谷氨酸和α-酮戊二酸对鳜生长、脱氨及糖代谢的影响

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

  • 摘要: 为探究谷氨酸(Glu)和α-酮戊二酸(AKG)对鳜(Siniperca chuatsi)摄食和氨排泄的影响, 实验以鳜初始体重(26.28±0.99) g为研究材料, 将Glu和AKG分别添加到鳜的基础日粮中(添加量2%), 进行了60d的养殖实验, 前40d等量投喂, 后20d饱食投喂。通过设置对照组、Glu组和AKG组, 比较了3种不同饲料饲喂下鳜的摄食与氨排泄差异情况。实验结果表明, 在等量饲喂期间添加Glu、AKG显著提高鳜生长和降低饵料系数, 且在一定程度上降低鳜的体外氨排泄量。在饱食投喂阶段, Glu、AKG组的血液中的葡萄糖含量增加, 肝糖原、肌糖原含量降低。两个投喂阶段结果都表明, 饲料中添加谷氨酸和α-酮戊二酸能显著促进鳜脑中npy表达并抑制pomc表达, 显著提高蛋白质效率比和特定生长率, 增加鱼体体重, 促进鱼体生长且降低饲料系数。同时, 肝脏中gdh表达及肌肉ampd表达均提高, 脱氨代谢供能水平升高, 最终导致其氨排泄量升高。此外, 饲料中添加Glu和AKG可促进肝脏pepckg6pasepkgk基因表达量增加, 糖代谢增强, 减少蛋白质的分解供能。综上所述, 在饲料中添加谷氨酸和α-酮戊二酸均能促进鳜的摄食并降低氨的排泄。研究结果将应用于鳜的低氨排放养殖, 并推进谷氨酸和α-酮戊二酸在鳜饲料中的应用。

     

    Abstract: This study 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 of (26.28±0.99) g. During a 60d 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.

     

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