 |
|
|
|
|
|
| |
|
|
 |
|
|
|
|
| USDA/ARS 2005 Report: Northern Plains Area (Marc, Fargo) Reports |
|
|
| | |
5428-32000-010-00D | | Project Title: Astragalus and Oxytropis Poisoning in Livestock
Project No: 5428-32000-010-00D
SY(s): James, Lynn;
Lee, Stephen;
Gardner, Dale;
Pfisher, James;
Ralphs, Michael;
Stegelmeire, Bryan;
Panter, Kip
Vacant;
Vacant;
Vacant;
Vacant
Location: Logan, Utah
Poisonous Plant Research
What was the single most significant accomplishment this past year?
Comparison of locoweed toxicity among animal species:
Reviews of the clinical, biochemical and histologic lesions of locoweed poisoning demonstrate that animals have species specific responses to poisoning. Horses are especially sensitive as when poisoned they become hyper excitable, frightened or violent when stimulated. Horses develop severe neurologic lesions. Cattle and sheep are intermediate. Rodents and mule deer are relatively resistant and develop few neurologic lesions. Poisoning in deer causes a wasting syndrome with extensive pancreatic and intestinal changes. Recent isolation of mannosidases with different swainsonine binding affinities suggests that differences in severity, distribution and progression of locoweed-induced lesions are probably due to tissue and species specific mannosidase expression.
List other significant accomplishments, if any.
Early effects of locoweed toxicity: Relatively high doses of swainsonine over short periods of time can result in fetal death and rapid onset of clinical effects of locoweed poisoning. Pregnant goats were fed locoweed (Astragalus lentiginosus) at a dose equivalent of 8 mg/kg per day swainsonine beginning on gestation day 30. Serum swainsonine was rapidly elevated, reaching concentrations of >400 ng/ml after one day and peaking at 600-800 ng/ml by gestation day 40. Ultrasound exams determined that fetuses were dead between 5 and 20 days after treatment began. Does showed characteristic locoweed poisoning including proprioceptive deficits, lethargy, intention tremors and severe rear limb weakness and partial paresis. Upon necropsy the fetuses were autolytic and leasions were typical of locoweed poisoning including vacuolation.
Locoweed increasing neonatal losses: The purpose of this series of studies was to determine if locoweed eaten during days 100-130 of gestation would affect the behavior of ewes and lambs at birth. About 20% of ewes receiving locoweed aborted their fetuses. Lamb birth weights were reduced about 25% from maternal locoweed ingestion. Locoweed had a major effect on maternal-infant bonding, primarily because lambs were poisoned. Lambs born to intoxicated ewes were generally not able to nurse without assistance. Newborn lambs born to intoxicated ewes took longer to stand, to find the mother's udder, and to suckle. Lambs born to intoxicated ewes showed impairments in their behavior and had a weakened maternal infant bonding. Intoxicated ewes were able to discriminate their own lambs; these ewes displayed an apparent locoweed-induced hypersensitivity and nervousness resulting in ewes spending more time with their lambs than control ewes. These results indicate that lamb survival after maternal locoweed exposure will depend greatly on human intervention. If locoweed-exposed lambs survive the first 24 to 48 hours after birth, then the prognosis for survival improves greatly.
Developing ELISA assays: The linkage of swainsonine (the locoweed toxin) to a large carrier molecule (protein) for the purpose of the induction of immunological activity has proven difficult because of the lack of chemical handles on such a small molecule. Swainsonine has been linked via the hydroxyls but no swainsonine specific antibodies were produced. It was assumed that linkage through one of the hydrosyl groups likely alters the three dimensional structure that characterizes the swainsonine specific epitope. We sought an alternate approach by searching for a possible linkage through the nitrogen with a diverse carbon skeleton such as a 4 carbon allylic system and 4-8 alkyl systems. A number of N-alkylated derivatives of swainsonine could be produced by the reaction of swainsonine acetonide with 1,4-dibromo-2-butene and 1,4-diiodobutane. We have recently completed the N-alkylation reaction directly with swainsonine, thus eliminating the use of the acetonide derivative. Reaction of the swainsonine directly with either 1,4-dibromo-2-butene or 1,4-diiodobutane in acetonitrile seems to work well. Future work will focus on direct linkage of the swainsonine derivative with carrier proteins and induction of antibody response for the purpose of analytical method development and vaccine development.
