Effects of human contraceptive on reproduction and offspring in Chrysomya megacephala

Abstract

Objective: To investigate the effect of human contraceptive (HC) as ability to suppress the reproductive success of blow fly, Chrysomya megacephala (Fabricius) (C. megacephala) and offspring under controlled laboratory conditions. Methods: Adult C. megacephala were fed with low (0.036 mg/mL) and high dose (0.072 mg/mL) HC (Microgest®, Thailand), containing levonorgestrel and ethinyl estradiol, in their drinking water for 7 days. Three experiments were set; experiment I with fed only in parental males, experiment II with fed only in parental females and experiment III with fed in both males and females. All experiments were then maintained for 3 generations after crossing and inbreeding. Results: A lower ovariole production and less fully mature ovarioles were evident in F1, F2 and F3 than control when parent males, females and both had been fed with high dose HC. Cellular changes during spermatogenesis in F1, F2 and F3 testes was confirmed usi ng transmission electron microscopy (TEM), showing the low level of condensed chromatin, necrotic chromatin, irregularities and degenerated nuclear envelope in the nucleus. In the cytoplasm, mitochondrial swelling, rough endoplasmic reticulum swelling as well as vacuolated cytoplasm were noticed. As for the sperm per se, we found the degenerated nuclei and/or incomplete mitochondrial derivative, axoneme and vacuolated flagella. Regarding deformity in F1, F2 and F3 ovariole, ultrastructural alteration observed by scanning electron microscopy (SEM) included malformations involving fragile enveloping peritoneal sheath, cracked ovarioles, peel away chorion, crumbled eggshell and incomplete development; whereas TEM presented malformed and disorganized mass of cells, proteic yolk granules and vacuolated vesicles. Conclusions: Administer of HC to adult C. megacephala caused ovariole reduction, less matured ovariole and affected cellular changes in testes and ovariole of offspring up to F3. © 2011.