Location: Harry K. Dupree Stuttgart National Aquaculture Research Cntr
2023 Annual Report
Objectives
1. Improve the performance of hybrid striped bass (HSB) fingerlings in intensive production systems.
1.A. Develop fish stocking and dissolved oxygen and dissolved inorganic nitrogen management strategies for intensive production of HSB.
1.B. Optimize production of advanced HSB fingerlings in the biofloc technology production system.
1.C. Determine the nutritional value of alternative ingredient mixes and supplemental exogenous enzymes for hybrid striped bass.
1.D. Evaluate practical fishmeal-free (FMF) and plant-based diets for HSB performance and nutrient (N & P) retention in intensive production systems.
1.E. Determine optimum feeding regime, live feed enrichment, and feasibility of microparticulate diets to increase growth, survival, condition, and fatty acid composition in moronid larvae.
2. Reduce on-farm mortalities to pathogens in HSB aquaculture.
2.A. Perform controlled challenges with white bass, striped bass, palmetto and sunshine hybrid striped bass to establish their susceptibility to emerging pathogens.
2.B. Detect genetic variation for resistance to disease in host.
2.C. Identification of Moronid Dermal Mucus Antimicrobial Peptides and Proteins.
2.D. Development of Natural Antimicrobials for Prophylaxis and Treatment of Bacterial Infections.
2.E. Develop methods for harmful algal bloom control.
3. Develop and implement technologies that enhance genetic improvement of HSB.
3.A. Create and release a first-generation white bass genome and transcriptome assembly.
3.B. Optimize a photo thermal manipulation protocol for offseason (fall) spawning of WB and create even/odd year class base populations for selective improvement of important production traits.
3.C. Identify phenotypic differences in WB for growth and utilization of plant protein- and plant oil-based diets and determine the genetic variation in protein, lipid and carbohydrate utilization for the identified traits.
3.D. Develop methods for the production of triploid HSB.
Approach
Develop fish stocking and dissolved oxygen and dissolved inorganic nitrogen management strategies for intensive production of hybrid striped bass utilizing both traditional and split-pond production systems; Optimize production of advanced hybrid striped bass fingerlings in biofloc technology production system; Determine the nutritional value of alternative ingredient mixes and supplemental exogenous enzymes for hybrid striped bass. Evaluate practical fishmeal-free and plant-based diets for hybrid striped bass performance and nutrient (Nitrogen and Phosphorus) retention in intensive production systems; Determine optimum feeding regime, live feed enrichment, and feasibility of microparticulate diets to increase growth, survival, condition, and fatty acid composition in moronid larvae; Determine optimum larval feeding regime for larval Morone using live feeds to increase growth, survival, and larval quality through metamorphosis; Determine the influence of live feed enrichment on growth, survival, condition, and fatty acid composition of Morone larvae; Determine the feasibility of replacing live feeds with formulated microparticulate diets from first feeding in moronid larvae; Perform controlled challenges with white bass, striped bass, palmetto and sunshine hybrid striped bass to establish their susceptibility to emerging pathogens; Detect genetic variation for resistance to disease in moronids. Identify microbial genes and pathways critical for pathogenesis in moronids; Identification of Moronid dermal mucus antimicrobial peptides and proteins; Development of natural antimicrobials for prophylaxis and treatment of bacterial infections; Develop methods for harmful algal bloom control; Create and release a first-generation white bass genome and transcriptome assembly; Optimize a photo thermal manipulation protocol for offseason (fall) spawning of white bass and create even/odd year class base populations for selective improvement of important production traits; Identify phenotypic differences in white bass for growth and utilization of plant protein- and plant oil-based diets and determine the genetic variation in protein, lipid and carbohydrate utilization for the identified traits; Develop methods for the production of triploid hybrid striped bass.
