2006 Annual Report 1.What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? Why does it matter? This research directly addresses several components of the National Program 106 Aquaculture action plan such as: Section E (Early Life Stage Development and Survival) of the REPRODUCTION AND EARLY DEVELOPMENT component, Sections C (Sustainable Sources of Nutrients) and D (Nutrient Use and Feed Evaluation) of the GROWTH DEVELOPMENT AND NUTRITION component, Section E (Live Aquatic Animal Handling, Transport, and Inventory) of the AQUACULTURE PRODUCTION SYSTEMS component, Sections A (Aquaculture Feeds) and B (Water Use and Reuse) of the SUSTAINABILITY AND ENVIRONMENTAL COMPATIBILITY OF AQUACULTURE component, and Section D (Off-flavor Delayed Harvesting) of the QUALITY SAFETY AND VARIETY OF AQUACULTURE PRODUCTS FOR CONSUMERS component. Spending on seafood by United States’ consumers presently stands at over $55 billion annually. Demand far exceeds domestic production, generating a $7 billion dollar annual trade deficit—the third largest U.S. trade deficit after petroleum and automobiles. Increasing seafood production from wild fisheries to meet this demand and offset the deficit is not possible because most national and global wild-catch fisheries are fully exploited. The only way to close the enormous trade deficit in seafood and reduce America’s dependence on foreign products is to dramatically increase domestic aquaculture production. The channel catfish is the most important aquaculture species in the United States. In 2003, just over 300 million kg of channel catfish were processed, representing over half the total United States aquaculture production. Catfish aquaculture has generally been a profitable and rapidly expanding industry in the southeastern United States. However, yield has not increased in recent years and profits have decreased. We have addressed these problems through a multidisciplinary program focused on improving the efficiency of catfish production. The overall goal of this project is to develop management practices that provide greater control of production activities in channel catfish aquaculture. Specific areas of research have been identified through interactions with industry, extension service representatives, and research personnel in other disciplines and other states. This research also directly addresses several components of the National Program 106 Aquaculture Action Plan, such as: Component 2 (Integrated Aquatic Animal Health Management) Problem a (Pathogen Identification and Disease Diagnosis), Problem b (Vaccines and Medicines), Problem c (Immunology and Disease Resistance), Problem e (Epidemiology), Problem g (Aquatic Animal Health Medicine), Problem h (Immune System Enhancement – Nutrients and Immunostimulants), as well as Component 4 (Growth and Development, and Nutrition). Taken as a whole, this project aims to develop an integrated system of managing catfish health problems and therefore all of the objectives ultimately address the primary stated goal of Problem g (Aquatic animal health medicine), which is to “improve health management practices currently used in aquaculture.” 2.List by year the currently approved milestones (indicators of research progress) Objective 1: Develop feeds and feeding practices for optimal nutrition, increased production, and improved water quality of pond-raised catfish. Hypothesis 1: Economic performance of traditional catfish diets can be improved by manipulating content and sources of protein and carbohydrate. Milestones 12-month – Initiate pond feeding trials in a 2 x 4 factorial design using 32% crude protein feeds with 2 fish meal levels (0% and 8% menhaden fish meal) and 4 feed ingredient combinations (soybean meal + corn, soybean meal + corn + wheat middlings, soybean meal + corn + cottonseed meal, soybean meal + corn + cottonseed meal + wheat middlings). 24-month – Complete first year of first pond feeding trial. 36-month – Complete first feeding study. Initiate pond feeding trials in a 2 x 4 factorial design using 28% crude protein feeds with 2 fish meal levels (0% and 8% menhaden fish meal) and 4 feed ingredient combinations (soybean meal + corn, soybean meal + corn + wheat middlings, soybean meal + corn + cottonseed meal, soybean meal + corn + cottonseed meal + wheat middlings). 48-month – Complete first year of second pond feeding trial. 60-month – Complete second pond feeding trial. All data evaluated. Optimum feed formulation recommended. Hypothesis 2: Interactions among fish size (fingerlings, stocker-size, foodfish) and feeding schedule (satiation vs. various restricted rations) affect economic performance of catfish farming. Milestones 12-month – Initiate long-term pond feeding trial using three feeding regimes:. 1)feeding to apparent satiation once daily;. 2)feeding to apparent satiation once every other day; and. 3)feeding once daily to no more than 90 kg/ha. Harvest marketable fish and restock with fingerlings (complete year 1 of grow-out cycle). 24-month – Harvest marketable fish from study and restock with fingerlings (complete year 2 of grow-out cycle). 36-month – Harvest marketable fish from study and restock with fingerlings (complete year 3 of grow-out cycle). 48-month – Harvest marketable fish from study; harvest all remaining fish (complete year 4 of grow-out cycle, study complete). 