Effect of Marine Macroalgae on Growth Performance and Immune Response in Rainbow Trout Fingerlings

Aims: Sargassum bovianum, Polycladia myrica, and Gracilariopsis persica can be used in aquatic diets due to their significant biomass and mass production capacity for artificial rearing. The aim of this study was to investigate the effect of marine macroalgae on growth performance and immune response in rainbow trout (Oncorhynchus mykiss) fingerlings.
The present experimental study was carried out on 210 rainbow trout fingerlings, which were randomly selected and cultured in Aquatic Laboratory, Faculty of Marine Sciences, Tarbiat Modares University, Noor, in 2016. These fingerlings were placed in 7 experimental treatments, including a diet without marine macroalgae (control) and by replacing different marine macroalgae powder levels of 5% and 10% with wheat flour. Lindo 5.3 software was used to analyze food items and SPSS 20 software was used to analyze the data.
Findings: The lowest weight gain, the lowest growth factor, the lowest protein efficiency ratio, and the highest feed conversion ratio were in the treatment containing 10% Sargassum bovianum powder and it had a significant difference with other treatments. Condition factor (CF) was at the highest level in control treatment and no significant difference was observed between treatments. There was no significant difference in survival of different treatments. The highest level of serum lysozyme was in the treatment containing 5% Gracilariopsis persica powder and the highest serum hemolytic complement activity was in the treatment containing 5% Sargassum bovianum.
Gracilariopsis persica, Sargassum bovianum, and Polycladia myrica have no effect on the improvement of growth performance in rainbow trout fingerlings, Gracilariopsis persica and Sargassum bovianum have an impact on their immune response.