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ABSTRACT: Abstract An integrated effort to reduce the occurrence of Salmonella in poultry products should include the control of Salmonella in poultry production in early stages, which requires an efficient monitoring of Salmonella spp. in poultry houses. Studies were conducted to evaluate the potential advantages of using air samples as an alternative to litter samples for PCR detection of Salmonella spp. from poultry houses. The air filter and litter samples from a poultry house were spiked with a culture of Salmonella typhimurium. The intact samples and the DNA extracted from the samples were used for amplification of Salmonella-specific DNA using hns gene specific primers. The ***hns gene was more effectively amplified with filter samples than litter samples when the intact sample was used as template. When extracted DNA was used, however, there was no difference between the two samples in their intensities of PCR products as visualized on an agarose gel. The dilution of the matrices from both sampling methods greatly increased the amplification efficiency, indicating that it was the background matrices that hindered the PCR amplification. The results in this study suggest that air filter sampling may be a labor-saving alternative to litter sampling, which can be used to increase the sensitivity of PCR detection of Salmonella spp. without prior sample processing.
Journal of Rapid Methods & Automation in Microbiology 11/2011; 7(2):103 - 111. · 0.58 Impact Factor
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ABSTRACT: Abstract The purpose of this research was to develop a microtiter-based assay procedure for assessment of virulence gene response of Salmonella Typhimurium to fresh homogenized vegetables. The microtiter procedure was adapted from a assay for β-galactosidase activity of a hilA fusion strain of S. Typhimurium with volumes of all reagents adjusted for microtiter plate wells. S. Typhimurium exposed to pH 7 saline yielded a higher level of hilA expression than responses after incubation in pH 4, 5 and 6 saline. Bacterial cells exposed to broccoli extracts yielded the higher levels of hilA expression while bell pepper and tomato yielded the overall lowest amounts of hilA expression. From this study, it appears that fresh produce extracts have different abilities to significantly alter virulence response in Salmonella. In conclusion, the hilA fusion stain assay can be successfully adapted to microtiter plates for testing Salmonella virulence response to vegetable extracts.
Journal of Rapid Methods & Automation in Microbiology 01/2011; 11(1):1 - 9. · 0.58 Impact Factor
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L M Donalson,
W K Kim,
V I Chalova,
P Herrera,
J L McReynolds,
V G Gotcheva,
D Vidanovic, C L Woodward,
L F Kubena,
D J Nisbet,
S C Ricke
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ABSTRACT: The objective of this in vitro study was to evaluate the effects of combining a prebiotic with alfalfa on fermentation by laying hen cecal bacteria. Cecal contents from laying hens were diluted to a 1:3,000 concentration with an anaerobic dilution solution and added to serum tubes filled with ground alfalfa or a layer ration with or without fructooligosaccharide (FOS) prebiotic. Samples were processed in an anaerobic hood, pressurized by using a pressure manifold, and incubated at 37 degrees C. Volatile fatty acid (VFA) and lactic acid concentrations were quantified at 6 and 24 h of substrate fermentation. In this study, fermentation of alfalfa resulted in greater production of acetate, VFA, and lactic acid compared with the layer ration. Although with a relative inconsistency in data between trials, the amendment of FOS to both alfalfa and the layer ration appeared to further increase fermentation as demonstrated by overall higher propionate, butyrate, VFA, and lactic acid concentrations. The effect was more pronounced after 24 h of fermentation, implying time constraints for the optimal production of fermentation products in the chicken gastrointestinal tract. These data indicate that in vitro cecal fermentation can be enhanced by the addition of FOS.