Progress Report
To determine the nutritional value of multiple supplemental feed enzymes (phytase, xylanase and cellulase) on hybrid striped bass and rainbow trout fed plant protein diets, test diets were extruded and fed to replicate tanks of fish during January-March 2023. Final sampling occurred in April 2023 and analyses of tissue samples has begun. Sub-objective 1C
We conducted a study to compare growth and mineral composition of sweet potato slips under commercial stocking conditions in an aquaponic system receiving supplementation of black soldier fly larvae frass produced from wither expired fish food or fruits/vegetables. Sub-objective 1C
An industry-sponsored study to compare production of 1-year-old carryover hybrid striped bass (HSB) grown to market size in conventional earthen ponds, split-ponds, and biofloc system tanks was completed. Results showed that HSB perform equally well in conventional and split-ponds. Fish production and feed utilization did not differ significantly between the two pond systems. HSB were grown successfully in the biofloc system, but additional research is needed to optimize stocking rate for production of market-size fish. Mean total ammonia-nitrogen concentration was significantly lower in split ponds. Sub-objective 1A
A second industry-sponsored pond study to evaluate the effect of ARS-formulated finishing diets on 1-year-old carryover HSB yield and body composition was completed. Sample analyses and data analyses are in progress. Sub-objective 1D
Our collaboration with Kentucky State University on an 1890 Capacity Building Grant continued. We completed a study that quantified denitrification dynamics in stopped-flow settling chambers on biofloc production system tanks used for HSB production. Data analysis is in progress. Sub-objective 1A
Select line and control line white bass (WB) families were stocked into earthen ponds in a common garden experiment and fed the all-plant protein selection diet to quantify selection effects. Ponds were managed according to industry practices. The families chosen comprise a portion of the progeny derived from five wild and domestic strains of WB. Sub-objective 3C
A study was initiated to further expand the range of stocking rates of small HSB fingerlings to produce 10-20-gram advanced fingerlings in the biofloc production system. While production of “jumper” HSB (fingerlings about 3 times bigger) in a previous study was reduced from 38% to 7%, higher stocking rates are being tested to produce uniform-size populations. Sub-objective 1B
In collaboration with an ARS researcher at Dale Bumpers National Rice Research Center, Stuttgart, Arkansas, we initiated a pilot study to evaluate the effect on rice production of stocking koi carp in a flooded rice paddy. Sub-objective 1A
We continue our collaboration with Keo Fish Farm (Keo, Arkansas) and professor/graduate students from the University of Arkansas at Pine Bluff (UAPB; Pine Bluff, Arkansas) to produce triploid sunshine bass. This spawning season, we attempted producing triploids using a range of hydrostatic pressures and times post-fertilization. Further research will be carried out during the next spawning season (mid-April through early-June) to investigate the timing of 2nd polar body release and temperature-shock of embryos to produce triploids. Sub-objective 3D
We recently completed our collaborations with researchers at The Freshwater Institute (Shepherdstown, West Virginia) and Hood College (Frederick, Maryland) on the toxicity of peracetic acid (PAA) to early life stages of Atlantic salmon. This research is also investigating the use of PAA in recirculating aquaculture systems to treat these systems to eliminate pathogens. In the past year, our labs have been instrumental in working with a PAA manufacturer to obtain the first United States Environmental Protection Agency (EPA) approval to use this compound to disinfect the water when fish are present. Sub-objective 3A
In collaboration with Evonik Industries (Philadelphia, Pennsylvania), we completed research which helped secure EPA approval for the use of peracetic acid (PAA) disinfectant in the presence of live fish. We have also made strides in expanding the use of PAA to include the control of parasites (in addition to bacteria and viruses). During this study, we evaluated the ability of PAA to control Trichodina parasitic infections in striped bass. Concentrations of 0, 1 and 2 mg/L PAA were applied every other day for 30-minute static treatments. Although PAA treatment was unable to completely eradicate the parasite, we found that a 2mg/L dose led to a 75% reduction of observed parasites. Sub-objective 3A
Our collaboration with researchers in Denmark, Germany, Norway, and the United States to establish the importance of peracetic acid as a disinfectant to the global aquaculture industry has continued.