Cool season grass competition against locoweed: Cool season grasses may effectively compete against locoweed. Cool season grasses were seeded following locoweed control in 1999 - 2002 in Colorado and New Mexico (drough caused several seeding failures). Grass establishment ranged from 48 to 70% (Colorado 2002, New Mexico 2003). Forage production of seeded grasses at Colorado exceeded untreated native range by 1.75-3.51 fold (Colorado 2003, New Mexico 2004). Seeded grasses produced significant competition against new locoweed seedlings reducing locoweed leaf length by 38% at Colorado 2004. Locoweed competition will be measured at New Mexico 2005.
Progress report.
Toxic species of the Astragalus and Oxytropis genera poison livestock and adversely affect the harvesting of forage by livestock. These species are prevalent and cause significant poisoning problems in the western U.S. and Canada, South America and China.
An analytical method was developed using gas chromatography, liquid chromatography and mass spectrometry to measure swainsonine in plant material. Several locoweed species from the U.S. and species of Ipomea and Sida from Brazil were shown to contain swainsonine. Researchers from New Mexico State University discovered an endophyte within locoweed that produce swainsonine. Cooperative research between PPRL and NMSU collected and tested several locoweed species and found high correlations between the endophyte and swainsonine concentrations. Future research will concentrate on the growth of the endophyte and its synthesis of swainsonine.
Livestock species differ in their susceptibility and response to locoweed poisoning. Horses are especially sensitive to poisoning and become hyper excitable, frightened or violent when stimulated. Rodents and mule deer are relatively resistant and develop few neurologic lesions. Cattle and sheep are intermediate in their susceptibility to locoweed. The locoweed toxin swainsonine adversely affects fetal health, resulting in death and abortions, and disrupts the estrus cycle in females and causes male infertility.
Previous and current research showed cattle could be aversively condition to avoid eating locoweed. Horses are generally of higher value due to their direct use for work and recreation.
Locoweed's population cycle, dying out in drought and increasing in wet years. The risk of poisoning increases in wet years. Aversive conditioning can be used to train horses to avoid eating locoweed. Improved varieties of grasses were planted following herbicide control of locoweed to suppress its reestablishment and provide an alternative green forage source in spring.
Natural selenium toxicoses are endemic and occur in areas of seleniferous soils and areas with selenium contamination. Organic selenium (selenomethionine) is the major component of Se-accumulating plants and more bioavailable but less toxic than the inorganic form, sodium selenite.
Back to top | |
5428-32000-011-00D | | Project Title: The Toxicity of Pyrrolizidine Alkaloid-Containing Plants and other Hepatotoxic and Neurotoxic Plants
Project No: 5428-32000-011-00D
SY(s): James, Lynn;
Lee, Stephen;
Gardner, Dale;
Pfisher, James;
Ralaphs, Michael;
Vacant;
Vacant;
Vacant;
Stegelmeier, Bryan;
Panter, Kip;
Vacant
Location: Logan, Utah
Poisonous Plant Research
What was the single most significant accomplishment this past year?
Vaccines to Pyrrolizidine Alkaloids: PA-protein conjugates were immunized into rats as a potential vaccine to alter toxicity. We were disappointed as few animals developed significant titiers to the PA conjugates. However, animals with high titers had less severe hepatic lesions than those with low titers when challenged with PA. More work is needed on this study to optimize immunization response and determine if a vaccine might be useful to alter animal susceptibility to poisoning.
List other significant accomplishments, if any.
