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1.
Poult Sci ; 100(12): 101476, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34710711

RESUMEN

After being banned by the European Commission in 2018, the use of formaldehyde as a feed amendment in the United States has come into question. Therefore, this study was conducted to explore alternatives to formaldehyde, such as formic acid and monoglycerides, and their effects on poultry production. In total, 1,728 Cobb 700 broilers were randomly assigned to 96-floor pens on day of hatch (18 birds/pen). Using a randomized complete block design (4 blocks), treatments were assigned to pens with blocking based on location within the barn, with the eastern half of the barn designated for digestibility and the western half designated for production (per experiment: 8 control pens and 10 pens per treatment). All diets were based on a negative control (NC), basal diet. Dietary treatments consisted of: NC, NC + 0.25% formalin (F), NC + 0.25 and 0.50% Amasil NA (AML and AMH; 61% formic acid and 20.5% Na-formate), and NC + SILO Health 104L (SILO; mixture of monoglycerides; 0.5% from 0 to 14 d, 0.4% from 14 to 28 d, and 0.2% from 28 to 42 d). Water and feed were provided ad libitum. Performance data were collected during feed changes on d 0, 14, 28, and 42, with digestibility data collected at d 14 (2 per pen) and carcass quality (6 per pen) assessed at d 46 with a randomly selected group of broilers. A one-way ANOVA followed by Dunnett's multiple comparison, where treatments were evaluated against F were conducted using JMP 14.0 (P ≤ 0.05). Main effect of treatment was significant for performance, nutrient digestibility, and carcass quality. Differences in body weight and ADG were observed from d 14 to d 28, resulting in a trending improvement in lysine digestibility on d 14 and carcass quality on d 46 of birds fed AML and AMH in comparison to those fed F (P < 0.05). Whereas birds fed SILO had reduced digestibility of methionine on d 14 and a decrease in meat quality on d 46 in comparison to those fed F (P < 0.05). Therefore, Amasil NA at 0.25 or 0.50% may be an effective alternative to formaldehyde as a feed amendment for poultry production.


Asunto(s)
Alimentación Animal , Pollos , Alimentación Animal/análisis , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Dieta/veterinaria , Suplementos Dietéticos , Formaldehído , Formiatos , Carne , Monoglicéridos , Nutrientes , Distribución Aleatoria
2.
Poult Sci ; 96(7): 2400-2411, 2017 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-28339832

RESUMEN

Biological supplements in poultry feed are of continued interest due to the improvements in growth performance, protection from pathogen invasion, and benefits in overall host health. The fermentation metabolites of Diamond V Original XPC™ (XPC) have previously been shown to improve commercial performance and reduce Salmonella in poultry. The current study sought to characterize the cecal microbiota using culture-independent analysis based on 16S rRNA gene in Coccivac-D sprayed broilers supplemented with XPC and/or Salinomycin (SAL). Ross 708 male broilers (n = 640) were assigned to one of 4 treatments: Cocci-vaccine (T1), Cocci-vaccine + XPC (T2), Cocci-vaccine + SAL (in the grower diet only) (T3), and Cocci-vaccine + SAL (in the grower diet only) + XPC (T4). Analysis with a PCR-based denaturing gradient gel electrophoresis (DGGE) indicated a shift in the microbial populations present at the various sampling ages - 16, 28, and 42 days. Phylogenetic analysis indicated further consistency in microbial communities directly related to bird age. Identification of microbial communities present and the assessment of their respective quantities using an Illumina MiSeq indicated treatment with XPC had no significant impact on microbial diversity (Chao1 index, observed operational taxonomic unit (OTU) and phylogenetic diversity (PD) whole tree). Sampling age revealed significantly greater diversity at 16 and 28 d (P < 0.05) as compared to the 42 d for the Shannon diversity index, while showing significantly decreased richness and diversity in the 42 d sampling age (Chao1 and observed OTU; P < 0.05). The results of the current study indicate that the chicken intestinal microbiota are impacted more by temporal changes rather than by the feed additive studied.


