Effect of salinity on survival, hematological and histological changes in genetically improved rohu (Jayanti), Labeo rohita (Hamilton, 1822)

The recent climate change and anthropogenic activity affects the agricultural land/soil as well as aquaculture sector via salinization of the aquatic zone. The present study aimed to investigate the effect of salinity on genetically improved farmed rohu, Labeo rohita popularly known as Jayanti and evaluation of its physiological response towards combating salinity stress. Genetically improved rohu (Jayanti) fingerlings were reared in laboratory condition at different salinities 2, 4, 6, 8 and 10 ppt to assess the effect of salinity on survival for the first time in India. The study revealed that the Jayanti rohu fingerlings could tolerate salinity upto 8 ppt range. The survival rate of the fingerlings varied from 100%, 95%, 80% and 75% at 2, 4, 6 and 8 ppt salinities, respectively and 100% mortality occurred at 10 ppt. The survival rate was significantly higher in lower salinities than other acclimation salinities. The hematological parameters analysis depicted that blood parameters were affected by increase in salinity beyond 6 ppt. The histological analysis reported mild lesions on gills of fishes exposed to higher salinities at 8 ppt. The present study revealed that exposure to salinity moderately affects the survival and physiological response of genetically improved rohu and thus the potential of the improved rohu "Jayanti" to tolerate salinity levels upto 8 ppt. These results suggest that there is great prospective for culturing selectively bred rohu (Jayanti) species in low saline areas or salt affected areas with good survivability and open new avenues for further research and development.