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Toxicosis of mirex for chick embryos and chickens hatched from eggs inoculated with mirex
Abstract:
Mirex, a hydrocarbon, was mixed with corn oil and injected into chick embryos to test its toxic effect. At a concentration of 0 05 mg mirex/egg, embryo mortality was 40%, at 0.5 mg/egg, mortality was 49%, and at 5.0 mg/egg, mortality reached 81%. Mortality of control eggs injected with corn oil alone was 36%. The body weights of newly hatched chickens and of 4-week-old chicks were not different from those of controls. No clinical signs of disease were seen during the 4 weeks of observation. However, liver weights were increased at all 3 dosages when the birds were killed at 4 weeks, but spleen and bursal weights were not. The results support the decision to discontinue the use of mirex as a pesticide in the environment for controlling the fire ant (Solenopsis sp.) until a better means of presenting it can be found.
Insights
Mirex pesticide exposure in chick embryos significantly increased embryo mortality and liver weight, even at low doses. These findings suggest discontinuing mirex use until safer application methods are developed.
Area of Science:
- Environmental Toxicology
- Developmental Biology
- Chemical Safety
Background:
- Mirex, a persistent hydrocarbon insecticide, was widely used for fire ant control.
- Concerns exist regarding the environmental impact and toxicity of Mirex on non-target organisms.
Purpose of the Study:
- To evaluate the toxic effects of Mirex on developing chick embryos.
- To assess the impact of Mirex exposure on chick growth, organ weights, and clinical signs.
Main Methods:
- Chick embryos were injected with varying concentrations of Mirex (0.05, 0.5, and 5.0 mg/egg) in corn oil.
- Control groups received corn oil alone.
- Embryo mortality, body weight, organ weights (liver, spleen, bursa), and clinical signs were monitored over 4 weeks.
Main Results:
- Mirex exposure led to dose-dependent increases in embryo mortality, ranging from 40% to 81%.
- Control group mortality was 36%, indicating baseline effects of injection.
- Increased liver weights were observed in chicks exposed to all Mirex dosages, while spleen and bursal weights remained unaffected.
Conclusions:
- Mirex exhibits significant toxicity to developing chick embryos, increasing mortality and affecting liver development.
- The study supports the discontinuation of Mirex as a pesticide until safer application methods are identified.
- Further research is needed to understand the long-term effects and environmental persistence of Mirex.