Growth and biochemical response of Nile tilapia (Oreochromis niloticus) to spirulina (Arthrospira platensis) enhanced aquaponic system

Experiments were conducted to examine growth performance and biochemical response of Nile tilapia (Oreochromis niloticus) to spirulina (Arthrospira platensis) enhanced aquaponic system. Fingerlings of O. niloticus, with an average initial weight and total length (TL) of 3.90 ± 0.015 g and 64.04 ± 0.18 mm (Mean ± SD) respectively were randomly distributed into four treatments and replicated four times. The treatments were four diets containing 0, 4.0, 8.0 and 12.0 g spirulina/kg of the basal diet of 30.4% Crude Protein (CP). The effect of spirulina enhanced aquaponic system on growth, feed utilization, haematological parameters and whole-body composition of O. niloticus was determined. A one-way analysis of variance (ANOVA) was used to determine the treatment effect and whenever the effects of the treatments were significant (p ≤ 0.05) means were compared using Turkey's test. Polynomial Contrasts were further used to determine the linear, quadratic and cubic effects of spirulina levels on O. niloticus.Polynomial contrasts analysis showed that the cubic trend for final total weight (FTW), gain in weight, final total length (FTL), specific growth rate (SGR), feed conversion ratio (FCR) and protein efficiency (PE) were significantly (p < 0.05) increased by inclusion of 8 g of spirulina/kg in the fish diet. The final crude protein (FCP), lipid (FL) and ash (FA) were significantly higher (p < 0.05) at 8 g of spirulina/kg. The contrasts analysis showed significant (p < 0.05) linear increment for final blood glucose (FBG), final red blood cells (FRBC), final white blood cells (IWBC) and final hematocrit (IH) content of O. niloticus. The results of the present study indicate the potential of the use of spirulina in promoting growth, feed utilization, and haematological parameters of O. niloticus.