Juvenile bluegill (Lepomis macrochirus) can be fed diets without marine fish meal without adverse effects on growth, survival, diet utilization, and body composition

Authors: Webster, Carl; Rawles, Steven - Steve; KELLY, ANITA - Auburn University; ROY, LUKE - Auburn University; ROSENTRATER, KURT - Iowa State University

Submitted to: Aquaculture Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/1/2021
Publication Date: 3/28/2021
Citation: Webster, C.D., Rawles, S.D., Kelly, A.M., Roy, L.A., Rosentrater, K. 2021. Juvenile bluegill (Lepomis macrochirus) can be fed diets without marine fish meal without adverse effects on growth, survival, diet utilization, and body composition. Aquaculture Nutrition. 27(4):1144-1159. https://doi.org/10.1111/anu.13255.
DOI: https://doi.org/10.1111/anu.13255

Interpretive Summary: There has been an increasing global demand for large bluegill to supply the food-fish market. Current bluegill diets resemble those for largemouth bass and contain a high percentage of marine fish meal (FM). Research into the use of alternative protein ingredients for bluegill diets need to be conducted to not only conserve finite marine resources, but to reduce cost and expand the supply of bluegill to the global market. We evaluated growth, survival, and body composition of bluegill fed diets in which FM was partially or totally replaced by various combinations of soybean meal, poultry by-product meal, canola meal, soy protein concentrate, wheat gluten, or a commercial protein blend. Seven diets were formulated to meet the known nutrient and energy requirements of largemouth bass and bluegill using nutrient availability data for most of the dietary ingredients. Juvenile bluegill were grown in a recirculating aquaculture system and fed the test diets for 70-d. The test diets in which various percentages of SBM, PBM or other proteins completely replaced FM resulted in similar growth performance, feed efficiency, and body composition of juvenile bluegill compared to fish fed diets containing FM. However, as formulated, the all-plant diet resulted in reduced growth. It appears that bluegill can be fed fish meal-free diets without reduced production (growth), but that currently, an all-plant diet does not provide for good growth compared to other diets, but that further study on formulating all-plant diets for bluegill is needed.

Technical Abstract: There has been an increasing global demand for large bluegill (Lepomis macrochirus) to supply the food-fish market. Current bluegill diets resemble those for largemouth bass and contain a high percentage of marine fish meal (FM). Research into the use of alternative protein ingredients for bluegill diets need to be conducted to not only conserve finite marine resources, but to reduce cost and expand the supply of bluegill to the global market. We evaluated growth, survival, and body composition of bluegill fed diets in which FM was partially or totally replaced by various combinations of soybean meal, poultry by-product meal, canola meal, soy protein concentrate, wheat gluten, or a commercial protein blend (Pro-Cision™). Seven isonitrogenous (40% protein), isolipidic (11%), and isocaloric (17.1 kJ/g) diets were formulated to meet the known nutrient and energy requirements of largemouth bass and bluegill using centrarchid nutrient availability data for most of the dietary ingredients. One of the test diets consisted exclusively of plant protein sources. Juvenile bluegill (9.1 g initial weight) were reared in a recirculating aquaculture system (3 tanks/diet; 30 fish/tank) and fed the test diets to satiation daily for 70-d. The test diets in which various percentages of SBM, PBM or other proteins completely replaced FM resulted in similar growth performance, feed efficiency, and body composition of juvenile bluegill compared to fish fed diets containing FM. However, as formulated, the all-plant diet resulted in reduced growth. Mean diet performance rankings based on response measures along with differences in essential nutrient and energy levels (i.e., amino acids, P and starch) provided some insight into subtle differences in performance among diets. However, it appears that bluegill can be fed fish meal-free diets without reduced production (growth). Further study on formulating all-plant diets for bluegill is warranted.