Biomedical subjects

D E Conner

Publications and source records attributed to D E Conner.

18 recordsLinked to original sources

PubMed1998

Peanut hulls as a litter source for broiler breeder replacement pullets.

Broiler breeder pullets were reared on either peanut hulls or pine shavings to determine effects of litter type on growth performance and litter characteristics. Pullets were reared to 20 wk of age in rooms initially bedded with 8 cm of clean shavings or hulls. Heating and ventilation were standardized in all rooms. Restricted skip-a-day feeding was used to attain recommended growth curves. Water was continuously provided for ad libitum consumption. Litter and environmental variables were measured throughout rearing and 2 wk after pullets were removed from the litter materials. Feed consumption, BW, mortality, and uniformity at 20 wk were not affected by litter type; however, gizzard weights were decreased in pullets reared on hulls. Litter bulk density increased with use and was greater for shavings through 11 wk, but not thereafter. Particle size decreased with use in both litter types. Through 11 wk, there were more particles in the > 4 mm range and less in the < 1.7 mm range with hulls. Litter moisture increased with use but was not affected by litter type. Litter pH was greater in unused shavings, but during and after use was generally greater in hulls. With both litter types, litter and environmental ammonia levels increased to 11 wk then decreased; however, this effect was more pronounced for hulls. Bacteria populations were not affected by litter type; however, greater fungal populations were observed in shavings at 7 and 15 wk. Aflatoxins were detected in unused hulls but not shavings. Because aflatoxin levels decreased during use and Aspergillus flavus and Aspergillus parasiticus populations were not detected in samples collected during use, aflatoxins observed were presumed to have been formed prior to use. Peanut hulls performed similarly to pine shavings as a litter source for breeder pullets; however, the specific influence of the aflatoxins contained in this litter source on bird performance deserves further study.

Aflatoxins↗

PubMed1998

Broiler skin color as affected by organic acids: influence of concentration and method of application.

Color of broiler skin was evaluated after exposure to organic acids under various concentrations and simulated potential plant application conditions. Breast skin from chilled broiler carcasses was treated with acetic (AA), citric (CA), lactic (LA), malic (ML), mandelic (MN), propionic (PA), or tartaric (TA) acids at 0.5, 1, 2, 4, and 6% concentrations. Each acid and concentration was applied in simulated dip (23 C for 15 s), scalder (50 C for 2 min), and immersion chiller (1 C for 60 min) conditions. A tap water control was included with each application method. Objective color values of L* (lightness), a* (redness), and b* (yellowness) were measured before and after the treatments to calculate color differentials under a factorial arrangement of organic acids and concentrations. Skin lightness increased (P < 0.01) in simulated chiller as compared to dip and scalder applications. Skin redness was reduced significantly in scalder, and yellowness in dip and scalder applications, respectively. In simulated dip application, with the exception of PA, all acids decreased lightness and increased redness and yellowness values. Propionic acid had little affect on lightness and redness values, but decreased yellowness values. In simulated scalder application, with the exception of PA, all acids decreased lightness with increasing concentration. The redness values changed little in scalder application. However, yellowness values were increased with all acids, except for PA, which decreased yellowness values. In simulated chiller conditions, all acids, except for PA, decreased lightness and redness and increased yellowness values. Propionic acid increased lightness and decreased yellowness values significantly in chiller conditions. Alterations in skin color should be taken into account in the selection and application of organic acids as carcass disinfectants.

Acetic Acid↗

PubMed1997

Specific identification of Campylobacter fetus by PCR targeting variable regions of the 16S rDNA.

Campylobacter fetus is recognized as a human and animal pathogen. The isolation and differentiation of C. fetus in diagnostic laboratories is hindered by its relatively slow growth and lack of distinguishing biochemical characteristics. We developed a fast, reliable PCR assay that specifically amplifies a 554-bp segment of the 16S rDNA from C. fetus. Fifty-two ATCC reference strains and 255 bacterial field isolates comprising the genera Campylobacter, Arcobacter, Helicobacter, Escherichia, Listeria, Salmonella, and Wolinella were evaluated using this PCR protocol. Only C. fetus strains were amplified. Sequence analysis of amplicons from ATCC and field strains of C. fetus confirmed the presence of the target DNA fragment. The detection limit of the technique was 5.9 x 10(3) CFU/ml. This PCR assay can yield reliable detection of C. fetus within 3 h after isolation of presumptive colonies on agar plates.

