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Shepherdstown, WV, United States

Davidson J.,Conservation Funds Freshwater Institute | Good C.,Conservation Funds Freshwater Institute | Barrows F.T.,U.S. Department of Agriculture | Welsh C.,Conservation Funds Freshwater Institute | And 2 more authors.
Aquacultural Engineering | Year: 2013

Feeding a fish meal-free grain-based diet (GB) was compared to feeding a fish meal-based diet (FM) relative to water quality criteria, waste production, water treatment process performance, and rainbow trout Oncorhynchus mykiss performance within six replicated water recirculating aquaculture systems (WRAS) operated at low exchange (0.26% of the total recycle flow; system hydraulic retention time=6.7 days). Rainbow trout (214±3 g to begin) were fed the GB diet within three WRAS and the FM diet within the other three WRAS for 3 months. Feeding the GB diet resulted in significantly greater total ammonia nitrogen (TAN) throughout the study, as well as significantly greater total suspended solids (TSS) and carbonaceous biochemical oxygen demand (BOD) over the greater part of the study. Greater counts of fine solids (2-30. μm) were associated with the GB diet. Water clarity was improved for the GB diet as reflected by significantly reduced true color and increased ultraviolet transmittance. Total and dissolved phosphorous, as well as the daily mass captured per kg feed of total phosphorous were significantly lower within the effluent associated with the GB diet. The daily mass of total nitrogen and TSS captured per kg feed and discharged from each WRAS was equal between diets, but waste load among three discharge flows varied. Waste removal efficiency across unit processes was similar between diets, with the exception of solids removal efficiency across the microscreen drum filter and the radial flow settler, which was generally lower for the GB diet. Rainbow trout growth, feed conversion, condition factor, and survival were similar between diets. Survival was 99.5±0.2% for both diet treatments. Skin-on fillet yield and whole-body protein levels were significantly greater at the end of the study for trout fed the GB diet. Overall, the GB diet evaluated during the present study proved to be a viable feed option for use within a low exchange WRAS. However, further refinements to grain-based diet formulations and/or use of ozone to improve water quality when feeding GB diets within low exchange WRAS could be beneficial. © 2012 Elsevier B.V. Source


Good C.,Conservation Funds Freshwater Institute | Vinci B.,Conservation Funds Freshwater Institute | Summerfelt S.,Conservation Funds Freshwater Institute | Snekvik K.,Washington State University | And 2 more authors.
Journal of Aquatic Animal Health | Year: 2011

To assess the suitability ofwater reuse technology for raising Pacific salmon Oncorhynchus spp. for stocking purposes, fish health and welfare were compared between two groups of juvenile Chinook salmon O. tshawytscha from the same spawn: one group was reared in a pilot partial water reuse system (circular tanks), and the other group was reared in a flow-through raceway. This observational study was carried out over a 21-week period in Washington State. Reuse and raceway fish were sampled repeatedly for pathogen screening and histopathology; fin erosion and wholeblood characteristics were also evaluated. By the study's end, no listed pathogens were isolated fromeither cohort, and survival was 99.3% and 99.0% in the reuse and raceway groups, respectively. Condition factor was 1.28 in raceway fish and 1.14 in reuse fish; this differencemay have been attributable to occasional differences in feeding rates between the cohorts. Fin indices (i.e., length of the longest dorsal or caudal fin ray, standardized by fork length) were lower in reuse fish than in raceway fish, but fin erosion was not grossly apparent in either cohort. The most consistent histological lesion was gill epithelial hypertrophy in reuse fish; however, blood analyses did not suggest any corresponding physiological imbalances. Overall, results suggest that water reuse technology can be employed in rearing juvenile anadromous salmonids for stocking purposes. © American Fisheries Society 2011. Source


Draghi A.I.I.,University of Connecticut | Bebak J.,University of Connecticut | Bebak J.,U.S. Department of Agriculture | Daniels S.,University of Connecticut | And 9 more authors.
Diseases of Aquatic Organisms | Year: 2010

Arctic charr Salvelinus alpinus production facilities, nonproduction water sources and effluents in the United States and Canada were sampled to determine if chlamydiae associated with epitheliocystis were present in water and were associated with inclusions of epitheliocystis in gill tissue. Gills from 607 fish from 13 sites were processed for histopathologic examination and DNA extraction. Water was collected from 21 locations for DNA testing. Eighteen fish from one location had inclusions of epitheliocystis with proliferative and inflammatory gill lesions. Inclusions were stained using the Gimenez technique and, at the ultrastructural level, consisted of intracytoplasmic membrane-bound vacuoles containing reticulate and intermediate bodies in a fibrillar matrix. PCR using Order Chlamydiales-specific primers performed on DNA extracts from 12 of 13 infected fish yielded amplicons that were identical to (GQ302988) or differed at one base from (GQ302987) the 16S ribosomal RNA gene signature sequence of 'Candidatus Piscichlamydia salmonis', which is the chlamydia that was previously identified in epitheliocystis inclusions of farmed Atlantic salmon. In situ hybridization using a ∼1.5 kb riboprobe corresponding to the 'Candidatus Piscichlamydia salmo-nis' 16S rRNA genetic sequence (AY462244) confirmed its presence within Arctic charr gill inclusions. DNA isolated from water samples was tested by Chlamydiales-specific PCR and yielded 54 partial 16S rRNA genetic sequences spanning the signature region; however, no 16S rRNA genetic sequences associated with epitheliocystis were identified. This is the first report of 'Candidatus Pisci-chlamydia salmonis' associated with epitheliocystis in Arctic charr, the first identification of 'Candi-datus Piscichlamydia salmonis' from a freshwater production location, and the first reported occurrence in North America. © Inter-Research 2010, www.int-res.com. Source

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