60-month – Data evaluation complete. Optimum feeding strategy recommended. Objective 2: Increase the reliability, efficiency, and cost-effectiveness of catfish fry production through the use of new and improved technologies. Hypothesis 1: Implementation of new nursery pond management strategies can improve fry growth and survival on a commercial catfish farm. Milestones 12-month – Initiate and complete year 1 studies of “best management practices” (BMPs) for fry nursery ponds on commercial farm. Year 1 management strategy evaluated, modeled, and incorporated into new model and management strategy. 24-month – Initiate and complete year 2 studies of “best management practices” for fry nursery ponds on commercial farm. Year 2 management strategy evaluated, modeled, and incorporated into new model and management strategy. 36-month – Initiate and complete year 3 studies of “best management practices” for fry nursery ponds on commercial farm. Year 3 management strategy evaluated, modeled, and incorporated into new model and management strategy 48-month – Initiate and complete year 4 studies of “best management practices” for fry nursery ponds on commercial farm. Year 4 management strategy evaluated, modeled, and incorporated into new model and management strategy. 60-month – All results analyzed. Final management strategy recommended. Hypothesis 2: Increased nitrogen fertilization rates will improve fry growth and survival. Milestones 12-month – Initiate studies in replicate fry ponds fertilized with different levels of nitrogen fertilizer. 24-month – Complete first N application rate study. Evaluate data and refine N application rate. Initiate second year of N application rate study. 36-month – Complete second N application rate study; analyze data; recommend optimum N fertilization rate to industry. Initiate P fertilization rate study. 48 month – Complete first P application rate study. Evaluate data and refine P application rate. Initiate second year of study. 60-month – Complete second P application rate study; analyze data; recommend optimum P fertilization rate to industry. Hypothesis 3: Zooplankton affect growth, survival, and immune response of catfish fry. Milestones 12-month – Initiate and complete first year of laboratory studies of the effect of feeding supplemental zooplankton on fry growth, survival, immune response, and survival to disease challenge. Refine diets based on year 1 results and repeat study using basic protocol. 24-month – Complete data analysis of second year study; refine diets and repeat study using basic protocol. 36-month – Complete data analysis of third year study; refine diets and repeat study using basic protocol. 48-month – Complete data analysis of fourth year study; refine diets and repeat study using basic protocol. 60-month – All results evaluated. Final recommendations made to industry. Objective 3: Apply engineering approaches to design new or modified live aquatic animal harvesting equipment. Hypothesis: Incorporating an induced electrical field into a seine improves harvest efficiency of pond-raised catfish. Milestones 12-month – Complete design, fabrication, and testing of components in vats. 24-month – Complete laboratory vat testing; redesign components. 36-month – Initiate and complete vat studies on capture efficiency of prototype seine; Initiate design and fabrication of pilot-scale seine. 48-month – Complete first year of comparative field study; modify seine as needed. 60-month – Commercial-grade seine developed and tested. Complete economic study. Objective 4: Increase the reliability, efficiency, and cost-effectiveness of catfish production through the use of new and improved culture system technologies. Hypothesis 1: Radical changes in the design of ponds, incorporating the concepts of fish confinement and water circulation, can improve catfish production efficiency. Milestones 12-month – Complete construction of “extensive” partitioned aquaculture system (PAS) and initiate performance optimization. Initiate construction of sidestream bypass partitioned aquaculture system. 24-month – Complete construction sidestream bypass partitioned aquaculture system; initiate performance testing and design optimization. 36-month – Initiate and complete year 1 of comparative fish growth trials in extensive and sidestream bypass partitioned aquaculture systems. 48-month – Complete year 2 of comparative fish growth trials in extensive and sidestream bypass partitioned aquaculture systems. 60-month – Complete year 3 of comparative fish growout trials. Results analyzed. Technology transferred. Hypothesis 2: Development of an environmental management system for pond aquaculture, consisting of proven or easily implemented technologies, can improve catfish production efficiency, reduce environmental impacts, and conserve water. Milestones 12-month – Develop Environmental Management System; initiate year 1 of comparative production trials. 24-month – Complete year 1 of comparative production trials; initiate year 2. 36-month – Complete year 2 of comparative production trials; initiate year 3. 48-month – Complete year 3 of comparative production trials; initiate year 4. 