Traditional and Modified Soy Oils as Substitutes for Fish Oil in Feeds for Hybrid Striped Bass

Abstract

In order to assess the relative merits of different soy oils as alternatives to fish oil, we evaluated the production performance and fillet fatty acid profiles of hybrid Striped Bass fed feeds containing fish oil (FO) or 50:50 blends of fish oil and standard (STD SO), saturated fatty acid-enriched (SFA SO), low alpha-linolenic acid (LOW ALA SO), or hydrogenated (HYD SO) soy oil for 12 weeks (4 tanks/diet, 8 fish/tank; initial weight = 67.8 ± 0.2 g, grand mean ± SE). Weight gain (214 ± 5%) and specific growth rate (1.4 ± 0.0% body weight/d) were unaffected by diet. Although some differences were observed for feed conversion ratio, none of the soy-fed groups were significantly different from the FO-fed group (1.2 ± 0.0). Feeding the soy diets altered fillet fatty acid composition, but coefficient of distance values indicated the SFA SO (Djh = 3.9) and HYD SO (Djh = 9.1) feeds yielded fillet fatty acid profiles that were more similar to the FO control than the STD SO (Djh = 17.3) and LOW ALA SO (Djh = 17.6) feeds. All of the soy oils assessed were acceptable as partial substitutes for fish oil in hybrid Striped Bass feeds in terms of production performance; however, SFA SO appears more suitable for maintaining fillet fatty acid profile.

Received April 10, 2012; accepted September 12, 2012

ACKNOWLEDGMENTS

Our sincere thanks to the Illinois Soybean Association for supporting this research project under grant 09-ISA-35-409-3. We also thank Archer Daniels Midland for providing the soy oils evaluated as well as Omega Protein for the donation of the fish oil and fish meal used in the experimental feeds. We further thank the many students and staff of the Fisheries and Illinois Aquaculture Center who assisted us with data collection, particularly Curtis Crouse, who also provided substantial assistance in the preparation of fillet samples for analysis.

Notes

¹In fatty acid designations of this nature, the number to the left of the colon is the number of carbon atoms in the compound, the number immediately to the right of the colon is the number of double bonds, and the number after the hyphen indicates the position of the first double bond from the methyl end.