Progress 09/01/06 to 08/31/09
Outputs
OUTPUTS: A mixed-sex group of Yellow Perch were selected as broodstock from a production trial at the Southwest Virginia AREC and were maintained in a recirculating aquaculture system. Low level, chronic mortalities began to occur. Samples were sent to a fish pathologist at the Virginia-Maryland Regional College of Veterinary Medicine. Examination revealed severe abdominal distension and exopthalmia due to excessive fat deposits and inflammation of fatty tissues and scoliosis and severe liver lipidosis. Sexual organs were poorly developed, hence, these fish were not acceptable broodstock. Yellow perch from VA Tech Aquaculture Center and pond-raised from Ohio State University's Piketon Research Center were introduced to the conditioning room in the hatchery area in two separate systems, and were exposed to a photothermal regime. A number of females died during the spawning efforts, and all egg ribbons were found to be unsuitable for hatching. Fish effluent was collected from recirculating aquaculture tanks for use in aquaponics. Ninety-4" pots each of WoodGro and ProMix, along with 90-4" cubes of Rockwool were seeded to Bibb lettuce (Lactuca sativa), then divided between two treatments-aquaculture effluent and comercial fertilizer solution. Seven heads of Bibb lettuce and water taken from the growing tanks were tested for total microbial populations and for selected human pathogens. Microbial analyses included total aerobic plate count, fecal coliform count, total vibrio count, and presence or absence of Listeria monocytogenes and Salmonella. Additional genetic work was conducted by the Horticulture Department at Virginia Tech as part of a rhizosphere study. Burkholderia pyrrocinia, which is implicated in respiratory disorders in people suffering from cystic fibrosis, was cultured from geranium produced in fish effluent and wood grow media. As a result of this finding, the taste panel was cancelled. A workshop was held for producers interested in generic information concerning recirculating aquaculture. A follow-up workshop was held at the Southwest Virginia Aquaculture Research and Extension Center for those individuals wanting more specific information on system design, species selection, and water quality. Another workshop was conducted with interested individuals for hands-on water quality training. An economic model was designed in cooperation with the Department of Agriculture Economics at Virginia Tech. This model was provided to several local producers who have begun aquaculture enterprises. An international exchange tour and workshop on the economics of aquaculture was conducted with a group of investment bankers from the Republic of Tajikistan. Specialized sessions on various aspects of aquaculture and hydroponic greenhouse production were conducted for the Virginia Farm Bureau (VFB), the VBF Young Farmers Association, Rich Valley Farmers Organization, Smyth County Chamber of Commerce, and the Southwest Virginia Agriculture Association. PARTICIPANTS: Dr. George Flick, Professor of Food Science and Technology, Virginia Tech served as prinicple investigator for this project. Ms. Rosa Slavik, Director Saltville Aquaculture Research and Education Center managed the research facility and was primary investigator for the aquaponic research; Dr. Greg Wellbaum, Professor, Department of Horticulture assisted with the aquaponic work. Zach Titman provided day-to-day help feeding fish and conducting water quality analyses. TARGET AUDIENCES: Individuals seeking supplemental income opportunities through aquaculture and aquaponics. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Yellow perch used in the study were determined to be beyond a reproductively viable age. Data collected during production cycles of yellow perch were provided to the Agriculture Economics Department at Virginia Tech for use in an aquaculture economic model computer program. The computer program has been provided to local aquaculture producers, and agricultural businesses for their use in determining economic feasibility and input needs for aquaculture ventures. No human pathogens were detected from any of the nine samples studied by the Food Science Microbiology Lab. There were no significant fecal coliforms, no Salmonella, no significant vibrios, and no Listeria monocytogenes found in any of the lettuce samples or in the treatment water used to grow the lettuce. The isolates identified from the Salmonella agar were Pseudomonas putida and were found in the effluent rockwool and the effluent harvested rockwool samples. The isolates identified from the two vibrio selective media were Pseudomonas aeruginosa, and were isolated from the effluent harvested rockwool sample and from both water samples. Citrobacter frundii was also found in both of the water samples. The isolates that were identified from the Listeria agar were Listeria innocua, found in the effluent soil treatment sample and in the effluent harvested rockwool sample. Listeria ivanovii was isolated from the municipal soil sample. Genetic sampling of the rhizosphere cultured Burkholderia pyrrocinia from geranium produced in wood grow media using effluent.
Publications
- Aquaculture Financial Planning Model 2008, VSG-08-05, produced by Virginia Tech's College of Agriculture and Life Sciences, Department of Agriculture and Applied Economics. Blacksburg, VA.
