Great Lakes' contaminants reduce sperm production and fertilizing ability in mice

The long‐term effects of Great Lakes' contaminants on male reproductive performance resulting from lactational and dietary exposure were investigated. Female C57BL/6 J mice (F‐0) were mated with DBA/2 J male mice to produce B₆D₂‐F₁ offspring. Dams (F‐0) were fed one of three treatment diets during lactation. The three treatment diets were: (i) diet C, containing lab chow and fish oil; (ii) diet I, containing 60% Iowa carp and 40% lab chow; and (iii) diet G, containing 60% Great Lakes' carp and 40% lab chow. Diet C served as a lab‐chow control treatment, while diet I served as a fish‐diet control treatment. Diet G contained 2500 µg of polychlorinated biphenyls (PCBs) and 300 µg of 1,1‐dichloro‐2,2‐bis‐[p‐chlorophenyl]ethylene (4,4′‐DDE) per kilogram of feed. The offspring (F‐1) were continued on their respective maternal treatment diets from weaning until termination. Greater neonatal mortality and lesser body weights were observed in the F‐1 male mice on diet G. Lesser fecundity was observed in one‐year‐old F‐1 male mice on diet G following pairing with non‐treated female mice. The sperm concentration of F‐1 male mice on diet G was less than 30% of that of mice on diets C and I. The in vitro fertilizing ability of the sperm decreased to 10% of that of mice on the two control diets. Sperm motility, velocity, linearity and amplitude of lateral head (ALH) displacement were also decreased in 15‐month‐old F‐1 male mice on diet G.