60-month – Complete year 4 of comparative production trials. Evaluate overall results and recommend EMS to industry. Objective 1: Develop diagnostic tools to detect and monitor diseases in commercially raised channel catfish and determine virulence factors associated with those diseases. Hypothesis 1: A real-time PCR assay can be developed to study the epidemiology of proliferative gill disease. Milestones FY 2005 – Validate the specificity of a pair of H. ictaluri PCR primers and initiate the development of methodologies for isolating spores from pond water (filtration or imuno-capture). FY 2006 – Develop real-time PCR assay and optimize conditions for its use. FY 2007 and 2008 – Conduct field investigations using the PCR assay and optimize conditions for its use. FY 2009 – Objective complete. Hypothesis 2: A real-time immuno-PCR assay can be developed to study the epidemiology of enteric septicemia of catfish. Milestones FY 2005 – Optimize real-time PCR assay for E. ictaluri and develop immuno-capture methodologies. FY 2006 – Conduct laboratory trials and optimize conditions for use of assay. FY 2007 and 2008 – Conduct field trials and optimize conditions for use of assay. FY 2009 – Objective complete. Hypothesis 3: Early stages in the pathogenesis of enteric septicemia can be elucidated by examining differential protein expression by Edwardsiella ictaluri exposed to channel catfish intestinal mucus. Milestones FY 2005 – Evaluate growth of Edwardsiella ictaluri in water and catfish intestinal mucus. FY 2006 – Characterize protein expression under above growth conditions using electrophoresis. FY 2007 – Develop antibodies to proteins of interest identified above. FY 2008 – Evaluate protection derived from isolated proteins and conduct challenges. FY 2009 – Objective complete. Hypothesis 4: Strain differences in Edwardsiella ictaluri and Flavobacterium columnare can be identified by genetic variation among isolates. Milestones FY 2005 – N/A FY 2006 – Optimize ERIC, Rep, and BOX PCR methodologies for Edwardsiella ictaluri and Flavobacterium columnare. FY 2007 and 2008 – Analyze archived strains of above bacteria for genetic variation. FY 2009 – Conduct challenges. Hypothesis 5: Edwardsiella ictaluri strains isolated during epizootics at abnormally high water temperatures vary in growth and genetic features from those isolated at normal temperatures. Milestones FY 2005 – N/A FY 2006 – Optimize culture methods for growth of archived E. ictaluri strains growing at higher than expected temperatures. FY 2007 – Determine growth characteristics of above bacterial isolates and perform challenge trials on channel catfish fingerlings. FY 2008 – Objective complete. Objective 2: Develop fish health management procedures to control economically important diseases of channel catfish. Hypothesis 1: Acute and chronic Bolbophorus sp. trematode infections decrease growth, production efficiency, and health status of channel catfish fingerlings. Milestones FY 2005 – Evaluate effects of acute Bolbophorus sp. infections on channel catfish. FY 2006 and 2007 – Evaluate relationship of acute Bolbophorus sp. infection on susceptibility to enteric septicemia in pond studies. FY 2008 and 2009 – Evaluate the effects of chronic Bolbophorus sp. infection. Hypothesis 2: Method of vaccine preparation and bacterial exposure influence the efficacy of AQUAVAC-ESC® in challenge trials. Milestones FY 2005 – Optimize conditions for AQUAVAC-ESC® vaccination and conduct challenge trials. FY 2006 – Objective complete. Hypothesis 3: Feed restriction and inclusion of natural feeds to the diet enhance resistance to enteric septicemia of catfish and improves vaccine efficacy. Milestones FY 2005 – Establish validity of restricted feeding practices for control of enteric septicemia. FY 2006 and 2007 – Evaluate interaction of restricted feeding and AQUAVAC-ESC® vaccination on survival of channel catfish exposed to E. ictaluri infection. FY 2008 and 2009 – Conduct field trials. Hypothesis 4: AQUAVAC-ESC® and AQUAVAC-FC® used in combination will reduce losses of channel catfish fingerlings to enteric septicemia and columnaris disease. Milestones FY 2005 - Optimize conditions for AQUAVAC-FC® vaccination and conduct challenge trials. FY 2006 – Evaluate efficacy of combined AQUAVAC-ESC® and AQUAVAC-FC® vaccination on survival of channel catfish. FY 2007 – Continue to evaluate efficacy of combined AQUAVAC-ESC® and AQUAVAC-FC® vaccination on survival of channel catfish. FY 2008 and 2009 – Conduct field trials. Objective 3: Determine factors associated with emerging diseases in pond-raised channel catfish. Hypothesis 1: An unidentified toxin is responsible for visceral toxicosis of catfish (VTC). Milestones FY 2005 – Isolate and characterize toxin responsible for development of VTC. FY 2006 – Examine immune system recognition of VTC toxin and develop antibodies against the toxin. FY 2007 – Develop ELISA method for detection of VTC toxin. FY 2008 and 2009 – Conduct field trials. Hypothesis 2: Iron deficiency is responsible for development of channel catfish anemia (CCA). Milestones FY 2005 – Examine response of channel catfish suffering from natural development of CCA to parenteral iron and determine the lifespan of the catfish erythrocyte. FY 2006 – Evaluate effect of feeding an iron deficient diet on development of CCA-like disease. FY 2007 and 2008 - Examine possible mechanisms for the disturbance of normal iron metabolism in the pathogenesis of CCA. FY 2009 – Objective complete. Hypothesis 3: A new streptococcal disease causes losses of brood-sized channel catfish. Milestones FY 2005 – Characterize the streptococcal bacteria isolated from an emerging disease of channel catfish and fulfill Koch’s postulates. FY 2006 – Objective complete. Objective 4: Use epidemiological methods to investigate new and emerging diseases, and to identify environmental and management factors that influence the onset and severity of disease outbreaks. Hypothesis 1: A systematic data-collection system can be used to identify risk factors associated with the diseases visceral toxicosis of catfish and channel