1a. Objectives (from AD-416):
Objective 1: Characterize genetic and phenotypic contributions of important production traits for Morone broodstock management and improvement. Sub-Objective 1A. Produce experimental hybrid striped bass families. Sub-Objective 1B. Assess the genetic basis of phenotypic variation of growth in hybrid striped bass. Sub-Objective 1C. Evaluate the performance of hybrid striped bass families under alternate stocking rates. Objective 2: Refine nutrient requirements, evaluate alternate sources of protein, and develop practical feed formulas for Morone culture. Sub-Objective 2A. Refine essential amino acid requirements of advanced juvenile hybrid striped bass using practical ingredients. Sub-Objective 2B. Improve the performance of commercial hybrid striped bass diets in which fish meal is replaced with by-products of poultry processing or a blend of plant products. Sub-Objective 2C. Develop practical feed formulas for hybrid striped bass culture. Objective 3: Develop strategies to improve production system efficiency. Sub-Objective 3A. Define stocking rate/biomass-yield relationship in a mixed suspended growth production system. Sub-Objective 3B. Compare catfish yields in a mixed suspended growth production system scaled up to ponds.
1b. Approach (from AD-416):
Identify and characterize genetic variation in commercially relevant traits of white and striped bass and implement a breeding program to develop superior hybrid striped bass parental breeding stocks. Evaluate growth performance of half-sibling families of hybrid striped bass reared communally in earthen ponds. Evaluate the performance of hybrid striped bass families under alternate stocking rates. Define requirements for hybrid striped bass for first-limiting indispensable amino acids in all plant protein diets. Evaluate amino acid supplementation for hybrid striped bass diets in which fish meal is replaced by alternative feed ingredients. Develop and evaluate in aquaria and tank culture, and validate in earthen pond culture diets for hybrid striped bass formulated with alternative feed ingredients. Evaluate the effects of stocking density, feeds and feeding strategies, and environmental conditions on survival and growth of hybrid striped bass and catfish in tanks and earthen ponds. Evaluate novel, intensive production technology in tanks and earthen ponds.
3. Progress Report:
Broodstock were conditioned and spawned, resulting in 48 half-sibling sunshine bass crosses that yielded 1,080,000 larvae and 19 half-sibling white bass crosses that yielded 94,000 larvae. Broodstock for the next phase of spawning are currently being conditioned. A study was also initiated to assess phenotypic variation in growth of 40 half-sibling families of sunshine bass in earthen ponds managed to maintain minimum dissolved oxygen concentrations greater than 25, 40, or 55% of the complete saturation concentration. In addition, a companion study was initiated in tanks to evaluate performance of industry pool hybrid striped bass exposed to constant dissolved oxygen concentrations of 25, 40, or 100% of saturation. Targeted genetic markers allowed the scientists to determine how fish cope with stressful low oxygen conditions at the molecular level. A study was completed to investigate how adult striped bass, white bass, and hybrid striped bass were able to cope with short-term exposure to low dissolved oxygen concentrations. A study was completed using recirculating aquaculture systems to evaluate the effect of three feeding regimes, and with or without the benefit of additional algae, on larval hybrid striped bass growth, survival, and early development of selected digestive enzymes. Standard growth and condition measurements and tissue sample analyses are ongoing. In collaboration with scientists from Montana State University and the USFWS Bozeman Fish Feed Technology Center, MT, dose-response trials evaluating the effect of dietary inclusion of grain distillers dried yeast on growth of carnivorous fish were completed. In collaboration with scientists from Southern Illinois University, Carbondale, and the USFWS Bozeman Fish Feed Technology Center, MT, studies were initiated to evaluate nutrient composition and nutrient availability from two sources of Asian carp meal for use in hybrid striped bass, catfish, cobia, and rainbow trout diets to assess their fishmeal replacement value. In collaboration with a researcher at the University of Arkansas at Pine Bluff, we conducted an experiment using a factorial arrangement to determine the effects of partial replacement of dietary fish oil with linseed oil, and the addition of a probiotic to the diet, to determine the effects on growth, body composition, immune response, and resistance to heat shock in hybrid striped bass. In collaboration with a researcher from the University of Arkansas at Pine Bluff, work was initiated on a grant funded by the Arkansas Soybean Promotion Board titled, Minimizing Use of Fishmeal in Hybrid Striped Bass Diets Using Non-GMO Soybeans Selectively Bred for Use in Aquafeeds. A study was completed quantifying the effect of fingerling stocking rate on the production of stocker catfish, and resulting development of phytoplankton communities and associated common off-flavors in a biofloc technology production system. An ensuing study was initiated to determine the effect of three stocking rates with large channel catfish stockers on production, water quality dynamics, and the development of common off-flavors in a biofloc technology production system.