Asunto(s)
Antibacterianos/farmacología , Pollos/metabolismo , Dieta/veterinaria , Microbioma Gastrointestinal/efectos de los fármacos , Sustancias de Crecimiento/farmacología , Vacunas Antiprotozoos/farmacología , Piranos/farmacología , Alimentación Animal/análisis , Animales , Antibacterianos/administración & dosificación , Ciego/microbiología , Suplementos Dietéticos/análisis , Sustancias de Crecimiento/administración & dosificación , Vacunas Antiprotozoos/administración & dosificación , Piranos/administración & dosificación , Distribución Aleatoria
3.
Poult Sci ; 96(6): 1820-1830, 2017 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-28339946

RESUMEN

When prebiotics and other fermentation substrates are delivered to animals as feed supplements, the typical goal is to improve weight gain and feed conversion. In this work, we examined pasture flock chicken cecal contents using next generation sequencing (NGS) to identify and understand the composition of the microbiome when prebiotics and fermentation substrates were supplemented. We generated 16S rRNA sequencing data for 120 separate cecal samples from groups of chickens receiving one of 3 prebiotics or fiber feed additives. The data indicated that respective feed additives enrich for specific bacterial community members and modulate the diversity of the microbiome. We applied synthetic learning in microbial ecology (SLiME) analysis to interpret 16S rRNA microbial community data and identify specific bacterial operational taxonomic units (OTU) that are predictive of the particular feed additives used in these experiments. The results suggest that feed can influence microbiome composition in a predictable way, and thus diet may have indirect effects on weight gain and feed conversion through the microbiome.


Asunto(s)
Pollos/microbiología , Fibras de la Dieta/administración & dosificación , Microbiota , Oligosacáridos/farmacología , Prebióticos/administración & dosificación , Prunus domestica , Alimentación Animal/análisis , Animales , Bacterias/genética , Bacterias/aislamiento & purificación , Ciego/microbiología , Dieta/veterinaria , Suplementos Dietéticos , Oligosacáridos/administración & dosificación , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN
4.
Poult Sci ; 96(6): 1831-1837, 2017 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-28340000

RESUMEN

Supplementation of poultry diets with Diamond V Original XPC™ (XPC) has been proposed as a means to ameliorate the commonly observed loss of appetite and depression of growth in birds given a live coccidiosis vaccine. A study was conducted to compare the effects on bird performance of a live coccidiosis vaccine in broilers, with and without the dietary inclusion of XPC (1.25 g/kg). Ross 708 male broilers (n = 1,280) were allocated to one of 4 feed treatments: cocci-vaccine (T1), cocci-vaccine + XPC (T2), cocci-vaccine + salinomycin in the grower diet only, (T3), and cocci-vaccine + salinomycin in the grower diet + XPC (T4). Birds consuming diets containing XPC (T2 and T4) and salinomycin (T3) exhibited increased (P < 0.05) feed intake and significantly heavier body weights at 28 d (1.70, 1.74, and 1.67 kg, respectively) and 42 d (3.29, 3.31, and 3.26 kg, respectively). Feed conversion ratio at 28 d was improved (P < 0.05) by adding XPC to diets (T2: 1.47 and T4: 1.44) compared to control diets (T1: 1.50 and T3: 1.47). Salmonella prevalence determined via selective media indicated the inclusion of XPC in the diet resulted in a significant reduction of Salmonella when compared to treatments lacking XPC. Molecular confirmation of Salmonella species indicated S. Kentucky to be present in 38 of the 39 positive samples. Results revealed the ability of XPC in reducing the prevalence of Salmonella. Results from this study also suggest that XPC could be used in conjunction with a live coccidiosis-vaccine to increase growth rate and improve feed conversion of broilers. However, further work is needed to delineate more specific effects directly attributable to XPC.


Asunto(s)
Pollos/inmunología , Suplementos Dietéticos , Salmonelosis Animal/tratamiento farmacológico , Salmonella/efectos de los fármacos , Vacunas Atenuadas/administración & dosificación , Alimentación Animal/análisis , Animales , Pollos/crecimiento & desarrollo , Pollos/microbiología , Coccidiosis/prevención & control , Coccidiosis/veterinaria , Dieta/veterinaria , Masculino , Enfermedades de las Aves de Corral/microbiología , Enfermedades de las Aves de Corral/prevención & control , Piranos/administración & dosificación , Piranos/farmacología , Salmonelosis Animal/prevención & control
5.
Poult Sci ; 91(12): 3295-9, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23155043