Animals↗

PubMed1997

Utilization of the skin attachment model to determine the antibacterial efficacy of potential carcass treatments.

Two experiments (EXP), utilizing the skin attachment model (SAM), were conducted to determine the bactericidal activity of six potential carcass disinfectants [EXP 1: 20, 400, and 800 ppm sodium hypochlorite; EXP 2: 5% acetic acid (AA), 8% trisodium phosphate (TSP), and 1% sodium metabisulfite (SS)] during simulated scalder (50 C for 2 min), chiller (0 C for 60 min), or post-process dip (23 C for 15 s) application. Efficacies of treatments were determined against populations of Salmonella typhimurium that were "loosely" or "firmly" attached to chicken breast skin (10 cm diameter). For comparison, activity of the six disinfectants was also determined against S. typhimurium in aqueous suspension. All disinfectants except SS reduced numbers of freely suspended S. typhimurium by > or = 4.5 log10 cfu/mL. The sodium metabisulfite did not reduce populations of salmonellae. In both EXP, there were disinfectant by application interactions (P < 0.05) on activity against loosely and firmly attached cells. Sodium hypochlorite at 20 ppm had little activity regardless of application, whereas higher levels were more effective (P < 0.001), particularly in the chiller application, in which loosely and firmly attached populations were reduced by 2.3 to 2.5 and 1.3 to 1.9 log10 cfu per skin, respectively. In EXP 2, SS showed no activity regardless of application. Trisodium phosphate was similarly effective (reduction by 1.2 to 1.8 log10 cfu per skin) in all applications (P > 0.05). In contrast, AA activity was affected by the application method (P < 0.05). Against loosely attached cells, AA was most effective in the chiller application (2.5 log10 reduction), whereas against firmly attached cells, AA was effective only in the scalder application (2.0 log10 reduction). Attachment of S. typhimurium to poultry skin apparently increased the ability of the bacteria to resist various disinfectants, and efficacy was influenced by extent of attachment of bacteria to skin and method of disinfectant application.

Acetic Acid↗

PubMed1996

Adverse effects of wide calcium:phosphorus ratios on supplemental phytase efficacy for weanling pigs fed two dietary phosphorus levels.

Ninety-six weanling pigs (initial BW = 9.3 kg, initial age = 37 d) were used in a 4-wk experiment to evaluate the response to three Ca: total (t) P ratios (1.2:1, 1.6:1, or 2.0:1) fed in combination with two P levels (.07 or .16% available that correspond to .36 or .45% tP) and two phytase levels (PY; 700 or 1,050 units/kg of diet). A 3 x 2 x 2 factorial arrangement of treatments was employed using a corn-soybean meal diet. Performance, serum mineral concentrations and alkaline phosphatase (ALP) activity, Ca and P digestibility and excretion, and bone mechanical measurements were examined. Average daily gain (P < .001), average daily feed intake (P < .01), and gain:feed (P < .05) were decreased linearly as the Ca:tP ratio became wider. The digestibility of P and Ca were decreased (P < .001) linearly as the Ca:tP ratio became wider. The digestibility of P (P < .001) and fecal P excretion (P < .01) were increased at the higher level of P. Increasing PY from 700 to 1,050 units (U)/kg of diet increased (P < .05) P digestibility and decreased (P < .01) P excretion but did not improve bone measurements. Shear force, stress and energy, and percentage of ash of both metacarpal and 10th rib linearly decreased (P < .001 to .05) as the Ca:tP ratio became wider, and bone measurements were generally greater for pigs fed the higher P level. Serum Ca concentration increased (P < .01) and the P concentration decreased (P < .001) as the Ca:tP ratio increased, but Mg, Zn, and ALP activity were not influenced by the Ca:tP ratio. Serum Ca and P concentrations were affected by PY supplementation over the 4-wk trial, but serum Mg and Zn concentrations were not affected by dietary treatments. Adverse effects of a wide Ca:tP ratio were greater at the low P diet for all responses. In addition, the activity of supplemental PY in diets seemed to be decreased as the Ca:tP ratio became wider and this negative effect of Ca:tP ratio seemed greater at the low P level, and seemed to parallel the effects of Ca:tP ratio on performance, P digestibility, bone, and serum measurements. Narrowing the dietary Ca:total P ratio from 2.0:1 to 1.2:1 led to an approximate 16% increase in phytase efficacy for improving performance, digestibility, bone measurements, and serum Ca levels.