1. Controlling sexual maturation in farmed fish. A major obstacle to genetic improvement and fingerling production of fish grown in aquaculture is the long period of time required for fish to reach sexual maturity. Kisspeptins are newly recognized proteins that naturally control when animals enter puberty. Scientists from the Stuttgart National Aquaculture Research Center in Stuttgart, Arkansas, showed that sexually immature male white bass entered puberty more quickly and that adult female white bass had larger ovaries containing more mature eggs following administration of kisspeptins. Together these findings highlight the potential of kisspeptin treatment in fish reproduction to accelerate a breeding program's fingerling production.
2. Fish feed ingredient nutrient digestibility database released. Digestibility coefficients, which tell animal feed manufacturers how much of the nutrients within each ingredient actually is digested, are critical to formulating least-cost fish feeds. As the result of intensive studies, scientists from the Stuttgart National Aquaculture Research Center, Stuttgart, Arkansas, and the Small Grains and Potato Germplasm Research Unit's Trout-Grains Project, Hagerman, Idaho, in collaboration with scientists at the US Fish and Wildlife Service Feed Technology Center, Bozeman, Montana, developed a database of nutrient composition and digestibility coefficients for a variety of common and emerging animal feed ingredients used in diets for rainbow trout and hybrid striped bass. The database is accessible on a federal website and is available on a CD, and provides the aquaculture industry and research community with data critical for developing improved diets for carnivorous fish.
3. Summer diets for hybrid striped bass. High daily summertime feeding rates can result in concentrations of ammonia in pond water that are toxic to hybrid striped bass. In response, farmers may curtail feeding or switch to a lower protein feed, both of which reduce production. With input from Mississippi-based hybrid striped bass producer, Nature's Catch, scientists at the Stuttgart National Aquaculture Research Center demonstrated that using digestibility coefficients developed recently in-house to formulate a diet that had higher digestible protein and fat than the standard industry diet, and that was also supplemented with deficient amino acids, maximized growth and nutrient retention and reduced ammonia waste production. Fish feed manufacturers are adopting these recently developed digestibility coefficients for their diet formulations for hybrid striped bass, and producers are using the new summer diet formulation.
4. Organic ingredients can substitute for fish meal in fish feed. The USDA is currently developing standards for organic aquaculture production. Suitable organic agricultural products that will meet these standards are sought as substitutes for fish meal in fish feeds that could be labeled as organic. A scientist from the Stuttgart National Aquaculture Research Center, Stuttgart, Arkansas, in collaboration with scientists from Kentucky State University, Frankfurt, Kentucky, showed that tilapia fry fed a diet formulated with organic soybean meal and organic yeast, and supplemented with deficient amino acids grew as well as tilapia fry fed a fishmeal based diet. Identifying organic agricultural products that can substitute successfully for fish meal in fish diets that meet the standards for an organic label is an essential step towards achieving organic aquaculture production.
5. Biofloc technology systems reduce the intensity of common off-flavors in channel catfish. Pre-harvest off-flavors described as "earthy-musty" in catfish that are produced in earthen ponds continue to present problems for this industry. A novel, highly intensive, static water production system, called the biofloc technology production system, produces high yields of channel catfish. An ARS researcher at the Natural Products Utilization Research Unit, Oxford, Mississippi, in collaboration with an ARS researcher at the Stuttgart National Aquaculture Research Center, Stuttgart, Arkansas, and a scientist at the University of Arkansas-Pine Bluff, Arkansas, demonstrated that the biofloc technology production system also inhibited the growth of common blue-green algae responsible for producing off-flavor compounds, and that the intensity of off-flavor problems were reduced in catfish grown in these systems. This discovery provides catfish producers with an alternative to using earthen ponds to grow catfish and directly benefits producers by reducing economic losses associated with additional feeding costs, potential loss of fish to disease and water quality problems, and still provide an on-flavor, high-quality product to consumers.
Beck, B.H., Fuller, S.A., Peatman, E., McEntire, M.E., Darwish, A.M., Freeman, D.W. 2012. Chronic exogenous kisspeptin administration accelerates gonadal development in basses of the genus Morone. Comparative Biochemistry and Physiology. 162A(3):265-273.