EFFECTS OF FEEDING DIETS CONTAINING DIFFERENT ALGAE SOURCES ON FISH GROWTH UNDER INTENSIVE CULTURE CONDITIONS

Abstract

The study was carried out in Faculty of Agriculture, Ain Shams University to assess the effect of two types of algae (spirulina and nannochloropsis) on growth performance of monosex tilapia fish (Oreochromis niloticus), were fed on a based supplemented diets with 0,3,5,7% of each alga species. Seven experimental treatments were assigned in three replicates each. The experiment was designed as follows: the 1st treatment was the control (without algae) , the 2nd treatment the was basal diet supplemented with 3% spirulina (spiru 3), the 3rd was the basal diet supplemented with 5% spirulina (spiru 5), the 4th treatment was the basal diet supplemented with 7% spirulina (spiru 7), the 5th treatment was the basal diet supplemented with 3% nannochloropsis (nanno 3), the 6th treatment was the basal diet supplemented with 5% nannochloropsis (nanno 5) and the 7th treatment was the basal diet supplemented with 7% nannochloropsis (nanno 7). Experimental tanks were a part of closed recirculating system, where environmental conditions were kept constant throughout the experimental period. Twenty-one quadrate fiber glass tanks 60 × 60 × 30 cm, width, depth, height, respectively, were stocked with 15 fish per tank. The individual initial body weight (2.7 g) was recorded at the beginning of the experiment. All fish in each tank were weighed every two weeks during the whole experimental period. The fish were fed the experimental diet for 95 days. At the end of the experimental period; twelve O. niloticus juveniles from each experimental group were randomly taken for blood sampling. And three fish were taken and dissected from each tank to obtain the liver, stomach and intestine to make histological investigation. The rest were taken fore carcass analysis. The results are summarized in the following: 1- When comparing the levels of spirulina with each other, it was found that there were no significant differences(p>0.05) between