Gravitational influences upon the maintenance requirements of rabbits

The gravitational component of the feed requirement for the maintenance of body mass has been reported previously for chickens. Similar measurements are reported here for chronically accelerated Polish rabbits, which have mature body masses around 2 kg, approximately the same as for the single-comb white Leghorn chickens used in the earlier experiments. The gravitational influences upon the maintenance requirement and upon body composition were found to be essentially similar for rabbits and chickens, indicating a general phenomenon for small homoiotherms. The principal response in both groups is a greater feed maintenance requirement which increases linearly with the applied acceleration field. The nature of this response is similar to that which follows lesioning of the lateral hypothalamus in rats, though no causal connection between the two phenomena is necessarily implied by these present studies. In monkeys a qualitatively different response of increased body fat is observed.