Whole body and muscle fatty acid composition were determined in pooled samples of 10 fish at the beginning and 10 fish per diet at the end of the growth trial. Additional sampling of muscle, hepatopancreas (Toledo-Cuevas et al., 2011) and gut tissue was done at the end of the growth trial from randomly selected fish killed by scission of the spinal cord. Following overnight fasting, tissue samples of 4 fish per tank (12 animals per diet) were excised and freeze-dried and enzyme activities for amylase, alkaline proteases, trypsin, and pancreatic and neutral lipases were determined as indicated below.