Effects of supplementation of algae (Sargassum ilicifolium) on growth, survival and body composition of rainbow trout Oncorhynchus mykiss

The effects of substituting dietary protein sources with different levels of Sargassum ilicifolium on growth, survival and body composition of rainbow trout Oncorhynchus mykiss were investigated over the course of a ۶۰ day experiment. A total of ۳۶۰ juveniles (۷۵±۲.۸ g) were randomly allotted to four treatment groups including (control: with ۱۰۰% basal diet (BD); T۱: ۵% sargassum meal (SM)+۹۵% BD; T۲: ۷.۵% (SM)+۹۲.۵% BD and T۳: ۱۰% (SM)+۹۰% BD. Each treatment group was divided into three replicates of ۳۰ fish per replicate. At the end of the experiment, our results showed that replacement of ۵% and ۷.۵ % of basal diet with sargassum meal showed significant differences in average weight and total length, feed conversion ratio (FCR), specific growth rate (SGR), weight gain percent (WG), condition factor (CF) and survival rate (SR). There were significant differences between calorie content of carcass in T۲ and control with T۱ and T۳ (p<۰.۰۵). The highest values of carcass protein content were observed in T۱ (p<۰.۰۵). There were significant differences between lipid content of fish in T۲ and control with that of fish in T۱ and T۳ (p<۰.۰۵). The highest values of carcass ash content were observed in T۱, (p<۰.۰۵) which were not significantly different from that in other treatments (p>۰.۰۵). Levels all of amino acids were higher in fish in T۲.

Keywords:

Protein sources , Sargassum ilicifolium , Growth , Survival , Body composition , Rainbow trout