Effects of oxidised dietary cod liver oil on the reproductive functions of Wistar rat

Weanling Wistar rats, males and females, were fed for 185 days with diets containing 15% of dietary fat in the form of a mixture of lard and partially oxidised cod liver oil. The proportion of cod liver oil in the dietary fat ranged from 0 to 100%, and the content of malonaldehyde from 0.3 to 19.6 mg/kg of the fat used. Animals fed with diets containing higher proportions of oxidised cod liver oil had higher concentrations of malonaldehyde in their livers. Serum lipid levels were lower in animals fed with higher proportions of cod liver oil than in animals fed control diets (milk fat or lard). The lowest concentration of serum lipid was found in the rats fed the diet containing half of its fat as fish oil. Increased intakes of cod liver oil resulted in lower body weight gains, weights of livers, kidneys, and weights of the reproductive organs. The relative weights of livers and kidneys/body weight were higher in the groups with higher intakes of cod liver oil. High intakes of cod liver oil led to a drastically impaired fertility of females, a decreased litter size, a higher postnatal mortality, and an increased incidence of morphologically abnormal spermatozoa in males.