Use of alternative lipids and finishing feeds to improve nutritional value and food safety of hybrid striped bass

The present study assessed the use of saturated fatty acid-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, and equivalent fillet long-chain polyunsaturated fatty acid (LC-PUFA) levels, and reduced fillet persistent organic pollutant (POP) concentrations. Final weight (597.8 ± 11.1 g, mean ± SE, p = 0.29), percent weight gain (2743.1 ± 45.1%, p = 0.11), feed conversion ratio (1.4 ± 0.02, p = 0.28), dress-out (23.5 ± 0.3%, p = 0.46), hepatosomatic index (0.9 ± 0.02, p = 0.54), or liposomatic index (1.5 ± 0.04, p = 0.62) was not adversely affected by any of the feeding regimens. However, fillet composition was altered, with fillets of fish consuming less fish oil having lower LC-PUFA (31.45 ± 0.75 to 16.94 ± 0.78 g/100 g FAME, p < 0.0001) and POP levels (53.93 ± 9.21 to 15.97 ± 9.49 ng/g dry weight, p < 0.0001). Finishing yielded a modest increase in fillet LC-PUFA and POP, but POP accumulated more readily than LC-PUFA with increased fish oil consumption during finishing. Replacing fish oil in aquafeeds produces fish with reduced LC-PUFA and POP in the fillet. Feeding fish oil results in more rapid accumulation of POP than LC-PUFA. Overall, fish consuming the lowest amount of fish oil in the diet yielded fillets with the highest ratio of LC-PUFA to POP, despite lower LC-PUFA content.