Biomedical subjects

L M Potter

Publications and source records attributed to L M Potter.

At least 19 recordsLinked to original sources

PubMed1998

Clonal dissemination of vancomycin-resistant Enterococci and comparison of susceptibility testing methods.

One hundred fifty clinical isolates of Enterococcus faecalis (88 isolates) and Enterococcus faecium (62 isolates) were tested in vitro for their susceptibility to vancomycin and high-level aminoglycosides (HLA). Remel's Synergy Quad Plates (RSQ) were used as the reference method and compared to Kirby-Bauer disc diffusion test, Vitek GPS-TA card, MicroScan Panel (GP-6), and Etest. Streptomycin susceptibility results for MicroScan GP-6 and RSQ were recorded at 24 and 48 h and all other methods and antibiotics were read at 24 h or less. When compared with the agar screen method, all of the methods demonstrated > 99% agreement. One isolate was falsely sensitive to gentamicin at 24 h, but resistant at 48 h, when tested on both MicroScan and RSQ agar screen. Thirty-nine isolates showed resistance to vancomycin with all methods. These isolates were from three different local hospitals and were identified as E. faecium. Pulse-field gel electrophoresis demonstrated that all of the vancomycin-resistant isolates were derived from the same clone. Of interest is the observation that high-level resistance to aminoglycosides varied between the clonally related isolates.

Aminoglycosides↗

PubMed1995

Bioavailability of phosphorus in various phosphate sources using body weight and toe ash as response criteria.

The relative bioavailability values of P from seven sources were determined using male chickens fed a basal corn-soybean meal diet (.40% total P and 1.10% Ca) with varying levels of test and standard phosphates from 0 to 3 wk of age. Each of seven test phosphates was added to the basal diet at .05, .08, .12, .17, .23, and .32% levels. In addition, standard diets were formulated by adding the same levels of P plus .44 and .60% levels from dicalcium phosphate dihydrate (CaHPO4.2H2O) to the same basal diet. Each of the 42 test diets was fed to two pens of 10 chicks each, and each of the standard diets was fed to six pens of 10 chicks each. Three-week body weight gain and percentage ash of dried toe data were fitted with nonlinear (asymptotic and sigmoidal) regression equations, and the ratios of regression coefficients were used to determine the bioavailability of various test phosphates relative to the reference standard. Based on the asymptotic regression equation of body weight gain and on the sigmoidal regression equation of toe ash on the percentage of P added to the diets from the seven phosphate sources, the average relative bioavailability of the P (compared with the standard given a value of 100%) was as follows: Lucaphos-48, 88.4%; Lucaphos-40, 95.1%; Rukana, 83.7%; Cefkaphos-N, 104.8%; phosphoric acid, 93.0%; monocalcium phosphate monohydrate [Ca(H2PO4)2.H2O], 111.8%; and Biophos, 92.0%. A difference of 7.7% units for the average bioavailability of the P was required for significance (P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗

PubMed1995

An evaluation of various response criteria in assessing biological availability of phosphorus for broilers.

The relative bioavailability of P from seven sources was determined in relation to a standard dicalcium phosphate dihydrate (CaHPO4.2H2O) in a 21-d assay involving 1,320 broiler male chicks using several response criteria. The seven sources (Lucaphos-48, Lucaphos-40, Rukana, Cefkaphos-N, phosphoric acid, monocalcium phosphate monohydrate, or Biophos) were added to the basal diet (.40% total P and 1.10% Ca) at levels to supply .05, .08, .12, .17, .23, and .32% P. Two additional levels (.44 and .66%) of P from dicalcium phosphate dihydrate were included for the standards. The criteria selected to evaluate included tibia ash, tibia specific gravity, tibia shear force, toe shear force, and metatarsal shear force. Other criteria: weight, length, diameter, and volume of tibia; weight, volume, and specific gravity of metatarsus; and weight, volume, and specific gravity of toe were not selected because their response to increasing P levels were inconsistent and quite variable. Nonlinear (asymptotic and sigmoidal) regression equations were fitted to the data than linear equations. The ratios of regression coefficients were used to determine the bioavailability of various test phosphates relative to the reference standard. The results indicated that the response criteria used for the determination will considerably influence the relative bioavailability estimates of a P source. Body weight gain and toe ash percentage were found to be an equally or a more sensitive criteria for assessment of P availability than tibia ash. Tibia specific gravity, tibia shear force, toe shear force, and metatarsal shear force were of limited value as response criteria in P bioavailability assays based on standard error and difference required for significance.

