Abstract
Fish meal sparing is more difficult for nutritionally demanding carnivorous fishes, but economic considerations and the limited supply of fish meal continue to incentivize investigations of alternative protein sources for aquafeeds. A promising alternative to traditional, marine-origin fish meal is fish meal derived from undesirable freshwater species, such as the invasive Asian carp Hypophthalmichthys spp. To assess the relative value of such ingredients, we evaluated growth performance of juvenile hybrid Striped Bass (White Bass Morone chrysops × Striped Bass M. saxatilis; initial weight, 21.9 ± 0.2 g [mean ± SE]), Rainbow Trout Oncorhynchus mykiss (15.1 ± 0.2 g), and Cobia Rachycentron canadum (57.2 ± 0.5 g) reared for 8 weeks on practical diets containing different levels of menhaden fish meal (MFM), Asian carp meal (CFM), or a 50:50 blend of these ingredients such that 0, 20, 40, or 60% of the estimated digestible protein content was derived from fish meal. Growth performance was generally consistent across taxa, and weight gain tended to increase with fish meal inclusion, regardless of its origin. However, Cobia did perform better on CFM-based diets, suggesting that MFM or CFM can yield improved performance for some taxa or life stages, but these differences are likely to be marginal in most circumstances. We conclude CFM is a suitable and perhaps lower-cost alternative to MFM in feeds for carnivorous fishes.
Received June 9, 2014; accepted August 13, 2014
ACKNOWLEDGMENTS
We extend our thanks to the Illinois Soybean Association for supporting this research project under grant 12-10-59-240-550-10. We also thank Omega Protein, Tyson, and Darling International for the donation of feedstuffs used to prepare the feeds evaluated in this work. We thank Crystal Lakes Fisheries for the donation of Rainbow Trout fingerlings used in this work. Paul Hitchens was instrumental in arranging the manufacturing and delivery of the Asian carp meal to our facility. We also thank Michael Schwarz, Steve Urick, and their staff at the Virginia Seafood Agricultural Research and Extension Center for conducting the Cobia feeding trial. Finally, we thank Jonah May, Michael Page, Chris Jackson, and Kelli Barry of the CFAAS for help with data collection and analysis.