Pyrrolizidine Alkaloid Diagnosis and Food Safety: The toxicity of various hepatotoxic plants including Senecio, Crotalaria, Cynoglossum and Amsinkia have been studied and documented. Techniques have been developed to isolate and identify PA toxins in plant and animal tissues. Class specific and alkaloid specific ELISA's have been developed to screen large numbers of feed and food samples. Methods and management schemes such as herbicide control and using less susceptible species such as goats and sheep to control PA-containing plants have been developed. Species specific and age related toxicity have been documented. This will be useful in developing risk assessment models and generating sensible exposure limits.
Senecio in Hawaii: Senecio madagascariensis, an invader weed in Hawaii, was collected from five locations and analyzed for PA's. All plants contained mixtures of toxic macrocyclic necine and otonecine diesters. The extensive infestations suggest these plants are a poisoning risk.
Switchgrass Toxicity: Switchgrass, an increasingly used biofuel and cover crop, was shown to cause liver damage and secondary photosensitization. Sheep, horses, goats, and rodents were fed switch grass and most developed subtle hepatic lesions. Poisoning is highly variable and goats appear to be most susceptible to poisoning.
Pheasant's Eye Toxicity: Adonis aestavalis and Solanum triflorum Nutt. were shown to be toxic in livestock and rodents.
Photosensitivity Diagnostics: Pylloerythrin is the cause of secondary photosensitization and it is an excellent marker of hepatic function in herbivores. Further progress was made in acquiring a fluorescence spectrophotometer and better developing our phylloerythrin assay.
Water Hemlock Toxicity: Green water hemlock seed was determined to be the cause of poisoning in a herd of cattle in central Utah. The seed contained similar toxins as are present in the highly toxic tubers. Seed and tuber extracts were equally toxic in a mouse bioassay.
Progress report.
Many plants contain hepatotoxins and neurotoxins and they frequently invade pastures and fields resulting in contamination of feeds, food and herbal preparations. Quick, sensitive, and reliable technology is needed to identify poisoned animals and monitor feed and food for contamination. Additional information is needed to better define the dose and risk of poisoning. The objectives of this research is to: 1) describe the clinical and pathological alterations of intoxications in animals; 2) develop diagnostic procedures to identify poisoned animals and to better prognose the potential outcomes of poisoning; 3) develop diagnostic procedures to identify poisoned animals and to better prognose the potential outcomes of poisoning; 4) develop knowledge of toxin metabolism and the effects of low dose exposures to highly susceptibly animals and neonates; 5) develop risk assessment models for poisoned animals; 6) develop screening and toxin identification technology to ensure quality food animal products and; 7) develop techniques to avoid or minimize the effects of these poisonous plants.
Accomplishments to date include development of immunologic diagnostic techniques (ELISA technology) to monitor feeds and food for PA contamination. Neonatal pigs were shown to be 3 to 4 times more sensitive to PA toxicity than adults. PA n-oxides were shown to be as toxic as the free base form in both monogastric and ruminate animals. Specific accomplishments for 2005 include: 1) PA-protein conjugates were immunized into rats as a potential vaccine to alter toxicity. Few animals developed significant titers to the PA conjugates; however, animals with high titers had less severe hepatic lesions than low titer animals when challenged with PA. 2) Senecio madagascariensis and invader weed in Hawaii was collected from five locations and analyzed for PA. All plants contained mixtures of toxic macrocyclic necine and otoecine diesters. The extensive infestation suggests these plants are a poisoning risk. 3) Switchgrass, an increasingly used biofuel and cover crop, was shown to cause liver damage and secondary photosensitization. Sheep, horses, goats, and rodents were fed switch grass and most developed subtle heptic lesions. Poisoning is highly variable and goats appear to be most susceptible to poisoning. 4) Adonis aestavalis and Solanum triflorum Nutt. were shown to be toxic in livestock and rodents. 5) Pylloerythrin is the cause of secondary photosensitization and it is an excellent marker of hepatic function in herbivores. Further progress was made in acquiring a fluorescence spectrophotometer and better developing our phylloerythrin assay.