Animals↗

PubMed1993

Supplemental dietary L-tryptophan effects on growth, meat quality, and brain catecholamine and indoleamine concentrations in turkeys.

1. An experiment was conducted to investigate the effects of feeding supplemental tryptophan during the two weeks before market on growth, mortality during transportation, meal quality and brain neurotransmitter concentrations in male turkeys. 2. Brain serotonin, 5-hydroxyindoleacetic acid and norepinephrine concentrations were increased dose-dependently with 1.0, 2.0 and 3.0 g/kg supplemental dietary tryptophan. 3. Supplemental dietary tryptophan had no effect on body weight gain, food intake, food efficiency or mortality. 4. Carcase and individual thigh weights were significantly heavier in those birds fed 1.0 g/kg supplemental tryptophan.

Animal Feed↗

PubMed1991

Self-selection of dietary protein and energy by turkey breeder hens.

1. An experiment was conducted to determine the effects of self-selection of dietary protein and energy by turkey hens on reproductive performance in a warm environment. 2. Dietary self-selection had no significant effect on egg production, egg weight, or body weight of turkey hens. 3. Fertility and hatchability of eggs produced by self-selecting hens were significantly reduced compared to eggs from control hens fed on a complete diet. 4. Protein intake was significantly reduced among self-selecting hens when compared to control hens fed on a complete diet (P less than or equal to 0.001). 5. Food and energy intake decreased as the ambient temperature increased. Nevertheless, protein intake of self-selecting hens increased over the course of egg production despite decreasing food intake. Therefore, self-selecting hens preferred a diet with a greater protein content (g protein/kg diet) in the last 10 weeks of egg production than during the first 10 weeks of egg production.

Animal Feed↗

PubMed1989

Saccharomyces cerevisiae pneumonia in a patient with acquired immune deficiency syndrome.

The clinical course of a patient with a polymicrobial pneumonia that included Saccharomyces cerevisiae infection is described. S. cerevisiae was recovered from autopsy cultures of the lungs, spleen, oral mucosa, and small intestine, and organisms morphologically consistent with S. cerevisiae were visualized in histologic sections of the lung. The role of this organism as a human pathogen is reviewed.

Acquired Immunodeficiency Syndrome↗

PubMed1989

Effects of dietary protein and added fat on turkeys varying in strain, sex, and age. 1. Live characteristics.

An experiment was conducted to determine the effects of dietary protein and added fat on body weight, feed consumption, and feed efficiency of male and female Nicholas Large White (N), Jaindl Large White (JL), and Jaindl Medium White (JM) turkeys at various ages. At 8 wk of age, 162 males and 288 females from each strain were divided equally into six pens of males and six pens of females per strain. Each of 6 pelleted diets containing standard or high protein and 0, 5, or 10% added fat was fed to one pen of each sex and strain of turkeys. At 20 wk of age, N, JL, and JM males weighed 14.77, 11.56, and 9.00 kg, respectively, and females weighed 8.97, 7.49, and 5.75 kg, respectively. At 28 wk of age, N, JL, and JM males weighed 18.32, 15.10, and 11.65 kg, respectively, and females weighed 10.35, 9.12, and 7.04 kg, respectively. The feeding of diets containing 10% rather than 0% added fat from 8 to 20 wk of age decreased feed consumption 11.1 and 13.1% and increased feed efficiency 16.3 and 16.4% in males and females, respectively. Feeding high protein diets significantly increased body weight gains. The apparent smaller increase than previously experienced in feed efficiency from dietary added fat may be associated with the use of pelleted feed in this experiment.

Age Factors↗

PubMed1989

Effects of dietary protein and added fat on turkeys varying in strain, sex, and age. 2. Carcass characteristics.

The effects of dietary protein and added fat on carcass characteristics were determined at various ages for female and male turkeys and from three strains: Nicholas Large White (N), Jaindl Large White (JL), and Jaindl Medium White (JM). A total of 1,350 turkeys was divided into 36 pens and fed diets containing 0, 5, or 10% added fat and standard or high protein levels from 8 wk of age to time of processing. One-fourth of the females and one-third of the males from each pen were processed at 16, 20, 24, or 28 wk and at 20, 24, or 28 wk, respectively. Breast meat weight, expressed as a percentage of carcass weight, was greater for JM and JL turkeys than for N turkeys (34.6, 33.9, and 31.7%, respectively), increased with age (31.9, 34.1, and 34.2% at 20, 24, and 28 wk of age, respectively), was greater for females than for males (34.2 and 32.6%, respectively), decreased with added fat (33.7, 33.4, and 33.1% for 0, 5, and 10% fat, respectively) and increased with a 3% addition of dietary protein (33.2 and 33.6%, respectively).

