Location: Harry K. Dupree Stuttgart National Aquaculture Research Cntr
Project Number: 6028-31630-009-006-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2022
End Date: Aug 31, 2024
Objective:
Through carefully designed and conducted feeding trials with hybrid striped bass and white bass, the overall objective of the project is to reduce (or eliminate) the use of marine fish meal in prepared diets for these two species, thereby allowing for sustainable growth of the aquaculture industry, while optimizing profit potential for domestic producers. Specifically, the objectives are:
1. Evaluate the growth performance, body composition, gut histology and gene expression of sunshine bass and white bass fed soy-based diets enhanced with palatants.
2. Evaluate the growth performance, body composition, gut histology and gene expression of sunshine bass and white bass fed diets with insect meals and oils.
Approach:
For the conduct of each feeding trial, the following generalized experimental design will be followed. Fish species to be evaluated will be stocked at a density for optimal growth (3-4 replicate tanks per dietary treatment). The experimental protocols will be approved by the HKD-SNARC Institutional Animal Care and Use Committee and conform to USDA Agricultural Research Service Policies and Procedures 130.4 and 635.1. Fish will be hand-fed their respective pelleted test diets twice daily (0700 and 1530) all they will consume in 20 min for the duration of the feeding trial. Mortalities will be replaced during the first week of the feeding trial. Light will be provided by overhead fluorescent ceiling lights set on a photoperiod of 15h:9h light:dark cycle. All tanks will be siphoned daily to remove uneaten diet and feces. If present, mortalities will be recorded and removed daily. All tanks will be covered with polyethylene mesh to prevent fish loss due to escapement or jumping to adjacent tanks.
Dissolved oxygen (DO) and water temperature (ºC) will be measured daily. Alkalinity, hardness, chlorides, total ammonia nitrogen (TAN), nitrite nitrogen, nitrate, and pH will be recorded weekly. TAN and nitrite nitrogen will be analyzed by multiparameter colorimeter using the salicylate method (TAN) and azo-dye method (nitrite nitrogen).
Diets will be formulated to be isonitrogenous (40% protein), isolipidic (11%), and isocaloric (17.1 kJ/g) and meet the known nutrient and energy requirements of hybrid striped bass. Lipid contribution from dry ingredients will be balanced with canola oil and menhaden fish oil to maintain the diets isolipidic and isoenergetic, while the contribution of fish oil to total lipid will be maintained constant in all diets. Diet 1 (control) will be formulated like a high-quality, commercial carnivorous fish diet containing 30% FM and 37% SBM. All other diets will be formulated to evaluate the use of either soy products or insect meal as partial and total replacement of marine fish meal. Diets will be produced by an extruder to be either floating or sinking pellets of the appropriate size to be consumed by the fish.
Proximate and amino acid compositions of the ingredients and diets will be measured based on the Association of Official Analytical Chemists (AOAC) standard methods (AOAC, 2002) for moisture (AOAC 930.15), protein (AOAC 990.03), lipid (AOAC 954.02), fiber (AOAC 962.09), and ash (AOAC 942.05). Nitrogen-free extract (NFE; i.e., carbohydrate) will be calculated by difference where NFE = 100 - (% protein + % lipid + % fiber + % ash). Available energy will be estimated from the physiological fuel values of 16.7, 16.7, and 37.9 kJ/g for protein, carbohydrate (NFE), and lipid, respectively. Amino acid composition of the diets will be quantified by ultra-performance liquid chromatography.
Fish will not be fed for 18-h prior to the conclusion of the study.
Subsequently, fish in each tank will be enumerated to determine survival (%) and individually weighed to the nearest 0.01 g on an electronic scale. Three (3) fish from each tank will be randomly selected for genomic analysis.
