Alternative Feeding Strategies to Maximize Fish Oil and Fish Meal Sparing in Largemouth Bass Culture while Maintaining Production Performance and Product Value

Abstract

AbstractFeeding trials were conducted to determine (1) the optimal inclusion of poultry byproduct meal (PBM) and poultry fat (PF) as alternatives to fish meal (FM) and fish oil (FO) in diets for Largemouth Bass Micropterus salmoides and (2) whether the poultry‐based formulations could be used in conjunction with FO‐based finishing feeds in a strategy to minimize the use of marine‐derived ingredients while maintaining performance and fillet composition. In trial 1, fish (mean ± SE = 16.0 ± 0.5 g) were reared for 9 weeks on diets (∼40% protein, ∼10% lipid) containing graded levels of FM (0, 7.5, or 15%) and FO (0, 3, or 6%), with PBM and PF replacing FM and FO, respectively. The results indicated that complete replacement of marine feedstuffs with PBM and PF had no significant effects on production performance; all diets yielded equivalent weight gain (mean ± SE = 277 ± 45%), feed conversion ratio (FCR; 1.4 ± 0.4), and feed consumption (39 ± 6 g/fish), although fillet fatty acid profile reflected the diet. Based on these results, the 7.5% FM–0% FO and 0% FM–0% FO diets were further evaluated. In trial 2, fish (mean ± SE = 39 ± 3 g) were reared for 16 weeks on the 7.5% FM–0% FO or 0% FM–0% FO feeds, followed by an additional 12 weeks on the assigned diet or a 15% FM–6% FO finishing diet. The performance and fillet composition of these fish were compared with those of their counterparts that only received the finishing feed or a commercially available Largemouth Bass feed. All approaches yielded equivalent weight gain (mean ± SE = 496 ± 65%), FCR (2.0 ± 0.2), and feed consumption (407 ± 65 g/fish). Fillet fatty acid profiles reflected dietary intake, but finishing significantly increased the n‐3 fatty acid and long‐chain polyunsaturated fatty acid levels. The use of poultry‐byproduct‐based Largemouth Bass feeds may offer cost savings, and undesired effects on fillet nutritional value may be attenuated by the use of finishing feeds.