Age Factors↗

PubMed1988

Bioavailability of phosphorus from various phosphates based on body weight and toe ash measurements.

Two experiments involving 1,152 turkeys were conducted to determine the relative bioavailability of phosphorus of eight phosphates from commercial and experimental sources. The basal diet, composed of 52% dehulled soybean meal and 41% ground yellow corn, contained 1.48% calcium and .44% total phosphorus. Phosphorus from the eight sources was added to the basal diet at levels of .09, .18, or .27% to form 24 diets with a constant calcium content. Each diet was fed to one pen of eight males and eight females from 1 to 4 wk of age in the first experiment and to two pens (one of each sex) of 16 poults/pen from 0 to 4 wk of age in the second experiment. Measurements of percentage ash of the middle toe pooled from all poults within a pen and of average body weight at 4 wk of age provided similar relative phosphorus availability values. With the phosphorus in monocalcium phosphate as the standard set at 100%, phosphorus from two sources of dicalcium phosphate and one source of defluorinated phosphate were found not significantly different in bioavailability (95, 105, and 103%, respectively). Phosphorus in curacao phosphate was only 55% available and in the three experimental defluorinated phosphates, phosphorus was 81, 70, and 87% available. Significant differences in bioavailability between two samples greater than 13 and 18% were found when using toe ash and body weight measurement, respectively.

Animals↗

PubMed1988

Effects of varying fat and protein in diets of growing large white turkeys. 1. Body weights and feed efficiencies.

An experiment was conducted to determine the effects of varying levels of dietary fat and protein in corn-soybean meal diets on body weight gain, feed consumption, and feed efficiency (gain:feed ratio) of Nicholas Large White male turkeys between 8 and 22 wk of age. Diets containing 0, 5, 10, or 15% added fat from one of three sources and 18, 21, or 24% protein were fed. At 12 and 16 wk of age, protein levels of all diets were decreased by 2%. A total of 917 turkeys in 36 pens was used. Additions of 5, 10, and 15% fat increased body weight gains 3.3, 7.5, and 6.0%, respectively. Feed consumption decreased 1.3% and feed efficiency increased 2.1% for each 1% fat added to the standard and high protein diets. The fat containing 15% free fatty acids and 1.5% moisture, impurities, and unsaponifiables (MIU) decreased feed consumption 1.5% and increased feed efficiency 2.3% for each 1% added fat, and the two fat sources containing 48% free fatty acids and 5% MIU decreased feed consumption 1.2 or 1.1% and increased feed efficiency 2.1 or 2.0% for each 1% added fat. The former fat source was estimated to contain 7.7% more metabolizable energy than the average of the latter two fat sources. Cumulative body weight gain, feed consumption, and feed efficiency decreased 13.2, 5.7, and 8.1%, respectively, from feeding low protein diets in comparison with results of feeding standard and high protein diets. Maximum increases in body weight gains were obtained with 10% added fat at all levels of protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Nutritional Physiological Phenomena↗

PubMed1987

Alterations in performance and muscle composition of young turkeys in response to dietary amino acid balance.

Two experiments were performed to determine the effects of essential (EAA) and nonessential amino acid (NEAA) supplementation of a 22% protein corn-soybean meal diet on the performance of muscle composition of male Large White turkeys from 7 to 21 days of age. The 22% protein diet was supplemented with DL-methionine (MET) or a combination of MET and L-lysine (LYS) in Experiment 1. Additions in Experiment 2 included MET; and EAA mixture of MET, LYS, L-threonine, and L-valine; and a mixture of NEAA equal to 2% crude protein combined with either the MET or EAA supplement. Controls received a 30% protein diet. Each diet was fed ad libitum to five and four pens of eight poults in Experiment 1 and 2, respectively. Maximum performance was obtained with the 30% protein diet in both experiments. Methionine was confirmed as the first-limiting amino acid in the 22% protein diet. Lysine addition to the MET-supplemented low protein diet adversely affected performance in Experiment 1, suggesting that LYS was not the second most limiting amino acid. The EAA supplement elicited growth equal to the 30% protein diet although feed efficiency remained inferior. Increases in growth and feed efficiency were associated with NEAA addition. Changes in the weights of the pectoralis and gastrocnemius muscles due to diet, albeit directly related to body weight, were independent of muscle composition. The composition of gastrocnemius muscle was relatively insensitive to dietary manipulation. Pectoral ribonucleic acid (RNA) and deoxyribonucleic acid (DNA) concentrations increased with a decrease in dietary protein. Amino acid supplementation reduced DNA concentration without altering muscle RNA.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗

PubMed1987

Biological values of phosphorus from various sources for young turkeys.

