Nutrient Digestibility and Retention of Potential Feed Ingredients for Rainbow Trout (Oncorhynchus mykiss W.) Aquaculture in Iran

Figure 1

Relative nutrient digestibility and productivity (%) for Iranian feather meal. CP, crude protein; NPV, nitrogen productive value; CL, crude lipid; OM, organic matter; IRFeM, Iranian feather meal; IRFeM⁺, Iranian feather meal diet treated with citric acid (dissolved 0.02 g citric acid, C₆H₁₂O₆, per 1 g Iranian feather meal and sprayed on IRFeM diet or 0.6% diet). The values are the mean of four replicates (n = 4). Error bars represent standard deviations from four replicate aquaria. Data with asterisks are considerably different ().