EFFECTS OF STOCKING DENSITY AND PROBIOTIC ON THE GROWTH PERFORMANCE AND NUTRIENTS EFFICIENCY OF NILE TILAPIA (OREOCHROMIS NILOTICUS L.)
Sameh H. Sayed; Ibrahim, E. M. and Khamis, M. K.
Central Laboratory for Aquaculture Research, Agriculture Research Center, Ministry of Agriculture, Egypt.
Received 2/ 1/ 2012 Accepted 3/ 2/ 2012
Abstract
The present study was carried out to evaluate the effects of stocking densities and probiotic (Tonilisat) as supplementary diet (0.00, 0.025, 0.05, 0.10 and 0.20%) on the growth, survival rate, feed efficiency, body chemical composition and hematological study of all male Nile tilapia (Oreochromis niloticus Lin.) fingerlings. Fish were reared at two different densities each with different levels of probiotic during the feeding trial (10weeks).Fish with initial body weight (mean weight, 3.3 g/ fish) were stocked at 10 and 20 fish/m-2 each with five experimental diets (three replicates), fish fed on diets at 5% as a feeding rate, four times daily, all experimental diets contained 30% crude protein and 446 kcal gross energy/100 g diet. The final mean weights of the fish stocked at low density had the highest record. Growth rate was fast up to 10 and 20 fish m2 with 0.1% probiotic The corresponding SGR values were higher in T5 and T9 groups (2.317 and 2.307% day–1, respectively). The obtained results revealed that stocking density had significant effects on growth, and survival rates chemical composition of whale fish of Nile tilapia fingerlings at lower stocking density. Fish reared at the highest density exhibited lowest growth rate and survival rates compared with lower stocking density. But the differences were not significant (P<0.05) of survival rates. Hematological parameters were recorded the highest value with low stocking densities and higher level of probiotic in diets. It could be concluded that the inclusion of the Tonilisat at 0.1 %/kg diet at lower or higher stocking densities of all male Nile tilapia fingerlings is useful to get the best growth performance with no adverse effects on the environmental and enhance the blood hematological parameters. Hence, an optimum density level in terms of economic viability of tilapia culture must be established. Thus, this study enables us to postulate an optimum stocking density level of tilapia for maximum utilization of food and space with minimum stress and energy expenditure resulting in higher growth potential of the fish.
Key Words: Nile tilapia, growth performance, probiotic, chemical composition and blood hematological parameters.