catfish anemia. Milestones FY 2005 – Develop infrastructure for data collection, including hiring of essential personnel and construction of database. FY 2006 – 2008 – Collect field data. FY 2009 – Evaluate associations from collected data. 4a.List the single most significant research accomplishment during FY 2006. Collaborators at MAFES are working on methods to improve production efficiency of pond-raised channel catfish. Nursery pond fertilization to enhance phytoplankton and zooplankton populations is a common practice among all cultured species of fish and is especially important in catfish farming to provide large numbers of healthy fingerlings for the largest U.S. aquaculture industry. Previous catfish nursery pond fertilization recommendations were developed based on data from ponds located in a different state and produced variable results in Mississippi. By recognizing that ponds are nitrogen limited and not phosphorus limited as previously thought, modifications of fertilization practices have already produced more consistent results and lead to more efficient, economical fry production. The new fertilization recommendations being developed from this research are being quickly adopted by catfish farmers, even before this project is completed. An article on the new pond fertilization strategies has been carried in 12 newspapers and appeared in some agricultural magazines. Feed cost typically accounts for about 50% of variable operating costs in catfish production, and feeding practices have marked impacts on fish growth, production, feed efficiency, and profit in channel catfish farming. Mississippi State University scientists initiated in 2004 a four-year study to compare. 1)feeding to apparent satiation once daily;. 2)feeding to apparent satiation once every other day; and. 3)feeding once daily to no more than 90 kg/ha under a multiple-batch cropping system. Results from the 2004 and 2005 growing seasons showed that fish fed once daily to satiation were fed more feed and more market-size fish were harvested than those fed once every other day to satiation. The total amount of feed fed and market-size fish harvested were intermediate for fish fed once daily at a restricted ration. These feeding regimens had no significant impact on processing yield and fillet protein level, but fish fed to satiation every other day had significantly lower fillet fat because of restricted nutrient and energy intakes. Collaborators at Mississippi State University are working on several issues related to channel catfish health. The trematode, Bolbophorus spp., has been associated with high mortalities and production loss in commercial catfish. Research was conducted to establish the prevalence, severity and economic impact of this disease on a commercial catfish operation. Of the 38 ponds sampled, 17 were categorized as negative, 6 as light, 6 as moderate and 11 as severe. Fish in the negative category consumed 73.4 lbs/ac/day, and fish categorized as light, moderate and severe consumed 62.2, 47.5 and 47.2 lbs/ac/day, respectively. Compared to trematode negative ponds, ponds in the light, moderate and severe categories produced 16.8%, 36.4% and 44.5% less fish weight per acre, respectively. Net returns from ponds in the light category were reduced by 80.8%. Ponds in the moderate and severe category produced net losses of $506 and $631 respectively. This data showed trematode infections decreased production, even with light infections. Tests were conducted in commercial ponds to determine the efficacy of copper application to ponds to eradicate snails. Results in ponds demonstrated that copper sulfate pentahydrate (2.5 and 5.0 mg/L CSP) was effective in killing snails around the margins of the pond and throughout the water column, but had a negative impact on fish health. These trials indicate copper application to pond water can be used with caution as an effective treatment against snails. On an annual basis, the Aquatic Diagnostic Laboratory processes between 1,600 and 2,000 case submissions. Routine services performed include gross necropsy, histopathology, bacteriology, virology, mycology, parasitology and water quality evaluation. The aquatic diagnostic laboratory works closely with producers to provide and evaluate treatment recommendations, monitor disease trends, provide surveillance for and investigation into the causes of new and emerging disease, and provide field service investigations. The objectives of the fish health research program are focused on the development of management programs designed to improve production efficiency and establish new effective measures for the detection, prevention and treatment of disease. Significant research accomplishments were associated with the control and pathobiology of bacterial and parasitic diseases, improved diagnostic technologies and diseases of unknown etiology. 