The effects of vitamin D₃ on some biological traits with the activity of P450 detoxification enzyme of Drosophila melanogaster (Meigen) (Diptera: Drosophilidae)

In this thesis study, the biological and biochemical effects of the fat-soluble vitamin D₃ on the model organism Drosophila melanogaster were investigated. The aim of the study was to examine the potential toxic effects of increasing D₃ vitamin concentrations on the life cycle, biological properties, and cytochrome P450 detoxification enzyme activity of D. melanogaster. Furthermore, the potential of using vitamin D as an insecticide in the control of agricultural pests was also ascertained. The preliminary concentrations of D₃ vitamin to be used in the experiments were firstly determined. Aside from diet control (without vitamin D₃) and tween 80 solvent control, D₃ vitamin concentrations of 5, 20, 80, 320, 1280, and 2560 mg/L were determined. In the diet control group, it was observed that 85% of the first instar larvae reached the third instar, pupal, and adult stages. At the tested concentration of 320 mg/L, the rates of reaching the third instar, pupal, and adult stages were determined to be 38.75, 36.25 and 33.75% respectively. In the case of the 2560 mg/L concentration, the adult emergence rate decreased to 7.50%. When examining the developmental times of the insects,the diet control group showed that the time to reach the third instar was 3.12 days, the time to pupation was 4.19 days, and the time to adulthood was 8.05 days. In contrast, at the 320 mg/L concentration of vitamin D₃, the time to reach the third instar was 3.54 days, the time to pupation was 4.60 days, and the time to adulthood was 8.51 days. The effect of vitamin D₃ on adult lifespan was found to be 17.88 days in the diet control group, while it dropped to 9.94 days at the 320 mg/L concentration. These findings indicate that increasing concentrations of D₃ vitamin exert toxic effects. High they concentrations of D₃ vitamin prolonged the developmental times of larvae and pupae while significantly shortened adult lifespan. Notably, more toxicity were observed at high concentrations such as 1280 mg/L and 2560 mg/L. The tested concentrations of D₃ vitamin increased the total protein levels in D. melanogaster larvae, but significantly reduced cytochrome P450 enzyme activity. Compared to the control groups, it was found that high doses of D₃ vitamin shortened the lifespan of adults and negatively affected biological development al parameters in pre adult stages. High doses of D₃ vitamin exhibit toxic effects on the biological parameters of D. melanogaster. This study highlights that high doses of vitamin D would lead to toxicity suggesting its potential as an alternative chemical agent in the control of agricultural pests.