Effects of Dietary Curcumin on Growth and Flesh Quality in Juvenile Genetically Improved Farmed Tilapia (GIFT, Oreochromis niloticus)

This experiment was designed to investigate the effects of curcumin levels on growth, flesh quality, and oxidative resistance in juvenile genetically improved farmed tilapia (GIFT, Oreochromis niloticus). Fish (initial mean weight: 4.5 ± 0.3 g) were randomly fed five diets with curcumin supplementation levels of 0 (control), 150, 300, 600, and 1,200 mg/kg. After 60 days of feeding, the hepatosomatic index was significantly reduced in the curcumin supplemented groups. The 300 mg/kg group had the highest crude protein content of the whole fish. Compared to the control group, the crude fat content of whole fish in the 150 and 300 mg/kg groups was significantly reduced by 18.83%–19.74%, respectively. The highest values for muscular hardness, chewiness, myofibrillar density, and proportion of small-sized myofibers (<40 μm) were observed in the 300 mg/kg group. The levels of total nonessential amino acids and bitter amino acids in muscle were significantly lower in the 150 and 300 mg/kg groups than in the other groups. The 300 mg/kg group had higher levels of free sweet amino acids in the muscle than the other groups. Muscles from the 150, 300, and 600 mg/kg groups had significantly higher levels of umami amino acids than in the other groups. The levels of total free nonessential amino acids and total amino acids in serum were significantly higher in the 300 mg/kg group than in the control group. Serum aspartate transaminase activity was significantly lower in the curcumin supplementation groups than in the control group, and the serum alanine aminotransferase activity was significantly lower in the 150 mg/kg group than in the other groups. Serum superoxide dismutase activity was significantly higher in the curcumin supplementation groups than in the control group. Serum catalase activity was significantly higher in the 150 mg/kg group than in the other groups. The serum malondialdehyde level was lowest in the 150 mg/kg group. These results suggest that dietary curcumin supplementation in the diet at 150–300 mg/kg can effectively improve the nutritional value, muscle flavor, and antioxidant capacity of tilapia.