Replacement of fishmeal with novel plant feedstuffs in the diet of red drum Sciaenops ocellatus: an assessment of nutritional value

This study assessed the nutritional value of corn protein concentrate (Corn-PC), barley protein concentrate (Barley-PC), soy protein concentrate (Soy-PC) and soybean meals [commercially available solvent-extracted soybean meal (SBM), and two new varieties, SBM-209, SBM-3010] in the diet of red drum, Sciaenops ocellatus. Two independent growth trials were conducted to evaluate the replacement of 50% (Trial I, 8weeks) or 88% (Trial II, 6weeks) of the protein (solely from menhaden fishmeal) in the control diet (400gkg(-1) CP, 13 or 13.8MJkg(-1)). In both trials, each diet was fed to juvenile red drum (1.5 and 3.3 g initial wt.) in triplicate aquaria connected as a closed recirculating system. Results indicated that Soy-PC and Barley-PC can replace 50% of fishmeal protein while producing fish performance, condition indices and whole-body composition similar to that of the control diet (P>0.05). However, a significant reduction in growth performance was observed when each of the soybean meals or Barley-PC was used in combination with Soy-PC (100gkg(-1)) to replace 88% of fishmeal protein. While high inclusion levels of these plant feedstuffs deserve further evaluation, Soy-PC and Barley-PC can readily replace half of fishmeal protein without adversely affecting growth performance of red drum.