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Browsing by Author "Kuhn, David"

Now showing 1 - 11 of 11
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    Comparative Pharmacokinetics and Tissue Concentrations of Flunixin Meglumine and Meloxicam in Tilapia (Oreochromis spp.)
    Martin, Miriam; Smith, Stephen A.; Kleinhenz, Michael; Magnin, Geraldine; Lin, Zhoumeng; Kuhn, David; Montgomery, Shawnee; Coetzee, Johann (MDPI, 2021-11-25)
    Evidence of pain perception in fish is well established, but analgesic use in aquaculture is limited. The objective was to investigate the comparative pharmacokinetics of flunixin administered intramuscularly (IM) and meloxicam administered IM or orally (PO) in tilapia. Two hundred and seventy fish were assigned to 1 of 3 treatment groups: flunixin meglumine IM (2.2 mg/kg); meloxicam IM (1 mg/kg); or meloxicam PO (1 mg/kg). Blood and tissue samples were collected from 6 fish per treatment at 14 time points for 10 days. Drug concentrations were determined using ultra-high-pressure liquid chromatography coupled with mass spectroscopy. Plasma concentration versus time data were analyzed with a non-compartmental approach using a commercially available software. Flunixin reached a mean maximum concentration (Cmax) of 4826.7 ng/mL at 0.5 h, had a terminal half-life (T1/2) of 7.34 h, and an area under the concentration–time curve extrapolated to infinity (AUCINF_obs) of 25,261.62 h·ng/mL. Meloxicam IM had a T1/2 of 9.4 h after reaching a Cmax of 11.3 ng/mL at 2 h, with an AUCINF_obs of 150.31 h·ng/mL. Meloxicam PO had a T1/2 of 1.9 h after reaching a Cmax of 72.2 ng/mL at 2 h, with an AUCINF_obs of 400.83 h·ng/mL. Tissue concentrations of both drugs were undetectable by 9 h. Flunixin reached a sufficient plasma concentration to potentially have an analgesic effect, while meloxicam, when administered at the given dosage, likely would not.
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    Fish Slaughter
    Kuhn, David; Smith, Stephen A. (Virginia Cooperative Extension, 2017-07-25)
    Discusses several methods that can used to slaughter fish for food.
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    The implications of switching from total coliform to Enterobacteriaceae as an indicator organism in a food manufacturing facility: a literature review
    AuWerter, J.P. (Virginia Tech, 2021-12-08)
    Coliform is the traditional indicator organism of choice for testing of the environment and finished food products in the United States, as current reflected in some federal rules, such as the Pasteurized Milk Ordinances. A positive test result can indicate the presence of potential pathogenic activity, which at its worst can cause adverse reactions to human health but can also have no ill effects. Further research, however, has proven that the scope of this test is limited in what it can detect. An alternative indicator test, Enterobacteriaceae, can pick up not only the bacteria falling under the standard definition of coliform, but also other gram-negative bacteria and potential pathogens, making this test more robust and thorough. A third option – for gram-negative bacteria, generally – would offer the most comprehensive indicator organism testing program, when combined with Enterobacteriaceae. This paper reviews relevant research studies regarding these first two indicator organism tests, concluding that Enterobacteriaceae is the superior test for the food manufacturing environment, with a focus on finished ready-to-eat food products. Testing for these pathogenic indicators has evolved from agar testing, which could take days, to 3M’s Petrifilm, which can take several hours to incubate and reveal possible contamination. The Petrifilm test can also help food safety practitioners differentiate between contaminants from the environment versus bacteria that are naturally present in certain foods, such as cheese. In fact, some members of the coliform family can be beneficial to cheese curing and ripening. In switching from coliform to Enterobacteriaceae, any company would be catching up to the European Union, which has used this test since 2005 as its pathogenic indicator test for ready-to-eat dairy products. Although the literature reviewed in this paper does point to Enterobacteriaceae as the superior test, some may be required to continue coliform testing in finished products to meet customer requirements and certain federal rules.
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    On-Farm Factors Affecting the Hatchability of Broiler Eggs in Parent Breeder Operations
    Hill, Jessica (Virginia Tech, 2017-11-15)
    This paper discusses different on-farm factors affecting the hatchability of eggs coming from broiler breeders. Inconsistent hatchability has been an on-going issue for the poultry industry. This review brings together information from previous research studies to determine areas where hatchability may be affected. Physical eggshell properties, including eggshell thickness for embryo protection, water loss, and nutrient supply set the stage for further hatchability discussion. This paper addresses the relationship between the current genetic makeup of commercial breeders and hatchability as well as the role of animal behavior and environmental enrichments. After the egg leaves the breeder house, other factors potentially affecting hatchability are discussed. These include egg sanitation, temperature regulation, and egg storage length in conjunction with hen age. Hatchability research is conflicting, but suggestions are made for further industry attention based on the evidence provided throughout the review.