6-Phytase↗

PubMed1996

Application of direct-fed microbial bacteria and fructooligosaccharides for salmonella control in broilers during feed withdrawal.

Providing direct-fed-microbial (DFM) bacteria and fructooligosaccharides (FOS) for the control of potential escalation of Salmonella colonization during simulated feed withdrawal and confinement was assessed. Eight hundred and eighty broilers (16 pens; 55 chicks per pen) were reared to 6 wk of age. Chicks were sprayed with a solution containing 10(6) nalidixic-acid resistant Salmonella typhimuriumNR cells per milliliter on the 2nd d after hatching. Because this first challenge did not yield a high infection rate, chickens were rechallenged per Os at Day 18 by providing water containing 10(7) cells of S. typhimuriumNR per milliliter. At 3 and 5 wk of age, 10 birds per pen were euthanatized and cecal Salmonella were quantified (log colony-forming units per gram). Feed was removed from all pens at 6 wk, and pens were randomly assigned to be either the treatment group or the control group. The treatment groups were provided a DFM (mixture of nine bacteria) and FOS 50 (R) (10%) in the drinking water. The control groups received drinking water only. After 6 h of feed withdrawal, chickens were cooped (eight per coop) and held 10 h. Immediately after confinement, 10 chickens were used for cecal enumeration of S. typhimuriumNR. Salmonella colonization declined from 99% at 3 wk to 44% at 5 wk. After feed withdrawal, application of the treatment, and confinement, 11 and 14% of the treated and control groups, respectively, yielded S. typhimuriumNR by direct plating from ceca (3.87 and 3.75 log 10 cfu/g, respectively). No difference (P > 0.05) in Salmonella colonization occurred between the treated and the control groups; however, enrichment of ceca (incubation in nutrient broth at 37 C for 24 h) yielded a higher incidence of S. typhimuriumNR in the control groups (32% in the treated vs 51% in the control). Ceca weights were greater in the treated group (P < 0.05). Simulated feed withdrawal and confinement did not escalate Salmonella colonization in the chicken ceca.

Animals↗

PubMed1995

Growth and survival of Escherichia coli O157:H7 under acidic conditions.

The effect of pH reduction with acetic (pH 5.2), citric (pH 4.0), lactic (pH 4.7), malic (pH 4.0), mandelic (pH 5.0), or tartaric (pH 4.1) acid on growth and survival of Escherichia coli O157:H7 in tryptic soy broth with 0.6% yeast extract held at 25, 10, or 4 degrees C for 56 days was determined. Triplicate flasks were prepared for each acid treatment at each temperature. At 25 degrees C, populations increased 2 to 4 log10 CFU/ml in all treatments except that with mandelic acid, whereas no growth occurred at 10 or 4 degrees C in any treatments except the control. However, at all sampling times, higher (P < 0.05) populations were recovered from treatments held at 4 degrees C than from those held at 10 degrees C. At 10 degrees C, E. coli O157:H7 was inactivated at higher rates in citric, malic, and mandelic acid treatments than in the other treatments. At the pH values tested, the presence of the organic acids enhanced survival of the pathogen at 4 degrees C compared with the unacidified control. E. coli O157:H7 has the ability to survive in acidic conditions (pH, > or = 4.0) for up to 56 days, but survival is affected by type of acidulant and temperature.

Acids↗

PubMed1995

Enumeration and identification of bacteria in chicken semen.

