Thermal tolerance, oxygen consumption and haemato-biochemical variables of Tor putitora juveniles acclimated to five tem
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Thermal tolerance, oxygen consumption and haemato-biochemical variables of Tor putitora juveniles acclimated to five temperatures M. S. Akhtar • A. K. Pal • N. P. Sahu • A. Ciji P. C. Mahanta
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Received: 2 November 2012 / Accepted: 18 March 2013 Ó Springer Science+Business Media Dordrecht 2013
Abstract A 30-day acclimation trial was conducted using Tor putitora to elucidate its thermal tolerance, oxygen consumption, haemato-biochemical variables and selected enzymatic activities at five acclimation temperatures (AT). Juveniles of T. putitora were randomly distributed among five treatment groups (20, 23, 26, 29 and 32 ± 0.5 °C). There was a significant curvilinear increase in critical thermal maxima (CTmax) (y = -0.0693x2 ? 1.7927x ? 34.628, R2 = 0.996) and lethal thermal maxima (LTmax) (y = -0.1493x2 ? 2.3407x ? 35.092, R2 = 0.991) with increasing AT. The oxygen consumption rate increased significantly with increasing AT. The Q10 values were 1.16 between 20 and 23 °C, 3.09 between 23 and 26 °C, 1.31 between 26 and 29 °C and 1.76 between 29 and 32 °C of AT. The acclimation response ratios were ranged between 0.37 and 0.59. Catalase, superoxide dismutase and ATPase activities were increased linearly in liver, gill and kidney, while brain acetylcholine esterase activity decreased linearly with increasing AT. Blood glucose remained unchanged up to AT of 26 °C and increased significantly at M. S. Akhtar (&) P. C. Mahanta Fish Nutrition Laboratory, DCFR, Bhimtal, Nainital 263136, Uttarakhand, India e-mail: [email protected] M. S. Akhtar A. K. Pal N. P. Sahu A. Ciji Division of Fish Nutrition, Biochemistry and Physiology, Central Institute of Fisheries Education, Mumbai 400061, India
AT of 29 and 32 °C. Haemoglobin content was increased linearly with increasing AT. The highest WBC count was observed at 20 °C, and no significant changes found till AT of 26 °C and significantly decreased at 32 °C. Total serum protein and globulin were significantly decreased with increasing AT. Highest values were observed at 20 °C and remained consistent till 26 °C, then decreased significantly. There was no significant change in A/G ratio through the AT 20–29 °C and increased significantly at 32 °C. The increase in CTmax, LTmax and oxygen consumption rate with increasing AT may suggest that the thermal tolerance of T. putitora is dependent on its prior thermal exposure history, and it could adapt to higher AT by altering its haemato-biochemical variables. Keywords Acclimation temperature Catalase CTmax LTmax Oxygen consumption Tor putitora
Introduction Tor putitora commonly known as ‘golden mahseer’ is an important cyprinid fish endemic to Asia with natural distribution encircling the trans-Himalayan region and thrives well in the temperature range of 20–25 °C. They are attractive as sport fish as well as have tremendous aquaculture potential (Ingram et al. 2005). In recent years, due to anthropogenic pressure, pollution, environmental degradation and indiscriminate
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Fish Physiol Biochem
fishing, the popul
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