Assessment of Optimum Salinity Level for Maximum Growth and Survival of Nile Tilapia, Oreochromis niloticus (Linnaeus 1758)

Abstract

Assessment of optimum salinity level (10‰, 15‰, 20‰, 25‰ and 30‰) for growth performance, food conversion, body composition and survival rate of Nile tilapia, Oreochromis niloticus (mean body weight 4.5±0.5 g) were investigated. Fingerlings were randomly distributed into the glass tanks (60 x 30 x 45 cm each). Ten fish per tank were stocked with two replications. Fish were fed with commercial floating pellet (35% protein) with 3% of total biomass day-1 for 50 days. Results showed that the growth increment reared on 10‰-20‰ salinity were significantly highest in term of weight gain, WG % of initial weight, daily weight gain, specific growth rate, condition factor and survival rate than those reared on 25‰ and 30‰. Feed conversion ratio was found similar in all levels which is not significantly different (P> 0.05). Whole body composition i.e. protein (53.16%-53.26%), moisture (71.16%-71.26%), lipids (2.49%-2.52%), ash (4.16%-4.18%) contents of fish whole body were not significantly (P>0.05) different at varying salinity levels. Mean values of water quality were found acceptable for tilapia i.e. temperature 28.42±0.08°C, dissolved oxygen 7.48±0.06 mg/L, pH 7.64±0.04 and ammonia 0.022±0.004 mg/L. Relationship between log body weight and log total length of the the fish shows that Nile tilapia fingerlings reared from 10‰-20‰ was significantly (P <0.05) higher than 25% and 30% salinity levels. Present study suggests that Nile tilapia can be reared up to 20% salinity to get good growth and higher survival rate.

Effects of salinity and plant-based diet or animal-plant combination diet on the performance and metabolic status of juvenile Nile tilapia

“…The negative effect of salinity on the performance of Nile tilapia has also been observed in other studies (Alvarenga et al, 2018;Herath et al, 2018;Malik et al, 2018), which reinforces the great impact of changes in salinity on the productive response of this species. In the present study, the highest survival rate (64.6%) was obtained at a salinity of 10 g L -1 (Table 3).…”

“…These results indicate that the osmoregulatory and metabolic adaptations of juvenile Nile tilapia were less stressful, and probably, demand less energy at a salinity of 10 g L -1 than in freshwater and at salinities of 20 and 30 g L -1 . Indeed, the best performance results have been reported within a range of 10-12 g L -1 for this species (Malik et al, 2018;You, Lu, Wang, Chen, & Li, 2019). This is justified by the fact that teleost fish maintain the osmolality of their extracellular body fluids relatively constant at approximately 9 g L -1 of salinity (Kültz, 2015).…”

“…However, the response of blood biochemical parameters to changes in salinity levels in juvenile Nile tilapia is not well understood. Furthermore, the performance and feed efficiency of this species have presented great variability to salinity (Alvarenga et al, 2018;Herath, Haga, & Satoh, 2018;Malik et al, 2018), and a better level of cultivation has not yet been identified.…”

Growth, length-weight relationship, and condition factor of NIFI (Oreochromis sp.) and Srikandi Tilapia (Oreochromis aureus x niloticus) at the grow-out stage in the high salinity brackishwater ponds

“…Pemanfaatan lahan pesisir untuk budidaya ikan nila dimungkinkan karena ikan nila mempunyai toleransi yang lebih tinggi terhadap salinitas dibandingkan ikan air tawar lainnya. Ikan nila dikenal mempunyai toleransi yang baik terhadap salinitas dan dikelompokkan dalam jenis ikan euryhaline (Kamal & Mair 2005) (Malik et al 2018). Dalam batas tertentu, ikan nila masih dapat mengatasi perubahan salinitas air melalui mekanisme osmoregulasi untuk mengatur keseimbangan ion di dalam tubuh dan menyesuaikan dengan kondisi perairan sekitar.…”