Toxicological studies with mirex in bobwhite quail

Area of Science:

• Environmental Toxicology
• Wildlife Biology
• Reproductive Science

Background:

• Mirex is a persistent organochlorine pesticide.
• Understanding the reproductive effects of mirex on avian species is crucial for ecological risk assessment.

Purpose of the Study:

• To investigate the long-term reproductive effects of dietary mirex exposure in bobwhite quail (Colinus virginianus).
• To determine mirex accumulation in various tissues and its correlation with dietary intake.
• To assess the impact of mirex on egg fertility, hatchability, embryo survival, and chick survival.

Main Methods:

• Bobwhite quail were fed diets containing mirex at concentrations of 1, 20, and 40 ppm.
• Residue analyses were performed on adipose tissue, breast tissue, and eggs.
• Reproductive parameters including embryo survival, hatchability, and chick survival were monitored across generations (F0, F1).

Main Results:

• Mirex accumulated in male adipose tissue (approx. 10x dietary level) and female adipose tissue (approx. 5x dietary level), with higher concentrations in fat and breast tissue directly proportional to dietary intake.
• No deleterious effects on embryo survival or hatchability were observed; higher mirex concentrations were associated with increased fertility and hatchability.
• No chick mortality attributable to mirex exposure was detected in F0 or F1 generations.
• Eggs from F1 breeders fed 1 ppm mirex showed no adverse effects on embryonation, embryo survival, or hatchability.

Conclusions:

• Dietary mirex exposure, even at elevated levels, did not adversely affect bobwhite quail reproduction in the studied generations.
• Observed mirex accumulation levels in experimental quail are comparable to those found in wild populations, suggesting mirex may not significantly impair wild quail reproductive success.
• Further research could explore potential subtle, long-term population-level effects or impacts on other avian species.