Abstract
Nowadays the need to find alternate feedstuff constituents able to supply similar nutritional value at low cost is becoming increasingly evident. To assess the inclusion of Spirulina platensis biomass in the diet of Nile tilapia, Oreochromis niloticus, an experiment in a random arrangement design was established with five treatments (0, 5%, 20%, 35%, and 50% S. platensis diets). The experiment lasted for 90 days. The chemical constituents of diets were estimated. The growth performance, biochemical constituents, and histological study of the kidney of tilapia were investigated at the end of experiments. The results showed that the different levels of S. platensis diets enhanced the growth performance and body constituents of tilapia. The maximum increments were observed in tilapia fed by 5% S. platensis diet compared to algae-free control diet. The tissues of tilapia had better profiles of fatty acid (high n-3, low n-6/n-3) with 5% S. platensis diet than those of the control. The diet of S. platensis induced an improvement in the histoarchitecture of the kidney in tilapia. Meanwhile, the control group exhibited some alterations in the cellular architecture of the kidney. As clear from the present results, supplementing 5% S. platensis in the diet has been found to increase the nutritional value of diet, and improve growth and tissue characteristic of tilapia.