The objective of the present study was carried out to evaluate partial and total replacing of the fishmeal protein supplied by sand smelt fishmeal (SSFM) (Atherina boyeri) in practical diets on fish health, growth performance and feed utilization of mono sex Nile tilapia (Oreochromis niloticus) fingerlings. The experiment lasted 16 weeks and includes five treatments 0, 25, 50, 75 and 100% sand smelt fish meal (SSFM), respectively. An experimental diet containing is onitrogenous diets (30% crude protein), Ten ponds includes five treatments (Two replicates-almost 4 m3/pond)
and Nile tilapia fingerlings stocked in 25 fish/m3 (7.65±0.3 g at initial body weight).
The highest weight gain WG (75.94 g) was recorded for fish fed the 25% replacing diet (SSM25) followed by those fed the diet SSM50 (75.24 g), SSM75 (74.26 g), SSM0 (73.16 g) and SSM100 (72.14g), respectively and the differences in
weight gain among the different fry groups were significant (P<0.05) and the same trend was observed for specific growth rate SGR. The average feed intake and feed conversion ratio and protein efficiency ratio of Nile tilapia were significantly (P<0.05) affected by the incorporation of sand smelt fish meal as a substitute of fish meal.
Dry mater in whole fish body ranged between 28.83 and 29.59 with insignificant differences. Crude protein ranged between 55.69 and 58.06, ether extract ranged between 25.16 and 28.67, ash ranged between 14.83 and 15.58 with significant differences for ether extract and protein content of whole fish bodies.
The present study indicated that replacing up to 75% of FM by SSM higher affected growth and feed utilization and reduced feeding costs by 13.99% for Nile tilapia (Oreochromis niloticus) fingerlings compared with control. Also, The results showed he can use sand smelt meal as an alternative to fish meal (Herring meal) at a rate of 100% in diets fed Nile tilapia without effect on the growth of total production compared to the control, which leads to higher economic returns.