The high cost and competing demand for fish meal in fish diet has made the search for alternative ingredients very expedient. A 12-week feeding trial was conducted with Nile tilapia (Oreochromis niloticus) to determine the effect of replacing fishmeal with soybean meal and methionine on growth, nutrient utilization, hematology, and plasma biochemistry.

Four experimental diets (40% crude protein) were formulated, with no soybean meal (control), partial Soybean Meal (PSBM), only Soybean Meal (SBM) and soybean meal supplemented with methionine (OSM+M).  Three groups of 15 fish each were fed at 3% body weight daily for 84 days.

Results showed that mean weight gain and fish length were significantly increased (p<0.05) in PSBM (22.77 g and 16.90 cm, respectively) and least in the control group (17.54 g and 14.63 cm, respectively).  Growth rate values were high in PBSM (1.62) and SBM+M (1.55) and least in the control group (1.48).  Based on the results of this study the researchers concluded that soybean meal can either be used to partially replace fishmeal or completely replace it with methionine supplementation, when growth, nutrient utilization and health status of Nile tilapia are considered.