DISCUSSION
Under the experimental conditions, the results of the study indicated that tilapia growth increases when increasing the soybean diet content. In other words, it decreases when increasing the SSM diet content. In fact, there is a polysaccharide in SSM called chitin, which is not readily digestible. The chitin can reduce tilapia growth regardless of the supplementation level (Shiau and Yu, 1999). The SSM in tilapia diets was provided up to 60% of the total protein (substituting SBM) without com-promising growth in nutrient utilization. In this study the partial replacement of SBM with SSM is also recom-mended. The better growth rate noted in terms of weight gain, SGR and FCR may be due to the supplementation of amino acids by FM in the formulated diet without SSM.