Poultry Science 08/2008; 87(7):1263-75. · 1.73 Impact Factor
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ABSTRACT: Induced molting by feed withdrawal has been a common practice in the commercial layer industry and usually involves the removal of feed for a period of up to 14 d. However, this is a practice that is believed to adversely influence the welfare of the hens and there is a need to examine behavioral responses to alternative molt regimens. The behavioral patterns of hens on 90% alfalfa:10% layer ration, 80% alfalfa:20% layer ration, and 70% alfalfa:30% layer ration molt diets were compared with feed withdrawal (FW) hens, and fully fed (FF) hens. The White Leghorn laying hens were approximately 54 wk old and were placed in 3 identical climate-controlled rooms. The hens were individually housed in 2-tier wire battery cages and provided treatment rations and water ad libitum. Nonnutritive pecking, walking, drinking, feeder activity, preening, aggression, and head movement were quantified during two 10-min periods each day for 6 hens from each treatment. Over the 9-d treatment period, hens in the FW, 70% alfalfa:30% layer ration, and 80% alfalfa:20% layer ration groups spent significantly more time walking than hens in the 90% alfalfa:10% layer ration group. The FF and 70% alfalfa:30% layer ration hens spent half as much time preening, whereas the FW hens displayed nearly twice as much nonnutritive pecking when compared with other treatments. Most differences in head movements occurred at the beginning of the molt period, whereas during the last half of molt, alfalfa-fed hens exhibited feeder activity similar to FF hens, and all were significantly higher than that of FW hens. After some initial adjustment by the hens, consumption of alfalfa molt diets appeared to reduce nonnutritive pecking behavior, which is characteristically associated with FW hens.
Poultry Science 07/2008; 87(6):1005-11. · 1.73 Impact Factor
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ABSTRACT: Molting is a natural process, which birds undergo to rejuvenate their reproductive organs. The US poultry egg production industry has used feed withdrawal to effectively induce molt; however, susceptibility of Salmonella Enteritidis has encouraged the development of alternative methods. Previous research conducted in our laboratory showed that alfalfa is effective at molt induction and provides equivalent postmolt production numbers and quality when compared with feed withdrawal. In the attempt to further increase the efficacy of alfalfa molt diet and decrease the chicken susceptibility to Salmonella Enteritidis during molt, fructooligosaccharide (FOS) was added to a combination of 90% alfalfa and 10% layer ration in 2 levels (0.750 and 0.375%). Ovary and liver colonization by Salmonella Enteritidis in 3 and 2 of the 4 trials, respectively, were reduced (P <or= 0.05) in hens fed FOS-containing diets compared with hens subjected to feed withdrawal. Significant decreases in ce-cal Salmonella Enteritidis counts were also observed in 2 of the 4 trials. In 3 of the 4 trials, the same diets did not affect (P > 0.05) the production of cecal total volatile fatty acids when compared with hens undergoing feed withdrawal. However, in all 3 alfalfa molt diets, the concentrations of lactic acid were greater (P <or= 0.05) than hens with feed withdrawal, but no differences (P > 0.05) were observed among hens fed alfalfa combined with FOS and hens fed alfalfa/layer ration without FOS. Overall, given the similarities between hens fed 0.750% FOS (H) and 0.375% FOS (L), molt diets combined with the lower level of FOS should be sufficient.
Poultry Science 07/2008; 87(7):1253-62. · 1.73 Impact Factor
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ABSTRACT: To generate an inducible plasmid-borne cad-gfpmut3 transcriptional fusion and develop a method for quantification of total lysine.
The cad-gfpmut3 transcriptional fusion was constructed by cloning the cad promoter (Pcad) upstream of a promotorless gfpmut3 located on a high-copy plasmid. The construct was electroporated into Escherichia coli ZK126 and the transformed strain was subsequently used to quantify lysine in feed ingredients. Lysine standard curves based on gene induction of the bacterial cells were used for estimating acid hydrolysate lysine concentrations in four feed ingredients. Except for sorghum, no substantial differences were observed when the data for lysine in soybean (2 x 49 +/- 0 x 37%), cottonseed (1 x 82 +/- 0 x 15%), and meat and bone meal (2 x 31 +/- 0 x 24%) generated by the newly developed construct were compared with previously published data.