We have developed collaborations and have signed agreements with the University of Maryland (UM), iNtRON Biotechnology, and Vanderbilt University Medical Center (VUMC; Nashville, Tennessee). Our UM collaboration has been highly successful, and we have identified, established the potency of, and evaluated the in vivo efficacy of three endolysins (antimicrobial proteins) against Streptococcus iniae bacteria strains. In our in vivo assays, these endolysins outperformed the carbenicillin antibiotic and prevented moribund infections in HSB when challenged with S. iniae. Our iNtRON collaboration is in the early phases, but we have signed a CRADA and co-authored a standard operating procedure for the in vitro and in vivo evaluation of iNtRON’s bacteriophage that target S. iniae and Aeromonas hydrophila. VUMC has agreed to identify, sequence, and establish the antibiotic susceptibility profile of isolated bacterial pathogens. Sub-objective 2D
We continue our highly successful work on the dermal mucus antimicrobial proteins. We have developed techniques that led to a 75% increase in the number of antimicrobial proteins in the dermal mucus. These results are very promising and may lead to simple, low-cost methods of disease control. We have also successfully purified each antimicrobial protein recovered from the dermal mucus and conducted antibacterial testing of these proteins. Twenty of these proteins demonstrated antibacterial activity in vitro tests. Sub-objective 2C
We continue to collaborate with producers at Keo Fish Farm, Keo, Arkansas, and researchers at North Carolina State University Pamlico Field Laboratory, Aurora, North Carolina, in the evaluation of select white bass broodstock in on-farm evaluations. These evaluations under production-level conditions will provide critical information for the direction of the white bass breeding program in Stuttgart, Arkansas. Sub-Objective 3C
There is increasingly a push to decrease the use of antibiotics in agriculture to preserve their efficacy for the treatment of human diseases. An antibiotic alternative therapy known as lysin therapy makes use of the hydrolytic enzyme bacteriophages use to cut bacterial cell walls. These enzymes are used in similar fashion to antibiotics i.e., lysins can be ingested or injected depending on the infection location. Through a collaboration with the University of Maryland we evaluated the in vitro and in vivo efficacy of three lysins. Our results to date have demonstrated one of the three lysins had greater efficacy than the carbenicillin antibiotic control group. This the first time effective lysin therapy has ever been demonstrated in aquaculture. Future plans include further refinement for efficient treatment in aquaculture and establishment of new collaborations. Sub-Objective 2D
Accomplishments
1. Successful development of a non-antibiotic treatment for Streptococcus iniae infections. Several hybrid striped bass (HSB) farms have been rendered bankrupt due to disease outbreaks caused by the Streptococcus iniae bacteria. Currently, the only available FDA approved treatment for this bacterial infection is the administration of feed coated with florfenicol antibiotic. The use of antibiotics in food products is socially undesirable; in addition, there are over a dozen florfenicol resistant genes known to be circulating globally. Thus, antibiotic-alternative strategies are greatly needed to prevent and treat S. iniae outbreaks in aquaculture. ARS scientists in Stuttgart, Arkansas, in collaboration with the University of Maryland synthesized an enzyme that specifically kills S. iniae but does not kill beneficial bacteria. In experiments using S. iniae infected HSB, the enzyme treated groups had a 95% survival rate whereas the antibiotic treated group had an 85% survival rate. The results represent the first successful use of an environmentally friendly antibiotic alternative with superior performance over antibiotics for the treatment of S. iniae infections.
2. Hybrid striped bass (HSB) is a promising candidate for the split-pond production system. Intensified fish production and improved pond water quality management are characteristics of the novel split-pond production system that is used by US catfish producers. Because hybrid striped bass are fed a higher protein feed during grow out than catfish, pond water ammonia concentration can increase and affect HSB performance. Elevated ammonia concentration is a prime concern of HSB producers. ARS scientists in Stuttgart, Arkansas, in two production-season studies evaluated production of market size HSB in split-ponds and conventional ponds. While HSB performed equally well in both systems, feed consumption was more consistent and feed conversion improved for fish in split ponds. More importantly, pond water ammonia concentrations were significantly lower throughout both seasons in split ponds and the occurrence of ammonia spikes was reduced by more than 50%. These results, communicated to producers, demonstrate the potential for HSB production in the split-pond system.