RESUMEN

Pasture-flock-raised poultry are becoming an increasingly popular product, but only limited options are currently available for maintaining gut health. For these producers, prebiotics are an attractive option because they are generally recognized as safe (GRAS) and can be mixed into the feed and thus do not require adjustments to production protocols. However, if prebiotic treatments reduce production performance, they would not be useful to producers. Thus, the objective of this study was to measure performance of pasture-raised broilers fed 1 of 3 prebiotic treatments. For these trials, 2 breeds of birds were used: Naked Neck slow-growing breeds and Cornish White Rock cross fast-growing breeds. The experimental design was replicated for each breed. A total of 340 birds were split into 4 groups, each group fed one feed additive: 1) galactoligosaccharides (2% wt/wt), 2) fructooligosaccharides (1% wt/wt), 3) plum fibers (1% wt/wt), or 4) no additives. During the 8-wk rearing period, 10 birds from each group were collected and euthanized to take small intestine samples. Histological preparations were made from the small intestine tissue, and 4 measurements of villi height and crypt depth from each cross section were taken. Throughout the study, mortality was monitored and BW measurements were taken at 2-wk intervals. For the Cornish White Rock cross, the group receiving the feed supplemented with fructooligosaccharides had higher (P < 0.05) 8-wk BW than those fed Plum; control and birds fed galactoligosaccharides were intermediate. For the Naked Neck breed, the group receiving the plum fibers had the highest final BW. It appears that all 3 feed supplements offered some protective effect for alterations in villi length and crypt depth due to feed withdrawal, but only for the Naked Neck breed. The data indicate the 3 prebiotics utilized in this study could be used without risk of decreasing production performance, but only for Naked Neck breeds.


Asunto(s)
Pollos/crecimiento & desarrollo , Pollos/genética , Dieta/veterinaria , Suplementos Dietéticos , Prebióticos , Alimentación Animal/análisis , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Composición Corporal , Cruzamiento , Intestinos/anatomía & histología , Aumento de Peso
6.
J Appl Microbiol ; 112(5): 1020-33, 2012 May.
Artículo en Inglés | MEDLINE | ID: mdl-22372962

RESUMEN

AIMS: The objectives of this study were to evaluate the antistaphylococcal effect and elucidate the mechanism of action of orange essential oil against antibiotic-resistant Staphylococcus aureus strains. METHODS AND RESULTS: The inhibitory effect of commercial orange essential oil (EO) against six Staph. aureus strains was tested using disc diffusion and agar dilution methods. The mechanism of EO action on MRSA was analysed by transcriptional profiling. Morphological changes of EO-treated Staph. aureus were examined using transmission electron microscopy. Results showed that 0·1% of terpeneless cold-pressed Valencia orange oil (CPV) induced the cell wall stress stimulon consistent with the inhibition of cell wall synthesis. Transmission electron microscopic observation revealed cell lysis and suggested a cell wall lysis-related mechanism of CPV. CONCLUSIONS: CPV inhibits the growth of Staph. aureus, causes gene expression changes consistent with the inhibition of cell wall synthesis, and triggers cell lysis. SIGNIFICANCE AND IMPACT OF THE STUDY: Multiple antibiotics resistance is becoming a serious problem in the management of Staph. aureus infections. In this study, the altered expression of cell wall-associated genes and subsequent cell lysis in MRSA caused by CPV suggest that it may be a potential antimicrobial agent to control antibiotic-resistant Staph. aureus.


Asunto(s)
Citrus sinensis/química , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Aceites Volátiles/farmacología , Aceites de Plantas/farmacología , Antibacterianos/farmacología , Pared Celular/efectos de los fármacos , Staphylococcus aureus Resistente a Meticilina/citología
7.
J Food Sci ; 74(6): M237-41, 2009 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-19723207

