This study evaluated the effects of dietary chitosan nanoparticles (CNP), α-tocopherol (VE), and their nanocomposite (CNP-VE) on growth performance, haematology, biochemistry, liver function, immunoglobulin, and intestinal histology of butter catfish (Ompok pabda). Four diets were tested: a control (T1), 5 g kg⁻¹ CNP (T2), 500 mg kg⁻¹ VE (T3), and 5 g kg⁻¹ CNP + 500 mg kg⁻¹ VE (T4). A total of 240 adult fish (13.56 ± 0.33 cm and 14.98 ± 0.78 g) were randomly assigned to the treatments in triplicate groups (n = 20) for a 60-day feeding period. Total length, body weight, feed conversion ratio, and specific growth rate, significantly improved in supplemented groups, with the best performance observed in T4 (p < 0.05). Haematological analysis revealed significant increases in red blood cells, haemoglobin, haematocrit, and MCHC in T4. While total protein, albumin, and globulin remained unchanged, glucose and bilirubin levels were significantly lower in T4, indicating improved metabolic status. IgM level was enhanced across treatments, with the greatest increase in T4. Histological examination showed improved intestinal structure in T4, including uniform goblet cell distribution and well-formed villi. These findings suggest that combined supplementation of CNP and VE has a synergistic effect in enhancing growth, physiological health, immunity, and gut morphology in O. pabda under intensive culture.

A global interest in the cultivation of Kalibaus (Labeo calbasu) has emerged due to decreasing natural stocks and a consistent rise in market value and demand. Given these concerns, understanding the species’ physiological responses to environmental changes is crucial. The present research aimed to assess the effect of varying environmental temperatures on metabolism, haemato-biochemical indices, hormonal concentrations and immune responses in L. calbasu. This study was conducted in triplicate using 100 L glass aquariums at four different temperatures: 22, 26, 30, and 34 °C. The highest weight and length gain were observed at 30 °C, while the lowest occurred at 22 °C. Notably, the best feed conversion ratio (FCR) of 1.51 ± 0.03 was also recorded at 30 °C. Although haematological and biochemical parameters remained within normal ranges, they varied with temperature changes. Indicators of cold and heat stress were evident through lower hematocrit levels and higher white blood cell (WBC) counts. Biochemical indicators such as serum albumin (1.84 ± 0.05 g dL⁻¹), serum globulin (1.64 ± 0.06 gdL⁻¹), HCO₃ (30.93 ± 0.62), Na⁺ (115.60 ± 3.72 mmolL⁻¹), alkaline phosphatase (93.33 ± 9.39 AP, IUL⁻¹), and AST/SGOT (21.00 ± 4.55 UL⁻¹) were significantly higher at 30 °C. Regarding hormonal responses, peak levels of growth hormone (GH), triiodothyronine (T3) (1.44 ± 0.07 ngmL⁻¹), and thyroxine (T4) were recorded at 30 °C. Meanwhile, serum cortisol (1.62 ± 0.06 µgdL⁻¹) and adrenocorticotropic hormone (ACTH) (18.01 ± 3.26 pgmL⁻¹) were highest at 34 °C. Immune responses were strongest between 26 and 30 °C. In conclusion, the results suggest that L. calbasu should ideally be cultured between 26 and 30 °C for optimum growth and health, making it ideal for commercial farming.