Brown trout is a very important salmonid species with high economic value and an important aquaculture potential. Due to various reasons, it is in danger of extinction in its natural environment. For this reason, both stocking studies have been carried out in natural environments and aquaculture potential
has been investigated. As functional feed additives prebiotics have been reported to have many beneficial effects on growth, survival, immune system, increased absorption in the gut, and improving the general welfare of some fish and crustaceans. The dietary supplementation of the commercial prebiotic Grobiotic®-A (Gb-A) has not been evaluated in Salmo trutta macrostigma. This study was planned a preliminary investigation of Gb-A prebiotic supplementation in brown trout diets. In this study, the effects of Gb-A on growth performance,
gut structure, and body composition of brown trout were investigated. For this purpose, 600 fish with a mean weight of 0.43 g were used. Gb-A was applied to fish with artemia and feed. After 90 days feeding of the experimental diets,
no effect on weight gain, specific growth rate, survival rate, and body structure was observed between the control and Gb-A added groups (1.4% Gb-A and 2.8% Gb-A). However, the intestinal villus length of fish fed 1.4% Grobiotic®-A was higher than fish fed the basal diet and 2.8% Grobiotic®-A. Also, lipid
accumulation was observed in both Gb-A supplemented groups in the distal intestine compared to the control group.