Progress 07/15/04 to 01/14/07
Outputs
Resource limitations currently prohibit the individual rearing of multiple larval families for striped bass performance testing, necessitating a breeding program that is based on communal rearing of progeny groups with molecular markers as genetic tags for offspring identification. We discovered nearly 500 new microsatellite DNA markers for such work and published them in the peer reviewed literature and the NCBI database. In addition, we developed new procedures for utilization of pooled DNA samples to assess population genetic characteristics and verified the viability of large-scale communal rearing trials based on microsatellite DNA markers as a practical approach to selective breeding of striped bass, having identified superior performing families of striped bass in such trials. We assessed whether compensatory growth (CG) can be better induced in hybrid striped bass (HSB) following complete versus partial feed restrictions. After 3-weeks of feed deprivation and
then realimentation to normal daily feeding HSB show increased specific growth by 2-fold, increases in food consumption and efficiency, a full restoration of the hepatosomatic index, a 3-fold increase in plasma IGF-I, and a paradoxical decline in hepatic IGF-I mRNA levels. Circulating GH, pituitary GH content and GH mRNA levels recovered from elevated levels observed during the catabolic state proceeding CG. The overall CG response following complete feed restriction was similar to that achieved with only partial feed restriction. Combinations of constant and natural photothermal regimes were used to inhibit maturation of juvenile yellow perch and to promote their uniform growth by reducing sexually dimorphic growth. Constant temperature and photoperiod together fully inhibited maturation in both genders, reducing the proportion of submarketable-size fish from 50% to 15%. Coldbanked yellow perch were later successfully brought to sexual maturation through photothermal conditioning and
were successfully induced to mature and spawn with implanted pellets containing a synthetic analogue of mammalian gonadotropin-releasing hormone (GnRHa). Data from the laboratory scale denitrification trials with wood chips as media were used to design 6 - 1 m3 pilot scale dentrification reactors. These six reactors were fabricated at the Lake Wheeler Road Fish Barn and filled with two different types of media. Three reactors were filled with wood chips while three reactors were filled with Kaldnes plastic media. The system was connected to a solid waste collection and removal system based upon a geotextile bag. A unique water distribution and flow control system was also designed and built to provide for simple and reliable low flow (1 lpm) control to each of the 1 m3 reactors.
Impacts
Results from performance evaluations provide evidence of genetic variation in economically important traits, which may be exploited for selective breeding of striped bass, and it provides fundamental information needed to accelerate selective breeding for the hybrid striped bass industry. Our results show that HSB can be manipulated to undergo repeated states of compensatory growth following simple feed manipulations and that the response has the potential to improve feed efficiency with minimal effects on overall growth. Our results also indicate that plasma IGF-I is a prominent mediator of the different growth states observed with induction of CG and suggest that it may be a valuable growth biomarker in HSB. Elevations in GH secretion and secretion during the poor growth phase of the catabolic period preceding the CG response may be critical to limiting protein degradation and muscle mass during states of catabolism. Our research on yellow perch demonstrates that
improved growth uniformity can be achieved bycoldbanking and that the coldbanked fish can later be matured under simulated natural photothermal conditions and induced to spawn using GnRHa implants, thus ensuring continuity of the fingerling supply. North Carolina aquaculture farmers are coming under more and intense scrutiny for effluent discharge. The results of our denitrification studies provide design paradigms and data for engineers and scientists to create biofilters to remove harmful nitrogen from aquaculture effluent. Wood chips offer a viable low-cost media for these biofilters.
Publications
- Couch, C.R. 2006. Microsatellite DNA marker-assisted selective breeding of striped bass, Morone saxatilis. Ph.D. Dissertation. Department of Zoology, North Carolina State University, Raleigh.
- Garber, A.F. 2006. Assessing genetic contributions to performance of communally reared families of wild and domesticated reciprocal hybrid striped bass. Ph.D. Dissertation. Department of Zoology, North Carolina State University, Raleigh.