Using the cad-gfpmut3 fusion, feed derived lysine induction was measured easily and accurately, and could be a useful tool for the estimation of lysine in acid hydrolysates of feed ingredients.
The described approach for lysine quantification in feed ingredients represents a cost- and time-efficient method offering rapid and accurate lysine quantification of multiple samples.
Letters in Applied Microbiology 02/2008; 46(1):107-12. · 1.62 Impact Factor
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ABSTRACT: To detect the presence of methanogens in the faeces of broiler chicks during the first 2 weeks of age.
Chicken faecal samples from 120 broiler chicks were incubated for methane gas formation and methanogenic archaea were analysed using real-time PCR. The copy number of the order Methanobacteriales 16S rDNA gene in chicken faeces when the broilers were 3-12 days of age, litter and house flies collected in the bird house ranged from 4.19 to 5.51 log(10) g(-1) wet weight. The number of positive methane culture tubes increased from 25% to 100% as the birds aged.
Methanogens were successfully detected in faecal samples from 3- to 12-day-old broilers, as well as litter and house flies using real-time PCR. The copy number of methanogenic 16S rDNA gene in these samples was also similar to the number observed in litter and house flies.
The same methanogens consistently appeared in chicken faeces a few days after birth. Detection of the methanogenic bacteria in litter and house flies implicated them as potential environmental sources for methanogen colonization in broiler chicks.
Letters in Applied Microbiology 01/2008; 45(6):629-34. · 1.62 Impact Factor
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ABSTRACT: Given the importance of riboflavin in human diets, a rapid riboflavin assay is needed by the food industry to allow simultaneous determination of riboflavin in numerous food sources. The growth responses of Lactobacillus rhamnosus to microaerophilic conditions and three reducing agents were examined as an attempt to reduce riboflavin assay time. Ascorbic acid, dithiothreitol and thioglycollate were applied at three concentrations. None of the concentrations of reducing agents caused a further increase of bacterial optical density (OD) or had a significant effect on the growth rates. More optimal microaerophilic conditions were achieved through the use of an anaerobic chamber. The growth rate of L. rhamnosus under microaerophilic conditions (0.30 ± 0.05/h) was not significantly different (P > 0.05) from the growth rate of the bacteria under aerobic conditions (0.34 ± 0.07/h). However, after 14 h of bacterial growth, the OD of the bacterial culture under anaerobic hood incubation (0.71 ± 0.09) was significantly higher (P < 0.05) than under aerobic incubation conditions (0.58 ± 0.05). Additional research is needed involving more controlled atmospheres for incubation during growth and a wider range of reductants to optimize and shorten the time required for riboflavin microtiter plate assay.PRACTICAL APPLICATIONSQuantifying riboflavin in foods and food ingredients is important to the food industry. Lactobacillus rhamnosus growth response to varying levels of riboflavin is used to estimate the amount of this vitamin. In an effort to optimize growth on microtiter plates and decrease assay time, microaerophilic conditions were examined. Although rate of growth was not altered, cell concentration measured as optical density (OD) did increase. Microaerophilic incubation of microtiter plates represents a potential approach to decrease assay time and provide the food industry with more timely results.
Journal of Rapid Methods & Automation in Microbiology 11/2007; 15(4):320 - 331. · 0.58 Impact Factor
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ABSTRACT: Using a fluorescent whole-cell Escherichia coli biosensor previously developed in our laboratory, we determined total and bioavailable lysine in four feed ingredients (soybean, cottonseed, meat and bone meal, and sorghum) and three complete feeds (chick starter and finisher, and swine starter). The same feed sources were analyzed for total lysine by high performance liquid chromatography (HPLC) and bioavailable lysine by chick bioassay. No significant differences were found between bioavailable lysine estimates for soybean, cottonseed, meat and bone meal, chick starter and finisher, and swine starter obtained by the fluorescent E. coli biosensor and chick bioassay. Except for sorghum, the E. coli biosensor estimates for total lysine were highly comparable to those obtained by HPLC. Comparisons were also conducted between conventionally performed optical density-based and the newly developed fluorescence-based lysine assay. The lack of significant differences in data obtained for total and bioavailable lysine by both detection modes indicated reliance and accuracy of the fluorescent E. coli biosensor. Overall results suggest that the microbial assay based on green fluorescent protein fluorescence represents a promising alternative method for lysine quantification.
