Effect of exercise on chickens with hereditary muscular dystrophy

Abstract

To assess the effect of daily physical exercise alone on the onset and development of muscle weakness found in chickens with hereditary muscular dystrophy, two separate exercise trials composed of 20 or 30 successive opportunities to right when placed in the supine position were conducted. The effects of exercise on the physically ability/disability were measured by a flip-test procedure administered to each exercised and unexercised animal every 5 days and at a time separate from the exercise procedure. The flip test consisted of giving each animal five successive opportunities to right after having been placed on its back. Blood samples were drawn weekly and assayed for plasma creatine phosphokinase (CPK) activities. Unexercised dystrophic chickens were found to reach a peak of physical ability as quantitated by the flip test at approximately day 23 ex ovo. Subsequently, a progressive decrease in flipping ability was observed. The dystrophic chickens which were exercised daily exhibited a temporary, yet significant improvement in righting ability to Day 48 ex ovo. Also, exercise elicited small but consistent increases in plasma CPK activities compared to the unexercised control values. Regular physical exercise alone was found to alter some of the measurable symptoms of avian muscular dystrophy. To evaluate the singular effect of drug treatment in dystrophic animals, we recommend that the periodic testing for physical improvement be at a time separate from drug administration and devoid of the influence of exercise.