Two experiments, each utilizing 540 turkeys, were conducted to determine the biological value of phosphorus from 13 different sources when compared with that from dicalcium phosphate (dihydrate, purified) as a standard. Each phosphorus source was added to a basal diet composed of 44% ground yellow corn and 52% dehulled soybean meal to supply .09, .18, .27, or .45% inorganic phosphorus. Each of 60 diets, which included duplicates of the standard source, was fed to a pen of 9 male poults from 1 day to 3 weeks of age in each experiment. Body weight and toe ash measurements of poults collected at 3 weeks of age were used in nonlinear (exponential) bioassays to obtain relative biological values of phosphorus from various sources. With the dicalcium phosphate standard set at 100%, the average relative biological values of three samples from each of commercial monocalcium phosphate (21% P), dicalcium phosphate (18.5% P), and defluorinated phosphate were 93, 81, and 70%, respectively. Four samples of experimental defluorinated phosphate averaged 75%. Differences of about 5% between values were required for statistical significance, indicating significant differences among these biological values of phosphorus from the various phosphate sources in diets of young turkeys.

Animals↗

PubMed1987

Deficient amino acids in protein of dehulled soybean meal for young turkeys.

Two 12-day experiments were conducted with Large White turkeys to determine which amino acids are deficient in a diet containing dehulled soybean meal as the sole source of protein. A 22% protein basal diet composed of 43.3% glucose monohydrate, 45.4% dehulled soybean meal, .5% DL-methionine, 6% stabilized fat, and added minerals and vitamins served as the negative control. Two positive control diets were formed by substituting either 16.5% dehulled soybean meal or a mixture containing amounts of essential amino acids equivalent to those in the added dehulled soybean meal in place of an equal amount of glucose monohydrate in the basal diet. Nine additional diets were formed by removing one or more amino acids from the mixture. Each of the 12 diets in a block design was fed to two pens of males and two pens of females with 8 birds per pen from 7 to 19 days of age in each experiment. Average body weight gain of poults fed the 22% protein diet with added amino acids approached that of poults fed the 30% protein diet (288 vs. 300 g, respectively). Removal of the amino acid mixture from the 22% protein diet depressed body weight gain by 19.0%. Depressions of 19, 16, 11, 7, and 6% in body weight gains resulted from the removal of valine, threonine, lysine, phenylalanine (or tyrosine or glycine), and isoleucine, respectively. A decrease of 5% was required for significance (P less than or equal to .05). When evaluated by this deletion technique, effects of valine and threonine deficiency were more pronounced than effects of lysine deficiency in dehulled soybean meal for young turkeys.

Amino Acids↗

PubMed1986

Salinomycin toxicity in turkeys.

Five 7-day trials using 336, 24, 24, 40, and 40 Large White male turkeys when 7, 11, 15, 27, and 32 weeks of age, respectively, were conducted to determine the toxic effects of salinomycin. Salinomycin became more toxic as the age of the turkeys increased. When 7-week-old turkeys were fed diets containing 44 or 66 ppm salinomycin, only 1 of 84 died; when turkeys 27 or 32 weeks of age were fed those amounts, 13 of 20 died. Salinomycin at 22 ppm tended to depress rate of growth at young ages and to prevent or decrease growth and to increase mortality at older ages. Caution should be exercised to avoid salinomycin contamination of turkey diets.

Animals↗

PubMed1985

Dietary protein and yolk sac inoculation with Escherichia coli in young turkeys.

An experiment was conducted to examine the effect of pathogenic Escherichia coli inoculated into the yolk sac of day-old turkeys. Escherichia coli was isolated from the yolk sac of stunted poults and inoculated directly into the yolk sac of day-old birds. Poults were administered either .1 ml of uninoculated sterile Todd-Hewitt broth or .1 ml of a 10(-3) or 10(-2) dilution of a 24-hr E. coli culture containing 3.4 X 10(8) viable bacteria/ml. In addition, poults were fed either 28 or 22% protein diets from 0 to 21 days of age to form a 3 X 2 factorial arrangement. Body weight gain and feed consumption were measured weekly, and dry matter and protein retention and nitrogen-corrected metabolizable energy were measured from 7 to 10 and 17 to 20 days postinoculation. Intestinal mucosal dipeptidase and maltase activities were determined at 21 days of age. Average mortality by 7 days of age was increased from 1 to 36% from the E. coli inoculation of the yolk sac. Escherichia coli significantly depressed body weight gain and feed consumption 27 and 30, 13 and 16, and 6 and 8%, respectively, during the first, second, and third weeks of the experiment but failed to affect feed efficiency. Feeding a 28% protein diet alleviated the depression in feed consumption and body weight gain to some extent compared with a substantial depression at 22% protein. Nitrogen content and gross energy of the excreta were increased by both dilutions of E. coli for the 7 to 10-day period; this was indicative of a malabsorption of nutrients.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1985

Varying fat and protein in diets of growing large white turkeys.