RESUMEN

Listeria monocytogenes (Lm) is a food safety concern that can be associated with ready-to-eat (RTE) meat and poultry products because of its persistence in the processing environment. Listeriosis has a fatality rate of 28% in immuno-compromised individuals. RTE meats receive a lethal heat treatment but may become contaminated by Lm after this treatment. Federal regulators and manufacturers of RTE meats are working to find additional ways to control postprocess contamination by Lm in RTE meats. This research was initiated to validate combinations of antimicrobials that would produce an immediate lethality of at least 1 log of Lm on artificially contaminated frankfurters, and also suppress Lm growth to less than 2 logs throughout the extended shelf life at refrigerated temperatures (4 degrees C). Based on our studies, 22-ppm lauric arginate (LAE, ethyl-N-dodecanoyl-L-arginate hydrochloride) gave more than a 1-log reduction of Lm surface inoculated onto frankfurters within 12 h. The combination of either 1.8%/0.13% or 2.1%/0.15% potassium lactate/sodium diacetate (L/D) in combination with 22 ppm LAE caused more than a 2-log reduction at 12 h. Storage studies revealed that complementary interactions of L/D and LAE also met the 2nd requirement. This combination initially reduced Lm by 2 logs and suppressed growth to less than 2 logs even at the end of the 156-d storage life for frankfurters. These results confirmed that the combination of L/D with LAE as a postprocessing-prepackaging application could be useful in complying with the USDA's Alternative 1 that requires validation for the control of Lm on RTE frankfurters.


Asunto(s)
Ácido Acético/metabolismo , Antibacterianos/metabolismo , Arginina/metabolismo , Microbiología de Alimentos , Ácido Láctico/metabolismo , Ácidos Láuricos/metabolismo , Listeria monocytogenes/crecimiento & desarrollo , Productos de la Carne/microbiología , Acetato de Sodio/metabolismo , Ácido Acético/administración & dosificación , Animales , Antibacterianos/administración & dosificación , Arginina/administración & dosificación , Recuento de Colonia Microbiana , Aditivos Alimentarios/metabolismo , Contaminación de Alimentos/legislación & jurisprudencia , Contaminación de Alimentos/prevención & control , Manipulación de Alimentos/métodos , Microbiología de Alimentos/legislación & jurisprudencia , Humanos , Ácidos Láuricos/administración & dosificación , Listeriosis/prevención & control , Sensación , Acetato de Sodio/administración & dosificación , Factores de Tiempo
8.
J Food Sci ; 74(2): M67-72, 2009 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-19323760

RESUMEN

The objectives of this study were to screen activity of citrus essential oil fractions (EOs) alone and in combination with organic acids against 2 species of Listeria. Five citrus EOs were initially screened by disc diffusion assay for antibacterial activity. Cold pressed terpeneless Valencia orange oil (CP terpeneless oil) had the strongest bacteriostatic (MIC) and bactericidal (MBC) properties at 0.55% and 1.67%, respectively. Four organic acids were tested for effectiveness against Listeria. Citric and malic acids proved to be the most effective with MBC of 1.1% alone. Assays were conducted to determine synergistic effects of EOs and citric or malic acids. There was a significant decrease in MIC and MBC to 0.04% EO plus 0.12% malic or citric acid. EOs from citrus paired with organic acids offer the potential as an all-natural antimicrobial for improving the safety of all-natural foods.


Asunto(s)
Ácidos Carboxílicos/aislamiento & purificación , Citrus/microbiología , Listeria monocytogenes/aislamiento & purificación , Listeriosis/prevención & control , Aceites de Plantas/química , Aceites de Plantas/normas , Colorimetría , Manipulación de Alimentos/normas , Humanos , Listeria monocytogenes/crecimiento & desarrollo , Terpenos/análisis
9.
J Environ Sci Health B ; 44(6): 571-7, 2009 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-20183064

RESUMEN

A total of 10 ciprofloxacin-sensitive (ciprofloxacin minimum inhibitory concentration, MIC < 0.5 micro g/ml) and 10 ciprofloxacin-resistant (MIC 16 to 32 micro g/ml) presumptive C. jejuni were further characterized and evaluated for their inhibition by natural orange oil fractions. Partial species identification was performed by using a hippuricase gene-based polymerase chain reaction (PCR) assay. One of the isolates appeared to be atypical and failed to hydrolyze hippurate. Of the ciprofloxacin-resistant C. jejuni isolates tested, six were found to have their quinolone resistance determined by a C --> T mutation in codon 86 of gyrA. Both groups of ciprofloxacin-sensitive and -resistant C. jejuni isolates were most susceptible to cold-pressed terpeneless Valencia orange oil (C4) which yielded inhibition zones from 44.0 +/- 1.4 to 80 +/- 0.0 mm. Less inhibitory responses were recorded for 5-fold concentrated Valencia orange oil (C3) and distilled d-limonene (C7) which exerted similar effects on both ciprofloxacin-sensitive and -resistant C. jejuni isolates. In general, ciprofloxacin-resistant and -sensitive C. jejuni isolates were equally susceptible to the respective orange oil fractions.


