Impact of Water Temperature Variations on the Growth, Feed Intake, and Blood Parameters of Pangasianodon hypophthalmus

This study examined the physiological and growth responses of juvenile Pangasianodon hypophthalmus to different water temperatures (24°C, 27°C, 30°C, 32°C, and 34°C) over a 9 weeks culture period. Fish reared at 27°C demonstrated optimal growth performance, achieving a final weight of 53.0 ± 4.24 g with a specific growth rate (SGR) of 0.59 ± 0.07%/day and weight gain of 44.8 ± 3.62 g. The 24°C treatment group showed slightly reduced but still significant growth (final weight: 48.0 ± 3.87 g; SGR: 0.61 ± 0.07%/day), with superior feed conversion efficiency (FCR: 1.22-1.28) that was significantly better than other groups (P < 0.05). Thermal stress became evident at higher temperatures. The 30°C group exhibited intermediate performance (final weight: 38.0 ± 3.07 g; SGR: 0.75 ± 0.06 to 0.14 ± 0.05%/day), while the 34°C treatment resulted in severely compromised growth (final weight: 21.0 ± 1.69 g; SGR: 0.22 ± 0.02 to 0.26 ± 0.05%/day) and poor feed utilization (FCR: 1.60-2.00). Feed intake followed a similar pattern, peaking at 8.3 ± 0.68 g/day at 27°C but declining to 5.0 ± 0.43 g/day at 34°C (P < 0.05). Notably, hematological parameters including RBCs count (1.24-1.42 × 10⁶/mm³), hemoglobin (7.38-7.40 g/dL), and PCV (22.8-24.6%) remained stable across all treatments (P > 0.05), suggesting effective homeostatic regulation within this temperature range. These findings concluded that 27°C is suitable for growth in P. hypophthalmus.