Page 86 - 《水产学报》2025年第10期

徐莹莹，等 水产学报, 2025, 49(10): 109606

Effects of leucine in a high-carbohydrate feed on growth performance and
liver glucolipid metabolism of Micropterus salmoides

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XU Yingying , WU Xitao , ZHANG Chunnuan , XU Chao , LIU Wenbin , GUO Jie 5
1. College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China;
2. College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China;
3. Fisheries College, Ocean University of China, Qingdao 266100, China;
4. College of Animal Science and Technology, Nanjing Agricultural University, Nianjing 210095, China;
5. Guangxi Key Laboratory of Marine Environmental Science, Guangxi Academy of Marine Sciences,
Guangxi Academy of Sciences, Nanning 530007, China

Abstract: Carbohydrates (CHO) play serve as primary energy and carbon sources for animals and are therefore widely used
incorporated into practical feeds. However, unlike mammals, teleosts are generally considered unable to utilize carbohydrates
efficiently, most species are "glucose intolerant" and often exhibit prolonged post-prandial hyperglycemia after glucose loading
or carbohydrate-rich meals. The underlying mechanisms remain poorly understood. Leucine, a branched-chain essential amino
acid required for optimal growth in mammals and fish, improves glucose tolerance and insulin sensitivity, yet the long-term
effects of leucine supplementation on growth and intermediary metabolism in fish fed high-carbohydrate diets have not been
examined. In this study, a 12-week feeding trial was performed to fish [body weight (5.35 ± 0.04) g] were randomly fed three
diets, namely CON group (10% carbohydrate level), high-carbohydrate group (HC, 20% carbohydrate level), high carbo-
hydrate + leu group (HCL, 20% carbohydrate level + 2.0% leucine). The results showed that fish fed the HC diet had a lower
final fish weight, specific growth rate (SGR), weight gain rate (WGR), feed coefficient (FCR), as well as the expression of
g6pase, pparα, cptIa and aco1 compared to those fed the CON diets, whereas plasma glucose, triglyceride (TG), advanced
glycation end products (AGES) and glycosylated serum protein (GSP) levels, liver lipid content, as well as the expression of
glut2, gk, pk, gs, srebp1, fas, acc1, chrebp and selp showed an opposite trend. FCR, the plasma glucose, AGES and GSP levels,
liver lipid content, as well as the expression of foxo1, fbpase, and g6pase of HCL groups were significantly (P < 0.05) decrease
compared to those of the HC groups, whereas the opposite was true for final fish weight, SGR and WGR, whole body lipid con-
tents, as well as the expression of glut2, gk, pk, gs, srebp1, fas, acc1, chrebp, selp, pparα, cptIa and aco1. Overall, leucine could
improve the growth performance and feed utilization of M. salmoides fed the high-carbohydrate feed through the stimulation of
glycolysis, glycogenesis, lipogenesis and fatty acid oxidation coupled with the depression of gluconeogenesis. These findings
advance our understanding of how leucine modulates carbohydrate metabolism in fish.
Key words: Micropterus salmoides; high-carbohydrate feed; leucine; growth performance; glucolipid metabolism
Corresponding author: XU Chao. E-mail: xuc1213@scau.edu.cn
Funding projects: Guangdong Basic and Applied Basic Research Foundation (2023A1515010199, 2025A1515012677);
Guangxi Natural Science Foundation (2025GXNSFBA069190); China Postdoctoral Science Foundation Project
(2023M743333)

https://www.china-fishery.cn 中国水产学会主办 sponsored by China Society of Fisheries
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