Back to top | |
5438-42000-010-00D | | Project Title: Develop on-line Verification and Intervention procdures for Haccp in slaughter/processing systems
Project No: 5438-42000-010-00D
SY(s): Arthur, Terrance
Vacant;
Bosilevac, Joseph;
Shackelford, Steven;
Koohmaraie, Mohammad;
Vacant;
Vacant;
Vacant
Location: Clay Center, Nebraska
U.S. Meat Animal Research Center
Meats Research
What was the single most significant accomplishment this past year?
Evaluation of Culture- and PCR-Based Detection Methods for Escherichia coli O157:H7 in Inoculatd Ground Beef
Scientists in the Meats Research Unit (MRU), Clay Center, NE, evaluated several commercial pathogen detection platforms for use in detecting E. coli O157:H7. Since ground beef is a highly perishable product, the testing methodology used must be as rapid as possible. Also, the test must have a low false positive rate, so product is not needlessly discarded, and false negatives cannot be tolerated. False negative results would allow contaminated product to be released and potentially cause disease. In this study, commercially developed methods for detecting E. coli O157:H7 in ground beef were compared for their abilities to meet the above criteria. With most commercial beef processor employing systems in which pathogen testing must be completed prior to release of the product, robust detection systems are required. This study has been used by commercial beef processors as a factor in deciding which pathogen detection system to use for detecting E. coli O157:H7.
List other significant accomplishments, if any.
Development and Evaluation of an On-line Hide Decontamination Procedure for Use in a Commercial Beef Processing Plant
Scientists in the MRU, Clay Center, NE, identified the most effective reagents to decontaminate beef hides and then evaluated their application in a novel hide washing cabinet system. The hides of cattle are the source of Escherichia coli O157:H7 that contaminates beef carcasses during commercial beef processing. Scientists in the MRU, Clay Center, NE, have previously shown that effective interventions that reduce hide contamination also reduce subsequent carcass contamination. In this current evaluation, sodium hydroxide wash and a chlorinated water rinse were found to provide the best decontamination. When the hide wash cabinet was evaluated using these compounds, hides were cleaner, but more importantly, the contamination of carcasses was significantly reduced. The prevalence of E. coli O157 on pre-evisceration carcasses was reduced from 17% to 2% when the cabinet was in use. As a result of this work, Cargill Meat Solutions has installed hide washing cabinets in all of their processing beef plants.
Back to top | |
5438-42000-012-00D | | Project Title: Control of Pathogenic and Spoilage Microoganisms on red meat
Project No: 5438-42000-012-00D
SY(s): Koohmaraie, Mohammad;
Arthur, Terrance;
Wheeler, Tommy;
Shackelford, Steven;
Kalchayanand, Norasak;
Brichta, Dayna;
Guerini, Michael;
Bosilevac, Joseph
Location: Clay Center, Nebraska
U.S. Meat Animal Research Center
Meats Research
What was the single most significant accomplishment this past year?
Effects of Low-Dose, Low-Penetration E-Beam Irradiation of Chilled Beef Carcass Surface Cuts on Escherichia coli O157:H7 and Meat Quality
Low-dose, low-penetration electron beam (E-beam) irradiation was evaluated by scientists in the MRU for potential use to kill bacteria on beef carcasses during processing. The objectives of this study were (i) to assess how well E-beam irradiation can reduce levels of Escherichia coli O157:H7 on a large beef surface and (ii) to evaluate the effect of the treatment on the taste, smell, and color of the product. A low dose of E-beam irradiation reduced E. coli O157:H7, inoculated onto sections of beef, 99.99%. In assessing for effects on beef quality, the flank steak was used as the model muscle and was treated with 5, 10, 25, 50, and 75% penetrating irradiation. None of the flank steak sensory attributes were affected by any penetration treatment. Ground beef formulations consisting of 100, 50, 25, 10, 5, and 0% irradiated beef were tested. A trained sensory panel did not detect any difference between the untreated and either the 5 or 10% treatments. These results suggest that if chilled carcasses were subjected to low-dose E-beam irradiation, aroma and flavor of ground beef would not be impacted. The data presented here show that low-dose, low-penetration E-beam irradiation has great potential for use as an antimicrobial intervention on beef carcasses during processing and minimally impacts the quality of the treated beef products.