4b.List other significant research accomplishment(s), if any. Inefficient harvesting is seriously affecting the profitability of the catfish industry because market-sized fish that escape harvest continue to grow and create additional inefficiencies resulting from higher feed conversion ratios and carry-over of large fish that are unacceptable to processing plants. At least $50 million of revenue is lost annually due to inefficient harvesting. The best solution to these problems appears to be the development of new or improved harvest gear and methods. One possibility to improve the efficiency of harvesting catfish from ponds is to use electricity as a means of repelling fish. Worker safety is the major issue when considering using electricity to enhance a conventional seine. Safety issues must be resolved if there is to be any hope that producers will adopt all or part of the technology developed under this objective. Therefore, the successful design of an effective electrical circuit that will cut off the power to each panel of electrodes as they come out of the water is a major accomplishment. The demonstration that the individual components of the low powered electrical modules can be reduced significantly in size and weight is also important because of concerns about the effect of the panels on the total weight of a modified seine. Most United States aquaculture production comes from ponds which have the advantage of low capital cost and the relative reliability of fish production. However, traditional ponds need continuous management of oxygen concentrations and are susceptible to algae-related fish off-flavors, losses to avian predators, difficulties in disease control, inefficient fish harvesting, and the finite limit on fish production. Mississippi State University researchers have initiated a long-term study of the partitioned aquaculture system (PAS), which attempts to partition pond fish culture into distinct physical, chemical, and biological processes which are then linked water flow from highly efficient, low-speed paddlewheels. Physical separation of the fish culture process from enhanced algal production allows separate optimization of both processes and maximizes overall system performance and productivity. In the first year of production, a simple version of the PAS was constructed and found capable of sustained fish feeding rates of 150 to 200 pouns/acre per day without deterioration of water quality. Fish grew from about 0.1 pounds per fish to an average of 1.45 pounds/fish in a 6-month growing season. Total harvest weight was 16,910 pounds per acre, for a net fish production of 14,506 pounds per acre. This is about twice that achieved in traditional ponds. Fish survival was 99.6% at a feed conversion efficiency of 1.87 pounds of feed per pound of fish produced. Mississippi State University scientists at the National Warmwater Aquaculture Center in Stoneville, Mississippi, are evaluating a simple environmental management system to reduce the amount of waste produced within catfish ponds and decrease the volume of water discharged from ponds. After 2 years of study, average water discharge from ponds managed with the system was 60% of that from unmanaged ponds. Reducing effluent volume caused a concomitant reduction in waste discharge: mass discharge of total nitrogen, phosphorus, suspended solids, and 5-day biochemical oxygen demand was reduced by over 45% in ponds managed with the system. Catfish farmers can easily adopt these practices, which will allow catfish farms to be operated with little or no impact on the environment. On an annual basis, the Aquatic Diagnostic Laboratory processes between 1,600 and 2,000 case submissions. Routine services performed include gross necropsy, histopathology, bacteriology, virology, mycology, parasitology and water quality evaluation. The aquatic diagnostic laboratory works closely with producers to provide and evaluate treatment recommendations, monitor disease trends, provide surveillance for and investigation into the causes of new and emerging disease, and provide field service investigations. The objectives of the fish health research program are focused on the development of management programs designed to improve production efficiency and establish new effective measures for the detection, prevention and treatment of disease. Significant research accomplishments were associated with the control and pathobiology of bacterial and parasitic diseases, improved diagnostic technologies and diseases of unknown etiology. Visceral toxicosis of catfish (VTC) is a disease of unknown etiology and is seen primarily in market size and brooder fish. Since spring 1998, outbreaks have been recognized as seasonal and occur in the early spring and late fall when pond temperatures are between 18-22 °C. In the spring of 2005, assays were performed using sera from affected fish that strongly suggested botulism type E as the cause of VTC. Because of the limited supply and lability of affected serum, further assays for botulism could not be performed at this time. With a new outbreak in the spring of 2006, more bioassays with catfish were performed which defined botulism as the cause of VTC. The validity of this assay was confirmed by The Centers for Disease Control and Prevention in Atlanta, GA., by Mass Spectrometry. Channel catfish anemia (CCA) is another disease of unknown etiology and generally affects market size fish. CCA was show to be caused by iron deficiency. While dietary iron supplements did not elevate hematocrit values, parenteral administration of iron dextran was shown to promote recovery. The data suggests iron deficient anemia associated with CCA is related to interference in the absorbtion or transport of iron and not a dietary deficiency. In unrelated laboratory trials, symptoms consistent with CCA developed in channel catfish fingerlings fed a commercial channel catfish diet. Summary of hematocrit values showed that approximately 14% of fish sampled had hematocrit values of 10% or less. None of the fish fed a standard reference diet developed symptoms consistent with anemia. Supplementing the diet with lysine, ferrous sulfate, folic acid or vitamin C was not shown