- Luckenbach, J.A., Murashige, R., Daniels, H.V., Godwin, J., and Borski, R.J. (2007) Temperature affects insulin-like growth factor-I and growth of juvenile southern flounder, Paralichthys lethostigma. Comparative Biochemistry and Physiology (Part A: Molecular, Integrative Physiology). (In press)
- Shewmon, L. N., T. M. Losordo, J. R. Godwin and H. V. Daniels. 2007. Environmental manipulation of growth and sexual maturation in yellow perch (Perca flavescens). Journal of the World Aquaculture Society (In press).
- Turano, M.J., Borski, R.J., and Daniels H.V. (2007) Compensatory growth in pond-reared hybrid striped bass (Morone chrysops x M. saxitilis) fingerlings. Journal of the World Aquaculture Society (In press).
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Progress 10/01/04 to 09/30/05
Outputs
We discovered 497 novel microsatellite DNA marker sequences and published them in the NCBI GenBank database (accession numbers BV678169- BV678666). Of 153 markers evaluated, 149 amplified in at least one of the parent species and 80% of the markers amplified well in the hybrid striped bass (HSB). An additional 71 markers were evaluated in two striped bass broodstocks. We have delivered 220 well-characterized DNA markers for selective breeding and genome mapping in temperate basses, with hundreds of primer sets remaining to be screened. We assessed whether compensatory growth (CG) can be better induced in HSB following complete versus partial feed restrictions. After 3-weeks of feed deprivation and then realimentation to normal daily feeding HSB show a 2-fold increase in specific growth rate relative to control fish and the CG response was accompanied by increases in food consumption and efficiency, a full restoration and overshoot in the hepatosomatic index, a 3-fold
increase in plasma IGF-I, and a paradoxical decline in hepatic IGF-I mRNA levels. The overall CG response following complete feed restriction was similar to that achieved with only partial feed restriction. Four combinations of constant and natural photothermal regimes were used to inhibit maturation of juvenile yellow perch and to promote their uniform growth by reducing dimorphic growth. Constant temperature and photoperiod together conferred the best overall growth performance, fully inhibiting maturation in both genders, and reducing the proportion of submarketable-size fish from 50% to 15%. Holding juvenile yellow perch in a cold bank system for up to 180 days did not significantly affect growth rates after introduction to the culture system. Coldbanking yellow perch on a commercial scale adds $0.15 to the cost of each fish, with $0.09 per fish attributed to maintenance (variable) costs. We evaluated wood chips and wheat straw as inexpensive media in denitrification reactors.
Nine 3.6-liter laboratory reactors filled with Kaldnes plastic media, wood chips, and wheat straw were built for treating both synthetic and real aquaculture wastewater. Synthetic wastewater was formulated for 50, 120, and 200 mg NO3-N/L. Methanol was added as carbon source with amounts based on the nitrate concentration, while other chemical constituents were determined by characterizing actual wastewater and comparing with previous studies. The study showed that both wood chips and wheat straw were comparable to Kaldnes in terms of reducing nitrate. Approximately 99 per cent of nitrate (with influent as high as 200 mg/L) was essentially removed at pseudo-steady state. Denitrification rates in grams of NO3-N per cubic meter per day averaged 1326 for wheat straw, 1365 for wood chips, and 1361 for Kaldnes media.
Impacts
The new microsatellite DNA markers are essential for progeny identification and pedigree tracking, for identification of introgression in backcross families, and for linkage mapping in marker-assisted selection, which will support major advances in selective breeding and domestication of temperate basses. Our results show that HSB can be manipulated to undergo repeated states of compensatory growth following simple feed manipulations and that the response has the potential to improve feed efficiency with minimal effects on overall growth. Our results also indicate that plasma IGF-I is a prominent mediator of the different growth states observed with induction of CG and suggest that it may be a valuable growth biomarker in HSB. Our research on yellow perch demonstrates that improved growth uniformity can be achieved by controlling temperature and photoperiod of growout systems and that coldbanking can be an effective means of staggering production flow in indoor tank
systems to compensate for the lack of availability of fingerlings year-round. Our biofiltration study suggest that wood chips would be a cost effective alternative to the more expensive, conventional plastic media. Low-cost, large-scale denitrification reactors will make the removal of nitrogen from wastewater possible in a simple on-farm application. The removal of nitrogen from the wastewater will reduce the land required to dispose of waste effluents and in turn significantly reduce the cost of waste treatment for intensive aquaculture farms.