List other significant accomplishments, if any.
Decreased Dosage of Acidified Sodium Chlorite Reduces Microbial Contamination and Maintains Organoleptic Qualities of Ground Beef Products
Scientists in the MRU investigated acidified sodium chlorite (ASC) spray at decreased dosages and application rates to determine its efficacy for reducing bacterial contamination on boneless beef trimmings used for production of raw ground beef products, while maintaining desirable consumer qualities in the finished ground beef products. Although ASC has been shown to be effective at reducing pathogen contamination of beef trim when used at these dosages, the ground beef produced from this treated trim can be discolored and non-typical tasting. Results indicated that decreased dosages of ASC do produce satisfactory microbial reductions in boneless beef trimmings and finished ground beef, extend shelf life of the ground beef products, and maintain desirable qualities of odor, color, and taste. The decreased dosages and application rates have been adopted by a U.S. ground beef supplier to many fast food restaurant chains.
Development and Evaluation of an On-Line Hide Decontamination Procedure for Use in a Commercial Beef Processing Plant
Scientists in the MRU identified the most effective reagents to decontaminate beef hides and then evaluated their application in a novel hide washing cabinet system. The hides of cattle are the source of Escherichia coli O157:H7 that contaminates beef carcasses during commercial beef processing. The MRU have previously shown that effective interventions that reduce hide contamination also reduce subsequent carcass contamination. In this current evaluation, sodium hydroxide wash and a chlorinated water rinse were found to provide the best decontamination. When the hide wash cabinet was evaluated using these compounds, hides were cleaner, but more importantly, the contamination of carcasses was significantly reduced. The prevalence of E. coli O157 on pre-evisceration carcasses was reduced from 17% to 2% when the cabinet was in use. As a result of this work, Cargill Meat Solutions has installed hide washing cabinets in all of their processing beef plants.
Efficacy of Ozonated and Electrolyzed Oxidative Waters to Decontaminate Hides of Cattle Before Slaughter
Scientists in the MRU determined the efficacy of ozonated and electrolyzed oxidizing (EO) waters to decontaminate beef hides, compared to similar water washing without the active antimicrobial compounds present. Based on previous results reported by scientists in the MRU, Clay Center, NE, a number of alternative interventions that reduce hide contamination and the subsequent carcass contamination are being sought since not all producers can implement hide wash cabinets. Experiments used a model system designed by scientists in the MRU, Clay Center, NE, to simulate hide-on carcasses. Ozonated and EO water both were shown to be effective interventions. The prevalence of E. coli O157 on hides was reduced from 89% to 31% following treatment with ozonated water, and from 82% to 35% following EO water treatment. These results demonstrate that ozonated and EO waters can be used as viable alternatives to hide washing cabinets to decontaminate hides during processing and hold potential as means to reduce pathogen load on beef hides, thereby reducing pathogens on beef carcasses.
Evaluation of Culture- and PCR-Based Detection Methods for Escherichia coli O157:H7 in Inoculated Ground Beef
Scientists in the MRU evaluated several commercial pathogen detection platforms for use in detecting E. coli O157:H7. Since ground beef is a highly perishable product, the testing methodology used must be as rapid as possible. Also, the test must have a low false positive rate, so product is not needlessly discarded, and false negatives cannot be tolerated. False negative results would allow contaminated product to be released and potentially cause disease. In this study, commercially developed methods for detecting E. coli O157:H7 in ground beef were compared for their abilities to meet the above criteria. With most commercial beef processor employing systems in which pathogen testing must be completed prior to release of the product, robust detection systems are required. This study has been used by commercial beef processors as a factor in deciding which pathogen detection system to use for detecting E. coli O157:H7.
Back to top | |
5438-32000-021-00D | | Project Title: Prevention of Zoonotic Pathogen Transmission from animal manure to human food
Project No: 5438-32000-021-00D
SY(s): Berry, Elaine;
Wells, James
Location: Clay Center, Nebraska
U.S. Meat Animal Research Center
Nutrition Research
What was the single most significant accomplishment this past year?
