Evaluation of Practical Bluegill Diets with Varying Protein and Energy Levels

Because bluegills Lepomis macrochirus are considered important both as a source of forage for largemouth bass Micropterus salmoides and as a sport fish, there is strong demand for juveniles and subadults for stocking purposes. Although spawning and extensive culture techniques are well established, there is a need to intensify culture systems to make juvenile production more cost effective. To move toward a more intensive culture system, we must establish basic parameters for the selection of commercial feeds. An 11‐week feeding trial was conducted with juvenile bluegills (1.76 g) to evaluate the effect of dietary protein and lipid level on growth, feed efficiency, and survival. Six practical diets were formulated, with varying levels of protein (32–44%) and lipid (6–12%). Final weight (9.4–12.1 g), feed intake (12.6–14.4 g), and feed efficiency values (60.6–72.1%) increased with increasing levels of dietary protein. Increasing the lipid content by 4% in the 32%‐protein diet (to 10% lipid) or the 44%‐protein diet (to 12% lipid) had little influence on the performance of the fish. Although the fish grew well on all diets tested, they grew best when offered a diet containing 44% protein and 8% lipid.