Applied Microbiology and Biotechnology 09/2007; 76(1):91-9. · 3.42 Impact Factor
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ABSTRACT: Salmonella is regarded as a primary foodborne pathogen commonly found in the gastrointestinal tract and internal organs of poultry. However, Salmonella is also capable of surviving in fresh water supplies. In this study, our efforts were to determine which media controls of varying nutrient availability would allow for accurately assessing the potential of a poultry house water source to influence virulence gene expression in Salmonella. The cages of the sampled layer house were divided into four separate quadrants. Virulence expression was measured using a β-galactosidase assay on a hilA:lacZY fusion strain of S. Typhimurium and calculated as Miller units to adjust for bacterial cell concentration measured as optical density. Virulence assays were performed with brain heart infusion broth (BHI) serving as the primary overall control which yielded values ranging from approximately 60–100 Miller units. Results showed that standing water obtained from quadrant 2 yielded a significantly different (P<0.05) virulence responses compared to other standing water samples from other quadrants. However, no significant difference was observed between the quadrants for the fresh water samples. BHI media proved to be the most consistent negative control for evaluating hilA response to poultry house water by yielding the lowest overall Miller unit values compared to other laboratory control media.
Journal of Rapid Methods & Automation in Microbiology 05/2007; 10(3):173 - 184. · 0.58 Impact Factor
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ABSTRACT: Microbiological assays for determination of bioavailable lysine appear to have many advantages. However, since the developed assay is based on bacterial growth and considerable optical density (OD) is required to detect distinguishable differences in extent of growth, it can be time consuming. The purpose of this study was to explore the fluorescence as an alternative method to measure bacterial growth instead of OD and examine the possibility to shorten the time required for the lysine assay. An assay based on SYTO 9 green fluorescent DNA binding dye (Live/Dead BacLight Protocol, Molecular Probes) was used to stain all bacteria in a population. Additional experiments were carried out to determine the ability of fluorescence based on SYTO 9 to overcome problems associated with high nonbacterial background that contributes to OD. From this study it appears that using fluorescence based on SYTO 9 green fluorescent staining, the E. coli lysine auxotroph growth assay can be completed in 9 h instead of 11 h and has the advantage of improved detection sensitivity. Problems associated with interference by high background nonbacterial OD can be partially resolved by fluorescence.
Journal of Rapid Methods & Automation in Microbiology 05/2007; 11(4):313 - 324. · 0.58 Impact Factor
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ABSTRACT: Zinc supplemented diets have been used to provide zinc as a nutrient and higher concentrations have been used to induce molt in laying hens. It is not known if the zinc in these diets would inhibit Salmonella spp growth. This study examines the effects of zinc compounds on the growth of S. typhimurium poultry isolate under aerobic and anaerobic conditions. The aerobic growth response of S. typhimurium was determined either in tryptic soy broth (TSB) or minimal (M9) broth containing five different concentrations (0.67, 2.01, 3.35, 4.69, and 6.03% [wt/vol]) of either Zn acetate [Zn(C2H2O2)22H2O] or Zn sulfate [ZnSO47H2O] while anaerobic growth response was determined in M9 broth with or without reductants (L-cysteine hydrochloride [C3H7NO2SHCl], and sodium sulfide [Na2S 9H2O]). Aerobic growth rates inhibited (P < 0.05) by Zn acetate than by Zn sulfate in TSB medium. The Zn source and concentration decreased (P < 0.05) aerobic growth response of S. typhimurium poultry isolate in M9 medium. The growth rates of S. typhimurium under anaerobic growth conditions were less responsive to Zn salts but were generally lower (P < 0.05) in the presence of reductant than in the absence of reductants at each concentration of Zn compound. The results in this study provide evidence that Zn may inhibit S. typhimurium under in vitro aerobic or anaerobic atmospheric conditions and S. typhimurium grows less optimally under anaerobic growth conditions.