3. Successful production of triploid hybrid striped bass (HSB) by temperature shock. Mature HSB females can become fertile and produce eggs, which is problematic in commercial foodfish production because feed energy is used to produce eggs instead of growth. Additionally, expulsion of eggs can cause water quality to deteriorate which can kill fish or slow production. Therefore, triploid fish are desired because they do not produce eggs. ARS researchers in Stuttgart, Arkansas, collaborated with the University of Arkansas at Pine Bluff, Pine Bluff, Arkansas and Keo Fish Farm, Keo, Arkansas to develop protocols for the production of HSB triploids. Combinations of either warm or cold temperature shock treatments on embryos at specific times within the first few minutes after fertilization were evaluated for the ability to induce triploidy. Results indicated that embryos treated with the warm-shock method (36°C, 3 min post-fertilization, 2 min exposure time) led to the highest percentage of triploids (14%). These results represent the first successful production of triploid HSB using a temperature shock treatment and provide farmers with a method to grow HSB to market size without the negative production impacts associated with egg development.
Review Publications
Thompson, K.R., Webster, C.D., Pomper, K.W., Krall, R.M. 2023. Use of aquaponics project-based environments to improve students’ perception of science, technology, engineering, and mathematics (STEM) disciplines and career pathways. Interdisciplinary Journal of Environmental and Science Education. 19(2). Article e2309. https://doi.org/10.29333/ijese/13102.
Straus, D.L., Ledbetter, C.K., Farmer, B.D., Deshotel, M.B., Heikes, D.L. 2023. Toxicity of copper sulfate to largemouth bass fry in naturally soft water. North American Journal of Aquaculture. 85(2):174-177. https://doi.org/10.1002/naaq.10284.
Maina, A., Lochmann, R., Rawles, S.D., Rosentrater, K. 2023. Digestibility of conventional and novel dietary lipids in channel catfish Ictalurus punctatus. Animals. 13(1456):1-13. https://doi.org/10.3390/ani13091456.
Redmen, N., Straus, D.L., Annis, E.R., Murray, M., Good, C. 2022. Assessing the toxicity of peracetic acid to early Atlantic salmon Salmo salar life-stages. Aquaculture Research. (53)14:5097-5104. https://doi.org/10.1111/are.15997.
Good, C., Redman, N., Murray, M., Straus, D.L., Welch, T.J. 2022. Bactericidal activity of peracetic acid to selected fish pathogens in recirculation aquaculture system water. Aquaculture Research. (53)16:5731-5736. https://doi.org/10.1111/are.16031.
Rawles, S.D., Fuller, S.A., Green, B.W., Abernathy, J.W., Straus, D.L., Deshotel, M.B., McEntire, M.E., Huskey Jr, G., Rosentrater, K., Beck, B.H., Webster, C.D. 2022. Growth, body composition, and survival of juvenile white bass (Morone chrysops) when dietary fish meal is partially or totally replaced by soybean meal, poultry by-product meal, an all-plant protein blend or a commercial plant-animal protein blend. Aquaculture Reports. 26. Article 101307. https://doi.org/10.1016/j.aqrep.2022.101307.
Kelly, A.M., Renukdas, N., Barnett, L.M., Beck, B.H., Abdelrahman, H.A., Roy, L.A. 2023. The use of kaolin as a prophylactic treatment to prevent columnaris disease (Flavobacterium covae) in commercial baitfish and sportfish species. Veterinary Sciences. 10(7):441. https://doi.org/10.3390/vetsci10070441.
Kaimal, S., Farmer, B.D., Renukdas, N., Abdelrahman, H.A., Kelly, A.M. 2022. Evaluating stress mediated microbial pathogenesis in golden shiners, Notemigonus crysoleucas. Frontiers in Physiology. 13. Article 886480. https://doi.org/10.3389/fphys.2022.886480.
Churchman, E.M., Parello, G., Lange, M.D., Farmer, B.D., Lafrentz, B.R., Beck, B.H., Liles, M.R. 2022. Draft genome sequences of flavobacterium covae strains LSU-066-04 and LV-359-01. Microbiology Resource Announcements. 11(7):e00352-22. https://doi.org/10.1128/mra.00352-22.
Romano, N., Webster, C.D., Sinha, A., Beck, B.H., Yamamoto, F. 2023. Dietary inclusions of black soldier fly (Hermetia illucens) larvae frass enhanced production of channel catfish (Ictalurus punctatus) juveniles, stevia (Stevia rebaudiana, and lavender (Lavaridula angustifolia) in an aquaponic system. Aquaculture. 575:739742.
