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Unilateral wing immobilization was used to study bone changes associated with lack of exercise in young chickens. With disuse, humerus bone weight, diameter, cortical thickness, radiographic density, and breaking strength were reduced significantly, whereas bone length, ash, calcium, and phosphorus were unchanged. The results of this study indicate that exercise-related bone changes can best be shown by radiographic density and breaking strength, but not by bone ash or mineral determinations.

The development of aortic and coronary atherosclerotic plaques were investigated in roosters fed an atherogenic diet with and without the addition of Valium (0.2 mg/kg twice daily) over a period of 5 months, as a step toward understanding the role of emotional factors in atherogenesis. Plasma levels of cholesterol and triglycerides, hemodynamic parameters, and body weight were measured. There was a progressive, and quantitatively similar, body weight gain in all birds. In addition, there were no significant differences in values for blood pressure, cardiac output, and heart rate between the various experimental groups. Conversely, birds receiving the atherogenic diet, as well as those receiving the atherogenic diet along with Valium, exhibited a marked hypercholesterolemia which reached a peak of 600 mg/dl in 4-6 weeks, before decreasing to between 200 and 300 mg/dl by the 10th week. Plasma triglyceride levels followed a qualitatively similar pattern as plasma cholesterol. Those birds fed an atherogenic diet alone developed atherosclerotic lesions on the aortic surface which was more pronounced on the abdominal than the thoracic aorta. Aortas from birds given Valium along with the atherogenic diet were completely free of lesions despite the fact that plasma cholesterol and triglyceride levels were not significantly different in the two groups. Histological sections of coronary arteries showed severe lesions in 4 out of 7 birds which were fed the atherogenic diet alone, whereas the birds given Valium along with the atherogenic diet had only an occasional slight lipid deposit. It was concluded that Valium provides some protection against the development of atherosclerosis in roosters fed an atherogenic diet.

Long-term effects of diazepam on plasma lipids and atheroma in roosters fed an atherogenic diet have been studied. Our data indicate that long-term administration (8 months) of diazepam (Valium) 0.2 mg/kg orally lowered the plasma cholesterol level when compared to the atherogenic group, but this was not statistically significant (P greater than 0.05). However, at the dose of 0.4 mg/kg of Valium the plasma cholesterol was significantly lowered when compared to the controls on an atherogenic diet (P less than 0.05). Both doses of Valium significantly decreased the incidence and severity of lesions on the endothelial surface of the aorta and coronary artery in roosters fed an atherogenic diet. No changes in plasma triglyceride values were noted. Administration of 0.4 mg/kg of Valium to birds receiving the atherogenic diet produced a small but significant increase of mean, systolic and diastolic blood pressures as compared to the birds receiving an atherogenic diet but no Valium. A similar increase in blood pressure was also noted in the control group on plain mash diet receiving 0.2 mg/kg of Valium. Microscopic examination of the coronary arteries showed that birds on an atherogenic regimen receiving Valium had less atherosclerosis than those not receiving Valium.