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Feeds that maximize reproductive potential are needed to ensure success of captive broodstock. Nutritional requirements for somatic growth of juvenile fishes differ from nutritional requirements of mature fishes and are largely species-specific. Broodstock nutritional research has focused primarily on lipid and fatty acid requirements and their effects on reproductive conditioning due to the importance of these nutrients in providing metabolic energy and structural elements, i.e. for phospholipids for embryonic development. Development of suitable broodstock feeds are limited by not knowing fatty acid requirements for many species. Once requirements are identified, plant, grain, marine, algal, and fungal lipid sources can be blended to develop least-cost diet formulations. The objectives of this dissertation are to (1) evaluate white bass Morone chrysops ovum fatty acid composition and reproductive performance after feeding maternal broodstock graded levels of squid to fish oil; (2) evaluate flax, canola, and corn oils as alternatives to marine oil(s) in white bass maternal broodstock diets; (3) determine extent to which grain oils can replace marine oils in female white bass broodstock diets in order to maintain reproductive performance and quantify fatty acid utilization of larvae with different initial fatty acid profiles; and (4) assess dietary supplementation of 20:4n-6, 20:5n-3, and 22:6n-3 concentrates to boost reproductive performance of female white bass fed primarily plant oil-based lipid sources. Of the marine and plant oils tested, menhaden fish oil provided female white bass broodstock the fatty acids (~3.9% n-3 long-chain polyunsaturated fatty acids; LC-PUFA; dry matter basis) necessary to maximize embryonic survival; however, flax oil, due to its low 18:2n-6 and high 18:3n-3 content, showed promise as a suitable plant oil candidate for partial if not complete marine oil substitution in female white bass broodstock feeds. Differential responses in embryonic and larval survival resulted in comparable total larval yields at 5 days post hatch (DPH) after feeding female broodstock graded levels (0, 33, 67, or 100%) flax to fish oils for 30 weeks prior to spawning. At the end of the endogenous feeding period, fatty acid compositions of flax and fish oil-fed broodstock progeny deviated from initial ova composition. Although n-3 LC-PUFA from menhaden fish oil are essential for embryonic survival, sunshine bass appear to have lower n-3 LC-PUFA requirements after hatch. Larval survival was highly dependent on the presence of C18 PUFA present due to flax oil inclusion in maternal diets. Embryonic survival of progeny produced from broodstock fed dietary saturated fatty acid-rich plant lipids supplemented with intact LC-PUFA concentrates (~3.4% n-3 LC-PUFA; dry matter basis) was similar to that of the broodstock fed the menhaden fish oil control diet containing 4.8% n-3 LC-PUFA. Although the dietary requirement for n-3 LC-PUFA was reduced by feeding these LC-PUFA concentrates in combination with plant lipids, menhaden fish oil is still the most viable option for least cost broodstock diet formulations intended for white bass.

Seafood represents the most important source of long-chain polyunsaturated fatty acids (LC-PUFAs) in the human diet. However, consuming fish can present risks from persistent organic pollutants (POPs) that bioaccumulate in edible tissues following dietary exposure. In farmed fish, POPs accumulate as a result of feeding diets based on fish oil (FO). Fish oil substitution can reduce POP accumulation, but also results in loss of beneficial LC-PUFAs. Fish oil-based finishing diets at the end of production can restore LC-PUFAs, but this strategy also increases POPs. The present study assessed the use of saturated fatty acid (SFA)-rich lipids to replace fish oil in grow-out feeds in conjunction with a fish oil-rich finishing diet to determine if this strategy could produce hybrid striped bass with equal production performance, equivalent LC-PUFA levels, and reduced POP concentrations. Triplicate tanks of hybrid striped bass were raised on diets containing fish oil (100% FO), fish oil spiked with additional POPs (100% FO Spike), or blends (50/50 or 25/75) of FO and coconut (CO) or palm (PO) oils (50% CO, 50% PO, 75% CO, 75% PO) with and without an eight week finishing period with the 100% FO diet prior to harvest. Production performance, fillet LC-PUFA, and POP content were assessed. Production performance was not adversely affected by any of the feeding regimens. However, fatty acid profile was altered, with fillets of fish consuming less fish oil having lower LC-PUFA and POP levels. Finishing yielded a modest increase in fillet LC-PUFAs and POPs, but POPs accumulated more readily than LC-PUFAs during finishing. However, harvest fillet POP and LC-PUFA levels in the experimental groups were lower relative to levels in the 100% FO group. Replacing fish oil in aquafeeds can produce fish with reduced LC-PUFAs, and also reduced POPs. Feeding fish oil results in more rapid accumulation of POPs than LC-PUFA. Overall, the 75% fish oil replacement feeds yielded fish with the highest ratio of LC-PUFAs to POPs. Despite lower LC-PUFA content, fillets of fish fed the 75% fish oil replacement feeds could be incorporated into a weekly meal plan with other dietary sources of LC-PUFAs to meet dietary recommendations for these essential nutrients.