Effect of climate change on hematotoxicity/hepatoxicity oxidative stress, Oncorhynchus mykiss, under controlled conditions

4. Discussion It is well known that secondary responses to prolonged high temperature are often observed in fish, such as increased hemoglobin and hematocrit, which are thought to occur as a result of transient catecholamine fluctuations and may help fish to cope [14]. In the studies, it has been determined that epigenetic modifications can mediate and induce stress coping skills of indi- viduals by exposing them to high temperatures in the context of global warming. These regu- late secondary stress response factors that alter the distribution of essential resources (such as energy to tissues and organs, as well as compromising hydro-mineral imbalance and the immune system). In our research findings, the change in enzyme activities revealed that seasonal variability in rainbow trout should be seriously questioned. In addition, increases in MDA levels indicate that temperature changes cause oxidative stress and acclimatization to higher temperatures leads to increased lipid oxidative damage in fish. It is known that aquatic organisms will go through physiological difficulties, especially the decrease in oxygen will increase the metabolic demand for oxygen, as a result of global Table 1. The effect of different temperature applications on blood, liver and muscle antioxidant status. Tissues Antioxidant enzyme Treatment groups A B C D Blood SOD 1.87±0.24 b 2.06±0.10 ab 2.12±0.40 ab 2.38±0.16 a CAT 0.39±0.09 b 2.65±0.8 a 1.87±0.12 ab 0.98±0.03 b GPx 1. 07±0.08 a 6. 62±0.5 a 9. 67±1.03 a 1. 09±0.6 a GSH 0.52±0.01d 1.16±0.02 c 2.88±0.27 b 3.29±0.21 a

MDA 10.12±0.7 b 10.37±1.04 b 13.65±6.09 b 26.44±6.9 a MPO 15. 69±1.05 b 22. 28±2.10 b 53. 60±5.30 ab 79. 25±8.3 a TAS 0.38±0.02 b 0.49±0.01 ab 0.59±0.06 a 0.39±0.1 b TOS 15.34±2.3 b 17.41±1.1 b 24.71±1.2 ab 30.66±3.1 a OSI 40.12±2.34 b 37.73±1.07 b 42.09±2.63 b 79.81±4.43 a Liver SOD 1. 73±0.2 b 2. 04±0.02 ab 2. 12±0.1 ab 2. 27±0.3 a CAT 0.85±0.5 b 0.87±0.03 b 1. 67±1.4 ab 3. 24±0.8 a GPx 5. 53±0.07 a 4. 96±0.1 a 3. 01±0.3 a 0. 52±0.02 a GSH 0.83±0.05 b 2.51±1.8 b 3.13±0.5 b 7.93±1.4 a MDA 9.68±1.0 b 10.18±0.9 b 10.37±3.2 b 30.91±5.8 a MPO 62.00±4.5 b 74.85±14.8 a 20. 44±0.4 b 27. 95±1.1 b TAS 1.11±0.07 a 1.06±0.08 ab 1.09±0.08 ab 0.92±.0.1 b TOS 21.49±0.5 a 25.06±1.8 a 27.81±0.6 a 43.21±1.3 a OSI 19.58±0.5 b 22.77±1.6 b 25.71±0.7 b 46.27±0.8 a Muscle SOD 4. 76±0.5b 6. 91±0.6ab 13. 79±0.1ab 15. 93±0.5a CAT 6. 58±0.3 a 10. 68±0.6 a 14. 64±1.1 a 16. 40±0.9 a GPx 5. 17±0.8 a 2. 58±0.3 a 2. 25±0.1 a 0. 22±0.1 a GSH 0.91±0.05 b 2.46±0.1 a 3.04±0.4 a 3.57±0.1 a MDA 8.48±0.3 b 11.19±2.5 b 11.63±3.1 b 24.86±1.7 a MPO 12. 77±0.3 b 30. 22±0.8 b 39. 52±4.4 b 96. 13±1.2 a TAS 0.79±0.06 a 0.62±0.02 a 0.75±0.01 a 0.78±0.02 a TOS 10.40±0.7 b 15.75±0.7 ab 16.95±1.9 ab 24.08±2.4 a OSI 13.58±1.0 a 30.68±2.6 a 22.94±0.3 a 32.14±0.9 a Lowercase superscripts (a,b,c) indicate significant differences among same colon within each experimental treatment group https://doi.org/10.1371/journal.pone.0294656.t001 PLOS ONE Effect of temperature on fish physiology and biochemistry

PLOS ONE | https://doi.org/10.1371/journal.pone.0294656 November 30, 2023 7 / 13