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    Ozone Application in Aquaculture
    Kuhn, David; Smith, Stephen A.; Taylor, Daniel P.; Scott, Durelle T. (Virginia Cooperative Extension, 2017-04-05)
    This document discusses the use of ozone along with mechanical means of filtration to clean water in aquaculture systems. It also details the advantages of using ozone and its potential risks to aquatic animals.
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    Safe and Nutritious Seafood in Virginia
    Villalba, Abigail; Jahncke, Michael L.; Schwarz, Michael H.; Kuhn, David; Farris, Alisha (Virginia Cooperative Extension, 2016-01-15)
    Provides the information consumers require in order to help ensure that the seafood they purchase and consume is safe and nutritious.
  • Shellfish Hatchery Water Sampling Guide
    Rusnell, Jasmine (Virginia Tech, 2017-05-05)
    The purpose of this peer reviewed extension article was to create a guide that helps hatcheries with proper water sample storage and protocols that are easy to read and understand. Shellfish aquaculture has become a profitable industry and will continue to grow however, water quality issues can drastically affect this. These issues have been causing problems in the Chesapeake Bay where oysters were already experiencing a decrease in population. To determine the cause of water quality issues it’s essential to take samples throughout the hatchery season therefore following proper sampling and storage protocols is a top priority for hatchery personnel. Water sample testing might include analysis of Harmful Algal Blooms, pesticides, herbicides, metals, and bacteria. Testing for these require sending samples to analytical laboratories for analysis. For this project I built upon the research and work already being conducted in the Chesapeake Bay by faculty and students at Virginia Tech. I searched for more supporting documents and collected different pieces of information from multiple faculty members to put it all together into an extension article. Additionally I created some tables to assist hatchery personnel. For example upon determining the need for water quality testing, hatchery personnel can exam the list of analytical labs and contact information as shown in the document to decide where to send their samples to. With proper water sampling protocols shellfish hatcheries can detect water quality issues sooner and determine the best actions to deal with their problem.
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    Trace minerals in tilapia fillets: Status in the United States marketplace and selenium supplementation strategy for improving consumer’s health
    Farzad, Razieh; Kuhn, David; Smith, Stephen A.; O'Keefe, Sean F.; Ralston, Nicholas V. C.; Neilson, Andrew P.; Gatlin, Delbert M. (PLOS, 2019-06-06)
    This goal of this study was to highlight the importance of minerals in the diet of fish for meeting micronutrient requirements in the human diet. First arsenic, calcium, cadmium, copper, iron, molybdenum, magnesium, manganese, sodium, phosphorus, potassium, selenium, and zinc concentrations of twelve commercially available tilapia samples were measured. The nutritional value of fillets in regard to their mineral content were assessed to establish potential health benefits or risks for consumers. The health benefit value of selenium was also calculated. Positive health benefit values indicate that tilapia fillets in the United States marketplace of this study do not pose health risks associated with mercury exposures. Selenium was the trace mineral of interest. After the market study, a seven-week fish feeding trial was conducted to study the influence of organic versus inorganic dietary selenium on Nile tilapia (Oreochromis niloticus). Fish were fed two different diets enriched with the same concentration (0.01g kg-1) of selenium in form of inorganic (sodium selenite) or organic (seleno-L-methionine) selenium in triplicate groups. There were no significant differences between growth and biometrics of fish fed different diets (p>0.05). At the end of trial twelve fish from each treatment were collected. Fillets of fish fed organic selenium had selenium concentrations of 0.55 ± 0.01 μg g-1 which were significantly (p<0.05) higher than fish fed inorganic selenium at levels of 0.22 ± 0.008 μg g-1 or fish samples from the marketplace with a selenium level of 0.2 ± 0.03 μg g-1. Fish fed organic selenium also had significantly higher (p<0.05) plasma and kidney selenium in comparison to fish fed inorganic selenium. No significant differences (p>0.05) were observed in glutathione peroxidase activities in either the plasma or liver of Nile tilapia in the different treatment groups. This study shows that organic selenium is a better option for production of Nile tilapia fillets rich in selenium.
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    Understanding Fish Nutrition, Feeds, and Feeding
    Craig, Steven R.; Helfrich, Louis A.; Kuhn, David; Schwarz, Michael H. (Virginia Cooperative Extension, 2017-07-05)
    Discusses feeds and nutritional needs for fish raised in ponds, and aquaculture facilities.
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    Water Sampling Guide for Shellfish Hatcheries and Growers
    Kuhn, David; Rusnell, Jasmine; Hudson, Karen; Beck, Aaron; Schwarz, Michael H.; Reece, Kimberly (Virginia Cooperative Extension, 2017-05-08)
    Offers advice about sampling water at shellfish hatcheries to monitor for harmful algal blooms, and the presence of metals, pesticides, herbicides, and bacteria.
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    Waterless Shipment of Warm-Water Shrimp
    Kuhn, David; Taylor, Daniel P. (Virginia Cooperative Extension, 2017-03-28)
    This document discusses the shipment of live shrimp to market places. New methods of shipping the shrimp without water are noted; these methods greatly lower transport costs, since the greatest expense was fuel usage related to weight of water. It also makes note of other issues of concern including market conditions, packing conditions, and more.