Document Type: Research Paper
University of Karachi, Pakistan
Centre of Excellence in Marine Biology, University of Karachi, Pakistan
The experiment was conducted to determine the optimal salinity and dietary protein levels on physiological, haematological changes and growth. The juveniles (Oreochromis mossambicus × Oreochromis niloticus) were stocked at 20 fish/ 50L. The initial weight was (2.1 ± 0.02) and reserved in salinity 0, 10, 20 and 35 ppt (S1, S2, S3 and S4 respectively) with 30% (P1) and 40% (P2) dietary protein levels for 45 days. The harvesting weight and SGR were not significantly (P > 0.05) varied in connecting S2-S3/P1 or in between S2-S3/P2. The food consumptions were significantly (P < 0.05) increased with decreasing protein levels and increasing salinities up to 0 ppt. The survival rates were not significantly (P > 0.05) differed among whole treatments. The lowest FCR and highest muscular hydration were achieved at intermediate salinities with low protein diet. No oblivious changes were occurred in Hct%, Hb, plasma protein, muscles and liver protein levels in whole treatments. Furthermore, the plasma cortisol and glucose levels were tended to high at higher salinity but did not significantly (P > 0.05) different among all treatments. The physico-chemical parameters of water were at satisfactory levels throughout the study. The aforementioned results showed that environmental salinity (0-35 ppt) do not adverse affect on growth and biochemical changes and also no required high protein levels in diets at any respected salinities.