DIETARY SUPPLEMENTATION WITH GLUTAMATE ON GROWTH, ANTIOXIDANT CAPACITY, AND MUSCLE QUALITY OF GRASS CARP (CTENOPHARYNGODON IDELLA)

The experiment utilized grass carp (Ctenopharyngodon idella) as the research object to investigate the effects of dietary glutamate on growth performance, muscle quality, and plasma antioxidant capacity. Three groups of isonitrogenous and isolipidemic experimental diets were prepared: the control diet (Con) and the control diet supplemented with 0.8% and 1.6% L-glutamic acid (0.8% GLU group and 1.6% GLU group, respectively). 540 grass carp with an initial body weight of (37.0±0.2) g were divided into three treatments and fed with experimental feed respectively. Each treatment consisted of three repeated cages, with each cage containing 60 fish. The experiment spanned 85 days. The results showed that the growth performance of grass carp fed with glutamic acid was not significantly different from that of the control group. However, compared with the control group, the dorsal muscle gap of grass carp in 1.6% Glu group decreased, and the muscle fiber density increased significantly (P<0.05). Moreover, the hardness, chewiness, adhesion, cohesion, and recovery of grass carp dorsal muscle in the 0.8% Glu group and 1.6% Glu group were significantly increased compared to the control group, while muscle elasticity in the 0.8% HYP group was significantly increased (P<0.05). Additionally, the plasma total cholesterol content of grass carp fed with glutamic acid was significantly decreased (P<0.05). The activities of alkaline phosphatase (AKP) and glutamic oxaloacetic transaminase got (GOT) in plasma of grass carp in the 1.6% Glu group increased significantly (P<0.05), while the activity of glutamic pyruvic transaminase (GPT) in plasma decreased significantly (P<0.05). Furthermore, the plasma superoxide dismutase (SOD) activity and total antioxidant capacity (T-AOC) of grass carp in the 0.8% Glu group and 1.6% Glu group were significantly increased (P<0.05). In conclusion, the addition of glutamic acid in feed can enhance the muscle quality of grass carp and improve the antioxidant capacity of grass carp plasma.