Arachidonic acid (C20:4n-6, AA) is a key component of fish physiology, affecting growth, survival and reproduction. However, imbalances in dietary AA can adversely affect fish health and performance. Despite its importance, the optimal AA requirement for rainbow trout remains unclear. The aim of this study was to investigate the effects of varying dietary AA levels on reproductive performance and egg quality in female rainbow trout broodstock.
Female rainbow trout broodstock were fed diets containing different levels of AA (0.6%, 1.3% or 2.7% of total fatty acids) over a ten-month period. Throughout the spawning season, their spawning performance was closely monitored and the quality of both unfertilised and fertilised eggs was evaluated and their fatty acid composition assessed.
Our results indicate that dietary AA levels have a significant effect on the reproductive performances of rainbow trout. Female broodstock fed the low-AA diet (0.6% AA) had a significant higher body weight than those fed the high- AA diet (2.7% AA) . Moreover , the low-AA diet positively influenced reproductive performance, resulting in larger eggs and improved post-resorption fry surface compared to the high-AA diet. In addition, elevated dietary AA levels was associated with increased production of AA-derived pro-inflammatory oxylipins, which may contribute to reduced egg and fry quality.
In conclusion, this study highlights the importance of providing adequate dietary AA levels to female rainbow trout broodstock. Indeed, e xcessive AA intake has been shown to be detrimental to the quality of eggs and fry , underlining the need for further research to determine optimal AA requirements for farmed fish.
Acknowledgements: This work was carried out as part of a project funded by the Nouvelle-Aquitaine Region (French local authorities) and AquaExcel-TNA 3.0 project (2024– PID21817).