to correct the development of this condition. This conditions appears to mimic the characteristics of CCA and is one potential cause of this disease. In October 2005, the U.S. Food and Drug Administration (USFDA) approved the use of Aquaflor® (Schering-Plough Animal Health) medicated feed for the control of ESC in catfish. In preceding years, MSU-CVM conducted the efficacy, palatability, and safety trials in support of this approval. Field usage of this antibiotic began in April 2006 in the Mississippi Delta. Farmers are reporting that Aquaflor® treated fish are feeding during ESC outbreaks, and there is decreased mortality in these fish. Decreased mortality has also been reported in ponds that are experiencing concurrent outbreaks with ESC and columnaris. The potential impact is that Aquaflor® will help increase catfish productivity during ESC season. Restricted feed practices and vaccination where also shown to significantly reduce ESC related mortalities by 50-60%. The combined use of these management options can greatly reduce ESC losses on commercial operations and improve production efficiency. Disease monitoring and risk assessment programs focused on enteric septicemia of catfish, columnaris disease, trematode infections, and proliferative gill disease. Immuno-capture beads were shown to be effective in recovering E. ictaluri and F. columnaris pathogens from raw pond water. Quantitative real time PCR was not shown be more sensitive than standard plate count procedures in enumerating captured bacteria. A quantitative real time PCR for the detection of Hennguya ictaluri spores, the causative agent of PGD, has been developed with a level of sensitivity of 10 spores per ml of pond water. Current studies are utilizing H. ictaluri PCR primers and probes to characterize the pathobiology of the parasite in catfish. These technologies and monitoring programs provide a means of monitoring pathogen levels in production systems and may provide a method of predicting potential disease epizootics. To assist disease monitoring programs, a computerized database has been constructed to collect information on feed consumption, stocking rates, harvest rates, mortality rates, water quality, and disease diagnoses. This project is being conducted in collaboration with a large commercial catfish producer and represents a major step forward in cooperation with the catfish industry. Four years of data will be collected and the information gained will be used to examine interactions between disease incidence, production parameters, and the environment. Virulence factors for E. ictaluri and F. columnare are being determined by 1D and 2D gel electrophoresis by extracting membrane proteins from bacteria grown in media, pond water and in vivo. Protocols, utilizing immuno-capture beads, have been developed to recover of bacterial pathogens from host tissues while maintains in vivo expression of proteins. Isolates of F. columnare and E. ictaluri from diagnostic case submissions have been collected, confirmed and archived. These isolates represent the majority of geographic regions in the southern United States that commercially produce channel catfish. ERIC/rep/BOX PCR conditions have been optimized to identify genetic variations in these isolates. Pulse field gel electrophoresis has identified three subgroups of F. columnare and disease challenge trials are being conducted to determine the virulence of each sub-group. 4c.List significant activities that support special target populations. Production inefficiencies related to feeding practices, nursery pond management, and harvesting in commercial catfish culture reduce profits and more efficient practices will benefit operators of small farms. The USDA Census of Aquaculture conducted in 2000 classified 84% of catfish farms as small businesses, with annual sales of less than $500,000. Of the 1,370 catfish farms in the United States, 38% (515) reported annual revenues of less than $25,000. Production inefficiencies disproportionately affect small farms because they are more susceptible to economic impacts related to interruption of cash flows. It is estimated that disease-related mortalities account for 45-50% of all losses incurred on farms and may account for as much as $100 million annually in direct economic impact. Production inefficiencies related to management and disease losses disproportionately affect small farms because they are more susceptible to economic impacts related to interruption of cash flows. The USDA Census of Aquaculture conducted in 2000 classified 84% of catfish farms as small businesses, with annual sales of less than $500,000. Of the 1,370 catfish farms in the United States, 38% (515) reported annual revenues of less than $25,000. The profitable operation of small farms is dependent on improvements in disease management to curtail monetary losses associated with disease. 4d.Progress report. None. 5.Describe the major accomplishments to date and their predicted or actual impact. All objectives are focused on improving production efficiency which, if attained, will improve the profitability of channel catfish farming. Application of successful research results will reduce dependence on fish meal as a feedstuff, lower feed costs, improve nutrient retention by fish (objective 1), and assure an inexpensive and dependable supply of seedstock for the industry (objective 2). Improvement of fish harvest (objective. 