Journal of Food Safety. 04/2007; 22(4):219 - 229.
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ABSTRACT: Feed deprivation is commonly used by the poultry industry to induce molting and stimulate multiple egg-laying cycles. However, feed deprivation has been observed experimentally to increase susceptibility of poultry to Salmonella infections. Previous studies indicated that alfalfa was efficacious in reducing Salmonella; the present investigation was designed to evaluate the efficacy of combined alfalfa and layer diets on Salmonella colonization. Leghorn hens over 50 wk of age were divided into 12 groups of hens and placed in individual laying cages. One week prior to dietary changes, hens were put on an 8L:16D photoperiod that continued for the 9-d experiment. Hens were challenged orally with 104 cfu of Salmonella Enteritidis (SE) on d 4 of treatment and cultured for SE at the termination of the 9-d study. Two independent experiments were conducted consisting of the following treatment groups: nonfed hens, full-fed standard commercial layer diet, 100% alfalfa meal diet, a 90% alfalfa meal/10% standard commercial layer diet, and a 70% alfalfa meal/30% standard commercial layer diet. When evaluating SE colonization in the ceca (Exp. 1), a reduction (P < 0.05) was seen in the 100% alfalfa meal diet and the 70% alfalfa meal/30% standard commercial layer diet treatment groups when compared with the controls with Log10 values of 0.54, 0.44, and 2.82, respectively. Evaluation of physiological parameters showed the alfalfa treatment groups had reductions (P < 0.05) in weight loss, ovary weight, and feed consumption when compared with the full-fed standard commercial layer diet hens, and these results were comparable with the nonfed hens. In Exp. 2, all of the treatment groups had a reduction (P < 0.05) in SE colonization of the ceca when compared with the controls. There were also similar physiological reductions in weight loss, ovary weight, and feed consumption when birds were fed the alfalfa diets in Exp. 2. These data suggest that alfalfa can potentially be combined with layer ration to limit SE infection and still induce a molt comparable with feed withdrawal.
Poultry Science 07/2006; 85(7):1123-8. · 1.73 Impact Factor
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ABSTRACT: To examine the utility of an Escherichia coli green fluorescent protein (GFP) containing biosensor for quantification of bioavailable lysine in selected feed samples under nonsterile conditions and to estimate the background fluorescence of analyzed feed samples and evaluate the risk of confounding GFP emission from the lysine assay organism.
Escherichia coli lysine auxotroph GFP based biosensor was used to determine the percentage of bioavailable lysine in two samples of soybean-, cottonseed-, and meat and bone meal under nonsterile conditions. The fluorescence emitted by GFP was successfully measured using a spectrofluorimeter to monitor bacterial growth response to protein-derived lysine and lysine containing small peptides. The autofluorescence of analyzed feed samples at different concentrations could also be estimated.
When feed protein concentrations are decreased, autofluorescence interference can be avoided.
The E. coli lysine auxotroph GFP-based biosensor can successfully be used for the determination of bioavailable lysine in these selected animal feed proteins under nonsterile conditions.
