Influence of Water Temperature and Salinity on Rearing of Nile Tilapia Fry under Biofloc Culture System | ||||
| Egyptian Journal of Aquatic Biology and Fisheries | ||||
| Article 6, Volume 25, Issue 6, November and December 2021, Page 61-77 PDF (636.64 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/ejabf.2021.210384 | ||||
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| Author | ||||
| M. A. Elnady et al. | ||||
| Abstract | ||||
| Nile tilapia fry (1.45 g each) were subjected to four salinity treatments (0.5‰, 5‰, 10‰, 15‰) under two temperature regimes (Statistical analysis: two-way ANOVA). Nile tilapia fry grew to harvest weights of 3.92 to 8.12 g/fingerling after 60 days of rearing. Tilapia fry reached higher harvest weights and daily weight gains when raised within 5-10 ‰ salinity range than those reared in 15 ‰ salinity. Among all treatments, there was an adverse effect of the highest salinity (15‰) on the growth performance of tilapia fry compared to other salinities. The better growth performance of Nile tilapia fry underwater salinity of 5-10% can be ascribed to the ease of osmoregulation under those salinities. Nile tilapia fry had better feed conversion ratio FCR performance when reared under high-temperature conditions (2.05-2.22) within the salinity range of 0.5-10% when compared to those of low temperature (3.04-5.38). Feed conversion ratios were deteriorated (4.01-5.74) when fry were raised in water salinity of 15 ‰ due to the adverse effect of increased salinity. The protein efficiency ratios were also better under high temperatures when fry were raised in 0.5-10 ‰ salinity range. Biofloc volumes were optimal and lower under high temperature and increased at low temperature due to the negative effect of low temperature on bacterial metabolism. Rearing Nile tilapia in biofloc system reduced ammonia and nitrite concentrations to recommended levels. Consequently, it is recommended to rear Nile tilapia fry under optimal range of salinity and temperature when reared in biofloc systems. | ||||
| Keywords | ||||
| Biofloc; Fry; Nile Tilapia; Temperature; Salinity | ||||
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