Asunto(s)
Antiinfecciosos/farmacología , Campylobacter jejuni/efectos de los fármacos , Ciprofloxacina/farmacología , Farmacorresistencia Bacteriana , Aceites de Plantas/farmacología , Animales , Campylobacter jejuni/genética , Campylobacter jejuni/metabolismo , Cromatografía de Gases , Ciclohexenos/farmacología , Limoneno , Espectrometría de Masas , Pruebas de Sensibilidad Microbiana , Aceites de Plantas/química , Reacción en Cadena de la Polimerasa , Quinolonas/farmacología , Terpenos/farmacología
10.
J Food Sci ; 73(1): M32-5, 2008 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-18211359

RESUMEN

Salmonella is a foodborne pathogen causing severe gastroenteritis. Three types of Maillard reaction products (MRP) generated by heat sterilization of D-glucose and L-lysine, L-histidine, and L-arginine were studied at 2 different levels of supplementation (0.5% and 1.0%) for their influence on growth and virulence of Salmonella. Two methods, namely, real-time polymerase chain reaction (RT-PCR) and a beta-galactosidase gene fusion assay, were used to determine the expression of hilA, a regulatory gene for Salmonella pathogenicity. Neither the type of MRP nor their quantities up to 1.0% affected the growth rates of S. Typhimurium EE658 (P > 0.05). When determined by beta-galactosidase assay, lysine MRP in both levels of supplementation were not found to have any effect on the hilA expression compared to the control. The addition of histidine and arginine MRP to M9 media (0.5%) increased by 2-fold hilA induction and up to 6-fold at the higher level (1%) supplementation of these compounds. Although somewhat inconsistent, RT-PCR analyses of hilA expression confirmed the greater induction effect of arginine MRP on hilA compared to lysine MRP. In contrast to beta-galactosidase assay results, however, lysine MRP were found to increase hilA expression compared to the control in both supplementation levels in all trials. The potential of MRP serving as a bacterial virulence modulator may be a factor to be considered in food thermal processing when assessing Salmonella risk for causing foodborne disease.


Asunto(s)
Proteínas Bacterianas/genética , Regulación Bacteriana de la Expresión Génica , Reacción de Maillard , Salmonella typhimurium/crecimiento & desarrollo , Salmonella typhimurium/patogenicidad , Transactivadores/genética , Proteínas Bacterianas/metabolismo , Seguridad de Productos para el Consumidor , Contaminación de Alimentos/prevención & control , Manipulación de Alimentos/métodos , Humanos , Reacción en Cadena de la Polimerasa , Intoxicación Alimentaria por Salmonella/prevención & control , Salmonella typhimurium/genética , Transactivadores/metabolismo , Virulencia , beta-Galactosidasa/metabolismo
11.
Poult Sci ; 85(1): 15-20, 2006 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-16493940

RESUMEN

The aim of this study was to evaluate effects of alfalfa and fructooligosaccharides (FOS) on molting performance and bone parameters compared with the conventional feed withdrawal molting procedure. A total of 36 Single Comb White Leghorn hens (84 wk of age) were used for this experiment. The hens were divided into 6 treatment groups with 6 birds per treatment: pre-trial control (PC), full fed (FF), feed withdrawal (FW), 100% alfalfa (A100), A100 + 0.375% FOS (A100L), and A100 + 0.75% FOS (A100H). At the end of the 9-d molt period, hens were euthanized, and tibia and femurs were collected to evaluate bone qualities using dual-energy x-ray absorptiometry (DXA), Instron (Model 1011 Instron Universal Testing Machine, Instron Corp., Canton. MA), and conventional bone assays. Egg production was recorded during the molting period to evaluate first day out of production, and ovary was also collected to measure ovary weight. Alfalfa molting diets had comparable molting parameters, such as percentage of BW loss, ovary weight, and first day out of egg production, to the conventional feed withdrawal molting procedure, and FOS supplementation did not have any detrimental effects on molting performance. Conventional bone assay and DXA results suggest that hens lose a considerable amount of bone minerals during a molting period. The tibia and femur bone strengths of the FF, FW, A100, and A100L hens were significantly lower than the PC hens, whereas hens fed A100H had similar tibia bone breaking strength to that of the PC hens. The bone parameters measured by conventional assays, bone breaking strength measured by Instron, and bone density and mineral content measured by DXA were highly correlated to each other.