Publications
- Garber, A.F., and Sullivan, C.V. 2006. Selective breeding for the hybrid striped bass industry: status and perspectives. Aquaculture Research (in press).
- Picha, M.E., Silverstein, J.T. and Borski, R.J. 2006. Discordant regulation of hepatic IGF-I mRNA and circulating IGF-I during compensatory growth in a teleost, the hybrid striped bass (Morone chrysops X M. saxatilis). Gen. Comp. Endocrinol. (in press).
- Rexroad, C., Vallejo, R., Coulibaly, I., Westerman, M., Sullivan, C.V. 2006. Identification and Characterization of Microsatellites for Striped Bass from Repeat-Enriched Libraries. Conservation Genetics (in press).
- Saliling, W.J.B. 2005. Denitrification of aquaculture wastewater using agricultural by-products as biofilter media. M.Sc. Thesis, North Carolina State University, Raleigh, 106 pp.
- Shewmon, L. 2005. Culture methods for growth enhancement and off-season production of yellow perch, Perca flavescens. M.Sc. Thesis. North Carolina State University, Raleigh, NC, 79 pp.
- Skalski, G.T., Picha, M.E., Gilliam, J.F. and Borski, R.J. 2005. Variable intake, compensatory growth and increased growth efficiency in fish: models and mechanisms. Ecology. 86 (6): 1452-1462.
- Vera Cruz, E.M., Brown, C.L., Luckenbach, J.A., Picha, M.E., Bolivar, R.B., and Borski, R.J. 2006. Insulin-like growth factor-I cDNA cloning, gene expression and potential use as a growth rate indicator in Nile tilapia, Oreochromis niloticus. Aquaculture (in press).
- Couch, C.R., Garber, A.F., Rexroad III, C.E., Abrams, J.M., Stannard, J.A., Westerman, M.E., Sullivan, C.V. 2006. Isolation and characterization of 149 novel microsatellite DNA markers for striped bass, Morone saxatilis, and cross-species amplification in white bass, M. chrysops, and their hybrid. Molecular Ecology Notes (in press).
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Progress 10/01/03 to 09/30/04
Outputs
The proposed research will combine pedigree tracking using microsatellite DNA markers, common garden performance trials of genetically tagged progeny from multiple families, and growth biomarkers (growth factor genes) that assess/predict fish growth performance to establish an integrated system for accelerated genetic improvement of striped bass and its hybrids for commercial farming. We also aim to define the fundamental nutritional requirements for southern flounder by examining protein utilization and protein/energy requirements of the fish during growout to market size, which will allow us to make preliminary economic projections for Southern flounder production. Finally, we will conduct a number of full-scale trials with chemical coagulants and screen filters to improve the rate and efficiency of the solid waste removal in a large-scale tilapia farming facility, which will provide a unique and non-biased data set for wastewater characterization and waste
treatment options for warmwater recirculating production systems. Our proposed research in all of these areas is in early stages, and no results are reportable at this time. Project personnel have been hired and/or trained to execute the research, fish and supplies have been assembled, fish rearing trials are underway, and methods for analysis of fish genotypes and gene and protein expression of fish growth factors have been established.
Impacts
Development of methods for quantifying growth factor mRNA and protein levels (biomarkers) and their correlative assessment to the growth status and genotype of striped bass will also provide critical tools to rapidly screen environmental and nutritional conditions that best promote growth of specific lines of fish without the need for lengthy and costly growth trials. Knowledge of the neuroendocrine basis of growth in tempretate basses also will also provide the technical framework needed to enhance production efficiency of other species. The information that we generate on nutritional requirements for Southern flounder will be critical for diet formulation and will allow us to make preliminary economic projections for commercial production of this species. Our investigations of methods to effectively separate organic solids from the waste flow stream emanating from tilapia production facilities will provide a unique and non-biased data set for wastewater
characterization and waste treatment options for warmwater recirculating production systems. The results from this study also will help define Best Management Practices for the industry before the EPA incorporates its new guidelines.
Publications
- No publications reported this period
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