Page 74 - 《水产学报》2025年第11期

苏金枝，等 水产学报, 2025, 49(11): 119606

Effects of astaxanthin on the structure and autophagy of hepatocytes and
intestinal epithelial cells of Epinephelus akaara

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SU Jinzhi , DENG Yuan , LI Zhentong 1,3,4 , LI Linlin 1,3,4 , WANG Linna 1,3,4 , LIU Yang 1,3,4 ,
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WANG Qingbin , ZHAO Xia , SUN Fangfang , TIAN Yongsheng 1,3,4* , LI Shengzhong 2*
1. State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute,
Chinese Academy of Fishery Sciences, Qingdao 266071, China;
2. College of Animal Sciences, Xinjiang Agricultural University, Urumqi 830052, China;
3. Hainan Innovation Research Institute, Chinese Academy of Fishery Sciences, Sanya 572000, China;
4. Laboratory for Marine Fisheries Science and Food Production Processes,
Qingdao Marine Science and Technology Center, Qingdao 266237, China;
5. Laizhou Mingbo Aquatic Co., Ltd., Laizhou 261400, China

Abstract: Cultured Epinephelus akaara generally suffers from slow growth and decreased skin beauty. It has been previously
verified that astaxanthin, as a feed additive, has a positive effect on the coloring and antioxidant capacity of E. akaara. Other
studies have found that astaxanthin can induce autophagy to regulate the body's lipid metabolism and promote liver and intest-
inal health functions. Therefore, this study conducted a three-month experiment on E. akaara fed with astaxanthin supplemen-
ted with different concentrations (0, 100, 200, 400, and 800 mg/kg). The effects of astaxanthin on HSI, hepatocyte and intest-
inal epithelial cell structure and autophagy of E. akaara were investigated by measuring hepatosomatic index (HSI) and using
transmission electron microscopy (TEM). The regression analysis model showed that with the increase of astaxanthin supple-
mental level, liver HSI of E. akaara showed a decreasing trend, and HSI in AST800 group was significantly lower than that in
control group (P<0.05). The ultrastructure of liver showed that the area of hepatocytes in AST800 groupwas significantly smal-
ler than that of the control group (P<0.05), and the number of autophagosomes, autophagolysosomes and mitochondria
increased significantly (P<0.05), while the number and area of lipid droplets were significantly decreased (P<0.05). The pres-
ence of small clumpy lipid droplets and mitochondria in the autophagosome contents suggested the occurrence of lipid droplet
autophagy and mitochondrial autophagy. The intestinal ultrastructure showed that the number of autophagosomes, autolyso-
somes and mitochondria in intestinal mucosal epithelial cells of AST800 group was significantly increased compared with the
control group (P<0.05), and the microvilli were more densely arranged, and the structure of tight junction between cells became
longer. Studies have shown that adding astaxanthin to the diet can induce autophagy, regulate cellular lipid metabolism, reduce
HSI, phagocytic mitochondria with abnormal structure, inhibit oxidative stress, and promote intestinal barrier function by regu-
lating cell tight junction. In conclusion, autophagy plays an important role in astaxanthin regulation of liver lipids and promo-
tion of intestinal barrier function in E. akaara, which is beneficial to its physiological activities. At the same time, the results of
this study suggest that lipid autophagy may be a new target for astaxanthin to improve the accumulation of excess fat in the
liver caused by dietary diet, and provide experimental basis for further development and utilization of astaxanthin in fish feed.
Key words: Epinephelus akaara; astaxanthin; hepatosomatic index; hepatocyte; intestinal epithelial cell; autophagy; lipid meta-
bolism
Corresponding authors: TIAN Yongsheng. E-mail: tianys@ysfri.ac.cn;
LI Shengzhong. E-mail: xndlishengzhong@sina.cn
Funding projects: National Key Research and Development Program of China (2022YFD2400502); Taishan Industry Leading
talent Project (LJNY202109); Key Research and Development Project of Shandong Province (2022LZGC016); Key Research
and Development Project of Hainan Province (ZDYF2022XDNY243); Qingdao Natural Science Foundation (23-2-1-53-zyyd-
jch); Ministry of Finance and Ministry of Agriculture and Rural Affairs: National Modern Agricultural Marine Fish Industry
Technology System Special Funding Project (CARS-47-G31); Central Public-interest Scientific Institute Basal Research Fund,
CAFS (2020TD19); Yellow Sea Fisheries Research Institute Research Fees (20603022021010); Qingdao Postdoctoral Applied
Research Project

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