Asunto(s)
Alimentación Animal , Densidad Ósea/efectos de los fármacos , Pollos/fisiología , Medicago sativa/metabolismo , Muda/efectos de los fármacos , Oligosacáridos/farmacología , Absorciometría de Fotón , Animales , Densidad Ósea/fisiología , Dieta , Femenino , Muda/fisiología , Oligosacáridos/administración & dosificación
12.
Lett Appl Microbiol ; 42(3): 265-70, 2006 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-16478515

RESUMEN

AIMS: 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. METHODS AND RESULTS: 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. CONCLUSIONS: When feed protein concentrations are decreased, autofluorescence interference can be avoided. SIGNIFICANCE: 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. IMPACT OF THE STUDY: E. coli GFP biosensor for lysine has potential for routine application in animal feeds.


Asunto(s)
Alimentación Animal/análisis , Técnicas Biosensibles/métodos , Productos Biológicos , Aceite de Semillas de Algodón/análisis , Aceite de Semillas de Algodón/química , Escherichia coli K12 , Proteínas de Escherichia coli , Proteínas Fluorescentes Verdes , Carne/análisis , Minerales/análisis , Minerales/química , /química
13.
J Environ Sci Health B ; 40(3): 475-84, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-15913019

RESUMEN

The objective of the study was to determine the frequency of spontaneous acquisition of resistance to select antibiotics by Salmonella Typhimurium (ST) when grown in glucose amended continuous flow culture at slow (D = 0.025 h(-1)) or fast (D = 0.27 h(-1)) dilution rates. The bacterium was grown in LB minimal medium (pH 6.25) containing no antibiotics. Upon achieving steady state, samples were plated to tryptic soy agar (TSA) alone or supplemented (per ml) with 2 and 16 microg oxytetracycline, 4 and 16 microg tetracycline, 2 and 64 microg kanamycin, and 0.25 and 2 microg enrofloxacin. Regardless of growth rate, CFU of resistant ST from the TSA containing antibiotics was less than 2 x 10(1) except for 2 microg kanamycin and 0.25 microg enrofloxacin treatments (higher than 1 x 10(9) and 4 x 10(7) CFU of resistant ST for trials 1 and 2, respectively). Frequency of recovering resistant ST from the TSA containing the higher antibiotic concentrations was less than 1 in 10(9) for all antibiotics, but was higher on the media containing 2 microg kanamycin and 0.25 microg enrofloxacin at both slow and fast growth rates. In general, minimal susceptibility differences were detected for isolates from slow and fast dilution rates.


Asunto(s)
Antibacterianos/farmacología , Glucosa/metabolismo , Salmonella typhimurium/efectos de los fármacos , Salmonella typhimurium/crecimiento & desarrollo , Recuento de Colonia Microbiana , Medios de Cultivo , Relación Dosis-Respuesta a Droga , Farmacorresistencia Bacteriana , Enrofloxacina , Fluoroquinolonas/farmacología , Kanamicina/farmacología , Pruebas de Sensibilidad Microbiana , Oxitetraciclina/farmacología , Tetraciclinas/farmacología
14.
Poult Sci ; 84(2): 204-11, 2005 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-15742955