Reduction of Campylobacter shedding by nursery swine. Dietary additives may influence intestinal microflora and pathogen carriage and shedding by swine. ARS scientists at Clay Center examined the impact of swine nursery diets with and without carbadox + copper sulfate or larch tree extract (commercial dietary additive) on selected fecal bacterial populations in nursery swine. Shedding of Salmonella spp in feces was not significantly affected by any dietary treatment, but in animals shedding Campylobacter spp. in feces, carbadox + copper sulfate significantly reduced shedding of this zoonotic pathogen. However, coliform and generic E. coli counts were nearly 10-fold higher from animals fed carbadox + copper sulfate. Animal gain was better with supplementation of either carbadox + copper sulfate or 0.1% larch tree extract, but feed efficiency (lb gain per lb feed) was only higher with diets supplemented with 0.1% larch tree extract. Overall, animal gain tended to be lower in animals persistently shedding Campylobacter spp. during the experiment.
List other significant accomplishments, if any.
Manure treatments to reduce bacterial pathogens. Cattle and swine manures may contain zoonotic pathogens, including E. coli O157:H7 and Salmonella enterica Typhimurium, and serve as a source of contamination of human food and water. Experiments were conducted by ARS scientists at Clay Center to evaluate the effectiveness of manure treatments for preserving urea nitrogen content (thus retaining fertilizer value) and reducing pathogen viability in cattle and swine manure slurries. Manure slurries with higher urea content resulted in more rapid death of E. coli O157 and Salmonella; however, the inhibition of urea hydrolysis appeared to prolong the viability of these pathogens. Typically, treatments with thymol or other related plant oils rapidly decreased pathogen viability, both alone or in combination with a urease inhibitor. However, in cattle manure slurries, some treatments combining a urease inhibitor and thymol resulted in increased pathogen concentrations. The research suggests that urea hydrolysis may be an intrinsic process in manure that is inhibitory to pathogens, and that if urea hydrolysis is inhibited, additional treatments may be required to decrease pathogen populations in the manure.
Back to top | |
5438-32000-020-00D | | Project Title: Prevention and Conrol of Shiga-Toxigentic E. Coli in Livestock
Project No: 5438-32000-020-00D
SY(s): Keen, James;
Bono, James;
Vacant;
Chitko Mckown, Carol;
Laaegreid, William
Location: Clay Center, Nebraska
U.S. Meat Animal Research Center
Animal Health Research
What was the single most significant accomplishment this past year?
Fair associated STEC O157 human outbreak investigations:
We collaborated with County and State Health Departments, State Departments of Agriculture and the U.S. Centers for Disease Control and Prevention in the investigation of human outbreaks of STEC O157 at fairs and petting zoos in Raleigh, North Carolina and Tampa, Orlando and Plant City, Florida. Using ambient environment and animal sample collection and laboratory bacteriological methodologies that we developed in-house, we were able to isolate STEC O157 from these various fair environments and help to determine the likely outbreak vehicle and sources.
List other significant accomplishments, if any.
Fair STEC O157 outbreak site decontamination:
In collaboration with State of North Carolina Department of Agriculture personnel, we completed a preliminary STEC O157 long-term survival and environmental decontamination trial at a heavily, naturally-contaminated agricultural site that had been associated with a large human outbreak. Data suggested that STEC O157 can survive for many months in agricultural soils. In addition, our data suggested that environmental decontamination techniques against STEC O157 will probably not be 100% effective and that some methods have the potential to worsen rather than alleviate environmental STEC O157 contamination.
Back to top | |
5438-32000-022-00D | | Project Title: Prevention of Infections by Enterohemorrhagic Escherichia Coli (EHEC) in Livestock
Project No: 5438-32000-022-00D
SY(s): Laegreid, William;
Bono, James;
Keen, James;
Vacant;
Vacant;
Chitko McKown, Carol
Location: Clay Center, Nebraska
U.S. Meat Animal Research Center
Animal Health Research
What was the single most significant accomplishment this past year?