3)will increase production efficiency by removing most market-ready fish from ponds, thereby reducing carry-over of slow-growing large fish. Improved harvesting technology will also reduce the time and labor required for seining. The development of novel pond production methodologies (objective. 4)can potentially enhance overall production efficiency, reduce environmental impacts, and reduce water use. The overall benefits of this project will be the development of techniques to enhance economic performance, improve global competitiveness, and allow domestic aquaculture to reduce dependence on imports to meet the U.S. demand for seafood. The catfish health research project was initiated on 08/01/02 to develop a comprehensive disease management program that addresses disease related problems that threaten the economic wellbeing of commercial channel catfish farming. The current project plan, approved in 2004, continues to enhance existing disease research and diagnostic programs at the Thad Cochran National Warmwater Aquaculture Center. Major accomplishments to date involve investigation of the prevalence, severity, and economic impact of Bolbophorus sp. trematode infections, as well as the development of practical management strategies. Other accomplishments include the determination of a link between iron deficiency and channel catfish anemia, identification of a new streptococcal disease of catfish, identification of the toxin responsible for visceral toxicosis of catfish, and the development management practices utilizing medicated feeds, restricted feeding practices and vaccines to control bacterial infections. Accomplishments expected over the life of the project are to: 1)develop state-of-the-art diagnostic tools and procedures to detect and monitor diseases in commercially raised channel catfish; 2)develop best management practices for improving fish health and increasing the profitability of catfish farming by limiting the economic impact of infectious and non-infectious diseases; 3)develop field and laboratory disease challenge models used to study pathogenic mechanisms of disease and develop effective control strategies; 4)maintain a field service program to investigate new and emerging diseases, identify environmental and management factors that influence the onset and severity of disease outbreaks; and 5)establish the epidemiology of economically significant diseases, particularly those of unknown origin. 6.What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end-user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? This is the first year of this comprehensive 5-year project, and opportunities for technology transfer specifically related to the project have been limited. Preliminary information from feeding practice studies and from the environmental management studies have been published in popular articles, bulletins, research reports, book chapters, and scientific journals, which are accessible to various audience including catfish producers, feed mill managers, and scientists. Some information has also been presented at workshops and scientific meetings. More definitive results on all objectives should be available in the third, fourth, and fifth years of the project. Technology related to fertilization and zooplankton management is being transferred to farmers through personal consultation and workshops. Mississippi State University Office of Agriculture Communications wrote an article on the new pond fertilization strategies. The story was used in 12 newspapers and appeared in some agricultural magazines. Several farmers in Mississippi have already adopted the nursery-pond fertilization practices studied in this project, even before the project is complete. By recognizing ponds are nitrogen limited and not phosphorus limited as previously thought, modification of fertilization practices have already produced more consistent results and lead to more efficient, economical fry production. Similarly, farmers and state regulatory agencies have shown interest in the promising preliminary results from the first two years of work on the Environmental Management System. Several farmers have adopted formal water management schemes similar to the one in this project. Activities of the Aquatic Diagnostic Laboratory, including case summaries and disease trends are and made available to producers, university and government officials in the form of an annual report. Research activities are described in a variety of formats, including publications of the Southern Regional Aquaculture Center, National Warmwater Aquaculture Center, a producer’s trade journal, and in scientific journals. Verbal transfer of information occurs through phone and laboratory consultations, and through various workshops, demonstration projects, on-farm visits, and at scientific meetings. Research associated with catfish health research has lead to 5 published abstracts in the proceedings of regional, national and international scientific meetings, 4 popular articles, and 11 scientific articles published in the Journal of the World Aquaculture Society, Aquaculture, American Journal of Aquaculture, Journal of the American Veterinary Medical Assoication, Veterinary Journal, Journal of Developmental and Comparative Immunology, and Journal of Veterinary Diagnostic Investigations. Specific projects that have generated Information and practical solutions to fish health issues are development of trematode management programs, identification and characterization of the toxin that causes visceral toxicosis of catfish (VTC), presentation of possible implications of VTC to industry and state agencies, and the development and implementation of management programs for the control bacterial infections using medicated feeds, vaccines and restricted feeding practices. 