PROCESSING FISH FEEDS
Pelleting and Extruding
Steam pelleting, through compression, produces a dense pellet that sinks rapidly in water. Extrusion is a process through which the feed material is moistened, precooked, expanded, extruded, and dried, producting low density feed particles that float in water. Steam pelleting is significantly less expensive than extrusion; however, extruded feeds are very popular with catfish farmers in the United States because they allow the feeder to observe the fish feed (see Figure 5.1).