GLUTAMATE AND Α-KETOGLUTARATE ON THE GROWTH, DEAMINATION, AND GLUCOSE METABOLISM OF CHINESE PERCH (SINIPERCA CHUATSI)

This work aimed to investigate the effects of glutamate (Glu) and α-ketoglutarate (AKG) on the feeding and ammonia excretion of Chinese perch Siniperca chuatsi; initial weight = (26.28±0.99) g. During a 60-day experimental period, Glu and AKG were added into the basal diet of Chinese perch. In the initial 40d, the fish received a fixed feeding rate while in the subsequent 20d, they were fed at a satiety level. A control group, a Glu group, and an AKG group were established to compare the differences in feeding and ammonia excretion of Chinese perch under the three different diets. Results showed that the addition of Glu and AKG during equal feeding significantly increased the growth and reduced the bait coefficient, as well as reduced the ammonia excretion of Chinese perch. During the satiety feeding phase, both the Glu and AKG groups increased glucose levels in the blood but decreased liver glycogen and muscle glycogen levels. Across both feeding stages, the incorporation of Glu and AKG into the feed significantly promoted the expression of npy and inhibited pomc in the brain. At the same time, it significantly increased the protein efficiency ratio and specific growth rate, increased the body weight of fish, promoted the growth of fish, and reduced the feed factor. Moreover, the study found that the expression of liver gdh and muscle ampd increased, resulting in heightened deamination metabolic supply and subsequent ammonia excretion. Notably, the expression levels of liver pepck, g6pase, pk, and gk genes in the Glu and AKG groups were significantly higher than those in the control group. The expression levels of gluconeogenesis and glycolysis genes increased, enhancing sugar metabolism and reducing protein catabolism for energy supply. The results of this study will be applied to the low-ammonia emission culture of Chinese perch and advance the application of Glu and AKG in the feed of Chinese perch.