Temperature changes alter the acute toxicity responses of cypermethrin in Zebrafish

Abstract

The study was carried out to determine the effect of temperature changes on acute toxicity of pyrethroid pesticide cypermethrin in zebrafish. A two-day renewal bioassay system for 96h was conducted to find out LC50 value of cypermethrin at two temperature regimes i.e. 25°C and 30°C considering as T1 and T2, respectively. During the determination of LC50 in both temperatures, blood glucose (mg/dL) levels were measured at lower concentration (0.25 µg/L) of cypermethrin. The results of acute toxicity test at 96h LC50 values were calculated through probit analysis. It was found that 96h LC50 for T1 and T2 groups were about 2.1 and 1.4 µg/L, respectively. Significantly lower LC50 of cypermethrin at T2 compared to T1 showed that higher temperature increased the toxicity of cypermethrin. There was a significant increase (P<0.05) in blood glucose level (mg/dL) in 0.25 µg/L compared to 0 µg/L concentration of cypermethrin at both treatments. Dissolved oxygen decreased and free CO2 increased significantly (P<0.05) with increasing temperature, while the pH of the water was almost unchanged throughout the study period. The present study indicated the impact of increased temperature on pesticide toxicity in the aquatic ecosystem.Progressive Agriculture 29 (1): 64-70, 2018

Sub-lethal toxicity of alphamethrin on biochemical indices in a freshwater fish, Cyprinus carpio

“…Ullah et al [37] observed an increase in the blood glucose level was observed in the silver carp (Hypophthalmichthys molitrix) treated with 2 µg/L of deltamethrin. Under stressed condition, the release of glucocorticoids and catecholamine (hyperglycemic hormones) degrades the glycogen and glucose, which further leaks out in the blood resulting in hyperglycemia [38] . The data on muscle glycogen level of fish Cyprinus carpio treated with sub lethal concentrations (Treatment I and II) of alphamethrin are presented in Fig.…”

Dietary supplementation of Polygonum chinense improves the immunity of Asian seabass, Lates calcarifer (Bloch, 1790) against Vibrio harveyi infection

“…Another common physiological index of energy regulation in aquatic organisms is the concentration of serum glucose, which rises in response to stressors of increasing magnitude [69] . Herein, the control-infected group had elevated serum glucose level, implying that glycogenolysis was enhanced with a decline in glycolytic pathway as a regulatory mechanism in response to glycogen mobilization into glucose to satisfy the increased energy demand in combating the stress caused by the bacterial infection [70] . Surprisingly, the groups supplemented with PCE presented lowered glucose levels, reflecting the potential of PCE to relieve the infection stress by improving insulin sensitivity and glucose metabolism.…”

Teratogenic and developmental toxic effects of etridiazole on zebrafish (Danio rerio) embryos

“…The relative resistance of the embryos is partly attributed to the presence of chorion [16], which may protect the embryos by slowing down the entry of toxicants. The temperature at which the assay is performed might be another important parameter that influences the LC 50 values [17].…”