Effect of litter size on the physical growth and maturation of the offspring of rats given alcohol during gestation.

A study was conducted to determine if retarded postnatal growth and maturation of the offspring of rats receiving alcohol prior to and during gestation could be corrected by adjusting litter size at birth to 3 pups. Female Sprague-Dawley rats (200 to 220 g) were divided into 3 dietary treatment groups. Group 1 (alcohol) was fed ad libitum a stock diet (Purina Rat Chow) plus 20% alcohol in drinking water for at least 4 weeks before mating and 30% alcohol throughout gestation. Group 2 was pair-fed the stock diet and corn starch calorically equivalent to the amount of alcohol consumed. Group 3 (control) received the stock diet and water ad libitum. In each group litters were reduced to 3 or 8 pups on the first day of birth. After birth all animals had free access to water and stock diet until day 51 post conception. In agreement with previously reported studies, the offspring of alcohol-fed rats were lighter in body weight and smaller in body and tail length at all ages than were the controls. However, animals maintained in litters of 3 were not significantly different in weight and length from those raised in litters of 8, either for alcohol group or the controls. The pair-fed litters were not significantly different from the ad libitum controls. Skeletal measurements and calf muscle widths of alcohol fed rats at day 51 post conception were significantly less than those of ad libitum controls of the same litter size, with the pair-fed animals lying somewhere in between. However, in no case did alcohol or control animals raised in litters of 3 differ from the same group maintained in litters of eight. Total bone maturity scores of alcohol-fed offspring were significantly retarded, relative to pair-fed and ad libitum controls, but within any group, litters of 3 did not differ from litters of eight. The results of this study indicate that retarded postnatal growth and maturation of the offspring of rats receiving alcohol prior to and during gestation represents a direct effect of alcohol and is not a consequence of underfeeding.