Effect of temperature on growth performance and immuno-biochemical changes in endangered golden mahseer, Tor putitora (Hamilton, 1923)

The present study to evaluated the effect of different thermal regimes on growth performance, oxidative stress, antioxidant enzymes, and immuno-biochemical responses of endangered golden mahseer, Tor putitora. A total of 144 healthy fingerlings were randomly distributed into four experimental groups (13 degrees C, 16 degrees C, 19 degrees C, 22 +/- 0.5 degrees C) in triplicate rectangular fiberglass reinforced plastics tanks. The highest and lowest Growth rate, Specific growth rate, Daily growth index, Thermal growth coefficient, Viscera-somatic index, and Growth hormone were observed at 19 degrees C and 13 degrees C, respectively. The lowest SGR and VSI were observed at 22 degrees C. The feed conversion ratio was significantly higher in the control group (p < 0.05), whereas there was a significant decrease in all the treatment groups. The highest and lowest hepato-somatic index was observed at a temperature of 13 degrees C and 16 degrees C, respectively, while no significant (p > 0.05) impact of temperature regimes were observed on the lengthweight relationship. Regarding hematological indices results, the hematocrit, hemoglobin, total erythrocyte count, and total leucocyte count were significantly higher at 13 degrees C, whereas the lowest was observed in all the treatment groups (p < 0.05). Higher myeloperoxidase activity and lysozyme activity were observed at 13 degrees C, whereas lowest at 22 degrees C. Anti-oxidant potential, SOD, and catalase (muscle) were significantly higher in the control group, whereas they gradually decreased with an increasing temperature. Catalase (liver) level was significantly higher at 22 degrees C. GST content was significantly higher at 22 degrees C compared to 13 degrees C, and GST content increased gradually with an increased temperature. The lipid peroxidation level in the liver and muscle was significantly higher at 22 degrees C and 13 degrees C, respectively. The present study concluded that the different phenotypic, antioxidative, and immuno-biochemical modulations of golden mahseer fingerlings in response to different temperature regimes could be used for better management and propagation.