E. coli GFP biosensor for lysine has potential for routine application in animal feeds.
Letters in Applied Microbiology 04/2006; 42(3):265-70. · 1.62 Impact Factor
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ABSTRACT: Dietary molt induction to initiate additional egg laying cycles in commercial laying hen flocks is a wide spread practice in the United States. Feed deprivation is the most commonly used method but this practice has generated several concerns which has lead to research for viable alternative approaches. From a management standpoint a single ingredient molting diet consisting of high fiber-low energy represents an easily adaptable diet for large laying hen production units. Alfalfa meal is readily available in most commercial locations and possesses many of the desirable properties of an ideal laying hen molt diet. In the current study hens at a commercial laying facility were molted by both alfalfa and feed deprivation. After the hens had reentered post-molt commercial egg production, eggs were examined for egg quality performance. Egg shell strength, albumen height, yolk height, weight, length, and yolk color were all tested using various mechanical techniques. The eggs were also sampled for testing by consumer sensory panels that assessed the desirability of the eggs' color and flavor/texture. Eggs laid by hens molted by alfalfa had a significantly lower (p<0.05) "a*" level of colorimetry. Eggs laid by hens molted with alfalfa also exhibited significantly higher (p<0.05) egg weights and length. In the consumer sensory test, there was no significant difference (p>0.05) in color or flavor/texture scores in eggs from either feed deprived or alfalfa molted hens. The consumer sensory and mechanical quality attributes indicates that alfalfa shows promise as an alternative molt induction diet by providing a single diet option for extending egg production into a second egg laying cycle.
Bioresource Technology 06/2005; 96(8):907-11. · 4.98 Impact Factor
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ABSTRACT: Molting is a process by which a hen's reproductive tract is rejuvenated prior to the beginning of a laying cycle. This process is often artificially induced in commercial settings in order to extend the productive life of a flock of hens. The most common method for the induction of molt is feed withdrawal for a period of several days. It has been noted that feed withdrawal, while effective in inducing molt and allowing an adequate reproductive rest period for the hen, may cause deleterious effects on the animal. This has prompted the investigation of alternatives to feed deprivation for the induction of molt in commercial laying hens. This study involved feeding alfalfa to hens to assess its ability to induce molt. Results show that alfalfa meal and alfalfa pelleted diets were equally effective as feed withdrawal in causing ovary weight regression in birds. Molted hens induced by alfalfa diets exhibited postmolt levels of egg production over a twelve week period that were similar to that of hens molted by feed withdrawal. The postmolt eggs laid by hens molted by alfalfa were of comparable quality to eggs from feed deprived hens. Alfalfa, a fibrous feed with low metabolizable energy, may be provided to hens on an ad libitum basis for an effective molt induction that retains comparable egg quality and production.
Bioresource Technology 04/2005; 96(5):565-70. · 4.98 Impact Factor
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ABSTRACT: Molting is a common practice used by the commercial egg industry to rejuvenate flocks for a second or third laying cycle. During this time the hens rest from production, and the reproductive organs are rejuvenated to increase production and quality during the next laying cycle. Although feed withdrawal (FW) is the most popular and effective method of molt induction, it has come under scrutiny due to food safety issues and animal welfare issues. This study involved feeding alfalfa mixed with layer ration at different ratios to hens to determine their ability to induce molt. The treatment ratios were 100% alfalfa (A100), 90% alfalfa and 10% layer ration (A90), and 70% alfalfa and 30% layer ration (A70). In addition, a fully fed (FF) nonmolted control and a FW negative control were used. Alfalfa is an insoluble, high fiber feedstuff with low metabolizable energy. Egg production for A90 and FW treatments ceased completely by d 6, whereas birds fed A100 and A70 ceased egg production by d 8. Ovary and oviduct weight of hens fed all molting diets decreased (P < 0.05) by an average of 1.5 to 2.5% (BW basis) compared with FF control during the 9-d molt induction period. As the percentage of layer ration increased, feed intake also increased and percentage of BW loss decreased during the 9-d molt induction period. Hens molted by FW lost an average of 25.8% BW, whereas A70 hens lost 18.9% BW. Nonmolted hens (FF) and A70 treatment hens had significantly lower (P < 0.05) egg production when compared with all other treatments over the 39-wk postmolt period. FF treatment hens also had lower (P < 0.05) albumen heights when compared with all other treatments. From these results, alfalfa or alfalfa mixed with layer ration appears to be viable alternatives to conventional FW methods for the successful induction of molt and retention of postmolt performance.
