The current study was conducted to determine the synergistic effects of dietary nano selenium (Nano Se) and vitamin C on growth, feeding, and physiological parameters of juvenile mahseer, Tor putitora. L-ascorbyl-2-polyphosphate (APP) was used as a source of vitamin C. Four semi-purified experimental diets were prepared. A basal diet kept without the supplementation of any micronutrient and the other three diets were formulated such that three different levels of APP (100, 200, and 300 mg kg−1) were used in combination with a pre-determined dose of Nano Se (0.68 mg kg−1). The results showed that both the micronutrients positively synergized the effects of each other. APP at the rate of 300 mg kg−1 showed strong interaction with Nano Se. The APP300 + Nano Se0.68 mg kg−1 diet supplemented diet significantly decreased (P< 0.05) the feed conversion ratio (FCR) while significantly increased (P< 0.05) the weight gain percentage (WG%), feed conversion efficiency (FCE%), specific growth rate (SGR), and serum growth hormone (GH) concentration. Similarly, the physiological parameters such as red blood cells count (RBCs), hemoglobin level (Hb), hematocrit value (Hct), and serum lysozyme activity were also significantly increased in group of fish fed diet supplemented with APP100 mg kg−1 in combination with Nano Se0.68 mg kg−1 as compared to the control group. The present results clearly indicated the beneficent synergistic effects of Nano Se and APP in mahseer fish. Moreover, the current finding also supported our hypothesis that Nano Se and APP potentiate positively the effect of each other when both the micronutrients are supplemented together in the same fish feed

The purpose of this study was to evaluate behavioral responses and biochemical changes induced by the extensively used pesticide cypermethrin (CYP) in liver, gills, brain and muscle tissues of mahseer (Tor putitora) fry. Behavioral changes in fish after exposure to an acute concentration of CYP involved jumping, abrupt swimming, loss of balance and equilibrium, increased surface activity and air gulping. These changes were more prominent with the passage of time. After a longer period of exposure, the fish became sluggish and before dying occasionally became motionless and sometimes showed a vertical position. Internal hemorrhage was also obvious. CYP exposure resulted in a significant decrease in total protein content in different tissues while antioxidant enzymes, catalase (CAT), peroxidase (POD) and glutathione reductase (GR) showed a time-dependent increasing trend in their activities in liver, brain, gills and muscle tissues. Similarly, lipid peroxidation (LPO) level also increased with time in different tissues of CYP-exposed fish. The results of the present study revealed that CYP is toxic to the mahseer Tor putitora. Therefore, its indiscriminate use can contribute in decreasing the population of mahseer in natural water bodies.