Early in FY2005 this project was combined with CRIS Project #5438-32000-020-00D. Milestones and accomplishments are highlighted in that project report.
Back to top | |
5442-32000-008-00D | | Project Title: Metabolic Variables Affecting the Efficacy, Safety, and Fate of Agricultural Chemials
Project No: 5442-32000-008-00D
SY(s): Smith, David;
Hakk, Heldur;
Shappell, Nancy;
Larsen, Gerald;
Shelver, Weilin
Location: Fargo, North Dakota
Red River Valley Agricultural Research Center
Animal Metabolism-Agricultural Chemicals Research
What was the single most significant accomplishment this past year?
Development of Sodium Chlorate Feed Additive as a Food Safety Tool.
Studies were conducted in cattle to determine the identity of chemical residues in edible tissues after treatment with an investigational chlorate-based feed additive. It was demonstrated that residues of sodium chlorate in edible tissues of beef cattle will not limit the development of chlorate as a food safety tool. Chlorate is being developed as a feed additive because it inhibits the growth of pathogens such as E. coli O157:H7 and Salmonella in live animals. We determined that the residues fell below safe tissue concentrations estimated by the US FDA Center for Veterinary Medicine. This technology has the potential to be a safe and effective pre-harvest tool to reduce the incidence of pathogens in live animals prior to entering the human food chain.
List other significant accomplishments, if any.
Zilpaterol Residue Method Developed.
A fellowship under the OECD co-operative Research Program: Biological Resource Management for Sustainable Agriculture Systems has been completed. The fellowship allowed cooperative research between Department of Agriculture and Rural Development (Ireland) and Agricultural Research Service. A surface plasmon resonance biosensor method was developed to evaluate 9 zilpaterol antibodies. The sensor method showed excellent recovery and reproducibility for low ppb zilpaterol concentrations. A comparison of the zilpaterol biosensor method with ELISA demonstrated that both methods give equivalent results with a high correlation between them. This rapid analytical method is available for use to screen animal tissues for illegal residues.
Progress report.
This report serves to document research conducted under a reimbursable agreement between ARS and the National Cattlmen’s Beef Association. Each year thousands of US consumers become ill because they have eaten food products that are contaminated with pathogenic bacteria. Intense efforts have been made to eliminate pathogenic organisms from beef animals before they are slaughtered and to remove contamination after slaughter. A new pre-harvest food safety strategy has been developed that has been shown to greatly reduce, or even eliminate gram-negative pathogens from live cattle. Use of this new feed additive has not yet been approved by regulatory organizations because it is not known whether residues present in edible tissues of treated animals would represent a health risk. The purpose of this study was to quantify residues of a novel chlorate based feed additive in edible tissues of beef animals. For all of the doses tested, chlorate residues in liver, kidney, muscle, and fat fell well below amounts that the FDA have estimated to be safe. The major metabolite of chlorate was chloride, a nutrient already present in almost all human food sources.
Back to top | |
5442-32000-009-00D | | Project Title: Dioxins and other Environmental Contaminants in Food
Project No: 5442-32000-009-00D
SY(s): Huwe, Janice;
Hakk, Heldur;
Shelver, Weilin;
Larsen, Gerald
Location: Fargo, North Dakota
Red River Valley Agricultural Research Center
Animal Metabolism-Agricultural Chemicals Research
What was the single most significant accomplishment this past year?
Development of an immunoassay for polybrominated diphenyl ethers. Polybrominated diphenyl ethers (PBDEs) are persistent environmental contaminants that can accumulate through the food chain, but rapid inexpensive methods of detection are not available. Antibodies were generated and incorporated into a rapid screening assay (magnetic particle immunoassay) with the collaboration of Abraxis, LLC. The assay is successful in detecting PBDEs in fish, water, and soil samples with high specificity and sensitivity. The cost and turn-around time for this new assay is significantly less than that of the traditional PBDE analysis; and, therefore, its use may result in affordable, widespread, monitoring of these persistent pollutants.
List other significant accomplishments, if any.
Assessment of the persistence of two flame retardants in mammals.