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Progress 09/01/07 to 08/31/08
Outputs
OUTPUTS: After a period of photothermal conditioning, broodstock being maintained at 10 degrees C with daylength of 10 hours, were exposed to gradual warming of water temperature to 14 degrees C. Females exhibited nesting behavior and began to expel egg ribbons. These first egg ribbons were examined, and determined to be non-viable. Consultation with other yellow perch breeding facilities suggested that these broodstock were held too long prior to attempts to induce spawning. As a result, a new protocol has been developed: the fish will be allowed to spawn naturally, experience a resting period, and then temperature and daylength will be gradually reduced to establish a period of recrudescence prior to attempting the next spawn. Fish effluent continues to be collected and utilized in the greenhouse for aquaponics projects investigating production of ornamental and food crops. Bibb lettuce and geranium work continued on plants remaining after initial food safety tests were conducted as reported previously. The relationship between epiphytic bacterial diversity onto leaf surface and the colonization of plants by bacteria was studied by measuring effects of inoculum density on different concentrations of KB and Soya Agar. Epiphytes populations were isolated by placing leaves from each randomly selected plants per treatment in 250-mL Erlenmeyer flask containing 10 mL of 0.1 M MgSO4 solution (pH 6.5) + 0.02% Tween 20 and washing by agitation on a rotary shaker for 30 min. 5:10 and 10:10 dilutions of the washing suspensions were prepared and were plated on KB Medium according to Miles and Misra (1938). Plates were incubated at 30˚C for 24h and number of cfu was recorded. The colonies were picked and preserved in TE buffer and will be sent for 16s rRNA gene sequencing. PARTICIPANTS: Dr. George Flick, Professor of Food Science and Technology, is the principle investigator providing oversight for this project. Ms. Rosa Slavik was responsible for the day-to-day operation of the recirculating aquaculture facility. Dr. Gregory Welbaum, Department of Horticulture, Virginia Tech, assisted with the work involving production of ornamental and food crops in fish effluent. TARGET AUDIENCES: The research for the yellow perch spawning project is directed at commercial aquaculture operations to improve the knowledge of reproduction of those species requiring a period of recrudesence prior to spawning. Successful spawning of yellow perch will provide an alternative to the present supply of yellow perch fingerlings produced in the wild. The aquaponics research benefits producers engaged in horticultural production of both landscape ornamentals and food crops in greenhouses. Development of safe production methods utilizing effluent will provide an alternative value-added product for recirculating aquaculture producers. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
A researcher investigating genetic activity within the rhizosphere of geranium grown in WoodGro and effluent, discovered Burkholderia pyrrocinia, a pathogen which is implicated in respiratory disorders in people suffering from cystic fibrosis. Burkholderia cepaciawas discovered in gernaium cultivated in effluent and rockwool, this pathogen is implicated in liver disease. Discovery of these pathogens led researchers to determine that Bibb Lettuce cultivated for taste testing would be destroyed and additional lettuce grown and evalulated for presence of these pathogens. A manuscript is currently being prepared for submission concerning this research.
Publications
- Slavik, R., Welbaum, G., (2008). Utilizing Fish Effluent for Food Crop Production. Seventh International Conference of Recirculating Aquaculture. Roanoke, Va.
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Progress 09/01/06 to 08/31/07
Outputs
OUTPUTS: Yellow perch broodstock were introduced to the conditioning room in the hatchery of the Southwest Virginia Aquaculture Research and Extension Center. While these fish were being exposed to a natural winter photothermal regime, equipment failure resulted in a 100% fish kill on two separate occasions. As a result, a third group of fish have been introduced to the conditioning room and are currently being exposed to the photothermal regime to attempt spawning in the near future. Fish effluent continues to be collected from the recirculating aquaculture tanks for use in aquaponics projects. On January 19, 2007, 90-4" (10 cm) pots each of WoodGro and ProMix, along with 90-4" (10 cm) cubes of Rockwool were seeded to Bibb lettuce (Lactuca sativa), then divided between the two treatments. Seven heads of Bibb lettuce weighing between 22 and 87 grams and two containers of water taken from the growing tanks were delivered to the Food Science Microbiology Lab to be tested for total
microbial populations and for selected human pathogens. The microbial analyses included a total aerobic plate count, a fecal coliform count, a total vibrio count, and the presence or absence of Listeria monocytogenes and Salmonella. Duplicate samples were sent from each growing treatment as well as samples of the water from each of the two treatments. Three additional samples were sent. Each sample was weighed and mixed with an equal amount of Phosphate Buffered Saline (PBS) to produce a 1:2 dilution and homogenized for 4 minutes using a Seward Stomacher 400 Circulator. Serial dilutions were made in PBS. From the initial one to ten dilution and from each subsequent dilution, 1 ml was transferred into each of two 3M Aerobic Count (AC) Petrifilm and incubated for 48 hours at 35 degrees C. Petrifilms were counted and recorded.
PARTICIPANTS: Ms. Rosa Slavik, Director Saltville Aquaculture Research and Education Center; Dr. Greg Wellbaum, Professor, Department of Horticulture.
TARGET AUDIENCES: Individuals seeking supplemental income opportunities through aquaculture and aquaponics
Impacts
No human pathogens were detected from any of the nine samples. There were no significant fecal coliforms, no Salmonella, no significant vibrios, and no Listeria monocytogenes found in any of the lettuce samples or in the treatment water used to grow the lettuce. The isolates identified from the Salmonella agar were Pseudomonas putida and were found in the effluent rockwool and the effluent harvested rockwool samples. The isolates identified from the two vibrio selective media were Pseudomonas aeruginosa, and were isolated from the effluent harvested rockwool sample and from both water samples. Citrobacter frundii was also found in both of the water samples. The isolates that were identified from the Listeria agar were Listeria innocua, found in the effluent soil treatment sample and in the effluent harvested rockwool sample. Listeria ivanovii was isolated from the municipal soil sample.
Publications
- Flick, G. J. Jr. (2007). Persistent Biofilms Problematic in Aquaculture Food Processing. Global Aquaculture Advocate. July/August 2007. 28-29.
- Slavik, R., Welbaum, G., (2007). Utilizing Fish Effluent for Food Crop Production. In Proc. Dean's Forum on Health, Food, and Nutrition. Blacksburg, Va.
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