Performance of rome strain brook trout fed the Pennsylvania fish and boat commission formulation contract diet and a bio-Oregon diet

In addition to the economics of purchasing feed, other performance features such as levels of mortality, feed conversion, growth rate, and reduction of solids in effluents may provide useful selection factors when procuring a grow-out diet.  In order to evaluate two production diets, Rome strain brook trout reared at the Northeast Fishery Center for the Pennsylvania Fish and Boat Commission (PFBC) were fed either a closed formula Bio-Oregon diet or a PFBC formulated contract diet for nine months.  Brook trout were stocked into 12 circular tanks (237 L) with water inflows of 30 L/min at 2.47 kg per tank.   Six tanks were fed Bio-Oregon diet and the remaining received the PFBC formulation.  Sample counts were taken for each tank every two weeks to record growth.  At each biweekly interval, feed rates were recalculated and fish were randomly removed as needed to maintain a consistent density index of 0.35.   Brook trout fed Bio-Oregon cost more per kilogram of fish flesh produced; however, the Bio-Oregon fish demonstrated lower feed conversions, faster growth rates, and experienced lower levels of mortalities during an outbreak of Infectious Pancreatic Necrosis.