RESUMEN

Feed deprivation is used in the layer industry to induce molting and stimulate multiple egg-laying cycles in laying hens. Unfortunately, the stress involved increases susceptibility to Salmonella enteritidis (SE), the risk of SE-positive eggs, and incidence of SE in internal organs. Leghorn hens over 50 wk of age were divided into 4 treatment groups of 12 hens each in experiment 1 and 3 treatment groups of 12 hens in experiments 2 and 3; hens were placed in individual laying hen cages. Treatment groups were 1) nonmolted (NM) and received feed and distilled water for 9 d, 2) force molted by feed removal for 9 d and received distilled water, 3) force molted by feed removal for 9 d and received 0.5% lactic acid (LA) in distilled water. An additional group (4) in experiment 1 only was force molted by feed removal for 9 d and received 0.5% acetic acid in distilled water. Seven days before feed removal hens were exposed to an 8L:16D photoperiod, which was continued throughout the experiment. Individual hens among all treatments were challenged orally with 10(4) SE on d 4 of feed removal. When compared with the NM treatments, weight losses were significantly higher in the M treatments, regardless of water treatments. When compared with NM treatments, crop pH was significantly higher in the M treatment receiving distilled water. Crop pH was reduced to that of the NM controls by 0.5% acetic acid in the drinking water. No consistent significant changes were observed for volatile fatty acids. The number of hens positive for SE in crop and ceca after culture and the number of SE per crop and per gram of cecal contents were higher in the M treatments, when compared with the NM treatments, but there was no effect of addition of either of the acids to the drinking water. Additional research using different acid treatment regimens may provide a tool for reducing the incidence of SE in eggs and internal organs during and following molting of laying hens.


Asunto(s)
Ácido Acético/uso terapéutico , Pollos/microbiología , Ácido Láctico/uso terapéutico , Enfermedades de las Aves de Corral/prevención & control , Salmonelosis Animal/prevención & control , Salmonella enteritidis , Animales , Peso Corporal/efectos de los fármacos , Ciego/microbiología , Buche de las Aves/química , Buche de las Aves/microbiología , Ácidos Grasos Volátiles/análisis , Femenino , Privación de Alimentos , Muda/fisiología , Tamaño de los Órganos/efectos de los fármacos , Agua/química
15.
Bioresour Technol ; 96(5): 565-70, 2005 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-15501663

RESUMEN

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.


Asunto(s)
Alimentación Animal , Fenómenos Fisiológicos Nutricionales de los Animales , Pollos/fisiología , Medicago sativa/química , Muda/efectos de los fármacos , Preparaciones de Plantas/farmacología , Reproducción/fisiología , Análisis de Varianza , Animales , Huevos , Femenino , Genitales Femeninos/efectos de los fármacos , Genitales Femeninos/fisiología , Muda/fisiología
16.
J Environ Sci Health B ; 39(5-6): 861-70, 2004.
Artículo en Inglés | MEDLINE | ID: mdl-15620092

RESUMEN

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.


Asunto(s)
Hierro/farmacología , Salmonella typhimurium/genética , Salmonella typhimurium/patogenicidad , Proteínas Bacterianas/genética , Quelantes/farmacología , Operón Lac/genética , Transactivadores , Virulencia
17.
Biol Trace Elem Res ; 101(2): 147-63, 2004 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-15557678

RESUMEN

Zinc is an important nutrient in animal metabolism. In poultry, zinc serves not only as a nutrient but can also be used as a dietary supplement to manipulate the reproductive system of the bird. This article summarizes the general biochemistry, physiology, and nutritional aspects of zinc metabolism to provide a brief overview on what is known regarding zinc. The potential role of zinc in poultry immune response, Salmonella infection, and molting are emphasized.


Asunto(s)
Fenómenos Fisiológicos Nutricionales de los Animales , Dieta , Aves de Corral/fisiología , Reproducción , Zinc/administración & dosificación , Animales , Femenino , Inmunidad Celular , Absorción Intestinal , Aves de Corral/inmunología , Zinc/metabolismo
18.
Biol Trace Elem Res ; 101(2): 165-79, 2004 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-15557679

RESUMEN

A commercial-feed-grade form of zinc propionate was examined as a potential feed amendment at a concentration of 1% zinc to induce molt in 90-wk-old hens. Dietary treatments consisted of 4 treatment groups of 28 birds each randomly assigned to either (1) molted conventionally by feed withdrawal, (2) 1% zinc as Zn acetate, (3) 1% zinc as Zn propionate, or (4) nonmolted control for 9 d. Ovary weights of hens fed Zn acetate or Zn propionate were not significantly different from each other, but hens fed Zn acetate or Zn propionate were significantly (p<0.05) lighter than the ovary weight of nonmolted control hens. Zinc concentrations in the kidney and liver were significantly (p<0.05) increased in both Zn acetate- and Zn propionate-molted hens when compared to either nonmolted control-fed hens or feed-withdrawal molted hens. Over the entire 3-mo postmolt period, there were no significant differences in interior or exterior egg qualities among the four treatments. Egg production of hens fed Zn acetate was significantly lower than feed-withdrawal hens, Zn propionate-fed hens, or nonmolted control hens (p<0.05). The data of the current study demonstrated that feeding a feed grade of Zn propionate (1% Zn)-supplemented diet can induce molt and retain postmolt egg quality and production comparable to hens molted by feed withdrawal.


