Effects of mixed feeding schedules on growth performance, body composition, and nitrogen- and phosphorus balance in rainbow trout (Oncorhynchus mykiss)

Reducing feed cost and the pollution originating from feed have been principal matters in fish nutrition. Mixed feeding schedules have been proposed as one of the methods to reduce both of them and successfully tested in many fish species. The aim of the Turkish study was to determine the mixed feeding schedules' suitability for culture of rainbow trout (Oncorhynchus mykiss). Five different feeding schedules were tried by alternating the presentation of a low-protein (28.1%) diet (A) and a high-protein (49.9%) diet (B). The feeding schedules employed were 1A/1B, 1A/2B, 1A/3B, 2A/2B, and 2A/3B where the numerical values refer to the number of days each diet (A and B) was offered continuously. Fish given diets A and B continuously served as controls. Totally, seven dietary treatments were tested in triplicate for 10 weeks. The fish maintained on the different mixed feeding schedules exhibited lower weight gain than those fed continuously on the high-protein diet (P