Using Spirulina platensis as Feed Additive to Improve Color and Immunity in Goldfish (Carassius auratus)

The present study was carried out to assess the effects of Spirulina platensis as a feed additive to enhance color and immunity of goldfish (C. auratus). Fish (3.5 g) were randomly assigned to eight concrete ponds (8 m3) with three fish / m3 capacity, and they were split into four treatments in two replicates. A commercial diet of 30 % crude protein was fed to fish in the four treatments as follow: the control group received no additive of Spirulina platensis, T1, T2 and T3 received 6, 8 and 10 g S. platensis per kg, respectively. The highest total carotenoids concentration in the skin of C. auratus was in T2 (1.32 ± 0.15 μg g-1). While MDA exhibited a considerable decline, antioxidants SOD, CAT, and GPx showed tremendous increases. At the termination of the feeding study, there was no discernible difference between the control and the investigated treatments concerning lysozyme activity, IGM, ALT, AST, and ALP. This discrepancy might be connected to spirulina's capability to improve fish health. Histological studies support these results, as no negative changes occurred in the cellular composition of liver tissue. Therefore, we conclude that using Spirulina platensis at a rate of 8 g / kg of feed improves the color quality of goldfish and thus increases their price.