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:
In collaboration with a feed company, we initiated an experiment to evaluate diet digestible protein and amino acid supplementation on the performance of hybrid striped bass (HSB) in summertime pond production. In collaboration with scientists from Southern Illinois University, Carbondale, and the USFWS Bozeman Fish Feed Technology Center, MT, studies were completed to evaluate nutrient composition and availability, and fishmeal replacement value of 2 sources of Asian carp meal for diets for HSB, catfish, cobia, and rainbow trout. In collaboration with the University of Arkansas at Pine Bluff, tissue analyses and statistical modeling were completed in a study to determine the effect of partial replacement of dietary fish oil by linseed oil and addition of probiotic to the diet on HSB growth, body composition, immune response, and resistance to heat shock. In collaboration with researchers from the UA at Fayetteville and at Pine Bluff, we continued work on the Arkansas Soybean Promotion Board-funded project, Minimizing Use of Fishmeal in Hybrid Striped Bass Diets Using Non-GMO Soybeans Selectively Bred for Use in Aquafeeds. We completed analysis on samples evaluating the effect of different salinities on nutrient availability from a fishery by-product meal, yeast protein, barley protein concentrate, canola protein concentrate, corn protein concentrate, menhaden fish meal, and Spirulina algae. In collaboration with a scientist from the Plant Genetics Research Unit, Columbia, MO, we initiated a study with HSB to evaluate dietary inclusion of soybeans that lack anti-nutritional factors. We completed a study to determine the histidine requirement for juvenile HSB and initiated a second trial to establish the whole organism histidine metabolism. We completed a larval HSB growth and survival study comparing dispersed kaolin clay, green water (algae present), and clear water culture. We completed a study to determine the effect of 3 stocking rates of large channel catfish stockers on production, water quality dynamics, and the development of common off-flavors in a biofloc technology production system. We initiated a study to assess phenotypic variation in growth of 28 half-sib families of HSB in earthen ponds at the approximate upper and lower limits of Phase II stocking rates used by industry. We initiated a study to quantify the effect of 2 solids removal rates on water quality and catfish production in a biofloc technology production system. We conditioned broodstock and produced 61 half-sib HSB crosses that yielded 1,900,000 larvae. We optimized total RNA isolation methods for HSB muscle and liver tissue, extracted RNA from HSB reared at summer pond temperatures, fed diets of varying ingredient and nutrient profiles and are analyzing RNA expression profiles. In collaboration with an Auburn University researcher, we initiated work on the USDA National Research Support Project-8-funded project, Moronid Reference Transcriptomes. In collaboration with researchers at Universities of New Hampshire, Maryland, and Connecticut, we initiated work on the Northeastern Regional Aquaculture Center-funded project, Striped Bass Selection for Marine Culture.
1. Amino acid supplements improve hybrid striped bass growth. Hybrid striped bass grow better when fishmeal-free diets are supplemented with amino acids. When fishmeal in fish feed is replaced with different plant proteins, fish performance often declines because of imbalances in essential nutrients and intestinal dysfunction caused by antigens in plant ingredients like soybean meal. When ARS scientists at Stuttgart, Arkansas, used the concentrations and ratios of three essential amino acids found in hybrid striped bass muscle to supplement practical fishmeal-free soybean meal-based diets, superior fish growth and nutrient retention was achieved. Because the concentrations of amino acids used were higher than those currently targeted by feed mills, this information allows feed mills to formulate more efficient fishmeal-free, soybean-based diets for hybrid striped bass, thereby reducing production costs and dependence on ocean-derived protein ingredients.
