ANDREW R. COURSEY, for the Master of Science degree in Zoology, presented 24 June 2011 at Southern Illinois University Carbondale TITLE: ALTERNATIVE FEEDING STRATEGIES TO MAXIMIZE MARINE FEEDSTUFF REPLACEMENT IN LARGEMOUTH BASS Micropterus salmoides CULTURE WHILE MAINTAINING PRODUCTION PERFORMANCE Advisors: Chris Kohler and Jesse Trushenski Harvest of marine resources for feedstuff production is at its maximum sustainable yield and alternative feedstuffs are needed to supply livestock production for an expanding human population having a growing desire for seafood. Aquaculture is currently the fastest growing sector of agriculture, but the high cost and limited supplies of marine feedstuffs for aquafeeds could ultimately limit production of foodfish. Replacement of marine feedstuffs poses a dilemma, however, as replacement of fish meal can affect animal growth, and replacement of fish oil in aquafeeds leads to altered fillet fatty acid profiles without the maximum benefit of high omega-3 (n-3) and long-chain polyunsaturated fatty acids (LC-PUFA) content. Two feeding trials were conducted to determine if poultry byproducts can replace fish meal and fish oil in diets for largemouth bass Micropterus salmoides without affecting production performance or fillet fatty acid composition. Poultry byproducts were able to replace fish meal and fish oil while maintaining production performance of largemouth bass, however, the altered fatty acid profiles of the feeds were reflected in the fillets. Finishing diets containing high levels of fish oil were implemented to restore n-3 and LC PUFA concentrations in the fillet. Twelve weeks of finishing proved suitable to partially restore n-3 and LC-PUFA concentrations while limiting the overall use of marine resources in the largemouth bass production cycle.