Evaluation of different stocking densities on growth parameters, digestive enzymes, hemato-immunological and stress responses of Cirrhinus reba (Hamilton, 1822)

The aim of this study was to investigate the effects of stocking densities, that is 10 (SD1), 20 (SD2) and 30 (SD3) per m3 on the growth performance, digestive enzyme activity, hemato-immunological, and stress response of Cirrhinus reba after 45 days of culture. Fish (3·81 cm and 0.59 g) were reared in nine cemented tanks/20 m2. Three stocking densities were considered as three treatments, each was stocked in three tanks as replicates. The results revealed that the mean final length (9.02 cm), final weight (6.62 g), specific growth rate (5.38% per day−1), survival rate (88.33%), apparent feed conversion ratio (1.05) and protease activity (1.43 units/mg protein/min) were significantly (p < 0.05) greater in SD1. Furthermore, the glucose and cortisol levels were significantly (p < 0.05) lower in the SD1 group than in the other groups. However, the hematological parameters did not differ significantly (p > 0.05) among the different stocking densities. Overall, the results of the present study revealed that growth performance and digestive enzyme activity were better and that plasma glucose and cortisol levels were lower at a lower stocking density (10/m3), suggesting that Cirrhinus reba can be cultured to maintain better health and reduce stressful conditions in aquaculture systems.