Three experiments were conducted to determine the bacteriological quality of chicken semen. Semen was collected from donor males, diluted, and surface inoculated onto seven different bacteriological media, from which randomly selected colonies were identified. Bacterial counts in semen averaged 5.14 log10 cfu/mL. Tryptic soy agar (TSA) was the best medium for the isolation of Gram-positive bacteria, whereas TSA + .3% bile salts (TSABS) and violet red bile agar + 1% glucose (VRBAG) were the best media for the isolation of Gram-negative and enteric bacteria. The genera of bacteria that were isolated depended on the medium that was used for isolation. The most frequently isolated genera included Escherichia, Staphylococcus, Micrococcus, Enterococcus, and Salmonella. Most of the bacteria that were isolated were endemic to poultry and were common environmental bacteria. This indicates that the environment and feed are important sources of bacterial contamination in broilers.

Animals↗

PubMed1995

In vitro fructooligosaccharide utilization and inhibition of Salmonella spp. by selected bacteria.

In vitro experiments were conducted to determine: 1) inhibitory capacities of potential direct-fed microbial bacteria against Salmonella serotypes; and 2) the ability of Bifidobacterium bifidum, Enterococcus faecium, Lactobacillus casei, Lactococcus lactis, Pediococcus sp., and Salmonella spp. to grow in media containing fructooligosaccharides (FOS-50 or FOS pure formulation) as the only carbohydrate source. Thirteen bacteria (two strains of Bacillus coagulans, Bacillus licheniformis, Bacillus subtilis, B. bifidum, E. faecium, two strains of Lactobacillus acidophilus, L. casei, Pediococcus sp., Propionibacterium acidopropionici, P. jensenii, and Propionibacterium sp.) were tested for inhibition of six Salmonella serotypes (S. california, S. enteritidis, S. heidelberg, S. mission, S. senftenberg, and S. typhimurium) using a spot-the-lawn technique. Bifidobacterium bifidum, E. faecium, all lactobacilli, and Pediococcus sp. clearly inhibited growth of all Salmonella serotypes. In the growth experiments, E. faecium, L. lactis, and Pediococcus sp. grew in media with either FOS-50 or the pure formulation of FOS as the sole carbohydrate source. All tested Salmonella serotypes utilized FOS-50 for growth; however growth varied among the serotypes. In contrast, none of the Salmonella serotypes grew in media containing the pure formulation of FOS as the only carbohydrate source.

Animals↗

PubMed1991

Characteristics of nonpathogenic strains of Listeria monocytogenes.

Five strains of nonpathogenic Listeria monocytogenes were characterized for (i) hemolysin production, (ii) cytolysis of Chinese hamster ovary (CHO) cells, and (iii) ability to attach and enter intestine 407 cells. Four of the five strains produced variable hemolysis and were weakly cytolytic for Chinese hamster ovary cells, whereas the other isolate was consistently hemolytic and strongly cytolytic for CHO cells. None of the strains was able to penetrate intestine 407 cells. In addition, two of the five strains were found to be nonmotile.

Animals↗

PubMed1986

Effect of temperature, sodium chloride, and pH on growth of Listeria monocytogenes in cabbage juice.

Human illness and death have resulted from the consumption of milk, cheese, and cole slaw contaminated with Listeria monocytogenes. Since the effects of temperature, NaCl, and pH on the growth of the organism in cabbage were unknown, a series of experiments was designed to investigate these factors. Two strains (LCDC 81-861 and Scott A, both serotype 4b) were examined. At 30 degrees C, the viable population of the LCDC 81-861 strain increased in sterile unclarified cabbage juice (CJ) containing 0 to 1.5% NaCl; a decrease in the population of both strains occurred in juice containing greater than or equal to 2% NaCl. At 5 degrees C, the population of the Scott A strain in CJ containing up to 5% NaCl was reduced by about 90% over a 70-day period; the LCDC 81-861 strain was more sensitive to refrigeration but remained viable in CJ containing less than or equal to 3.5% NaCl for 70 days. Growth in CJ at 30 degrees C resulted in a decrease in pH from 5.6 to 4.1 within 8 days. Death of L. monocytogenes occurred at 30 degrees C when the organism was inoculated into sterile CJ adjusted to pH less than or equal to 4.6 with lactic acid. No viable cells were detected after 3 days at pH less than or equal to 4.2. At 5 degrees C, the rate of death at pH less than or equal to 4.8 was slower than at 30 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)

Brassica↗

PubMed1986

Growth and thermal inactivation of Listeria monocytogenes in cabbage and cabbage juice.

