A study on growth, feed efficiency and hematological changes in Pearlspot, Etroplus suratensis (Bloch, 1790) in response to varied salinities in raceway-based culture system

Abstract

A 60 days experiment was conducted in raceway tanks to determine the impact of salinity on growth, survival, carcass composition and hematology of <em>Etroplus suratensis </em>fingerlings. The experimental unit consisted of three treatments <em>viz.</em>, T1 (0 ppt), T2 (15 ppt), and T3 (25 ppt). Complete randomized design (CRD) was followed with each treatment in triplicate. A total of 1500 fingerlings were stocked in each tank with an average body weight of 22.43±0.88 g. The results of the present experiment showed that fishes reared in 15 ppt salinities has showed an improved growth performance in terms of specific growth rate (0.35±0.01 % day^-1), feed conversion ratio (0.11±0.01), feed efficiency ratio (8.72±0.52) and protein efficiency ratio (0.20±0.01), compared to 0 ppt and 25 ppt. Similarly, fishes reared in lower salinity (0 to 15 ppt) showed a better proximate composition compared to higher salinity of 25 ppt. In addition, fishes reared in 15 ppt salinity showed higher levels of hemoglobin (7.63±0.08 gm dl^-1), red blood cell (1.6±0.12 million cum m^-1), white blood cell (253000±57735 cells cum m^-1) and packed cell volume (21.63±0.08 %). Likewise, low levels of platelet, mean corpuscular volume (135.80±0.32 Fl), mean corpuscular hemoglobin (48.53±0.17 pg) and mean corpuscular hemoglobin concentration (35.46±0.20 gm %)) were observed in 15 ppt reared fishes. From the current study it is concluded that <em>E. suratensis</em> can be acclimatized to different water salinity and thereby it can be suggested as a potential candidate for farming at 15 ppt salinity.