|Rawles, Steven - Steve|
Submitted to: Book of Abstracts Aquaculture America
Publication Type: Abstract only
Publication Acceptance Date: 8/4/2004
Publication Date: 1/6/2005
Citation: Gopinathan, B., Lochmann, R., Rawles, S.D. 2005. Growth and hematological parameters of largemouth bass Micropterus salmoides fed practical diets with different lipid sources [abstract]. Book of Abstracts, Aquaculture America. p. 157. Interpretive Summary:
Technical Abstract: The production of largemouth bass (LMB) is important for ethnic food markets and sports fishing. Little work has been done on LMB nutritional requirements or practical diets. Currently, LMB are fed salmonid diets that contain high levels of marine fish meal (FM) and oil (FO). LMB are freshwater carnivores and may not require marine-based oils or proteins. This study determined the qualitative fatty acid (FA) requirements of LMB based on growth and immune system status. Diets contained 10% total lipid from the one of the following sources: Canola oil (CAN),poultry oil (POUL), menhaden fish oil (MFO), and a 50:50 mixture of POUL + MFO. The FM used in the diet was solvent extracted to minimize endogenous lipid. One diet contained non-extracted FM and 10% POUL (NEFM+POUL) to control for unintended extraction effects. A commercial salmonid diet was fed to another group of fish as a positive control. Diets were fed to satiation to replicate (4) groups of 10 fish(5 ± 0.05 g) each for 12 weeks. Survival was 100%. Weight gain and feed conversion were not different among dietary oil treatments. Alternative complement activity in fish fed the POUL or the POUL + MFO diets was significantly lower than that of fish fed diets with MFO alone or CAN. Serum lysozyme and hematocrit was not affected by dietary oil. FA profiles from liver and muscle showed limited abilities of LMB to elongate and desaturate short-chain polyunsaturates to long-chain highly unsaturated FA. Although non-specific immune response was stimulated by n-3 FAs (CAN or MFO), MFO was not superior to CAN. POUL was also effective in supporting other important performance criteria. These data suggest that a significant portion, though not all, of the FO in current LMB diets could be replaced by less expensive oils.