Asunto(s)
Alimentación Animal , Pollos/fisiología , Huevos , Muda , Propionatos/administración & dosificación , Animales , Peso Corporal , Femenino , Concentración de Iones de Hidrógeno , Riñón/metabolismo , Hígado/metabolismo , Tamaño de los Órganos , Ovario , Propionatos/metabolismo
19.
Poult Sci ; 83(1): 24-33, 2004 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-14761080

RESUMEN

This study was conducted to determine the ability of an alternative salt form of 1% Zn, Zn propionate, to induce molt in 66-wk-old hens. The hens were randomly assigned to 4 treatment groups of 27 or 28 birds each: a) molted conventionally by feed withdrawal, b) 1% Zn as Zn acetate, c) 1% Zn as Zn propionate, or d) nonmolted control for 9 d. Feed intake was (P < 0.05) depressed in Zn acetate and Zn propionate hens when compared with nonmolted control hens during the 9 d. Ovary weights of hens undergoing feed withdrawal, Zn acetate, or Zn propionate were not (P > 0.05) different from each other, but all were (P < 0.05) lighter than the ovary weights of nonmolted control hens. Zinc concentrations in the kidney and liver were (P < 0.05) increased in Zn acetate and Zn propionate molted hens when compared with nonmolted hens on the control diet or hens molted by feed withdrawal. Bone ash values were (P < 0.05) increased for Zn acetate and Zn propionate molted hens or nonmolted control hens as compared with molted hens on feed withdrawal. Over the entire 3-mo postmolt period, there were no significant differences in interior egg qualities, but egg weights from hens fed Zn propionate were (P < 0.05) heavier than those from hens on feed withdrawal. The data of the current study demonstrated that feeding a Zn propionate (1% zinc)-supplemented diet can induce molt.


Asunto(s)
Pollos/fisiología , Huevos/normas , Muda/efectos de los fármacos , Oviposición/efectos de los fármacos , Propionatos/administración & dosificación , Alimentación Animal , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Peso Corporal , Densidad Ósea , Pollos/metabolismo , Buche de las Aves/química , Femenino , Privación de Alimentos/fisiología , Concentración de Iones de Hidrógeno , Riñón/metabolismo , Hígado/metabolismo , Tamaño de los Órganos/efectos de los fármacos , Ovario/metabolismo , Ovario/fisiología , Oviposición/fisiología , Propionatos/farmacocinética , Distribución Aleatoria , Distribución Tisular
20.
Lett Appl Microbiol ; 37(6): 458-62, 2003.
Artículo en Inglés | MEDLINE | ID: mdl-14633099

RESUMEN

AIMS: To generate a stable Escherichia coli lysine auxotroph for the lysine bioavailability assay. METHODS AND RESULTS: An E. coli lysine auxotrophic strain was constructed by deleting the entire lysA gene and replacing it with a gene that confers resistance to ampicillin (bla). The linear DNA contained 50 bp homologous sequence of upstream of lysA in one end and 50 bp of downstream of lysA in the other end. CONCLUSIONS, SIGNIFICANCE AND IMPACT OF THE STUDY: The deltalysA::bla strain exhibited a linear response to lysine supplementation and can be used for quantifying lysine.


Asunto(s)
Proteínas Bacterianas , Carboxiliasas/genética , Escherichia coli/enzimología , Escherichia coli/genética , Lisina/metabolismo , Recombinación Genética , Resistencia a la Ampicilina/genética , Carboxiliasas/metabolismo , Escherichia coli/crecimiento & desarrollo , Eliminación de Gen , Genes Bacterianos , Lisina/biosíntesis , Lisina/genética , Lisina/aislamiento & purificación , Mutación/genética , Transducción Genética , Transformación Bacteriana
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