Poultry Science 03/2005; 84(3):362-9. · 1.73 Impact Factor
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ABSTRACT: The standard method for molting to stimulate multiple egg-laying cycles in laying hens is feed deprivation. However, the physiological changes within hens caused by feed deprivation increase susceptibility of the hens to Salmonella enterica serovar Enteritidis (SE) infection. In an effort to develop an alternative method to induce molting without increasing susceptibility to SE, an alfalfa diet was compared with the standard molting method for the level of ovary regression and SE colonization. Hens over 50 wk of age were divided into 3 treatment groups (12 hens/group): nonmolting by normal feeding (NM), molting by feed deprivation (M), and molting by alfalfa diet (A). Individual hens on all treatments were challenged orally with 10(5) cfu of SE on the fourth day after feed changes and were analyzed for ovary weight and SE colonization or invasion in crop contents, cecal contents, liver, spleen, and ovary on the ninth day. In 3 of the 4 trials, there was a significant decrease in SE colonization of the crop between the alfalfa diet (A) and the feed deprived molt (M). In most of the 4 trials, there was a significant reduction in SE infected organs in birds fed the alfalfa diet (A) compared with birds undergoing feed deprived molt (M). Most of the trials showed no significant difference in overall SE between A and NM. Therefore, the results of this study suggest that an alfalfa diet has the potential to be used as an alternative method for forced molting, without increasing the incidence of SE in eggs and internal organs.
Poultry Science 03/2005; 84(2):185-93. · 1.73 Impact Factor
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ABSTRACT: A study was conducted to evaluate effects of different bone preparation methods on bone parameters and the correlations between bone breaking strength and the other bone parameters. Bone breaking strength is dramatically changed depending on bone preparation methods, whereas other bone parameters such as ash content and ash concentration are not significantly influenced by bone preparation methods. Thus, the objective of this study was to evaluate the effects of 3 bone preparations (fresh, dry, and fat-free dry) on bone parameters and the relationship between bone breaking strength and bone parameters. Sixty Single Comb White Leghorn hens were used for this study. Hens were euthanized by CO2 gas, and the right tibia and femur were collected. The bones were divided into 3 treatment groups: fresh, dry, and fat-free dry. There were no significant differences in fresh weight, bone volume, dried weight, ash weight, and ash concentration of tibia and femur among the treatments. However, fresh tibia (24.13 kg) exhibited more bone breaking strength compared with the dried (9.90 kg) and fat-free dried bones (7.41 kg) (P < 0.05). The bone breaking strength (20.97 kg) of fresh femur was also significantly higher than the dried (9.22 kg) and fat-free dried femurs (6.94 kg). The bone breaking strength of the fresh bone was highly correlated with dried weight, ash weight, and ash concentration, whereas that of the fat-free dried bone was poorly correlated with the other bone parameters. The results indicate that fresh bone gives better bone breaking strength correlated to the other bone parameters than dry or fat-free dry preparation.
Poultry Science 10/2004; 83(10):1663-6. · 1.73 Impact Factor
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ABSTRACT: Virulence expression of Salmonella enterica serovar Typhimurium under iron limited condition was measured by beta-galactosidase (beta-gal) assay using a hilA-lacZY fusion strain and calculated as Miller units. hilA-lacZY beta-galactosidase assays were performed in brain heart infusion (BHI) and minimal media (M9), after iron chelation with 2, 2-dipridyl and iron-supplementation respectively. Before performing virulence assays, concentrations of iron in the media were estimated using ferrozine. Iron content was found to be more in BHI (42.6 microg dL(-1)) as compared to M9 (10.03 microg dL(-1)). beta-gal activity of Salmonella Typhimurium in BHI was generally less than that observed in M9. After exposure to various combinations of iron chelator in BHI, hilA-lacZY activity only increased at the highest concentration of chelator (2001 microM) but decreased in M9 media for all iron concentrations when compared to controls with no iron amendment. These results indicate that iron availability may influence S. Typhimurium hilA expression.
Journal of Environmental Science and Health Part B 02/2004; 39(5-6):861-70. · 0.89 Impact Factor
