## 3 Results and Discussion
### Correlation Analysis  
Correlation analysis between exposure concentrations and hematological, growth, endocrine, and biochemical indices is given in Figure 5. Exposure concentration showed the strongest negative correlation with MCH, K, SGR, T\({}_{3}\), T\({}_{4}\), and TSP, indicating that the values of these parameters reduced from the control group to the highest exposure concentration. In addition, exposure concentration showed a strong positive correlation with HSI and TSG, indicating that the values of these parameters increased from control to the highest exposure concentration. While toxicology studies have demonstrated the disruptive effects of pesticides on erythropoiesis tissues [89; 90; 91; 92; 93], the relatively higher sensitivity of MCH compared to other hematological parameters in fish at elevated toxicant exposure concentrations have been reported [94]. The significant reduction in MCH across exposure groups (\(p<0.05\)) when compared with the control could be attributed to lowered levels of cellular blood iron or heme-synthesis dysfunction, which stresses the fish by reducing the oxygen-carrying capacity of its blood [89; 95]. The negative correlation between exposure concentration and the K condition factor also reflects a deteriorating physiological condition of exposed fishes with chronic higher toxicant concentrations. In particular, lowered condition factor highlights disrupted food intake of lowered conversion  
Figure 4: **(a,b)** Mean and SD values of different biochemical parameters of _Clarias batrachus_ exposed to different concentrations of diazinon (0.64 and 1.28 mg/L) for different exposure times (15, 30, and 45 days). **—**denotes significant differences to control within the same exposure time (*** \(p\) < 0.0001); TSG—total serum glucose, TSP—total serum protein. of food intake into tissue development [64]. A low body condition may also suggest muscle wasting (proteolysis), indicating a starvation response [96; 97]. The strong negative correlation between exposure concentration and specific growth rate (SGR) indicates decreased growth also attributable to impaired fish feeding activity [98]. The significant inverse correlations between diazinon exposure concentrations and T\({}_{3}\), T\({}_{4}\) levels in the fish highlight the endocrine disruptive potential of diazinon under chronic-exposure regimes. This endocrine disruption will, in turn, impact the growth and development of exposed fishes. Thyroid hormones are essential for somatic growth and for early development in fishes, including larval-juvenile transitions and induction of metamorphosis [99; 100; 101]. The significant inverse relationship between exposure concentration and total serum protein also reflects its sensitivity to toxicant-related stress after the onset of physiological effects. Changes in serum TP (total protein) may be due to liver damage, reduction absorption, and protein loss and thus may be a suitable indicator of the health status of fish [102]. Retarded growth responses alongside a reduction in serum protein with elevated diazinon exposures in this study also give credence to the possibility that the lowered condition factor and specific growth rate is caused by an underlying starvation response and muscle wasting (proteolysis) [96; 97]. The strong positive relationship between diazinon exposure concentrations and TSG indicates that glucose content was lowest in control and increased in diazinon chronic-exposure groups. This strongly highlights remnants of ongoing physiological-level compensatory reactions to out-with the effects of the toxicant. Prior elevation of serum glucose level and eventual decline until the depleted level was attained has been reported for prolonged exposure to toxicants [103; 104]. Thus, the higher levels in diazinon-exposed groups reflect not-yet depleted energy reserves to cope with diazinon-related exposure and uptake.