low-fat, low-cholesterol diet). There were no interactions between diet and genetic background on cholesterol accretion or on the percentage of fat in the tissues.

Adipose Tissue↗
PubMed1993

Milk cholesterol concentration in sows selected for three generations for high or low serum cholesterol.

Female crossbred swine (Chester White x Landrace x Large White x Yorkshire) selected for three generations for low (L, n = 24) or high (H, n = 26) serum cholesterol at 8 wk of age were milked at d 20 or 21 of their first lactation to measure cholesterol, fat, lactose, protein, and ash concentrations. A contemporary, unselected control (C) group from the same original population (third lactation, n = 7) was sampled concurrently. All sows were fed a standard gestation, then lactation, diet that contained no cholesterol or added fat (all plant, corn-soybean meal). Genetic selection for low or high serum cholesterol at 8 wk of age induced corresponding changes in milk cholesterol and fat concentration in the third generation of selection, but not in any other milk constituents. Milk cholesterol concentrations (milligrams/100 grams fresh weight) were L, 25.3 +/- 3.0; C, 35.7 +/- 8.0; and H, 41.4 +/- 6.9 (L < C < H, P < .01). Corresponding values for milk fat were 5.7 +/- 1.3, 7.2 +/- .8, and 7.0 +/- .8 mg (L < C = H, P < .01). Serum cholesterol concentrations at 8 wk of age were L, 66.1 +/- 8.1; C, 93.7 +/- 13.7; and H, 126.2 +/- 9.7 mg/dL (P < .01). Milk cholesterol concentration was significantly correlated with serum cholesterol (r = .782, P < .01) and milk fat (r = .36, P < .01). It seems that selecting swine for low or high serum cholesterol at 8 wk of age induced changes in lipid metabolism reflected in differences in milk cholesterol concentrations.

Animals↗
PubMed1993

Direct and correlated responses to divergent selection for serum cholesterol concentration on day 56 in swine.

Divergent selection for serum cholesterol concentration on d 56 was practiced in a four-breed, composite population for three generations. High and Low lines, representing high and low levels of serum cholesterol, respectively, were each maintained with approximately 10 males and 25 females per generation. Pigs from a contemporary Control line were evaluated only in the last generation. In the last generation, mean serum cholesterol concentration was significantly different among lines (107.1, 85.6, and 65.5 mg/dL for High, Control, and Low lines, respectively). Realized heritability was .31, .33, and .31 for high, low, and divergent selection (SE = .03), respectively. Terminal evaluation indicated that average birth and weaning (28 d of age) weight was lower (P < .05) for Low pigs (1.25 and 6.25 kg, respectively) than for High pigs (1.43 and 7.10 kg, respectively) and was intermediate for Control pigs (1.34 and 6.53 kg, respectively). At 56 d of age, High (15.1 kg) and Control (13.5 kg) pigs were heavier (P < .05) than Low pigs (11.9 kg). However, pigs sampled after 56 d did not differ (P > .05) in average daily gain, 164-d weight, feed consumption, or feed efficiency. Serum cholesterol concentration at 165 d of age was significantly different among lines (110.1, 98.5, and 85.6 mg/dL for High, Control, and Low pigs, respectively), although differences were smaller than at 56 d of age. When slaughtered at approximately 106 kg (188 to 195 d of age), Low pigs had significantly shorter carcasses than High and Control pigs (77.5 vs 78.7 and 78.9 cm, respectively). Low pigs had significantly more fat at the first rib (5.70 vs 5.28 cm) than High pigs. Lines did not differ significantly for fat thickness at the last rib, last lumbar vertebrae or 10th rib, or for longissimus muscle area. At 60 d of gestation, ovulation rate, measured as number of corpora lutea, was lower (P < .05) for High (9.84 eggs) than for Low (11.79 eggs) or Control (11.17 eggs) gilts. Differences in ovulation rate were reflected in smaller but nonsignificant differences in number of fetuses (7.97, 9.00, and 8.55 fetuses for High, Low, and Control, respectively).

Analysis of Variance↗
PubMed1993

Effects of carbadox, copper, or Yucca shidigera extract on growth performance and visceral weight of young pigs.

Two identical trials, each with 128 crossbred weanling barrows (6.8 +/- .2 and 7.6 +/- .2 kg for Trials 1 and 2, respectively), were conducted. In each trial, pigs were allowed to consume ad libitum a 16% CP corn-soybean meal basal diet (B), B + 55 ppm of carbadox, B + 250 ppm of copper (Cu), or B + 125 ppm of Yucca shidigera extract for 56 d (four pens/diet; eight pigs/pen). At d 56 of the test, eight pigs/diet (two pigs/pen) were slaughtered for carcass and viscera measurements. Data of carbadox treatment in Trial 1 are excluded from this paper because of an error in mixing of the diet. In Trial 1, during the test period from d 0 to 28, pigs fed Cu had greater (P < .05) ADG and ADFI than those fed B, whereas pigs fed yucca extract had higher ADFI (P < .05) but similar ADG (P > .05) compared with those fed B. During the period from 29 to 56 d, ADG was similar among pigs fed different diets (P > .05) but ADFI was affected (P < .05) by diet (yucca extract > Cu > B). No differences (P > .05) among diets were detected for gain/feed (G/F) and visceral weights expressed as a percentage of slaughter BW. In Trial 2, during the first 28 d, the ADG, ADFI, and G/F responses of pigs to Cu, yucca extract, and B were similar to those observed in Trial 1.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗
PubMed1993

Body weight gain is correlated with serum cholesterol at 8 weeks of age in pigs selected for four generations for low or high serum cholesterol.

We determined the relationship of BW at birth, weaning (4 wk of age), and 8 wk of age to serum total cholesterol (C), high-density lipoprotein-cholesterol (HDL-C), and triglycerides (TG) at 8 wk of age in pigs, from the fourth generation that had been selected for low (10 litters, 75 pigs, LC) or high (10 litters, 63 pigs, HC) C at 8 wk of age. Mean C concentration at 8 wk of age was 81 +/- 30 mg/dL for LC groups and 136 +/- 19 mg/dL for HC groups. Serum C, HDL-C, and TG concentrations were not correlated with birth weight, suggesting that the physiological factors that may cause reduced weight gain in older animals are not operative in newborn pigs. All three constituents were correlated (P < .05) with BW at weaning and at 8 wk. However, only 4% of the variation in weight at weaning and 7% at 8 wk could be explained by a relationship with serum TG. There was a positive correlation between C and BW at 8 wk (r = .46, P < .05), which was apparent within the subgroups of LC and HC females and LC males (r = .46, .48, .68, respectively); the correlation was low (r = .26) in HC males.

Animals↗