2004 Volume 57 Issue 6 Pages 371-376
Seven Japanese Black steers were divided into two groups. The restricted group (RG, 4 steers) was fed a vitamin-A-restricted diet throughout the examination period (phases I and II). The control group (CG, 3 steers) was fed the same diet during phase I then a diet supplemented with vitamin A during phase II. Nutritional status and endocrine functions of the two groups were compared. In both the RG and the CG, plasma retinol levels correlated positively with feed intake and serum-albumin concentration (P< 0.01). When the plasma retinol concentration dropped to less than 20 IU/dl, feed intake declined sharply. At slaughter time, serum-albumin concentrations (2.6 vs 3.7g/dl, P< 0.01) and the albumin/globulin ratio (0.61 vs 1.12, P < 0.01) were significantly lower in RG than in CG steers. Some RG steers were anorexic and heavily deficient in protein and energy at that time. Clear intermuscular edema was observed in one of these steers. Although no difference in leptin concentration was observed, depression of the plasma tri-iodothyronine level and an increased plasma growth hormone level in this animal were typical hormonal features of malnutrition. Decrease in plasma oncotic pressure caused by hypoalbuminemia resulting from hypovitaminosis A is considered one of the causal factors of intermuscular edema.