Body composition, growth performance, and product quality of rainbow trout (Oncorhynchus mykiss) fed diets containing poultry fat, soybean/corn lecithin, or menhaden oil

The suitability of soybean/corn lecithin and poultry fat as partial replacements for menhaden oil in feeds for post-juvenile rainbow trout (initial weight 46.0 g) was investigated. For 16 weeks, fish were fed experimental diets in which either 10% menhaden oil (FO), 10% poultry fat (PF), 10% lecithin (soybean/com, L10), or 15% lecithin (soybean/com, L15), plus 5% supplemental menhaden oil was added to fish meal-based diets. There were no significant differences in body weight gain among all treatments (328-347 g/fish), although fish fed the L15 diet consumed significantly more feed (299 g/fish) than fish fed the PF diet (269 g/fish). Sensory analysis indicated that raw L10 fillets stored for 4 and 12 weeks at -20 degreesC were significantly more yellow than raw FO fillets. Raw and cooked L15 fillets stored for I and 8 days at 5 degreesC, or for 17 days, 4 weeks, and 12 weeks at - 20 degreesC had significantly higher colorimetric b* values (more yellow) than raw and cooked FO, PF, and L10 fillets. There was a trend for FO fillets to have higher TBARS values compared to fillets of the other treatments when stored under all time/ temperature conditions tested. Although fillets of fish fed diets containing soybean/corn lecithin were more yellow in color, either lecithin (soybean/com) or poultry fat was a nutritionally suitable substitute for most of the fish oil added to fish feeds. (C) 2004 Elsevier B.V. All rights reserved.