Submitted to: Book of Abstracts Aquaculture America
Publication Type: Abstract Only
Publication Acceptance Date: February 4, 2007
Publication Date: February 26, 2007
Citation: Mcentire, M.E., Rawles, S.D., Gaylord, T.G., Freeman, D.W. 2007. Evaluation of poultry by-product meal in commercial diets for hybrid striped bass in pond production [abstract]. Book of Abstracts Aquaculture America. p. 581. Technical Abstract: The efficacy of replacing fishmeal with petfood grade poultry by-product meal (PBM-PFG) on an ideal protein basis in commercial diets for hybrid striped bass (HSB) was evaluated in ponds under commercial production conditions. A typical commercial diet (GEN) for HSB was formulated to contain 40% protein, 12% lipid, and 3.7 kcal/kg. Protein in the generic diet was supplied by a mix of animal and plant sources typically used by the industry that included more than 20% select menhaden fishmeal and less than 10% PBM-PFG. A positive control diet (GEN+AA) was formulated by supplementing the generic diet with feed grade methionine and lysine to match the level of those amino acids found in HSB muscle. Three substitution diets were formulated by replacing 35%, 70%, and 100% of the fishmeal in the GEN diet with PBM-PFG on a digestible protein basis and then supplementing with Met and Lys as needed to maintain equity with the GEN+AA diet. Diet formulation and extrusion were conducted by a commercial mill and all diets met or exceeded known nutritional requirements for HSB. Twenty 0.10-ha ponds (4 ponds/diet) were randomly stocked with juvenile HSB (76.4 ± 10.0 g; mean ±STD) at a density of 7,400/ha and fed for 600 d (Oct 2004 - May 2006). Diets were fed once daily to apparent satiation to a maximum of 95 kg of feed/ha. Total weight and number of fish in each pond were determined at harvest. A random sample was taken from each pond by selecting every 15th fish during enumeration in order to estimate weight distributions. Subsets of 10 fish from each of these samples were randomly selected for the determination of body composition and nutrient and energy retention. Most production characteristics were not statistically different (P > 0.10) among the dietary treatments (Table 1). There was a tendency toward decreasing average weight (P = 0.22), percent marketable fish (P = 0.22), food conversion (P = 0.12), and yield per hectare (P = 0.12) in ponds receiving diets of more than 35% PBM substitution. Size distributions tended to be more peaked (P = 0.05) and skewed toward smaller fish (P = 0.18) in ponds receiving the 100PBM diet than in ponds receiving the generic diets. Fish fed the 70PBM and 100PBM diets had greater (P = 0.001) visceral somatic indices than fish fed the generic diets. These results support our previous work and demonstrate the efficacy of poultry by-product as a partial replacement for fish meal in commercial HSB diets.