EFFECTS OF STOCKING DENSITY AND PROTEIN LEVEL IN DIET ON GROWTH PERFORMANCE, SURVIVAL RATE AND FEED EFFICIENCY OF NILE TILAPIA (OREOCHROMIS NILOTICUS L.) FRY MONOSEX DURING THE NURSERY PERIOD. | ||
| Egyptian Journal of Aquatic Biology and Fisheries | ||
| Article 5, Volume 10, Issue 3, July 2006, Pages 69-84 PDF (1.14 M) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/ejabf.2006.1863 | ||
| Author | ||
| Ramadan Abou-Seif | ||
| Central Lab. For Aquaculture Research, Abbassa, Abou- Hammad, Sharkia Governorate, Egypt. | ||
| Abstract | ||
| The effects of stocking density and dietary protein levels on growth performance, larval survival and feed utilization efficiency of Nile tilapia (O. niloticus L.) fiy monosex (0.014 g average initial body weight) were investigated in a single-stage nursery-rearing system using 1389 and 2778 hatchlings/ m3 as stocking densities within each density 29.71, 34.43 and 39.11% dietary protein levels. Twelve fiberglass tanks (180 liter volume for each) on a flow- through system (100%/day)were used to represent the two stocking densities and the three protein levels in replicates. The dietary treatments were fed 7 days/week (twice daily) at a rate of 15% of the total biomass during the 1st 45-days then reduced to 10% of total biomass from days 46 to 75, after that it was reduced to 5% of total biomass till the end of the experiment (105 days).The results revealed that there was significant increase (P< 0,01) in growth rate with decreasing stocking density and increasing dietary protein level during all experimental periods. The same trend was also observed for mean body weight (g), specific growth rate (SGR%/day), condition factor (k) and survival rate (SR %). The best final mean body weight (g), SGR, K and (SR %) were recorded in groups of fish stocked in 1389 hatchlings /m3 and fed on the diet containing 39.11% CP)(T3SR1).The effects of stocking density and dietary protein levels on growth performance, larval survival and feed utilization efficiency of Nile tilapia (O. niloticus L.) fiy monosex (0.014 g average initial body weight) were investigated in a single-stage nursery-rearing system using 1389 and 2778 hatchlings/ m3 as stocking densities within each density 29.71, 34.43 and 39.11% dietary protein levels. Twelve fiberglass tanks (180 liter volume for each) on a flow- through system (100%/day)were used to represent the two stocking densities and the three protein levels in replicates. The dietary treatments were fed 7 days/week (twice daily) at a rate of 15% of the total biomass during the 1st 45-days then reduced to 10% of total biomass from days 46 to 75, after that it was reduced to 5% of total biomass till the end of the experiment (105 days).The results revealed that there was significant increase (P< 0,01) in growth rate with decreasing stocking density and increasing dietary protein level during all experimental periods. The same trend was also observed for mean body weight (g), specific growth rate (SGR%/day), condition factor (k) and survival rate (SR %). The best final mean body weight (g), SGR, K and (SR %) were recorded in groups of fish stocked in 1389 hatchlings /m3 and fed on the diet containing 39.11% CP)(T3SR1). | ||
| Keywords | ||
| Nile tilapia; stocking density; protein level nursery; rearing period | ||
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