Fish meal replacement by corn gluten in feeds for juvenile spotted rose snapper (Lutjanus guttatus): Effect on growth performance, feed efficiency, hematological parameters, protease activity, body composition, and nutrient digestibility

Abstract

The replacement of fish meal (FM) by corn gluten meal (CGM) in practical diets for juvenile spotted rose snapper, Lutjanus guttatus, was evaluated. Six isonitrogenous (47% crude protein), isoenergetic (19.03 kJ g−1) diets were formulated by replacing 0, 20, 40, 60, 80, or 100% of FM protein with CGM protein. Diets with CGM inclusion were supplemented with crystalline Arginine (Arg) and Lysine (Lys). Juvenile fish (mean body weight 31.2 ± 0.3 g) were fed the experimental diets (n = 45 per diet) for 70 days. Growth performance, feed efficiency, hematological parameters, protease activity, body composition, and nutrient digestibility were evaluated. Growth performance and feed efficiency at 60% FM replacement showed no significant differences (P < .05) versus the control diet, although trypsin activity and dry matter digestibility were significantly reduced. Dietary inclusion in excess of 60% CGM caused hypercholesterolemia, while fish fed the maximum level of CGM inclusion showed hypertriglyceridemia. Juvenile fish fed a 60% CGM inclusion showed high protein retention and reduced lipid retention in their whole-body composition. A second-order polynomial regression showed that juvenile snapper attains a maximum growth rate when fed up to 40% CGM inclusion. Our results show that CGM can be used as a suitable ingredient to supply up to 60% of protein in diets for spotted rose snapper, provided these are supplemented with crystalline Arg and Lys.