2. Enhanced soybean oil in catfish diets improves health benefits to consumers. One benefit of consuming farmed fish is the amounts and types of healthful fatty acids, such as omega-3, found in farmed fish. Another fatty acid with benefits to human health, including reduced risk of cancer and better weight management, is Conjugated Linoleic Acid (CLA). ARS and University of Arkansas scientists in Stuttgart and Pine Bluff, Arkansas, determined how four different oils in the diet of channel catfish affect fish growth, fatty acids in the fillets, fillet quality, and consumer taste preference. The four oils were menhaden fish oil, regular soybean oil, soybean oil enhanced with CLA, and a high omega-3 oil extracted from algae. The four oils did not reduce growth or change the quality of the fillets after refrigeration or freezing. While fish fed diets containing fish oil or algae oil had higher amounts of omega-3 fatty acids, the fillets were less favored by consumers. On the other hand, fish fed diets containing the CLA-enhanced soybean oil were highly favored by consumers for taste and had levels of CLA in the fillets that made them a healthy choice.
3. Novel biomarkers for environmental stressors developed for warm water fish. Both wild fish and farmed fish alike often are exposed to numerous environmental stressors such as high temperature or low dissolved oxygen that can negatively affect fish metabolism, ultimately resulting in poor growth and increased disease susceptibility. To better understand how stress specifically affects cellular metabolism in fish, scientists at the Stuttgart National Aquaculture Research Center, Stuttgart, Arkansas, examined the metabolic responses of cells derived from three important species of warm water fish (white bass, channel catfish, and fathead minnow) to compounds inhibiting respiration and to rapid temperature increases. This study was the first to use extracellular flux technology on fish cells, and led to the discovery that each cell type responded uniquely to stressors. The newly identified biomarkers can be used by scientists to predict how the different fish species will react to specific stress event, like lack of oxygen, which could improve the heartiness of the species to producers.
4. Short-term feed deprivation alters the physiology of channel catfish. Short-term feed deprivation (or fasting) in farmed fish species can occur because of seasonal changes, production strategies, or as a means to combat certain disease outbreaks. To better understand the impacts of fasting on fish physiology, scientists at the Stuttgart National Aquaculture Research Center, Stuttgart, Arkansas, in collaboration with scientists from Auburn University, Alabama, examined changes at the genetic level in the gill and skin of channel catfish that were subjected to a 7-day fast compared to fish fed daily. Expression levels of over 1,500 genes involved in the immune system, metabolism, and the cellular stress response changed in response to fasting. These results enhance our understanding of the effects of fasting on the physiology of channel catfish, and represent a key foundation for improvements in feeding regimens employed by producers.
5. Green water improves hybrid striped bass larval culture. The availability of larval fish is critical for the successful development of aquaculture. Aggressive behavior by the fastest growing fish and the need to provide an adequate quantity of food items are constraints to larval culture of hybrid striped bass. In a study using recirculating aquaculture technology, scientists at the Stuttgart National Aquaculture Research Center, Stuttgart, Arkansas, demonstrated that introducing algae into the culture water (green water) increased larval survival by more than 20% and decreased variation in individual fish size relative to those reared without the addition of algae (clear water). Green water reduced the ability of larger fish to locate and attack smaller fish and improved the ability of fish to find and consume food items. Increased larval survival of hybrid striped bass has been shown to reduce the cost of production by 10% for each 5% increase in survival, thereby resulting in more efficient utilization of culture facilities.
6. Hybrid striped bass growth linked to dissolved oxygen concentration. Fish need oxygen to live, just like people do. But where people get the oxygen from the air we breathe, fish get oxygen from the water they live in. The oxygen that is present in water is called "dissolved oxygen". Dissolved oxygen (DO) is a critical limiting factor in aquaculture, and rapid fish growth during culture requires maintaining adequate DO concentrations specific to each species. When ARS scientists at Stuttgart, Arkansas, grew juvenile hybrid striped bass (HSB) at three constant DO concentrations, they found that fish consumed more feed on a daily basis and grew faster as DO concentration increased. At the lowest constant DO concentration, HSB not only grew more slowly because they consumed less feed on a daily basis, but also converted consumed feed to biomass less efficiently. Identifying an optimal DO concentration to ensure rapid growth is an important factor in ensuring sustainable hybrid striped bass production in the United States.
Beck, B.H., Fuller, S.A. 2012. The impact of mitochondrial and thermal stress on the bioenergetics and reserve respiratory capacity of fish cell lines. Journal of Aquatic Animal Health. 24(4):244-250.