7.List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below). Hargreaves, J.A., Tucker, C.S. 2005. Conditions associated with sub-lethal ammonia toxicity in warmwater aquaculture ponds. World Aquaculture. 36(3):20-24. Li, M.H., Peterson, B.C., Janes, C.L., Robinson, E.H. 2006. Comparison of diets containing various fish meal levels on growth performance, body composition, and insulin-like growth factor-I of juvenile channel catfish of different origin. Catfish Farmers of America Research Symposium, San Antonio, TX. Abstract No. 30. Li, M.H., Robinson, E.H., Hogue, C.D. 2006. Catfish nutrition: feeding food fish. Mississippi State University-Extension Service Publication No. 2414. Li, M.H., Robinson, E.H. 2006. Trials find feeding frequency factor in catfish performance. Global Aquaculture Advocate. 9(3):46–49. Li, M.H., Robinson, E.H., Mischke, C.C., Torrans, E.L., Bosworth, B.G. 2006. Effects of organic fertilization and “organic” diets on production of channel catfish in earthen ponds. Aquaculture America, Las Vegas, NV. Abstract No. 162. Lim, C., Yildirim-Aksoy, M., Shelby, R., Li, M.H., Klesius, P.H. 2006. Influence of dietary levels of fish oil and vitamin E on growth and resistance of channel catfish to Edwardsiella ictaluri challenge. Aquaculture America, Las Vegas, NV. Abstract No. 167. Mischke, C.C. 2006. Managing natural productivity in channel catfish nursery ponds. Global Aquaculture Advocate. 9(3):52-55. Mischke, C.C., Avery, J. 2005. Thad Cochran National Warmwater Aquaculture Center. Fish Culture Section of the American Fisheries Society Newsletter. 2005. (July):4-6. Mitchell, A.J., Wise, D.J., Snyder, S., Mischke, C.C. 2006. Optimizing slurried-hydrated lime pond-shoreline treatments for aquatic snails vectoring trematodes to cultured fish [abstract]. Catfish Farmers of America.. Paper No. 21-30. Robinson, E.H., Li, M.H. 2005. A summary of nutrition research conducted under a cooperative agreement between MAFES and Delta Western Research Center. Mississippi Agricultural and Forestry Experiment Station Bulletin No. 1144. Robinson, E.H., Li, M.H. 2006. Catfish nutrition: use of all-plant diets to grow food fish. NWAC News. 9(1):8. Robinson, E.H., Li, M.H., Hogue, C.D. 2006. Catfish nutrition: feeds. Mississippi State University-Extension Service Publication No. 2413. Robinson, E.H., Li, M.H., Hogue, C.D. 2006. Catfish nutrition: nutrient requirements. Mississippi State University-Extension Service Publication No. 2412. Tucker, C.S. 2006. Water-level management and BMPs cut water use and pond effluents. Global Aquaculture Advocate. 9(3):50-51. Tucker, C.S. 2005. Limits of catfish production in ponds. Global Aquaculture Advocate. 8(6):59-60. Tucker, C.S. 2005. Pond aeration. Southern Regional Aquaculture Center Publication 3700. USDA Southern Regional Aquaculture Center, Stoneville, MS. Tucker, C.S. 2005. Improving reproductive efficiency to produce hybrid catfish fry. The Catfish Journal. 19(8):14. Tucker, C.S., Silverstein, P., Camus, A., Bilodeau, L., Wise, D., Waldbieser, G. 2005. Channel catfish virus disease and NWAC103 catfish. The Catfish Journal. 19(5):8. Zimba, P.V., Mischke, C.C. 2006. Plankton-nutrient dynamics in channel catfish fry and freshwater shrimp growout ponds. World Aquaculture. 37(2):28-31. Bilodeau, A.L., Small, B.C., Wolters, W.R., and Wise, D. J. 2005. Early host response improves disease resistance in channel catfish. Global Aquaculture Advocate. 8(3):84. Gaunt, P. and Schnick, R. 2005. Industry gathers to discuss aquaculture drug status. The Catfish Jounal. 20:(2)21. 2005. Hanson, T. R. and Wise, D. J. 2005. Economic analysis projects 10% loss to Bolbophourus trematode in U. S. channel catfish industry. Global Aquaculture Advocate. 8(6):64. Camus, A. C., Guant P., Mauel, M. J. 2006. 2005 CVM Aquatic Diagnostic Laboratory Summary. NWAC News. 9(1):6-7. Steeby, J., Wise, D., Byars, T.,Thompson, L. 2006. Use of smallmouth buffalo (Ictiobus bubalus) to reduce the incidence of proliferative gill disease. NWAC News. 9(1):3. Wise, D., Hanson, T., Byars, T. 2006. Economic impact of trematode infections in commercially raised channel catfish. NWAC News. 9(1):4-5. Presentations: Wise, D. J. 2005. NWAC Fall Seminar. 2005. The effect of trematode infections on production of catfish. November 10, 2005. Delta Research and Extension Center, Stoneville, Mississippi. Wise, D. J. 2005. NWAC Fall Seminar 2005. The economic impact of trematode infections on production of catfish. December 2, 2005. , Mississippi State University, Starkville, Mississippi. Gaunt, P. 2006. Overview of florfeniol (Aquaflor®) research in channel catfish: Efficacy, safety, residue depletion studies, and implication for the catfish industry. Catfish Marketing Association Meeting, April 4, 2006, Greensboro, AL. Thompson, D. J., Khoo, L. H., Wise, D. J., and Hanson, L. A. 2006. Epidemiology of channel catfish virus disease. WAS International Symposium on Aquatic Animal Health. September 2-6, 2006. Wise, D. J. 2006. Texas Aquaculture Association. Impact of trematode infections on channel catfish. Jan 25-27, 2006, Bay City, Texas. Wise, D. J. 2006. Vaccination and integrated fish health management. American Chapter of the World Aquaculture Society. Feb 16-19, 2006. Las Vegas, Nevada. Wise, D. J. 2006. Producers meeting on the use of vaccines in an integrated fish health management program. Tribbet, MS. March 18, 2006.