Studies were done to determine the interacting effects of pH, NaCl, temperature, and time on growth, survival, and death of two strains of Listeria monocytogenes. Viable population of the organism steadily declined in heat-sterilized cabbage stored at 5 degrees C for 42 days. In contrast, the organism grew on raw cabbage during the first 25 days of a 64-day storage period at 5 degrees C. Growth was observed in heat-sterilized unclarified cabbage juice containing less than or equal to 5% NaCl and tryptic phosphate broth containing less than or equal to 10% NaCl. Rates of thermal inactivation increased as pH of clarified cabbage juice heating medium was decreased from 5.6 to 4.0. At 58 degrees C (pH 5.6), 4 X 10(6) cells/mL were reduced to undetectable levels within 10 min. Thermal inactivation rates in clarified cabbage juice (pH 5.6) were not significantly influenced by the presence of up to 2% NaCl; however, heat-stressed cells had increased sensitivity to NaCl in tryptic soy agar recovery medium. Cold enrichment of heat-stressed cells at 5 degrees C for 21 days enhanced resuscitation. Results indicate that L. monocytogenes can proliferate on refrigerated (5 degrees C) raw cabbage which, in turn, may represent a hazard to health of the consumer. Heat pasteurization treatments normally given to cabbage juice or sauerkraut would be expected to kill any L. monocytogenes cells which may be present.

Brassica↗

PubMed1986

Vibration-induced carpal tunnel syndrome.

The authors reviewed the median nerve decompressions performed by the senior author between 1976 and 1985 and found 787 surgical cases, of which 42 potentially occurred secondary to the use of vibration tools. All 42 patients presented with the classic history of carpal tunnel syndrome (CTS) and demonstrated a positive electromyography (EMG) or nerve-conduction study (NCS). Another six nonoperated patients with positive EMG or NCS were added to the group for a total of 48 patients with what the authors term vibration-induced carpal tunnel syndrome (VI-CTS). Of the 42 operated cases, 23 were bilateral, so a total of 65 median nerve decompressions are presented. Eight patients in the operated group also underwent incision of the flexor sheath for trigger fingers. The potential association between CTS or trigger finger and vibration syndrome is presented. The authors conclude that in the properly selected patient with VI-CTS, good subjective results can be obtained by median nerve decompression and/or trigger finger release.

Adolescent↗

PubMed1984

Sensitivity of heat-stressed yeasts to essential oils of plants.

Eight strains of yeasts (Candida lipolytica, Debaryomyces hansenii, Hansenula anomala, Kloeckera apiculata, Lodderomyces elongisporus, Rhodotorula rubra, Saccharomyces cerevisiae, and Torulopsis glabrata) were examined for changes in sensitivity to eight essential oils of plants (allspice, cinnamon, clove, garlic, onion, oregano, savory, and thyme) after being sublethally heat stressed. With the exception of garlic oil for all test yeasts, onion oil for S. cerevisiae, and oregano oil for R. rubra, the essential oils at concentrations of up to 200 ppm in recovery media did not interfere with colony formation by unheated cells. However, some oils, at concentrations as low as 25 ppm in recovery media, reduced populations of sublethally heat-stressed cells compared to populations recovered in media containing no test oils. This demonstrates that the yeasts were either metabolically or structurally damaged as a result of being exposed to elevated temperatures and that essential oils prohibited repair of injury. The size (diameter) of colonies produced on oil-supplemented recovery agar by heat-stressed cells was reduced compared to that observed on unsupplemented agar. Pigment production by heated R. rubra was inhibited by oils of oregano, savory, and thyme, but enhanced by garlic and onion oils. The influence of essential oils on survival of yeasts in thermally processed foods and in the enumeration of stressed cells in these foods should not be minimized.

