Interaction of Dissolved Oxygen and Feed Fat Levels on Physiological Functions of Nile Tilapia

Strategic Insights -

New research published in Progress in Fishery Sciences has found that the interaction between dissolved oxygen and feed fat levels has a significant impact on the physiological functions of Nile Tilapia. The study, conducted by a team of researchers from Guangxi University, aimed to investigate the effects of different dissolved oxygen levels and fat levels on the growth performance, hepatic antioxidant capacity, immune parameters, and liver tissue structure of Nile Tilapia. The results of the study show that low oxygen levels and excessive dietary lipid levels can lead to severe liver oxidative damage, fat accumulation, dysfunction of lipid metabolism, and reduced immune capacity.

Key Takeaways:

  • The farming model for Nile Tilapia in China is shifting from traditional flowing water systems to high-density factory farming systems, but oxygen deficiency is a common factor that leads to fish mortality in high-density intensive farming settings.
  • The interaction between dissolved oxygen levels and feed fat levels has a significant impact on the physiological functions of Nile Tilapia, with low oxygen levels and excessive dietary lipid levels leading to severe liver oxidative damage, fat accumulation, dysfunction of lipid metabolism, and reduced immune capacity.
  • Feeding a diet with a fat content of approximately 4.41% during low oxygen conditions promoted the growth of Nile Tilapia and alleviated hypoxic stress, whereas feeding a diet with a fat content of approximately 7.61% in normoxic environments benefited the growth of Nile Tilapia.
  • The CAT activity and T-AOC in group B and T-AOC in group A first increased and then decreased with the increase in fat level, with the T-AOC in group A being lower than that in group B.
  • MDA content in group B increased gradually with the increase in fat level, while that in group A decreased first and then increased, with the MDA content in group A being higher than that in group B.
  • Immune indicators, including immunoglobulin M, interferon-gamma, tumor necrosis factor-alpha, and interleukin-1 beta, were significantly lower in group A compared to Group B and were not affected by fat level.
  • Complement C3 in the liver of Tilapia was significantly affected by DO and dietary fat levels, with the content first decreasing and then increasing with an increase in fat level.
  • The number of hepatic lipid vacuoles gradually increased in group B with increasing fat levels, whereas the cell morphology in group A2 was normal.

Statistics:

  • Initial weight of Tilapia: (7.62±0.29) g
  • Number of replicates per group: 3
  • Duration of the experiment: 60 days
  • DO content: hypoxia [(2.0±0.1) mg/L, group A] and normoxia [(5.0±0.1) mg/L, group B]
  • Fat levels: 1.57%, 4.41%, 7.61%, 10.51%, and 13.01%
  • WGR and SGR were significantly higher in Group B than in Group A
  • Hepatic enzyme activities and content of various parameters were significantly affected by the interaction between oxygen levels and fat levels
  • ATPase activity was not affected by the interaction between oxygen levels and fat levels

Sources:

  • Interaction of Dissolved Oxygen and Feed Fat Levels on Physiological Functions of Nile Tilapia. Progress in Fishery Sciences, 2025, 46(3): 53-65.
  • Progress in Fishery Sciences - http://journal.yykxjz.cn/yykxjzen/ch/index.aspx
  • Science Press, PR China
  • Dandan WANG, College of Animal Science and Technology, Guangxi University, Nanning 530004, People's Republic of China
  • Kai HUANG, Ting LIU, Ruijie GUO, Yuda LI, Xiangli LI