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ORIGINAL RESEARCH article

Front. Immunol.
Sec. Nutritional Immunology
Volume 16 - 2025 | doi: 10.3389/fimmu.2025.1525992
This article is part of the Research Topic New Progress of Nutritional Immunity on Aquatic Animals by Functional Feed Additives under the Condition of Low Fish Meal View all 11 articles

Dietary supplementation of mulberry leaf oligosaccharides improves the growth, glucose and lipid metabolism, immunity, and virus resistance in largemouth bass (Micropterus salmoides)

Provisionally accepted
Donglai Zhou Donglai Zhou 1,2Wenhao Zhong Wenhao Zhong 1,3*Bing Fu Bing Fu 1Er-na Li Er-na Li 1,2Le Hao Le Hao 4*Qingrong Li Qingrong Li 1*Qiong Yang Qiong Yang 1*Yuxiao Zou Yuxiao Zou 1Zhenxing Liu Zhenxing Liu 4Fubao Wang Fubao Wang 2*Sentai Liao Sentai Liao 1*Dongxu Xing Dongxu Xing 1*
  • 1 Sericultural and Agri-Food Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, China
  • 2 Guangdong Provincial Engineering Technology Research Center of Special Aquatic Functional Feed, Foshan, China
  • 3 College of Food Science and Technology, Guangdong Ocean University, Zhanjiang, Guangdong Province, China
  • 4 Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou, Guangdong Province, China

The final, formatted version of the article will be published soon.

    This study investigated the effects of dietary supplementation of mulberry leaf oligosaccharides (MLO) on the growth performance, serum biochemistry, glucose and lipid metabolism, antioxidant activity, liver health, and virus resistance in largemouth bass (Micropterus salmoides). The fish were fed with CK (basal diet), MLOL (basal diet supplemented with 0.5%MLO), and MLOH (basal diet supplemented with 1.0% MLO) for 80 days, and then subjected to a 21-day viral challenge experiment. The results showed that MLO supplementation had no adverse effect on the weight gain rate, specific growth rate, feed intake, and condition factor (P > 0.05), but significantly decreased the feed conversion rate and viscerosomatic index (P < 0.05).Moreover, the MLOL and MLOH group had significantly lower contents of triglyceride, blood glucose, and malondialdehyde and activities of serum alanine aminotransferase and aspartate aminotransferase, while significantly higher levels of serum and liver total superoxide dismutase and lower levels of glutathione than the CK group (P < 0.05). MLO supplementation significantly up-regulated the relative expression of glycolytic genes gk and pfk and lipid catabolism genes ppar-α and cpt-1, while obviously down-regulated that of acc, fas, and dgat related to fatty acid synthesis in the liver tissue (P < 0.05). In terms of liver health, MLO supplementation significantly up-regulated the relative expression of anti-inflammatory cytokines il-10 and tgf-β, while decreased that of pro-inflammatory cytokines nf-κb, il-8, and tnf-α in the liver tissue (P < 0.05). The viral challenge test showed that MLO supplementation significantly improved the survival rate of M. salmoides after largemouth bass ranavirus (LMBV) infection. Dietary MLO supplementation promoted liver glucose and lipid metabolism, and improved the immunity and resistance of M. salmoides to LMBV by regulating the PPAR signaling way and inhibiting the NF-kB signaling pathway. The appropriate addition amount of MLO to the diet was determined to be 1.0%.

    Keywords: Largemouth bass, Growth, Serum biochemistry, Liver metabolism, Inflammation

    Received: 11 Nov 2024; Accepted: 09 Jan 2025.

    Copyright: © 2025 Zhou, Zhong, Fu, Li, Hao, Li, Yang, Zou, Liu, Wang, Liao and Xing. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence:
    Wenhao Zhong, Sericultural and Agri-Food Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, China
    Le Hao, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, Guangdong Province, China
    Qingrong Li, Sericultural and Agri-Food Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, China
    Qiong Yang, Sericultural and Agri-Food Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, China
    Fubao Wang, Guangdong Provincial Engineering Technology Research Center of Special Aquatic Functional Feed, Foshan, China
    Sentai Liao, Sericultural and Agri-Food Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, China
    Dongxu Xing, Sericultural and Agri-Food Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, China

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