Condiments↗

PubMedDate not supplied

Ulnar deviation of the fingers in gout simulating rheumatoid arthritis.

Two cases of gout with marked ulnar deviation (UD) are reported. Both cases were previously diagnosed rheumatoid arthritis (RA) at referral, but gout was clinically suspected because of atypical features of RA, and subsequently confirmed by demonstration of monosodium urate crystals under the polarized microscope. No definitive evidence of associated RA was present in either case. Although UD in gout is distinctly rare, it is important to recognize this deformity in gout in order to avoid inappropriate therapy. Mechanical factors might have contributed to the hand deformities in both cases.

Aged↗

PubMedDate not supplied

Salmonella colonization and shedding patterns of hens inoculated via semen.

Two experiments were conducted to determine the effect of inseminating hens with semen contaminated with marker strains of Salmonella enteritidis and S. typhimurium. Eggs were collected and examined for salmonellae. In Expt. 1, 3/57 (5.3%) of eggs from S. enteritidis-challenged hens and 2/50 (4.0%) of eggs from S. typhimurium-challenged hens were contaminated with salmonellae. Salmonellae were recovered from only the shell. In Expt. 2, however, no eggs from S. typhimurium-challenged hens were contaminated; 2/73 (2.7%) of the eggs from S. enteritidis-challenged hens were contaminated. In Expt. 1, S. typhimurium was present in 30% of the oviducts and 20% of the ovaries; S. enteritidis was present in 20% of the oviducts and 20% of the ovaries. No salmonellae-containing oviducts or ovaries were found in either S. enteritidis- or S. typhimurium-challenged hens in Expt. 2. S. enteritidis and S. typhimurium were found in fecal samples taken 24 hr after insemination, but only S. enteritidis was fecally shed 7 days after insemination (20% in Expt. 1). Data indicate that semen may severe as a vehicle for transmission of salmonellae to the hen, which may result in sporadic production of contaminated eggs.

Animals↗

PubMedDate not supplied

Effect of mating activity on the ability of Salmonella enteritidis to persist in the ovary and oviduct of chickens.

Experiments were undertaken to determine whether female leghorn chickens that had been mated had a lower incidence of salmonellae colonization in the ovary, oviduct, internal organs, and eggs than did unmated birds from the same flock when both were inseminated with Salmonella enteritidis-contaminated semen. Eggs were sampled at approximate 3-day intervals, and fecal samples were taken at 24 hours and 7 days after insemination. Fourteen days following insemination, hens were euthanatized and the ovary, oviduct, liver, spleen, gall bladder, and ceca were removed. None of the previously mated hens had salmonellae present at any sampling time. Virgin birds showed salmonellae colonization in all samples. This indicates that mating activity and the environment of females offers some protection against salmonellae colonization in the reproductive tract.

Animals↗

PubMedDate not supplied

Incidence of campylobacters in the intestine of avian species in Alabama.

Avian species necropsied at the C. S. Roberts Veterinary Diagnostic Laboratory, Auburn, Alabama, from December 1993 until May 1994 were examined for the incidence of intestinal campylobacters. Ninety-one intestinal swabs, representing 66 separate cases and 17 different avian species, were collected and placed into Cary-Blair transport medium. Selective enrichment and culture media were used for initial isolation of Campylobacter spp. Presumptive colonies were identified as Campylobacter spp. by phase-contrast microscopy and Gram stain, and they were confirmed by serological latex agglutination. Campylobacter spp. were isolated in 18 (19.7%) of the 66 cases. From the remainder of the cases, 13 (15%) yielded presumptive colonies on Campy-Cefex agar; however, they were not confirmed serologically as Campylobacter spp. Use of Cary-Blair transport medium held in refrigeration for up to 24 days did not hinder the determination of campylobacters in intestinal samples. A variety of avian species, including chicken, emu, hawk, ostrich, and parrot, harbored commensal campylobacters and therefore should be considered potential reservoirs.

Alabama↗