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ARS Home » Pacific West Area » Aberdeen, Idaho » Small Grains and Potato Germplasm Research » Research » Research Project #443820

Research Project: Evaluation of Corn DDGS in Practical Feeds of Tilapia

Location: Small Grains and Potato Germplasm Research

Project Number: 2050-21310-006-021-T
Project Type: Trust Fund Cooperative Agreement

Start Date: Mar 15, 2023
End Date: Mar 14, 2024

The objective of this agreement and associated research project is to determine if the level of distiller's dried grains with solubles (DDGS) can be increased to levels higher than presently accepted by growers and feed manufacturers. Evaluation of growth and physiological performance of tilapia fed varying levels of dietary corn DDGS with and without enzyme (phytase and xylanase) treatment will be used to answer this question.

Experimental Design Diets Eight diets will be manufactured by USDA-ARS at the Bozeman Fish Technology Center (BFTC) to evaluate the level (0%, 15%, 30%, and 45% of diet) of distiller’s dried grains with solubles from corn (corn DDGS) with and without enzyme (phytase and xylanase) treatment on growth performance and physiology of tilapia. Specific ingredients will be based on least-cost formulation, and ingredient sourcing discussions with US Grains Council (USGC) experts. Diets will then be shipped to the Hagerman Fish Culture Experiment station for experimentation. Fish and Rearing Twenty, all-male Nile tilapia, Oreochromis niloticus, will be stocked in 140-L fiberglass tanks (n = 24) at approximately 10-g fish weight. Each diet will be fed to three replicate tanks of fish. Water quality will be measured weekly during the trial. Fish will be fed to apparent satiation twice daily and weighed every 3 weeks to determine growth, feed intake, and feed efficiency. At the end of the study, fecal samples will be collected for proximate analyses, calculation of digestibility coefficients, and measurement of amino acids and phosphorus contents. Three 10 g samples from each experimental diet will be retained and frozen for use in carbohydrate composition analysis, phosphorus, and proximate composition. Final evaluation of the effects of experimental diets on growth will be evaluated after the weighing at the end of the study. Chemical Analyses Proximate analysis (dry matter, crude lipid, crude protein, and digestible energy) of select ingredients (protein sources), experimental feeds, and collected feces will be performed according to standard methods. Yttrium and phosphorus will be determined in diets and feces by inductively coupled plasma atomic absorption spectrophotometry. Apparent digestibility coefficients (ADCs) of each nutrient in the test diets and for the test ingredient will be calculated using yttrium oxide (Yt) as the inert marker and performed by USDA-ARS. Feed and fish samples will be dried and analyzed for proximate composition using standard, approved methods. Amino acid content of feed samples will be quantified using an outside source. Crude fiber, sucrose and oligosaccharide contents, and total CHO content of experimental diets will also be determined by USDA-ARS using standard methodology.