A particular group of polybrominated diphenyl ethers (a class of flame retardants) are persistent in the environment and have been shown to be accumulating in humans. Two of these compounds (BDE-154 and BDE-209) were studied in laboratory rats to examine the absorption, disposition, metabolism, and excretion characteristics of this group of pollutants in animals. The results of the studies show that BDE-154 is well absorbed and persistent in the animals, but BDE-209 is poorly absorbed and quickly excreted. Because BDE-209 is the predominant member of this flame retardant class (soon to be the only member), this data lends scientific support to the decision to allow continued use of BDE-209 while discontinuing use of products containing BDE-154.
Back to top | |
5442-32000-010-00D | | Project Title: Prevent the occurrence of toxins in water to protect food anf the environment
Project No: 5442-32000-010-00D
SY(s): Larsen, Gerald;
Hakk, Heldur;
Shappell, Nancy;
Vacant;
Shelver, Weilin
Location: Fargo, North Dakota
Red River Valley Agricultural Research Center
Animal Metabolism-Agricultural Chemicals Research
What was the single most significant accomplishment this past year?
Factors effecting fate and transport of estrogens in soil.
When the natural female hormone, estradiol, which is found in animal manures, was applied to soil-filled columns, we found that estradiol and estrone (estadiol degradation product) were the predominant compounds found to elute from the column. The amount and timing of the estrogens eluting from the column showed that if the organic content of the soil increased, more of the estradiol was absorbed to the soil. Further, we observed that if soil organic content increased the time to achieve complete estrogen-soil binding also increased. The absorption of estradiol or estrone to soil was also studied by mixing soil, water and estradiol or estrone in vials then sampling the amount of hormone remaining in water over time. It was found that a constant amount of absorption of both estrogens to soil was observed with time until a time point was reached when no more estrogen absorbed to the soil. For estradiol and estrone these time points were 5 and 24hours, respectively, which may help explain why hormones are consistently detected at low concentrations in the environment despite their strong soil absorption and ease of degradation.
List other significant accomplishments, if any.
Atrazine inhibits phosphodiesterase in pig heart, lung, and brain.
We found that atrazine, one of the most widely used herbicides in the U.S., inhibited the important signal transduction enzyme phosphodiesterase in pig heart, lung, and brain, but not kidney and liver. There are over 50 different types of phosphodiesterase distributed among all tissues and in various subcellular locations. To determine which phosphodiesterases from tissues and subcellular locations were inhibited by atrazine exist, we fractionated tissues into cell cytosol (liquid inside), cell membranes and other cellular organelles. Only phosphodiesterase from heart cytosol was inhibited by atrazine. These studies are important because claims have been made that atrazine disrupts the endocrine system which could affect the proper maturation of animals. Previously, we showed that endocrine disruption did not occur by atrazine directly binding to the estradiol/estrogen receptor, but instead atrazine inhibited phosphodiesterase. Atrazine inhibition of phosphodiesterase may be the mechanism by which maturation is disrupted.
List any significant activities that support special target populations.
Swine wastewater was evaluated for estrogenic activity and Kjeldahl nitrogen (TKN) as it was sequentially treated by a two stage anaerobic lagoon and a constructed wetland system over three seasons. Estrogenic activity of water from the manure pit was ~900 picomolar estradiol equivalents (pM E2 Eq) in both spring and summer. The E2 Eqs dropped dramatically in the primary lagoons to 1% of pit values (12 to 14 pM). The estrogenic activity of lagoon wastewater was so low as it entered the wetlands in these seasons (~3 pM E2 Eq) that little to no change in activity was found across the wetlands. In the cooler temperatures of November, the E2 Eq entering the wetlands was ~100 pM, yet ~94% of the activity was removed by the wetlands, while the TKN was reduced by ~75% for wetlands. These data indicate that wetlands are useful in reducing both N and estrogenic activity from animal waste.
Back to top | |
|
|
 |
- This document was created by
USDA.
Users are encouraged to provide feedback and comments.
- This document was created in Nov 2005.
|
|
|
|
|
|
|