Two series of three consecutive 4-week experiments with a total of 1,370 Large White turkeys between 8 and 20 weeks of age were conducted to determine the effects of varying levels of dietary fat and protein on body weight gain and feed efficiency. Diets containing 0, 5, and 10% added fat and 18, 20, 22, and 24% protein in a 3 X 4 factorial were each fed to a total of three pens of males and three pens of females. At the end of each 4-week period, the turkeys were rerandomized to form 12 new equivalent groups, and similar diets with 2% less protein were fed. As part of this study, two fats, varying in fatty acid composition, were also compared but found not to affect significantly body weight gain or feed efficiency. Interaction effects of fat and protein on body weight gain, feed consumption, or feed efficiency were not significant. Body weight gain increased .5, .6, and 1.1%, feed consumption decreased 1.1, 1.0, and .9%, and feed efficiency increased 1.7, 1.8, and 2.2% for each 1% added fat during the 8 to 12-, 12 to 16-, and 16 to 20-week periods, respectively. The greater-than-expected increase in feed efficiency from added fat to diets of older turkeys is postulated to be due to stimulated feed consumption and body weight gain rather than to an extra caloric content of fat per se.

Aging↗

PubMed1984

Methionine, cystine, sodium sulfate, and Fermacto-500 supplementation of practical-type diets for young turkeys.

Two experiments were conducted using a total of 1,296 poults divided into 144 pens to determine the effects of adding .10% DL-methionine, .10% L-cystine, .50% sodium-sulfate, and .125 or .250% Fermacto -500 to their diets. Large White and Medium White turkeys were raised to 7 and 8 weeks of age in Experiments 1 and 2, respectively. Each of the 24 diets was fed to one pen of each sex in a 2 X 2 X 2 X 3 factorial design in the first experiment and to two pens of each sex in the second experiment. The basal diet, composed primarily of ground yellow corn and dehulled soybean meal, contained 28% protein, .49% methionine, and .41% cystine. Average body weights at the end of the experiments were increased 3.6% from .10% added DL-methionine, 3.4% from .10% added L-cystine, and 5.3 and 6.0% from .125 and .250% added Fermacto -500, respectively. Although sodium sulfate failed to increase final body weights, 2- and 4-week body weights were increased 3.2 and 2.1%, respectively. Sodium sulfate increased body weights more in the absence of added cystine, indicating a sparing effect of sodium sulfate on cystine. The increases in body weight from methionine and cystine were additive, indicating that the sulfur amino acid requirement is probably in excess of 1.10% and that .51% may be cystine.

Animals↗

PubMed1984

Influence of basic and branched chain amino acid interactions on the lysine and valine requirements of young turkeys.

Two experiments were conducted to determine the influence of amino acid interactions on the lysine and valine adequacy of a low protein diet fed to Large White turkeys from 7 to 19 days of age. Corn-soybean meal diets containing 22 and 30% protein served as controls in both experiments. Test diets involved supplementation of the 22% protein diet with several essential amino acid mixtures. Each diet was fed ad libitum to two pens of eight males and two pens of eight females in each of three trials, except that the 22% protein control diet was fed to four and two pens of each sex per trial in Experiments 1 and 2, respectively. Experiment 1 varied the levels of lysine (0, .60, and 1.20%) and arginine (0, .64, and 1.28%) included in the amino acid mixture. A decrease in supplemental lysine from .60 to 0% reduced weight gain and feed efficiency by 8.6 and 2.4%, respectively. The lysine deficiency was not exacerbated by arginine supplementation up to 179% of the requirement. The effects of altering the leucine (0, .54, and 1.08%) and isoleucine (0 and .4%) contents of the amino acid mixture on the valine requirement were investigated in Experiment 2. Leucine and isoleucine supplementation of diets containing 1.25% valine acted independently to reduce weight gain and feed intake, but the depressions were reversed with the addition of .44% valine. Maximum weight gain and feed efficiency were not achieved with diets containing 1.25% valine and no added leucine or isoleucine, which were indicative of a true valine deficiency in the basal 22% protein diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